Vaillant Heat Pump and Mixergy tank installation experiences - Dorset, UK

[@Ben-gm9lo]

What a lovely couple. Thanks so much for having the courage and energy to document your journey and share it with us. We are waiting for Custom Renewables to fit our 7kW Vaillant based system, so it was good value to watch your experience. We initially tried Octopus in 2023, but they are trying to promote economic solutions to help mass adoption, so their product doesn't flex well to individual requirements. We want to fit our external unit above a flat roof and they only install at ground level. We tried BT too, but their beaurocracy defeated that attempt too. We ended up going through Heat Geek, not cheap, but definitely promising for a quality product. Time will tell.

[@jeffjsmith]

Thanks for your kind comments. I am sure that you will get an excellent job from Heat Geek. The installer choice is even more important than the heat pump choice!

[@reganovich]

thank you for all the information..Peace from Ireland!

[@dorsetengineering]

Nice to see another Dorset resident posting their heat pump journey on KZbin. I’m also in Purbeck.

[@jeffjsmith]

It is proving to be a good journey so far here. Thanks!

[@robertriebli1263]

Thank you for the good Info!

[@jeffjsmith]

Thanks for the comment!

[@jeanh9641]

Well done for your perseverance.

[@jeffjsmith]

Yes, we did wonder sometimes ... But it was worth it certainly.

[@reeshar1234]

Great video Jeff. I'm just trying to learn as much about air-to-water ASHPs as I can for our house in London. I'm amazed though that you needed a 7kW unit as I think we could probably get away with that on our 4-bed detached! We already have a couple of air-to-air ASHPs on our house in France (they call air-to-air and units "reversible aircon" there) but they're hugely simpler.

[@jeffjsmith]

Hi, thanks for the reply. I’m not sure if it is over-sized or not, it is hard to say for sure until it gets really cold. Right now the AroTherm is purring away, and only gets a little more energetic when heating up the hot water tank when the flow temperature gets to just about 60C degrees. The house is very comfortable right now, and time will tell if it could have had a smaller unit. When heating the house, the power peaks at just under 800W and stabilises at 550W. The COP while heating the house seems to be about 4.2.

[@reeshar1234]

That's very good CoP-wise! So if I'm working it out right, your peak heat output at the moment is 4.2 x 800W = 3.4kW so well within the capabilities of your heat pump. What was your EPC prior to upgrade? I'm waiting to get an EPC here which I'm expecting will be around a D...

[@reeshar1234]

I'm guessing you're an engineer, BTW, given how comfortable you seem to be with the technology. I'm of the same generation as you, an electrical engineer by training and have spent my life in consultancy (now retired) so very into technology.

[@jeffjsmith]

@@reeshar1234 Our EPC at the time was C, and indeed the house seems to retain heat pretty well, it being mid-terrace and having thick stone walls. I used to work in IT and so the computing side is fine - but I struggle sometimes with electrical things, though I guess I am learning more all the time. I do rather like the Home Assistant and the flexibility and integration that it gives in monitoring and controlling things. Though I have learnt also that a smart home is only as smart as the person who configures it ... 😉

[@reeshar1234]

😂

[@willj1927]

Fortunately our forefathers had the foresight to build you a plant room for all the kit!

[@jeffjsmith]

Yes, it used to be the outside loo - just big enough for the equipment.

[@adamsweet3587]

I'm building a passive house in Cornwall That will ultimately use a Vaillant heat pump. I have just finished the heat geek course Mastery, and wondered if an accurate heat loss survey has been done before sizing the heat pump and if you have zoning, i.e. thermostats in rooms. The general thinking now to minimise cycling, is now to have no zones and to balance out your house using the weather compensation facility. This will reduce the system flow temperatures and improve COP (efficiency). Regards Adam

[@jeffjsmith]

There was a heat loss survey done, whether it was accurate is hard to say. The upstairs bedrooms have angled ceilings which are pretty close to the roof, and I'm not convinced they were accounted for in detail. We have the Vaillant indoor display with the temperature gauge on it, and an OEM thermostat for reference in the lounge. The heat pump id set to weather compensation and it seems to do a good job for us, as well as seeming to be efficient. We do have TRV's on the radiators to give some adjustment if needed.

[@derekpaisley620]

Good video, installation looks good. Only the heat pump base looks a bit suspect. Keep an eye on the unit keeping level. Thanks for the upload.

[@jeffjsmith]

The heat pump is bolted onto those rubberised feet and seems pretty stable. The ground underneath seems very stable, so I'm hopeful, but it is a good idea to keep an eye on it for a continued level placement. Thanks!

[@peterthefoxx]

Great video. The Daikin heat pump is a little noisier than I’d like so this seems like a great choice. It’s not ‘noisy’ but I there is a noticeable background hum when it’s running.

[@jeffjsmith]

Yes - it was the upside of the planning delays!

[@angiej4865]

Thanks for posting. I'm on the ASHP journey too, in my Purbeck area renovation. I'd have been interested to know the final cost of the installation.

[@jeffjsmith]

Hi, it was affordable with the Boiler Upgrade Scheme help. Probably not as cheap as a replacement gas boiler would have been, but it allows us to stop using gas, removes the gas standing charge, and make great sense by having solar panels and a battery too. I would contact Octopus and a couple of local installers - especially those who have been recommended personally. I hope you can move forward with a local installer. Best regards, Jeff

[@philreilly6959]

I enjoyed watching your video. I'm just waiting for Octopus to produce a design for our system. Fingers crossed that we don't have the problems that you had. However, Ecobubl certainly found you a really great install team. It looks like an excellent installation. Your outside storage cupboard was ideal as a plant room, wasn't it! (On a different subject entirely, I noticed that you have a piece of guttering catching rainwater from the storage cupboard. Have you thought of extending the gutter on the left hand side at a right angle until it's above the garden and putting the downpipe there instead of its current position? That way it would be out of the way! Just a thought.)

[@jeffjsmith]

Thanks for the comments. You are right, the guttering in the video was a temporary arrangement. It now runs to the existing downpipes from the roof by being extended above the heat pump. We had to wait until the gas boiler had been removed to be able to do that part. All good fun!

[@FRZ5951]

Thanks for posting,... you refer to it as a split system, but it looks more like a standard arotherm plus with a hydraulic station?

[@jeffjsmith]

It is split, with the heat extraction being done by the outdoor unit, the refrigerant carrying the heat to the indoor unit, and the heat being exchanged there to the water - for the radiator circuit or the hot water cylinder. It is a more complex install, but it got round the issue we had with the R290 refrigerant since it uses R410a instead. Not so environmentally friendly, but it is unlikely to have a leak I hope.

[@FRZ5951]

@@jeffjsmith Thanks for the reply, ah yes when i looked again i see the difference.

[@normanboyes4983]

Thank you for taking the time to document your installation. A very good move to install the monitoring equipment. Are you running this system using weather compensation or fixed flow temperature?

[@jeffjsmith]

Thanks for the comment. Yes, we are running with pure weather compensation set on the heat pump.

[@WestYorkshireCyclist]

Jeff out of interest, what was the projected heat loss of your property? I'm in the process of a heat pump at the moment, 1900's end terrace with a heat loss predicted of 5.6

[@jeffjsmith]

The EPC says: “Estimated energy needed in this property is: 8,630 kWh per year for heating 2,479 kWh per year for hot water”. The total floor area is 61 square metres. Does that help?

[@speedbird300]

Isn’t that closer to window tham installation guide?

[@jeffjsmith]

The issue with proximity to windows was the problem using the standard mono block Arotherm Plus which uses R290 refrigerant - propane. This led us to use the AroTherm Split which uses R410A which doesn't have the installation constraints.

[@jchidley]

7kW does seems large for your property but you are getting good performance. Clearly cycling isn't a problem. It must be a well installed good design.

[@jeffjsmith]

Yes, it might be larger than absolutely required, but it does seem to run efficiently.

[@ram64man]

the radiators installed were they k3 or k2+?

[@jeffjsmith]

Hi - I think we have a mixture of K3 and K2 radiators. The installers did the design and then gave us some options depending in the width that we preferred in each location.

[@ram64man]

@ thank you, how have you found the cold snap at that location or haven’t you gone back recently, I know it’s a lot milder, but interested in the k3 performance compared to the old boiler since I’m used to 55c rads and if they truly can help on a cold room , on the pump

[@jeffjsmith]

@@ram64man I can't really say, except the house is wonderfully warm, much more than when we had the old gas boiler, even though the radiators are running at a much lower temperature. The constancy of the heating keeps the place cosier. We have no regrets!

[@ram64man]

@ thank you for the feedback

[@pmbpmb5416]

Bureaucracy ! A couple of decibels , you could understand in your case with neighbours so close if it were a little higher perhaps , but a couple , this is the contradiction, you are implored to do this and then big government gets in the way , although for some regs I believe they are changing .

[@jeffjsmith]

Yes, it did seem crazy that we are being encouraged on one side to help in reaching net zero, and on the other hand public health is inflexible. I do believe that this will be sorted out soon, I certainly hope so. The saving grace was that due to the delay we got a bigger boiler upgrade scheme grant!

[@bordersw1239]

Decibels are not linear.

[@pmbpmb5416]

Ok , so the point really is if it were that close why apply the rule so rigidly ? You surely get the point in the current environment using what borders on petty bureaucracy to put obstacles in the way of someone trying to do as requested , it’s pencil necks gone mad .

[@ciaranclose192]

This seems very strange that planning were such a big obstruction to you just fitting a monoblock unit... if i were you i would make a big deal of this considering we are trying to promote heat pumps.. terrible... you cant even hear a monoblock unit!

[@jeffjsmith]

We did make a reasonably push against the Planning people - but our life is too short and we actually ended up with a better solution I think. But the process does need sorting out.

[@markchristohperowen6806]

the problem came from installation guys at the start(years ago) installing them too close to neighbours windows in old small 1 bedroom quarry mens cottages etc. the units were LOUD. lines were drawn and DB levels need to be followed. its great having an environmentally friendly holiday/permanent home but not at neighbours expense. lovely couple glad they persisted and worked around it. btw personally i agree with you very doubtful in that instance it would have caused a problem, maybe it was too close to that bedroom window? people should be allowed to leave their windows open and have a good nights sleep during warm weather. fans and internals dont sound like they used to, octopus should go back to dakin and make their heatpump designers aware so they can bring their units inline.

[@johnj4860]

I struggled to hear you.

[@jeffjsmith]

Hi, sorry about that. You could try turning on subtitles - KZbin does a pretty good job generating them from the audio track. Best wishes, Jeff

[@matthart5215]

@UrbanPlumbers