A COMPLETE GUIDE to Decentralised Single Room Heat Recovery!

[@CharlieDIYte]

🛠Charlie DIYte Amazon Tool Store amzn.to/3fcLnY4 - all my tried, tested and much loved DIY tools. ☕Patreon membership www.patreon.com/charlieDIYte - includes Discord access. ☕Buy Me a Coffee bit.ly/3xuQ3zb - to help support my Channel - also use it for membership a bit like Patreon. 👚Charlie DIYte Official Merch Store charlie-diyte.myspreadshop.co.uk/ - all new range of professionally designed merch.

[@wielvanhorck7215]

I have mine for about 6 years now. Mine are from Südwind from Italy. They can be coupled together and now they also have them as smart units. I love them. Especially as I can also use them as positive of negative airflow. I put the one in my living room to extracting to outside. Then turn on my AC to cool my house and in a jiffy the living room will be filled with cold air from the AC in another room. Works like a charm. Also the inter climate increased amazingly after installing 2 from these units. I always have them running. In my living room I don't hear the unit, but in the bedroom, that 70 seconds is just to short to get used to it. So I have mine of night mode. Never that smelly bedroom in the morning again! My windows can't open, so this was perfect, 10/10 recommend it. Next to how they work, compare the electric bill of a centralised unit with decentralised units. I mean, mine do les then 10 watt. Less power usage, more effort. BTW, my Südwind units have a different inner unit. And to be honest, a better design! As the inner unit opens to top side. Put a chair under yours, and you will get cold, but when it opens to the ceiling, this is not an issue. No cold down fall.

[@sabinpreda3878]

These are good products !

[@apmeehan]

As someone who lives in perpetual frigidity due to their wife opening all the windows to “let the house breathe” even in the dead of winter, I’ve never clicked “Save to Watch Later” so fast.

[@richardknight1170]

😂

[@OmarSamehTantawy]

😂😂😂

[@CharlieDIYte]

She's right though.. But maybe not too often 😉

[@apmeehan]

@@CharlieDIYte Oh she's absolutely right (I quickly learnt she almost always is). And coming from a country which takes ventilation much more seriously than we do (even their Soviet-era tower blocks have proper chunky wind-shielded window vents), she couldn't help but laugh at our piddly trickle vents. So I have both her and yourself to thank for opening my eyes to the importance of fresh air (not just to avoid damp issues but also the effects of CO2 buildup on cognition and mental health), and leading me down the rabbit hole of PIV, MVHR, etc. 🙂

[@davidlittle7182]

haha...I live in Sweden now and my (Scottish) dad comes to visit. He still hasn't got used to not having to open shower room windows and hang his towel on a radiator when he visits

[@GosforthHandyman]

Great video as per usual Charlie! Thanks for the shout-out. Bit of an update on mine - bear in mind mine isn't in a domestic environment, it's in a studio. The Kair MVHR fixed my mould and damp issues, which was my primary objective. However since my studio isn't heated 90% of the time I doubt the heat recovery side is doing much and in reality it's destroyed my soundproofing 😂😭. A future project will be to fix this properly but it's not particularly urgent. Sadly that will probably involve removing the MVHR since the simultaneous 'IN & OUT' through a single hole really complicates things when it comes to making a soundproof enclosure. But it's been running on trickle for over a year with no issues and more importantly my studio is now mould-free. The BSK system looks great! 👍

[@CharlieDIYte]

Thanks for the great update Andy. Yes it's a nice bit of kit but the Kair seems to be pretty tech/ hardware heavy in comparison. Possibly more efficient on the heat recovery, or maybe the BSK is just a brilliant design? Who knows. I'll be really interested to see how you solve this whilst keeping the studio sound proof. 👊

[@GosforthHandyman]

@@CharlieDIYte Yeah, me too. 😅

[@justinsenryu7308]

I think there's a way of making ... would it be called a baffle? Basically making the air vent on the outside of the wall go through three 90 degree turns in quick succession, and you could make it out of dense material lined with foam to stop reflections. It's similar to the open corridors that you can soundproof also by making successive turns.

[@CharlieDIYte]

@@justinsenryu7308 Yep, that's exactly what @gosforthhandyman is thinking of doing

[@imprezaaudi]

I used BPC to design a whole house MHVR on my newbuild. The design worked perfectly, very little wastage in pipe runs. Fantastic humidity/temperature control throughout the building. No cold spots in corners of rooms with a gentle circulation of air

[@KilianKennedy]

Thanks Charlie, love your videos. I put 3 of these BSKs into our poorly insulated 1990s 3-bed semi. Definitely helped with air quality, humidity and winter window condensation (however it certainly didn’t eradicate the condensation). We have the humidity auto-boost switched on and (while it's useful) we find the beeper/sounder quite annoying when it changes back and forth between normal and boost. Especially at night. So I plugged up the sounder with a little toilet paper and glue! Worked perfectly. 😊 All the best from Ireland.

[@CharlieDIYte]

Thanks, that's great feedback. How did you set them up in terms of working together? It's very hard to eradicate condensation particularly if you've got single glazed windows. You can see the difference here kzbin.infolQv5FIZd9Qc?feature=share - I don't think I'll ever eradicate condensation in that bay! PIVs seem to be the answer for that though

[@KilianKennedy]

@CharlieDIYte Hi again, Charlie. To answer your question: I set up 2 units in the 2 occupied bedrooms in parallel with each other. And the 3rd unit running opposite them (in the upstairs home office). Theory was to encourage continuous air movement upstairs. In practice, I agree with some of your other viewers' comments and feel the 3 are not strong enough to push ALL the air around our leaky old house. But they definitely helped us, I enjoyed doing the work and l learned a thing or two at it. So 'jobs a goodun' as you Brits like to say. I'm smiling here at your positivity: that condensation on the window = a free dehumidifier :-). I like that! All the best.

[@timmetcalfe5541]

Lots of informative and well presented content across many videos so thanks.

[@CharlieDIYte]

Thanks so much Tim. Really appreciate that and I'm chuffed you've found my videos useful. 👊

[@stephen-boddy]

You made a maximally effective metal cold bridge between outer wall and inner wall with the galvanised ducting. You can see it in the IR shots from 15:18 onward.You probably should have swapped that out for the plastic one.

[@CharlieDIYte]

I did worry about that. Don't forget it's completely insulated behind by the foam though.

[@stephen-boddy]

@@CharlieDIYte Not going to argue with you, as you have all the experience here. I just looked at the IR footage and immediately spotted the colder blue ring, compared to the surrounding wall. Maybe it is not as dramatic as it looks in real life.

[@Rob-ln7dd]

I was thinking exactly the same. as soon as I saw the metal ducting. But absolutely loved the method of joining the duct to the membrane inside, genius. Oh and a perfect chain drill instead of a core drill, work of art. 👍

[@CharlieDIYte]

​​@@stephen-boddyI know. I was properly kicking myself for doing that. The important thing is I don't think anyone else will be making the same mistake. I'm not convinced their telescopic option is brilliant either though as you've got leakage between the pipes mid way though but as you say, better that than having a cold bridge from front to back.

[@JPEight]

Nothing stopping you from running a bead of sealant around the telescoping part once you’ve got it to the right length.

[@Tensquaremetreworkshop]

OK, I have run the numbers. At its highest setting (60 cu m /hr) if you leave it extracting for 5mins (10 mins total, as it only extracts half the time) then if it is freezing outside and 20C inside you will have saved 18Whrs of heat. Which, with electric direct heat will cost you around 0.48p (gas or heat pump around a quarter of that). Used twice a day (but savings only in Winter), that will be a buyback of just over 100 years... So not for bathrooms then... Air change for the rest of the house? Well, you will need 2 or 3 running flat out to meet recommended minimum air change- and a hermetically sealed house. Do you run out of breathing air at the moment? If not, it is getting in somewhere, and that would need to be sealed. Night mode is a quarter the flow, so eight hours a night for say 120 freezing equivalent nights (generous) is about £1.30 worth of gas a year. Less the 26p it would cost to run it. More than 100 years then. And assuming that it needs no maintenance, like filter cleaning.

[@tommotube]

This is gold! Thanks for your work. Questioning why we put them in most new build apartments now

[@Tensquaremetreworkshop]

@@tommotube It looks good on the adverts... Having said that, centralized systems can do better. What I can get no-one to answer is- why are we using air to water heat pumps in this country? The rest of the world uses air to air. If you do that, you can couple your air change system to your heating system, use the same fan and add heat all in one place. Heating companies, if you have not thought of that, you can have the idea for free.

[@CharlieDIYte]

Thanks, brilliant analysis. Yes I hear what you say on the payback. Trouble is if I ran that analysis on everything I do in this old cottage I'd never do any renovations 😉 I'll never get the money back on the ufh and wall insulation but it gives us joy every time we go in there particularly in these cold months - it's typically 2 degrees warmer in there than the heating is set to and I guess you'd say it's transformed the thermal footprint of the house.

[@Tensquaremetreworkshop]

@@CharlieDIYte Sorry, I cannot help analyze such items- especially when the specification is vague and rings alarm bells. For many years I was a consulting engineer, often asked to appraise a design before it went to market. It was alarmingly common for the physics involved not to be examined. In some cases, the objective was actually impossible, and no-one had spotted it. This item is one that works, but so poorly that it is not worth its cost never mind its installation. It also has issues with dust retention and maintenance. If ventilation is needed, a simple extractor is better- spend the difference on draft proofing. The claims made are wild- the best heat recovery systems are, at best, 80% (often measured with ~24C inside and ~-5C outside) and I am deeply suspicious of the power requirements- they are around a tenth of the Kair unit... Heat recovery can work, but it requires a whole house approach designed into the build. BTW, removing that metal duct ( a serious thermal bridge) will save more heat than the unit.

[@CharlieDIYte]

​​​​@@Tensquaremetreworkshop No need to apologise. You're absolutely right - and this calls for a follow up video at some point. Yes I'm painfully aware of the issue with that duct - I've created a flawless cold bridge when I'm always at pains to tell people the danger of cold bridging. Crazy how you miss the most obvious things when you're mired in the details of a project. It'll need some thought though as that telescopic pipe they provide isn't perfect either - it needs siliconing to prevent moisture getting through the gap between the two pipes. Yes the dust filter is ridiculous, again something I should have made more of a point of. I did at least highlight the issue if not the problem of that dust being blown back in the supply phase.

[@martinrothwell8275]

Love the reference to keyboard warrior people saying you should use a core drill.. - Personally, i love that you show people how to do this with stuff they actually might already have in their tool kit! I've said it before, but your videos are an inspiration and yours (along with Mr Mac's) jump to the top of my viewing list when they appear. Looking forward to the next video!

[@aesopshair6690]

Another channel worth watching is 'the aiden project' if just for entertainment 🤣.. always honest about his mistakes.

[@martinrothwell8275]

@@aesopshair6690 Thanks, will check it out.. - Actually, thats another thing i really like about Charlie's videos.. He doesnt try to make out he is something he is not. He owns up when he made a mistake, and gives full disclosure as to his involvement with a company. "they gave me this, and i get to keep it, but they dont have any editorial say" - and in the case of this video, "i bought a pipe, but didnt need to" - then makes the best of the situation, often to advantage. The internet needs more channels and KZbinrs like Charlie.

[@CharlieDIYte]

Thanks Martin, can't tell you how much I appreciate that. Yes the mistakes are a very important part of it for me. Take them out and it's not real life 😉👊

[@JurassicJungle]

A great video. We have installed MVHR as we did our massive bungalow reonovation and it has made a huge difference to the house. It was quite hard for us to do that so something like this for older properties are a great option.

[@SurfSeeker]

Can I ask what system you had?

[@robertpatrick3350]

Cut into the render with a Stanley knife around the external hole to avoid tearing the render finish. Regardless of whether you’re chain drilling or using a core bit in render.

[@TJP32]

[Pedant Mode] Humidity drop from 56 to 48 is 8 percentage points - that actual improvement is 14.5%. I'll get my coat! ;-) [leaves quietly]

[@Tensquaremetreworkshop]

Never apologize for pedantry! Especially to the 'its good enough' brigade...

[@CharlieDIYte]

Fair point 🤦😂

[@smellypunks]

So now we just need to install two or three of these in every old house in the UK and the mould problems would be sorted. Would be good to see more people install these to get a buzz around them and so the market grows.

[@TinyOffGridHouseResearch]

Great video; very informative ! The "Tiny Off-Grid House Research" interest in decentralized ventilation is not primarily focused on just providing ventilation, or heating the incoming fresh air but more importantly the removal of moisture and humidity from the indoor air space which can facilitate the growth of microbial molds and fungi which can be harmful to the occupants respiratory health and cause structural damage to the house

[@Tensquaremetreworkshop]

True! As you can see from my calculations (main post) the heat recovery is trivial. Humidity and CO2 control is much more important. Worth buying a version that monitors that.

[@THEG12EG]

Good video. What people can learn from this in general is it doesn’t always go to plan and the key is working out ways to overcome your problems..

[@CharlieDIYte]

Thanks. I'm mid-way though replacing that metal duct for the plastic one though.

[@1x3dil]

Hi Charlie Contentious topic , which in a way highlights the difference in how we live in the modern age . The more we do to increase the temperature in our homes the more challenges we encounter , the main difference is the change in the way we actually build and design our homes . Certainly compared to the terrace house I grew up in my youth back in the early 50s . A fire place in every room and single glacéd sash windows that leaked like sieves . And I think here we have a possible compromise that is worth considering , I now live in a well insulated double glazed detached house . Yet we also have a wood burning stove , that is only used in the coldest of weather . Yet it sits there providing a passive form of ventilation , this ability I think we have lost sight of with the passing of time . Yes the powers that be , seem determined to prevent the use of wood burners . But even if this came to pass , I would still keep ours for its ventilation properties, and have a bunch of dried flowers inside . Kind regards as always .

[@Tensquaremetreworkshop]

If you are able to run your log-burner without opening a window, that suggests you have other sources of ventilation too. There are probably dual air vents to the fireplace area.

[@CharlieDIYte]

So true. We also have a wood burner which is now almost redundant since we installed under floor heating. But you're absolutely right in well insulated double glazed houses it's critical to have some form of ventilation - trickle or otherwise. I suppose the only question is whether in the absence of trickle vents, your open wood burner is providing sufficient ventilation. Better than nothing though!!

[@Tensquaremetreworkshop]

@@CharlieDIYte Log burners leak like a sieve- unless you have a flue valve. And there has to be air ingress to allow it to work. Your heat loss from this will almost certainly. exceed that fan recovery. To save heat, a flue valve would have been a better purchase...

[@shiftone242]

I fit the same unit in my garden office as the CO2 levels were quote high, I switched the filter out for HEPA, but does a good job. Dont really notice any reduction in heat/cooling in the room. Planning to do the same in a couple rooms within the house soon. Only things missing is integration with Home Assistant, and I wish the app could do full scheduling instead of just an entire day.

[@Tensquaremetreworkshop]

The filter is to protect the unit, not you! It is actually detrimental - it traps dust, spores, etc on the way out, and then blows them back into the room when it reverses. (the outside air is much cleaner than the internal air- use a particulate meter if you do not believe me.)

[@ElekTrikPurple1]

Excellent information in this video, thanks Charlie, very informative as per usual. It's tough getting your head around MVHR and all the different ways to keep moisture being a problem in older homes. You've done really well to try eradicate damp problems. 😁👌

[@CharlieDIYte]

Thanks. I do need to change that metal duct though. I spend all my life lecturing to people about cold bridging and I've installed the perfect one!

[@bikerchrisukk]

Nice one Charlie, I fitted one of those (not that model, a 4" one) and it failed within 6 months. Was very close to getting one of those 6" but the reviews were pretty rare, I'll be keen to know if it lasts a fair while. Keep up the good work 👍

[@CharlieDIYte]

Thanks. I'll be doing a review. Possibly even this weekend as I'm currently replacing the metal duct for plastic.

[@bikerchrisukk]

@@CharlieDIYte Welcome, are you replacing metal for plastic because of thermal transfer of metal, or just for fun? Enjoy the weekend all the same!

[@CharlieDIYte]

@@bikerchrisukk Yep. I've created a massive cold bridge with the metal duct and negated any benefit that the heat recovery element gives.

[@GoingsoloinFrance]

Great video, thank you Charlie, It's seems to be quite difficult to find reliable information regarding the science of ventilation online. You seem to be the go to channel for this kind of stuff. I am currently working on my own project with virtually a zero budget so I am not able to source 'high tec' gadgets. So everything I do is trial and error all in the name of saving money.

[@micdev42]

We have some brilliant DIY channels in the UK and Charlie's is probably the best. Great info delivered quickly as usual. I've just started looking at decentralised ventilation with heat recovery, so this video is very timely. The product I discovered was Venti Fluxo but I will be researching other options. The reason I started looking at this was as an alternative to trickle vents in windows. I'm about to move into a property that will need new windows. The idea of spending a lot of money on modern, beautiful triple glazed windows, maybe aluminium clad (have a look at Internorm UK) - and then having a gorilla drill misaligned holes in the frames and glue on a plastic trickle vent is completely stupid. So if I do get the new windows I plan to have one of these units in each room. BTW for this 4 bed, 2 bath bungalow I was informally quoted 8-9K for a centralised MVHR system. Bungalow installs are generally cheaper as the loft access is generally good. HTH.

[@CharlieDIYte]

Thanks for the kind words 🙏 I would say go centralised. I know it's expensive but you won't regret it. It will solve all your trickle vent problems in a heartbeat. I had some triple glazed bifolds installed and luckily building regs said I didn't need trickle vents. The installers said it was very unusual to see them without. I agree though and terrible cold bridging.

[@CharlieDIYte]

The Venti Fluxo looks very similar to the BSK but without a servo motor opening flat on the inside. And it's a lot more expensive. The Envirovent HSA 100/330 seems a better option albeit pretty ugly - in that it's recovering the heat the whole time rather than in cycles.

[@micdev42]

​@@CharlieDIYte Yes the Vento Fluxo is expensive and I'm not sure what the justification is. I'm certainly not committed to it. It was mentioned by the sales rep. at Internorm windows. At that point I hadn't come across the concept of dMEV, but I can now see there are many options. I don't know who designed the HSA 100/330 but they should be fired! Diabolocal lol. I've not discounted your tip re. whole of house MVHR and will look at that when we move in. I'm interested to know why your bi-fold doors didn't need trickle vents.

[@micdev42]

@@CharlieDIYte The BSK Zephr looks good: great video that explains how it works. Plus Wi-Fi and a remote - what's not to like!

[@ajaysudan6834]

Looking forward to a longer term review. Also go buy another one and let us know how the paired function works. Then I just gotta find a decent electrician to put the mains wire in.

[@casperme6552]

Is a 3 degree difference between outside air and supply air really worth it? Would be interesting to see how quickly the core cools down

[@andrewh1510]

That was roughly the midway point between the 2 temperatures. If, when it is much colder, it can still deliver the midway point, that would be a huge saving.

[@kchiem]

An ESP32 is a microcontroller with WiFi/bluetooth capability (although I don't think you can use both at the same time). It's cheap (costs a few quid) and commonly used in a lot of devices, such as smart plugs. What's more important is that there's a software framework that allows you to program them by writing a config file (ESPHome), and there's tie in with Home Assistant. So you mentioned that it would be nice to be able to pair two of them to synchronize doing intake/exhaust. If the included app doesn't support that feature, with some reverse engineering, you could conceivably flash them to run ESPHome and automate their synchronized use with HA. You could have a separate temp/humidity sensor and control their activation based on thresholds you set in HA.

[@JohnoLapse]

They actually do synchronise by design so no need for all of that.

[@plica06]

And since it's an ESP32 you could use Tasmota firmware on it to make your own apps to control it that don't report any of your data back to the cloud... Not sure if it actually does that or not by default.

[@dartmoordragon8257]

Nice video. We fitted the same model around a month ago. Quite impressed with performance so far.

[@CharlieDIYte]

Thanks. Glad to hear that. You and me both 😉

[@jellyandme]

This is exactly the video I needed!

[@micro-house]

The PIV love is ridiculous honestly. Be as well just open your front door, they're a serious waste of energy when mvhr/dmvhr exists! Nice video!! Only thing is your metal duct probably isn't a great idea, being as conductive as it is 😅

[@furTron]

Looks interesting, but when you were scrolling the website, I spotted something even more interesting - Vent Axia Tempra P It seems to be a real recovery system just in mini size, and costs minimal more than your current solution. As I understand, it doesn't cause under/overpressure and air leaks so such be more efficient Maybe take a look at it

[@CharlieDIYte]

Thanks. Yes someone else mentioned in the comments yesterday - might have even been that system. I like the minimalist design of the Zephyr though.

[@kendavis5686]

Charlie, you have at last caught up with single unit heat recovery ventilation. I was using these 20 years ago.

[@smellypunks]

and yet they still not know about by many. Not sure why.

[@CharlieDIYte]

Yes it took me a while! Great work - a man before your time - or do you live outside the UK? 😉

[@michaelharding7969]

Great vid well done

[@CharlieDIYte]

Thanks Micheal. I'll be swapping out that tube for the plastic one though.

[@cristopian]

Great video Charlie. I installed the Blauberg Vento Duo in my bathroom. Some years ago. When using multiple units how does stack effect and wind pressure effect these? I believe they would become unbalanced with inefficient use of the ceramic core, unless perhaps the units could monitor and compensate for changes in pressure/fan-speed....

[@CharlieDIYte]

Thanks mate. I think it would be tricky if I'm honest as wind is such a massive factor in the efficiency of this.

[@johnh9449]

Hi Charlie, Very interesting video about air extraction. What's the "efficiency" overall is it about 80% from your heat camera just in terms of temperature in/out or higher on average? I was thinking of installing MVHR with some of them claiming up to 96% efficiency. They all have ducting to be installed which is going to be a pain in my bungalow with the need to keep it all underneath the loft insulation so it stays in the heated envelope and doesn't lose heat through the ducting into the loft space. Or I need bigger insulated ducting. Threading the non insulated plastic corrugated pipe ducting through the existing insulation without compromising it is going to be difficult as it's all installed and boarded over and there are plenty of pipes and other buried obstacles in the way. I did think that perhaps I could get away with only ducting into part of the house and relying on all the rooms having open doors with no zoning (I have a heat pump) so I could perhaps rely on natural mixing. Your single fans are another possibility. The main problem I have is moisture and CO2 build up as the house is pretty well sealed. At the moment I'm having to open windows and external does to do a quick air exchange but I also lose heat in the process.

[@m.o.2085]

It's a breeze in a bungalow. Do it once and do it well starting centrally and covering all rooms. If the loft is boarded keep the ducting over and insulate them separately. Might also be worth adding a few rolls of some type of breathable superfoil insulation on the underside of the rafters to increase its thermal performance.

[@CharlieDIYte]

I agree with @@m.o.2085 mvhr is brilliant for bungalows particularly as yours is so well sealed. A lot of people have previously commented that they've installed PIVs in their bungalows to great effect. You would need to think about where all that moisture is going though with a PIV given how well sealed your place is.

[@tarassu]

Metal pipe is a huge thermal bridge and also it stores heat.

[@CharlieDIYte]

Yes I'll be swapping it out

[@stewwi00]

an esp32? can we connect this to home assistant? This unit is very interesting. Thanks for sharing!

[@6wheels646]

Potentially with the ESPHome integration

[@capitalinventor4823]

The company would have to have an API available. Hopefully they do and not just have a private API that they use for their own app. What processor they use doesn't actually matter for whether it may be used with Home Assistant. The processor only matters if one wants to overwrite the firmware on the device with a different version.

[@t1nma5k22]

1)What about a PIV Unit?(supposedly the best thing to tackle Condensation) 2)Dry Rods near the base of walls alongside liquid dpm like Drybase (best for any potential riding damp) 3)Stormdry or any other Premier top of the line Siloxane Mixture of External Brickwork (optimal for Bare), if already painted then a Silicone Paint 4) Dmev/inline/centrifugal fans for wet rooms? 5) What material would you recommend as being optimal when replacing MDF baseboards/Skirting in a Wet room(this entails Shower rooms or Bath rooms)

[@CharlieDIYte]

Thanks. Probably tricoya MDF. It's basically impervious to water.

[@t1nma5k22]

@@CharlieDIYte Interesting Response Charlie In Your most humble Opinion would you say they are, even more so, recommended than tile skirting?!

[@DoctorRetina]

Great video. Can you tell me about the efficiency of this system vs a centralised unit?

[@georgec2932]

Could I replace an existing ceiling extractor fan (which has a short soft walled run to outside) with one of these?

[@paulb5714]

Have installed the BSK units our house (four of them), they are not intended to extract moist air from a bathroom, from a shower say.

[@RS-Amsterdam]

Excellent video. Nice MacGyver trick with the tape at 7:25 Job well done again What kind of thermal imaging tool or lens do you use ?

[@CharlieDIYte]

Thanks although it has been pointed out I've created a perfect cold bridge with that metal pipe. Should have ripped it out and started again really. It's a TopDon TC001 Not cheap but I was gifted it a couple of years back.

[@Alex82pd]

a supply temperature of 14.5/15 degC with 14 degC outside does not show much heat recovery really. The way to test the heat recovery capability of this device would be with some colder weather, with something like 5 or 0 degC outside, where I would expect the supply during the 7 minutes cycle to remain at least above 10deg C, possibly higher, and see how it goes down while the thermal energy stored in the ceramic mesh depletes. Also, another thing to consider is that unless you work with 2 devices meshed in "push-pull" configuration, with only 1 device (or odd numbers) you would always have cold air pushed in from any gap available when "extracting" and some good warm air being pushed out of the building without recovering when "supplying", because there would be a negative and then positive pressure in the building. And even if the house was air tight (unlikely), then there would be no air flow through the fan, right? :)

[@Tensquaremetreworkshop]

Pressure change in the house during the 70sec cycle is trivial (~0.004 bar) but there would be some effect. But then the amount of heat recovered by this unit is also trivial- it would take over 100 years to recover its cost in saved heat. See my main posts for calculation. More importantly, it traps dust, spores, etc (dual direction filters!)

[@capitalinventor4823]

The temperature of the air outside was between 11.5C and 12.5C which was shown after the thermal imaging. The internal air temperature was stated to be around 19C. Having an average of 15.5C for the incoming fresh air is pretty good and the best one could hope for in the larger whole home systems that pass the two streams of air in close proximity to one another in order to transfer heat energy from one to the other. I'd prefer to have seen thermistors measurements of the air temperatures immediately outside the unit for a prolonged period of time in order to get a good comparison instead of using the thermal camera as the thermistors would be more accurate. However, for a quick and somewhat accurate test the thermal camera is good enough.

[@Alex82pd]

@@Tensquaremetreworkshop I didn't think about this too... Basically it works well to keep the outside stuff "out", but any pollutant that is filtered coming from indoor would just simply be blown back in once the flow is inverted, true. It is definitely better than an extractor fan by miles, but I am not sure about a decent MVHR. And at least in the uk, unless you have plans to extend on the roof, all the roof space is there to store the MVHR unit and the hoses to direct flow to the rooms, while extracting from another room creating a constant small air flow circulating between supply and exhaust. Ideally, with the exhaust in a bathroom, recovering the best heat, getting rid of the most humidity and even working as odour extraction with fresh air coming from the other rooms... Ideal world I guess

[@Tensquaremetreworkshop]

@@capitalinventor4823 Yes, it shows an efficiency of around 40 - 45% at these temperatures. These devices are usually quoted with 24C inside, and -4C outside! Even then it would not make 90%- the best systems only make ~80%, and this method is seriously compromised. More important is the total heat transfer- which is trivial.

[@Tensquaremetreworkshop]

@@Alex82pd It is certainly true that air change systems work best when the system is designed into the house build. For one, it needs an hermetically sealed house. Actually, I think an extractor fan is better than this unit. The heat recovery is trivial, as I showed it is >100year payback. And it recycles dust etc. And it is only extracting half the time. And you need to clean filters that only exist to stop the heat exchanger blocking. And it is moderately complex, with moving parts, so there will be a failure rate ( I have a conventional timed extractor, and I am on my third in 10 years...).

[@waynecartwright-js8tw]

Be a great idea in an extractor hood , more heat to recover.

[@CharlieDIYte]

The ceramic would get clogged up too quickly

[@waynecartwright-js8tw]

@@CharlieDIYte yes would need good filtration , great if its only steam though (condensing for more heat)

[@GlennPierce]

I looked at these a while back but decided against due to the cost and difficulty of getting electrics in particular places of the wall. Interesting it uses ESP should be easy to install esphome or tasmota on it to get it on home assistant.

[@lksf9820]

A good video, thank you. Have you ever done one on the thermal imaging dongle thingy? As a seasoned pro who has drilled thousands if not millions of holes in his time you're doing it right. Core drills suck, especially in hard brick.

[@CharlieDIYte]

Thanks, and no I haven't done a video on the TopDon TC001. I should though. It's a great bit if kit.

[@GoingsoloinFrance]

Just to add, I have found a simple 'solution' to condensation.... I have placed a simple fan in front of my single glazed window. I think it's a 12 inch fan that you would use in the summer from a supermarket. I have found that condensation cannot form if the air is constantly moving in front of the glass.

[@kennethmunnoch1493]

Could you simply duct the exhaust air from the building into the intake of an ASHP? That would increase the COP of the heat pump and be simple to do.

[@TheKlink]

given that the membrane isn't all that stiff, the oscilo-tool probably wouldn't have damaged it. also, d.i-wife. love it!!

[@CharlieDIYte]

Thanks mate!

[@livingladolcevita7318]

need to get a humidity sensor have you done a review on any?

[@CharlieDIYte]

Yes it's a hygrometer. I talk about them here kzbin.info/www/bejne/hJPXmp1-gN5ljNEsi=xXkq7o-vEEtYSvFF You want something like this amzn.to/4gfooIk or if you're not worried about reading data on your phone you can get 2 for £9.99 amzn.to/3VoF9cq Seriously, once you start measuring your relative humidity (it's important you know why it's relative and I explain that in the video) you're 3/4 of the way there towards taking damp and mould 👌👊

[@RisinT96]

Its got an esp32, so we can probably flash a custom firmware and hook it up to local operation via home assistant

[@retockirtap]

I came across something like this a couple years ago. They seem like a really good idea as a retrofit. However, I do wonder about sucking in damp warm air. Those expensive centralised heat exchange units do dehumidify the air coming in before running it over the heat sinks before dumping it into the house. These isolated decentralised ones I don't think do this. Do they?

[@CharlieDIYte]

The air outside isn't damp as discussed here kzbin.info/www/bejne/hJPXmp1-gN5ljNEsi=hoTvnhgsLu2fWyH0 It might feel damp and run a very high relative humidity but that's because in the cold weather the air can hold very little moisture. That's why you get chapped lips.

[@Purge00]

I have mold, crazy damp readings and relative humidity like the tropics and a bad smell. I was advised to get units like this and an insane moisture barrier on the walls but cant afford that system and I think it is overkill. Would two or three of these units cure the humidity, how much power do they use and are the electrics chased and connected to the ring mains or is all new wiring involved ?

[@aesopshair6690]

If you haven't already got a dehumidifier it is a great asset... they work better in warmer rooms, but are a massive help to reduce damp... we have a shower room with no extractor fan and still are able to effectively dry washing with only a 60w towel radiator and dehumidifier (no damp walls).👍

[@renegerritsen6178]

I wonder what the centralized heat recovery systems will look like with all that ducting inaccessible in the ceiling. Is there any data on that? Dust and mould, etc should collect there, right? I know there are filters involved, but filters never stop everything and clog up if you don't maintain them. I have recently opened up my dryer and was surprised about the amount of lint I found on the inside. A decentralized system is much easier to clean and has very short ducts you can actually access.

[@CharlieDIYte]

Funnily enough I was wondering this the other day. I agree but they're such a fantastic option I guess it's a small price to pay.

[@Elberto71]

Did the metal ducting require an earth connection? As the cable is so close

[@CharlieDIYte]

The unit is sheafed in plastic and the plastic pipe I slotted in prevents any contact with the duct.

[@shaun30-3-mg9zs]

Hi Charlie, Good to see your thoughts on heat recovery system, always full of good tips and ideas, great video, catch you soon, take care

[@kasgraham6348]

Do you think it would be possible to replace the filter with a HEPA filter?

[@CharlieDIYte]

I've been thinking that. The problem with this filter is it's designed to protect the ceramic core from dust rather than filter air to improve air quality. And on the supply cycle it's pummelling rust dust back into the room, thinking about it. I suppose the issue is it'll reduce air flow. I might look into it!

[@andrews3137]

I'm not sure how effective these would be if you didn't have them in different rooms running out of phase with each other. My main concern with a single device or multiple if they were all running in unison would be whether or not this kind of device would actually provides a net benefit. I don't know the rate at which a typical house with equalized pressure gains or loses air when a fan is running and then suddenly stops. However, I suspect that while the fan is running for 70 seconds, the low pressure created inside the house would draw cold air through crevices all over. When the fan switches to pulling air in, the incoming air won't be as hot as the outgoing air, which is expected for any heat exchanger. This lukewarm air will pressurize the house, which already contains a mix of cold air. This mix is presumably warmer than the air being pulled in through the heat exchanger, causing the air to be pushed out of the same crevices that previously drew in cold air. Maybe this effect is slower than I expect and this unit has a net positive but because of these reasons I think there's a decent potential for it to be a moot point without multiple working out of phase.

[@thetigers2803]

Love the idea but I'm not certain the loss in insulation is offset by the meagre returns offered by the heat exchanger.

[@CharlieDIYte]

You're right. But when you've got to put a fan in...

[@KumaMooMoo]

As somebody not very experienced with DIY yet, is there a company or type of tradesman that could install this to replace trickle vents in my house? I'm new to DIY and not yet comfortable drilling holes through brick walls or doing anything electrical yet

[@CharlieDIYte]

I think you'll have to Google around approved local installers. You shouldn't really tackle electrics - leave that to an electrician.

[@TekknoBob]

Steel duct is bad for thermal bridging, as shown on your thermal camera. Otherwise good install. Is the thermal efficiency about 40%?

[@CharlieDIYte]

Yes I know. I messed up there. I'll be replacing it shortly.

[@DTech101]

ESP32 sounds like it will be good with Home Assistant 😉 I’m still rocking my PIV having a chimney makes it way to shift air in the exchange, I’ve added it to Home Assistant and turned it on max it comes on for 2 hours full blast in the day and two dehumidifiers at night one downstairs and one upstairs all using HA 😉 PS now my kitchen fan extracts if the fire alarm in the kitchen or dining room sound the kitchen fan is massive I got a iCON60 due to the iris shutter as the other extractor was letting out all the hot air, now I can just control this with Siri and HA 😊

[@sethkazzim731]

Love that!

[@Tensquaremetreworkshop]

Even more- 1) This unit contains a filters (unlike normal extractors)- presumably to protect the heat exchanger from dust. Problem is, the air flow is reversed every 70 seconds, so most of the dust trapped on the way out will be blown back in again (did no-one explain to the designer how filters work?) So, all the dust, spores, etc are retained in your home. And you get to clean the filters. Not very often, because this reversing air flow will keep them clean! 2) In sleep mode, this runs at 15l/min. But the capacity of the tube is ~ 6l - so a third of the air is just being returned to the house! 3) Energy consumption- the claim is it uses less than 20% of the power the Kair uses for the same airflow. Does this seem likely? Kair recovery claim 'up to 86%' this one 'up to 90%' - at around half the price... As a design engineer, I am constantly amazed that ideas that ignore the laws of physics come to market.

[@aesopshair6690]

Interesting points you have made.. It appears that the Kair product is a shell and tube heat exchanger, so no reversal of direction, but a potential issue is the cross contamination of exhaust and supply being relatively close. Another issue with the Zephyr is that when it is in extract mode, there is no heat recovery unless it is paired with a secondary unit, and as you have indicated around 40% of the extracted air will find its way back into the house, so 'extraction efficiency' is unlikely to be great! 😂 I might be mistaken, but think that gas boiler exhaust flues use a twin pipe construction to exhaust and supply air through the same opening, so would be interested to see more ventilation systems utilise this (like kair) - surely it would be a bit more efficient than the reversal method?

[@capitalinventor4823]

@@aesopshair6690 I had a whole home HRV in my last house and it use a single point for the input and output. They got around the cross contamination of the supply by extending both pipes slightly from the house and bending the exhaust downwards. The vent cover also helped to keep the supply and exhaust from combing. From the video I noticed that the Kair product appeared to extend further out from the house and I'm guessing that they probably do something similar. There's going to be cross contamination on this product because there doesn't seem to be a pause between the supply and exhaust cycles. Some of the air that is being blown out will be caught when the product turns to supply mode. A simple two or five second delay after the fan stops spinning between the two modes would have greatly reduced this risk.

[@Tensquaremetreworkshop]

@@aesopshair6690 The Zephyr relies on stored heat between in and out cycles. This has issues, some of which I have addressed. Co-axial heat exchanges are, as you say, used for boiler systems. They benefit from the hottest exhaust meeting the final inlet- it slopes in matching temperature (flow in opposite directions), making it fairly efficient. The problem is that you need a long duct, but it can be done. Since thin polythene can be used for the tubing (little pressure differential) it can be very cheap. The most efficient system uses rotating plates- but that is only practical for a large centralized system. I have some doubts about the power consumption on the zephyr - they claim about 12% of what the Kair one uses. Seems unlikely...

[@CharlieDIYte]

There is a few seconds' delay between each cycle. I'm cross I didn't show that in the video.

[@Tensquaremetreworkshop]

@@CharlieDIYte Not sure what relevance this has- the dust retention would not be affected by such a pause. It is probably done to allow the fan (and air) to stop, so avoiding braking power being applied.

[@frankkimono2255]

Can those vents be shut close when not in operation? I wouldn't want to have a permanent hole in the wall that cannot be sealed.

[@CharlieDIYte]

Not the outside but when you switch it off the inside cover shuts

[@YouJohnTubeify]

Is it possible to sleep next to it? I want to use this in my sleeping room

[@CharlieDIYte]

I think it is, in night mode.

[@Metal-Spark]

I live in a very old house and our kitchen is in the basement. The house is split level so the front wall is underground, the back wall opens to the outside and the two side walls connect to the neighbour's since it's a terraced house. Something like this would be great, but with only one wall opening to the outside, I'm not sure what my options would be. I could get just the one, but then there won't be any other air supply to the basement. I'd genuinely appreciate some thoughts as I've had at least 5 damp proofers out to look and not only are they clueless when it comes to this kind of tech, none of them seemed particularly trustworthy. Every single one of them bad-mouthed the advice I'd been given by the others and it seemed like they were just saying anything to get the job.

[@CharlieDIYte]

I think one in that outside wall would be better than nothing?

[@fast_eddie3441]

Looking for just a one way filtered flap for my kitchen for when the powerful extractor hood is switched on. Its currently pulling from any open window but I'd rather install a local fresh air supply in the kitchen but can't find anything suitable? Any ideas anyone?

[@ewanrollo5562]

I'm having real trouble finding a decent unit for my situation. My walls are sandstone about a meter thick, including the internal insulation panels. I already have a 100mm hole for an extractor fan. I don't want to enlarge it as I fear it will weaken the wall too much. Also I'm living in a conservation area so I will probably get in trouble for doing anything to the walls. They're over 200 years old, so I actually think it's wrong to mess with them. I can't find a good quality quiet running unit for this situation. There all for thinner walls or require a bigger duct. Also I really like the self closing vent cover on this BSK unit, but they don't sell it in a 100mm configuration.

[@CharlieDIYte]

Is it condensation that's the issue? Could you install a PIV in the roof space instead?

[@Martin-cc5xn]

Interesting, but the issue with these is that unless you install at least two then their effectiveness is likely to be very localised, especially if doors are shut. Im interested in split air conditioning units that use heat pump technology, many of these dehumidify, so you can heat, cool and dehumidify making them more versatile, anyone any thoughts on this?

[@chrishughes7633]

I am right in thinking this could be used in a bathroom and toilet instead of a standard extractor fan set up?

[@ifallelsefails2]

No, they are not designed to be used in bathrooms. They cannot cope with the quantity of moist air that is generated.

[@ronancoakley307]

Would anyone know how well these perform in the cold winter months with a low temp outside and a bedroom that is prone to condensation thanks.5

[@CharlieDIYte]

Ronan if you scroll down to Andy Mac's comment you'll see how his has fixed the mould and damp in his outdoor room. Check out my video on this kzbin.info/www/bejne/hJPXmp1-gN5ljNEsi=e2GhJqRymLVh2gGt You could install 2 fans to work as a pair to maximise air circulation, or consider installing a PIV.

[@abievelyn]

Can I take us back to PIV units, I had one installed two years ago, but it made zero difference to the amount of condensation we experienced in our house. Why might that be? I had heard such great things and am so gutted. Really intrigued by this! Is this something you would use instead of a standard kitchen extractor fan? Ours is incredibly loud!

[@JamesTombs]

Friend who works at biggest manufacturer of PIV told me they're useless for most people, apparently very few properties actually benefit so I stopped looking.

[@edc1569]

Problem with PIV is getting the air movement to where it’s actually needed, maybe you can shut doors and open/close trickle vents to assist.

[@edc1569]

Yes the idea with these units is you just run them 24/7 at low speed.

[@DTech101]

Couple of parts to this PIV is great but the air needs to go somewhere. Sources of water need there own way of getting rid of moisture ie water source areas need there own,bathrooms wash area kitchen areas need there own extraction devices. I use to run my PIV all the time but in winter the heating went on too much as it was cold it did drop the humidity though I saw 37% one night I have a chimney so I’ve got a permanent opening and you have got to seal the loft hatch to stop it just circulating I used fire form to seal the wires going through the ceiling just to make it harder for the air to return to the loft basically forcing it to use my chimney as that’s the path of least resistance. In the end I turned it off got two dehumidifiers not the compressor kind so I can get a bit of heat from them at night and keep condensation down when we sleep in the morning the PIV is turned on max to do an air exchange for two hours and then shuts off all automagically through Home Assistant.

[@matthewwakeham2206]

PIV needs places for the air to exit so vents/window vents in the affected areas. Possibly even leaving the window slightly open if not windy. Also PIV won't work that well if the house is very leaky as it'll just blow out the nearest big hole. You need to be able to control the ventilation for each room. Doors need to have a finger width gap underneath for air flow. Also they work by a temperature difference between outside and inside. The inside air needs to be warmer than the outside air otherwise they work in reverse making it damper inside. For this reason they are more effective at night. They are also not a replacement for proper extraction fans in kitchens and bath/shower rooms. These need to be powerful and have an overrun for a good amount of time to dry the room after you've finished making moisture.

[@jjjacer]

trying to find a solution for my mobile home (in USA), especially to get fresh air in while keeping the cool/warm air inside. just not many solutions for thin walls

[@johnhunter4181]

Charlie's opening comments: "we can't have ducted MVHR in old houses" isn't true. Bungalows are very easy to convert and Victorian houses could use the chimneys for ducting with further ducts and the MVHR in the attic. Our 40 year old Swedish kit house came with ducted extraction which was easily converted to MVHR. The fan speed is regulated by CO2 and RH% - it's now late evening and running at 34% rpm - extracted air is 18.5°C and supply is 13.2 but outside is 5.5°C I think that's worth having. I can't see how two of these Kair units running push/pull all the time would ever manage that efficiency. The diagram of two units working together implies some through flow of air but if one was blowing all the time and the other extracting - you would recover nothing - it would be no more efficient than opening the window. I think Vent-Axia make one that has concentric pipes and a proper crossflow heat exchanger - a much better idea.

[@CharlieDIYte]

Thanks John. It's a fair point. What I perhaps should have said was it's not something most people are going to take on because of the practicality but you're right, it's perfect for bungalows and is far superior to any decentralised option.

[@JPEight]

Pretty sure two units together would still reverse every 60s, but do so in tandem so that the air has to go through the vents and can’t sneak through any gaps where the heat would not be recovered.

[@HubbHubbs]

But if you install just 1 of these units surley all the while its extracting and warming the ceramic core isnt cold air being pulled in for 70 seconds from elsewhere in the house. I have an envirovent heat recovery unit with the in and out flow both at the same time and even thats only 60-70% efficient.

[@drsquirrel00]

Looks like its simply blowing the internal warm air through a ceramic thermal store, then brings it back in when reversing the fan? Seems a good simple cheap idea - being sold for way too much.

[@ricos1497]

But, there's an app. They could have doubled the cost with AI and blockchain.

[@drsquirrel00]

@@ricos1497 The ESP32 isn't the worst way to go about it really, problem here is possible limited firmware. This is the same chip used in the sonoff devices... they are sub £1 chips.

[@pasternakel]

I had this in my livingroom, found the 70 sec switch way to disturbing, always recommend a central system.

[@Tensquaremetreworkshop]

A metal duct acts as a heat duct- avoid. Strangely, the motor is mounted on the cold side- meaning its heat is lost... The efficiency claim is 'up to 90%' - but zero is up to 90%! cannot help feeling that a really good system would graph performance against differential temperatures- what have they got to hide? Update- research suggests this type of recovery has a max efficiency of 80% - and that is best case... Your test of temperatures suggest 40-50% efficiency. A 'buyback' calculation would be interesting... There are two reasons for air change. The minor one is for odour extraction, the main one is for air to breathe. The latter is not really helped by bathroom extractors, the door tends to be shut when not in use, and only occupied for a few minutes. The obvious place to do the air change in modern 'one room living' is the cooker extractor. It is also where the air will be hottest when the hotplates are in use! In this case a plate heat exchanger would probably be the way to go.

[@geoffhaylock6848]

Came here to say the same!! In the thermal camera image you can see that cold, dark ring. The plastic would have worked better I think.

[@ricos1497]

"The minor one is for odour extraction" Not in my bathroom

[@Tensquaremetreworkshop]

@@ricos1497 You prefer asphyxiation to a bad smell?

[@CharlieDIYte]

​@@geoffhaylock6848Yep, that was a big error on my part. I'm currently mid way though ripping out the duct to put the plastic one in.

[@CharlieDIYte]

Thanks for this. Yep I made the point about kitchen extractor on my last video where I installed this monster kzbin.info/www/bejne/aJnaaot3btZ7oKM kzbin.info/www/bejne/aJnaaot3btZ7oKM

[@JPEight]

Whilst it’s cool tech, it’s ability to only recover about 50% of the heat is a significant compromise vs a central system. Whilst I do care about efficiency, what I and most other people really care about are the bills. And, vs a basic extractor, what is the ROI? I suspect the extra £150 per fan is going to take a fair while to pay for itself.

[@dorinclisu9601]

Judging by the thermal camera readings, the thermal efficiency of that ceramic core is pretty low, definitely less than 50% but hey it's ventilation and better than nothing.

[@CharlieDIYte]

I agree. Plus I have a perfect cold bridge I need to eliminate by changing that metal duct back to the plastic.

[@ecoworrier]

If it pushes air out of the house for a certain period (negative intern pressure) and then pulls air in for a certain period (positive internal pressure), where is that extra air coming from? On the out phase - cold winter air will be pulled into your house, probably through windows and doors, on the in phase, your nice warm internal air will be pushed out through the same route. Pointless! Much better to get a single room system with split or concentric air ducts (like the in and out of a gas flue) which can recover the heat by a counter flow method and does not change the air pressure inside the room and encourages draughts.

[@ecoworrier]

Basically, if you have a high level of air-tightness in your house (which is something you should aim for), this system will not work.

[@nZebco]

The problem as I see it is the metal tube, A bigger thermal bridge than the PVC version.

[@CharlieDIYte]

Yep. Agreed. I will be replacing it shortly.

[@frankkimono2255]

@@CharlieDIYte Is that also a problem in the video about the kitchen extractor installation? If I understand correctly, the foam was supposed to alleviate the issue. But the hole the metal pipe went in was sealed with mortar (kzbin.info/www/bejne/aJnaaot3btZ7oKM) so does that also need fixing? Would it make sense to use a plastic pipe inside the hole instead and then couple it with the metal one? Or would that be a fire hazard even that far away from the heat source from say the oil residue inside the pipe catching fire and spreading all the way to the hole? Excellent videos by the way and cover exactly the topics I'm very interested in right now. Thanks for sharing your experience.

[@CharlieDIYte]

@frankkimono2255 Yes. I've been wondering that recently, and think maybe a plastic break in the metal duct would have been a good idea, but the reality is that metal duct is so long, and insulated along its length that the cold bridging isn't going to be an issue. Also, I did spray expanding foam around it. I only rendered the last 20mm or so - you can see the foam in the clip where I'm using the mortar.

[@MuddathirQ]

I do not understand gow this system could work with multiple units and still recover heat of some are only extracting and some only supplying? How the heck would the heat be recovered?

[@CharlieDIYte]

Because they're still working in 70 second cycles but some are expelling whilst others are supplying.

[@D-Khaz]

I’d buy this in a heart beat if BSK had a local only control for the ESP32 so I could integrate it with Home Assistant. I’m fairly certain all of these companies will stop supporting their app/cloud before their hardware fails…

[@CharlieDIYte]

Pretty sure this can be integrated with HA

[@EssGeeSee]

So, it doesn’t work.

[@GMC-qo9xi]

Why do you say it doesn’t work? Based on the minimal differential between the outside air and the inside air he still gained a few degrees in the incoming air. Imagine the outside air was -10ºC and the inside +20ºC, the exchanger would instead warm the incoming air to something approximating 5º (+/- whatever the exact efficiency is). Obviously as the 70 second cycle nears its end, the temperature difference between the incoming air and the outside temperature will decrease… with the first half of the cycle having a much higher difference.

[@tooslownotfast]

The metal pipe is not good for insulation

[@CharlieDIYte]

Probably fair enough but it's got expanding foam behind and 3/4 of it is sheafed in the plastic I should have used.

[@livingladolcevita7318]

ha ha core drills? had a plumber installing my gas boiler and went through 2 core drills the bricks were so hard.

[@CharlieDIYte]

Exactly 😉 That's why I drill instead

[@frankkimono2255]

@@CharlieDIYte The core drill isn't that expensive from what I've seen (and can be sold later anyway) to give it a go first instead of risking an unsightly scar on the external wall. Might not be a big deal if your wall has render on it but if it's bare bricks it's going to look crap. I have a hole in a brick wall where the cable from the satellite dish went in. Someone didn't drill the hole nicely and chipped off a piece of brick. It was hidden by a plastic cover, now is exposed and looks ugly, but it's a small hole unlike a cave like here - you chip off too much, the cover might not be enough to hide it. In the worst case when you cannot get through you'd at least end up with a nice pilot circle to guide the standard drill.

[@sabinpreda3878]

Good video but, unfortunately the product, made in Turkey, is showing fake airflow data. Instead of 60m3/h airflow it bearly reach 42-46. There are independent tedting report showing it. Also pay attention, in good quality products, the ceramic core is from a special alumina porcelain that dont absorb water. Yours, please check it, will suck water like a piece of chalk. The ceramic is not allow to absorb moisture as by condensating during cold days, water+ dust+a porous surface=mold. So became a health issue. So, again, nice video but you choose a bad product.

[@CharlieDIYte]

Thanks. I'll take this on board for any update review.

[@marklloyd6433]

the difference made by the 'ceramic gizmo' is pitiful. Thanks, at least I know what a waste of time and money it is

[@johnzach2057]

Frankly I do not like them. They might look nice but they really have bad efficiency. You can easily DIY HRVs with much better efficiencies although it will take effort to make them look good and they certainly won't be compact.

[@mchlbk]

Nice idea, but too expensive, too noisy and not efficient enough.

[@CharlieDIYte]

We don't really notice the noise to be honest.

[@frankkimono2255]

@@CharlieDIYte The noise is a valid concern. How far away do you have to be from it not to hear it at all when on the lowest setting? Then there is a matter of the noise not being constant due to the direction change every 70 seconds, I imagine the noise of the fan spinning down and up again can be even more distracting. Maybe when the fans are positioned strategically this can be alleviated or even eliminated if the property is large enough to allow for that. In my 3-bed semi the bedrooms are so small I can almost reach the opposite walls by stretching out my arms (in one of them I actually can) so my ears are never that far away from the furthest spot in the room. That probably rules them all out (=the entire first floor) as the location for this fan.

[@Shane_O]

The efficiency of this unit vs the payback?….. I think I’ll wait a few years until they’re more standard and then cheaper.

[@JohnoLapse]

Depends if you value just living in a more comfortable place. I can't put money on that. What's the payback of a new kitchen?

[@orange1666]

@@JohnoLapseyes quality of air is a huge factor as opposed to living in a toxic box , there is an old saying that goes “ pay for your health now or pay later “

[@drsquirrel00]

Probably 10-15 years. Maybe just in time for the unit to fail and need replacing.

[@qkayani]

This is only good in well insulated rooms from my research. This should be mentioned. In a leaky house this is useless.

[@Self-Sustainable_Homes_UK]

Not completely useless, just less effective. Only as it’s controllable whereas ventilation in a leaky house is sporadic. But yeah you’ll see better results in a more airtight home

[@theo48512]

If you install only one it will evidently just pull in fresh air from some other leak and push out moist air through that while in reverse. It would add the moisture control and you should still see a relative benefit half of the time. If one use two on the other hand, it should reduce leaks somewhat. (

[@theo48512]

Unless the pressure gradients are too local due to leaks.

[@apmullen]

In response to your previous core drill comments about me that you missed, using the proper tools for the job you won't have the problems you described. Hard brick! That's why they use it to drill for oil.

[@solidus784]

have you asked someone to get you a life for christmas?

[@apmullen]

​@@solidus784you comment has taken a lot of thought!

[@jacko791]

Where I live most people tend to use the method as shown in this video due to the hard brick. A core drill takes roughly 2 hours to get through but as he says, it can be done in 20-30mins with multiple small holes. I do have all the kit to drill a core hole but it just takes too long in hard brick areas. I'll usually start off a hole with a core drill to get a neat outline then switch to smaller bits. In softer brick, block or concrete I would just core drill the whole way

[@CharlieDIYte]

@@jacko791 Exactly!

[@CharlieDIYte]

I don't agree. The last time I used a core drill on this wall it was before I owned an SDS and I hired a massive core drill from our local hire centre. Also brand new bit. It literally took hours and hours.