Heat pumps - What’s your experience of the benefits and downsides to an ASHP?

That is part of the overall catapult project.

Ovo lead that part. Sunamp and Kaluza are part of it.

There is some information on the catapult website. 

But it does not mention SGS Energy who installed the low temp trial kit MisterW and I have

Oh goodness, this is all starting to sound scarily complicated 😧

Which is partly why we don't want to rush in. We have a lot to learn yet. Heat batteries? Yet another new term I've not come across before. I need a Dummies guide 😃

Ah, just looked it up, heat batteries, thermal batteries, they look like modern versions of electric storage heaters. 

I think this thread is digressing a little. The key point was the importance of having a good company to design and install your heat pump. Many of the bad experiences people have had with heat pumps are because their systems were badly specified or poorly installed.

@Gum168  I had an air source heat pump installed Feb/March on an earlier phase of the same trial. No heat batteries, we had radiators, a heat pump and a replacement to our old hot water cylinder and immersion. The heat pump works very well, we have the house at 21 deg and hot water at 44 or 49 deg C (it’s heated twice a day by the heat pump).

It’s a very different experience having radiators as our old heating was a gas powered warm air system. We used to only switch it on when we were in the house, and off at night. It went on and off with a thermostat, but we were either too hot or too cold ! Now we have the thermostat at 21 deg all day and night. The house is warm all the time. I tried turning down the thermostat at night but it took hours to reheat the house, and that’s not a good way to run the heat pump. It’s a low temperature system, the radiators heat to 42 deg C * (a gas system is 60 - 70 deg C), but they’re fairly big so work fine. Our biggest one is 8 foot long in our main room. The bedroom radiator is sized to heat that room to 18 deg C, at night we have the window open and the door closed so it’s very comfortable, meanwhile the rest of the house stays nice and warm. 

Our old system was very inefficient, but we didn’t know that ! Just kept paying the bills  .

You can see when the pump took over from the gas heating and how much the immersion used !

With the old warm air system it was difficult to identify draughts and cold spots in the insulation. Now we are very aware of them and have been addressing them throughout the year. I’ve come to the conclusion that the double glazing has to be improved, also the heating pipes that run in the loft. I’ve improved the insulation the installers used, but they still need a further layer. It’s cheap to do but time consuming.

This time next year, after those improvements have been done, I hope the energy input will  be much less, even if the actual bills will be more with the price rises.

(* though the radiators run at 42 deg C now, I hope to change this to vary with the outside temperature by setting up a weather dependant curve on the controller, which is more efficient I believe)

So I'm hearing that an ASHP system is run differently compared to a gas system. Are there smart controls? Are there TRV's, smart or not. And what about when the house is empty, say everyone is at work? 

I am struggling to understand how keeping the heating on day and night can be efficient? Even with heavy duty insulation that doesn't make sense to me. I can't sleep at 21°c, that's very warm for a bedroom surely?

We also have several rooms unused most of the time since our kids grew up and left home. However, now they have children of their own, and we all love a grandchildren sleepover , the spare bedrooms can be required at fairly short notice sometimes. It feels wasteful to have those rooms heated for 5% or so usage. One of those rooms doubles as my sewing room and I don't want to have to plan many hours ahead just to do a job that may take me less than half an hour.

It looks like living with these new systems involves a change in routine and mindset. Living in a small home with fully used rooms would seem easier, but it looks more tricky for a 4 bed house like ours, that once was overflowing with 7 occupants, but now has 2, sometimes 3 for a week or 2, and 6 plus every few weeks. And the house is empty when we work at least 2 days a week. How does a heat pump system cope with that without heating empty air unnecessarily?

Sorry for all the questions, but these are practicalities that I think will affect many homes. 

There are 2 trials underway with Ovo with Heat Pumps; 1) a High Temp trial, with a split heat pump and buffer tank and oversized traditional radiators and 2) a Low Temp trial using a single outside Mitsubishi heat pump, Sunamp heat batteries instead of the a buffer tank and Mitsubishi Climaventa radiators that fan warm air and have no TRVs. 

I think the inability to control the Climaventa radiators (beyond walking round and manually turning them down or off) is causing part of our issue. On our old gas system we have wifi TRVs that means we could heat just one room, on a schedule, set from smartphone. None of that is possible with a Climaventa radiator and as such our house is chilly on cold mornings like today (-2c right now)

@hambrook I’m not sure your details about the OVO heat pump trial are correct. 
From what I have observed the heat pump trial split is across

1 - ASHP with traditional heat emitters (radiators and/or underfloor heat where it was already fitted), these are a mix of manufacturers Mitsubishi and Daikin, and also a mix of low temperature and high temperature ASHP, as well as split across monobloc and split units. None have significant buffer tanks, most only have small tanks to deal with defrost cycles, none for energy storage. I have a low temp monobloc and standard radiators. Daikin we’re not a supplier when I signed up but I’m guessing lack of supply during the start of the trial meant they needed more partners. 
2 - A few sites have ASHP with Sunamp batteries like yours. 

They might be separate trials or just different solutions within the same trial. Sunamp were mentioned in my T&Cs but I’ve got no idea how they decided I wouldn’t get them and others would. 

OVO also have trials looks at battery storage and vehicle to grid battery storage. 
 

Howdy!

I just wanted to jump in for a second to say that I think this is one of the best discussions we’ve ever seen on the forums, certainly is for me! I really wish I could give you all a reward of some kind, but that’s not something I have within my own toolkit. However, I will say this. If you keep this up, a reward might come from somewhere else...