What sort of heating?

Reed_Richards

Martyn1981 said:
... the addition of two 3.5kW A/C units has reduced our annual gas consumption (heating, DHW and oven) from about 8MWh pa to about 5MWh [Edit - Should have said that leccy consumption has gone up about 1MWh as a result.]

So 1 MWh of electricity instead of 3 MWh of gas implies a CoP of 3? 

I too am highly impressed by the pioneering spirit of those using air conditioning units as highly efficient heaters but I wonder how effectively the heat is spread around the house, whether there are cold spots and/or if you have to leave all your internal doors open?  

Dunesquad

Thanks for all the advice.  We are planning to be there for the next 5-10 years and want to be green and moneysaving at the same time.  Just wanted to know if it is do-able with a small house.

Dunesquad

I don't think the solar panels will work at the moment.  There is not much roof space being mid-terrace.

Martyn1981

Reed_Richards said:

Martyn1981 said:
... the addition of two 3.5kW A/C units has reduced our annual gas consumption (heating, DHW and oven) from about 8MWh pa to about 5MWh [Edit - Should have said that leccy consumption has gone up about 1MWh as a result.]

So 1 MWh of electricity instead of 3 MWh of gas implies a CoP of 3? 

I too am highly impressed by the pioneering spirit of those using air conditioning units as highly efficient heaters but I wonder how effectively the heat is spread around the house, whether there are cold spots and/or if you have to leave all your internal doors open?  

Actually, I may be wrong. I'm trying to compare old leccy consumption to new, but have probably overestimated the heating part, as I've not allowed enough for the move to BEVs, which partly co-incides, as does being able to measure (not estimate) export, which in turn gives me a more accurate consumption figure. Lots of spinning plates to balance.

We were using almost 3,000kWh pa, but now it looks like being closer to 5,200kWh, let's say +2,300kWh. Looking at mileage, and also trying to allow for some charging away from the house, I'd say 1,700kWh at least, is from car charging. So perhaps 600kWh or less, is for the HP heating.

I appreciate this is incredibly messy.

If the gains look too much, then don't worry, as the HP's will have a bit more bias towards the warmer months, and also towards day use, when air temps will typically be higher than night temps. Also important to remember, that warming the two rooms in use (living room and front room (now my Wife's work from home office)) means you don't heat all the house as much, which you would do with GCH, even with TRV's. This works perfectly on those sunny mornings, when the house is nippy, but will warm with solar gain, by say noon, or early afternoon. The HP's warm the rooms you are using, whilst the sun slowly heats up the house.

Regarding doors, yes, they are used to conserve heat in a room, or help to spread it further, and in the case of the newer unit in 'the office', that door is left wide open if the unit is run overnight - temp set to 18C just to spread some E7/HP heat around the house to reduce the GCH morning burn.
If there is spare PV, then again doors left wide open and temp put up higher, perhaps 22C to spread more heat, but just to be clear, the room temp will be closer to 20C due to heat escaping.

Just throwing out stuff now, as I think about it, but another noticeable use is on cold sunny days, let's say Nov as an example. The GCH will warm the house with a morning burn, and with outside temps of (again, just an example) 12-15C, the house would normally cool down slowly, and need more GCH, but the HP's can 'fight' the nippy'ness, running on PV, until the late evening GCH burn.

So important though that I stress, that 2 x 3.5kW units, for a larger house, can help, and even handle all heating on days when the air is warmer, and less heating is needed, but the GCH does the heavy lifting on the coldest and darkest days. For a smaller property, and running 24/7 when necessary, then as CW has proven, more can be achieved.

Coastalwatch

Having reset the timings of programmes on the heat pumps to suit cooling periods in order to cope with  the recent hot weather, then for the entire month of June they've been on cooling cycles since. That is until yesterday when, to my surprise and with temperatues a tad on the chiily side, the unit in the lounge kicked in with some welcome warmth to maintain a comfortable temperature. Simple me, I'd quite forgotten that when resetting the timer I'd also reset the cycle from, heating only, for winter, to Auto in the summer so it could choose itselt whether heating or cooling was required.

I may well be wrong, but I don't believe GCH heating systems have yet been updated with this option!