Why NOT TO Fit Smart Radiator Thermostats to ALL Your Radiators. Pros & Cons, Best Way to Fit Them

[@kaasmeester5903]

Good advice about how these things can potentially affect the efficiency of your furnace. I'm a smart home enthusiast but not a heating engineer of any kind; I just went ahead and tried a few things, trial and error. In the end I got it working fairly well: 3 thermostats (office, living room and bedroom), controlled from the hub on a schedule (or from an app). Radiators in those rooms are slaved to those thermostats. And some additional rooms without their own thermostat, where turning on the light will demand heat from the furnace if the room temp is low, and open the radiators. That way we no longer heat rooms we are not in, and we're saving a ton of gas. The whole system is set up so that we no longer even touch the thermostats (physically or in the app); every room in the house is at a comfortable temperature, or it is cold (15C) when we're not in it. That is what a smart home is supposed to do: fewer buttons and controls, not more. As for the cons of smart thermostats... Besides Wifi and Bluetooth (both crappy options for home automation), you can also get Z-Wave or Zigbee smart TRVs. These are far more reliable, but they do require a hub that can talk to them (which is more expensive). And they work independently of your internet connection... some of them can work independently of your hub as well, and be driven by a (smart) thermostat directly. Batteries: the TRVs I got have rechargable ones. Every few months I get a low battery poke from my smart home system, and I just plug in a USB cable for a few hours to recharge. About your example of the cloak room: that sort of stuff can usually be programmed into the hub. If you really want, it can even be programmed into the TRV itself (the ones I have allow for a locallyl programmed schedule) My advice for anyone interested in this: be prepared to start an entire new hobby! 😁

[@MiracleManMatt]

I have Drayton Wiser for the last ~3/4 years with a number of the smart TRV's. I have an oil heating system and fitted a smart pump with an auto mode to mitigate the effect of the pump cavitating - however the issue I found was that as the boiler is not modulating - I found the system started to short cycle - therefore reducing the efficiency of the condensing boiler as you mention. You are quite right with some of your recommendation's. I have actually manage to reduce the jet size (KW) of the boiler to help reduce the issue. So I have a mix of normal TRV's, smart TRV's and programmable TRV's to help balance the heat load. To me it would make sense if you could program the drayton TRV's to 'open/close' per the program - but NOT switch the heating on. i.e. if the heating is on anyway, the room heats up - but not if nothing else is. I found that I got round this by combining the system with programmable TRV's on some radiators - but its not ideal and seems like it could be a really easy addition in the app. I think for these sorts of systems to work optimally - you need a heat store type system - or at least a buffer tank to mitigate the short cycling.

[@MarkBallardLTD]

I find to make systems run really efficiently is super hard. What we're told to do half the time is just not achievable. I find it very frustrating.

[@evanofelipe]

Thanks Mark, you highlight many interesting scenarios and cons resulting in me deciding to stick with TRV’s

[@grahamwoodier5066]

I have a Tado system with 12 radiators and 9 smart valves. I don't use smart valves on bathroom or cloakroom radiators. However I agree that you do have to be sensible with how you control the system - just turning one small radiator on is unlikely to work well for the reasons you describe. I tend to use the additional control provided by smart radiator valves to determine room temperatures in rooms at different times of the day. We tend to live in the kitchen during the day and move to a lounge in the evening so I adjust room temperatures to suit this behaviour. Batteries tend to last over a year when using alkaline. However I am moving to rechargeable since you can do that with Tado but I don't have much experience with these yet.

[@dc99yt]

tado has this feature, which allows a chosen TRV to be disconnect from the zone controller. So the TRV only operates when the rest of the zone is on. Also adding a separate wireless temperature sensor away from windows and radiators, will prolong the battery life, as the TRV doesn’t need to do a lot of micro-adjustment because it’s too close to the radiator.

[@lindalewis2321]

Thank you mark never new about the batteries just had a new boiler fitted wish I never changed my boiler it has played up since I put the heating on the people who put it in have been out so much they can not fix it so will show this to my son

[@JohnThomas-ey1hx]

Great video and some very valid points, but just a few things to note. The Drayton TRVs and Room Stats communicate with the Hub using Zigbee and not WiFi. The Wifi connection is only between the Hub and your router and this is the connection that can go offline, but it shouldn't stop the TRVs/Room Stats talking to the Hub and continre to work (assuming batteries not dead). It will stop you controlling the heating whilst you are away from your home using the App until that Hub-Router connection is restored. Also worth pointing out that when you only heat specific zones/rooms at specific times and/or to different temperatures, can cause additional internal heat loss from the heated rooms into the unheated rooms. This means the radiator from the heated room will need to work a bit harder to combat the extra internal heat loss. I personally do not like over zoning and only use two zones in my home - upstairs and downstairs. I also do not turn off the heating completely in zones, but just set it back 2-3 degrees, and I find this prevents big swings in heating the zone back up when required as we have a high thermal mass. Last thing is that there is no calibration on the Drayton smart TRVs which means if they are out of step with the correct room temperature you have to manage different schedules and either overheat/underheat the zone to get the temperature you want. I have no idea why Drayton do not include this feature as its pretty standard across every smart thermostat system on the market expect Wiser??

[@MarkBallardLTD]

Again some excellent points. It's great to hear from people like yourself, what you're thinking, and how you're setting up your systems. To the layman who may be reading this. I hope you can see that setting up your central heating to work efficiently. There's way more to it than just adding a few thermostats.

[@brianridley1102]

Thanks for this vlog, I was considering doing this but it really isn't worth it as my main aim like yourself was to run one radiator where I work which just doesn't work. Saved me a lot of money

[@almota7]

I have fit the tado thermostats a couple of years ago and the only difference is that we literally stopped noticing if rooms were too cold or warm, every room is independent and once you set the schedule you can forget about it.

[@my_carp_life3424]

Its probably best if you set the temps on them and leave them to turn on and off by them selfs, certain rooms heat up quicker then others so the rad stat will turn off when room has hit the required temp, thats what i do anyways. Open therm will help as well.

[@robertlamont9455]

I'd looked at electronic valves some time back and concluded what you found by experiment, deciding instead to go with good quality but standard trvs throughout, only the principal radiators (where the main thermostat is) are trv free. However, a few minor points Mark - It's all very well referring to radiators by their D50 specification, but when operating them on a condensing boiler they are at ca D20 - eg my Lounge rads combined are 5.1kW at D50 spec, but in the real world their combined power is ca 1.5kW at D20, and that's a HUGE difference to the boiler. - On balancing - I fitted the Heimeier version of the pressure agnostic control valve so that whichever radiator is open or shut, balance is maintained across all the rest, something which cannot be guaranteed with a lockshield. However, by setting them according to spec, they will pass higher flows at D20, something I didn't realise at the time, but explains why I couldn't get a Dt of 20 - By deploying a manual version of weather compensation, I managed to get my previous boiler (min. 8kW) consistently seeing a 30c return on a ca 18 minute cycle, even when running max temp at -16 outside. My own project - High thermal mass lower floor, low thermal mass upstairs, 100m2 floor space, heating runs 24/7 throughout winter as the high thermal mass is cheaper to maintain at steady state..... - Completed the last of the insulation this year, pulling heat losses down to 20% of the original. - This summer upgraded 2 rads and swapped others around to provide the same overkill on all of them on a new boiler (min 3.2kW) on load compensation ( I'll re-balance the system when heating becomes regular, another huge benefit of insulation ) - At -3 the REAL rad system capacity is 300% of heat loss, at -16 it's 200% - The idea is that the boiler will be maxing out condensing this winter, as it should be seeing a 21c return for most if not all the heating season.... A nice little project which didn't cost an arm and a leg, and has paid back handsomely - Last year's heating bill was 370 quid, next year's should be 270. ;)

[@MarkBallardLTD]

Wow! You certainly know what you're doing there. Unfortunately for most people I find it difficult Just explain relationship between boiler temperature, radiator, temperature and room stat temp and TRV temp. My video was really just a point out. Don't just jump in and do something because we're told we should do it. Good luck with your project

[@robertlamont9455]

@@MarkBallardLTD Had to learn as I went along as it's not my discipline (ret water engineer), but thanks for the compliment, I'm an amateur unlike yourself, but with a DIY monitoring system for utilities, temps etc.. What kicked off my interest was trying to figure out why the old Buderus boiler (min 8kW) had consumed 1.3m3 in dead of winter when a normal "55" cycle would be 0.5m3 at ca 20 minutes. Timed the next cycle at 40 minutes but why 1.3m3 ? - Clipped a couple of temp sensors on the feed and return, and the answer soon became obvious - My feed was actually 50 not the indicated 55, but the return ramped up in the second 20 minutes from 30 to 45, reducing the condensing advantage and increasing gas consumed. Tried increasing the Dt at the rads from an effective 5 to 20, and soon hit the brick wall of the boiler having a panic attack as it was unable to dump heat as you described - It was to much later before I was to realise the D50 was misleading me, that it was D20, 30% of the stated D50 power... Anyhow, set all the valves back as original (balanced), and started cranking the feed temp up until I got to a 20 minute cycle and observed the return at ca30c, recording results in a table - It was my introduction to the concept of weather compensation, and realising just how crucial the return flow temp was to efficiency irrespective of Dt - Effectively I was filling the rads up, then letting them dump kW, rinse repeat... A hydraulics equivalent would be plug-flow - Heating is treated as having a constant flow, but disregards the convective characteristics of radiators. - From vague recollection it used ca 0.75m3 at max out (display 82, real 68), but it wasn't 1.3m3 any more, and no brainfarts from the boiler either. Couldn't find a WC device for the Buderus, so was stuck with doing it manually until last March when the Buderus blew it's motherboard when it was -6 🙄 . Together with phased insulation, it saved a small fortune over the next 6 years, cumulatively ca 6 grand at today's rates.... Load compensation is a new one to me on the new Viessmann, but in the short time it was in play, it seems to be reacting to the return temp and keeping it under control. The boost in rad capacity should build on that capability, but will find out this winter. I'm not knocking what you're doing at all, you have a wide ranging audience to cater to, and your caution over electronic trvs is fully justified as you've found out yourself. - Now I'm going to throw a bit of a spanner in the works over heating in a high thermal mass building - It is pointless shutting down heat overnight, as it uses more energy to re-establish temps in the structure than you saved, trust me I tried and measured it - In a low thermal mass building you can get away with it as you're heating the air, less so the mass, but I'd hazard a guess most of your audience are in the former category.... Thereafter, I only ever turned the heating down if I went away for a few weeks in winter, but after one such break landed me a huge gas bill, I no longer whacked the heating back up on return, but stepped it up in increments with a gap to let the rads dump heat - It took exactly the same time to return to normal function, but used a fraction of the gas ;) The Viessmann may rewrite that rule, but we'll see... Anyhow, keep up the good work...

[@MiracleManMatt]

Hi, can you explain more about what Heimeier valve you used as Im interested for my setup? cheers

[@robertlamont9455]

@@MiracleManMatt Sure. It is (or was) marketed as an 'Eclipse' valve and can be had in various configurations, comes with an orange protective cap. Heimeier (IMI) just happened to be on the market here at the right price when I was looking to replace the cheapos originally fitted, which heads stuck out into the room. They also made a "Halo" head which is marked in degrees C so that clinched it - With axial valves, all the heads are now all parallel to the wall... The same valves are fitted to the Lounge rads, just white capped instead of a thermo head. Honeywell, Danfoss and other quality brands make similar, sometimes referred to as 'auto-balance' valves. Hope that helps

[@DH-tv2yw]

I've had Evohome in my previous house and Wiser in this house. My in-laws have Hive. For me the big pro is how much more comfortable the rooms feel compared to the old thermostat in the hallway which was very unrepresentative of the room temperatures of the actual rooms we were occupying. I also like keeping my bedroom at 18 when sleeping so I don't overheat in the night. We do have the bathroom radiators without any TRVs so there is always a bypass. With the heating just the office issue, would one of those powered radiator fan units that you put on the top of the radiator help? I have a Valiant EcoTec plus 424 boiler, so will that modulate based on the return temperature? What effect will that have when only heating one room?

[@robert.wigley]

Connect your Wiser system up to Home Assistant and you can take real control of your heating, including adding Passive Mode that will set the TRVs to only come on when the rest of the system is heating.

[@graham81111]

Set up the away mode with a min temp for heating , I have the same same system and so i put into away mode during summer so the heating wont come on but the hot water will .

[@demonkey123]

I was considering this solution as I wanted my bathroom towel radiator to come on individually during the summer months. You give a great description of why that wasn’t possible.. I’m very grateful for your advice thank you! any idea where I can get a long towel heater element that I can fit to the top of my towel radiator? I can’t fit one in the bottom because the pipes come from below and foul the installation of a dual fuel element.

[@monkwearmouthsa]

Just to note - when the wiser system tells you to replace the batteries, they aren't dead - just not enough power for the TRV. These batteries still contain significant charge and can be used effectively in other devices - keep them for your battery powered Christmas lights!

[@jono9547]

yes it is situational we have a new build and have two thermostats 1 in the hall downstairs one upstairs in the front bedroom, as we get all the sun on the front of our house the two bedrooms at the front are always warmer than the rest upstairs and therefor never click on but the back two bedrooms and main bathroom are freezing because it gets no sun, and downstairs is the same hall and front room are always warmer while the kitchen and back room are always freezing, i did complained to the company that fitted the system for the new build and they said it was fitted correctly and that's how most are laid out these days, we have 3 radiators none of them in the bathrooms which i call bleed radiators ie no valve on them to turn the heat up or down, now I'm not pro but really. Great video by the way Mark, would you recommend hive in my situation as redoing the system completely would be very expensive and hive with the individual thermostats fitted on each radiator would seem to fix our problems.

[@MincraftPartner]

Smart TRVs in the colder rooms would help keep them rooms warmer. However the rooms you have the thermostat on will be on even when it's already met its target temperature. You wouldn't want to put a TRV on the radiator that is in the same room of the thermostat either due to it causing a feedback loop and then your boilers gonna be on constantly

[@jono9547]

Indeed, thanks for the info.

[@tm2204]

Mark, the Wiser smart thermostats (room or radiator TRV's) do not communicate with the Wiser HubR over WiFi, they connect over their own proprietary interface (Zigbee) . If your WiFi goes down the Wiser system will still operate to it's schedules and you can connect your phone to the proprietary Wiser Zigbee inferface and use the Wiser Home App as normal. The HubR connects to the Wiser cloud over WiFi.

[@sodd1000]

Moanathom right here.

[@abdulhakim-ali5215]

Hello Great video, there something thats bugging me, i would like to introduce these smart valves in my upstairs bedrooms only i would like to set a minimum temperature at night and or switch them off during the day. i dont want the smart valves turning the boiler on and off i.e. i dont want independent zones controlling my boiler. I just want the option to control certain radiators without me adjusting the thermostats by hand. One scenario would be during the day i am downstairs, bedrooms do not need heating as much, if i control the bedroom smart valves, my downstairs would heat up quicker, reach desired temperature quicker and therefore drive efficiency? could there be any problems to what i have mentioned above. Please help

[@pb871]

Good video Mark. I fitted Tado smart thermostats to all my radiators bar the hallway and I've had all the issues you've mentioned. And I'm pretty sure my 12 year old Worcester Bosch combi boiler doesn't appreciate so many radiators shutting off when it's running either. Where you've removed the smart thermostats from parts of your system, have you replaced these with dumb thermostatic valves?

[@curranhouse]

On the downstairs toilet / cloakroom. Cant you wire the smart TRV in series with whatever boiler timer / nest / hive etc you use? This way if the radiator calls for heat but you haven't a schedule for the boiler it is blocked. :) It needs boiler to be one and scheduled and the TRV to be active for a call for heat to take place,

[@steveincork3669]

Retrofit only on a cleaned or necessarily Power flushed system otherwise valve body may lock up leading to cold Rads and expensive drain downs

[@brendanmcparland3430]

As a landlord running a number of HMO, what would you recommend? Especially based on multiple houses

[@fnordianslippers]

I am curious why it is worse to use smart TRVs than regular TRVs in these scenarios. Surely the same problem occurs with regular TRVs if they are set at different temperatures?

[@MiracleManMatt]

you are correct in that in theory it would be similar - however in practice most people have their TRV's set at similar settings and balanced so you get mostly even heat during normal usage (as your unlikely to go around individually turning TRV's on or off) - also TRV's generally have a slower and more gradual 'on/off'. smart TRV's you are trying to zone as much as possible so you end up with far less radiators on (take it from my experience) - hence the reduced heat load.

[@MarkBallardLTD]

It's not worse, you just need to plan it carefully. You can't just go sticking them anywhere and expect your boiler to like it. Check some of the other comments people have made who've done an awful lot to make their systems work efficiently.

[@robshorts]

There is also a problem with noise of the motor operating, it can be quite intrusive in a quiet bedroom.

[@twsteele1977]

Because of your repeated use of the phrase "the boiler wont like that" I don't actually understand the consequences of just having one radiator on. Will it cause actual damage to the boiler? Or will it just be less efficient? If it is less efficient, is it really so much less efficient that I'd *save* money by turning on a second, third, nth, radiator? If it does require more then one radiator to be on to avoid damage or waste, why does that mean you shouldn't use smart valves? Like why not just set it up so enough radiotors turn on instead of just the one?

[@maxnmilly]

What a waste of money all this is, just manual thermostats would do all this without the expense and trouble

[@dc99yt]

If you add a smart temperature sensor into the system, away from the radiator, the system can be quite efficient 👍