Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
How is everyone’s system performing in this current cold snap?
Just curious to see if everyone is happy with their comfort and running costs, given that we are now well into ‘design conditions’ for the heat loss calcs.
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
180sqm detached house built in 2000 so insulation isn't bad but isn't great either, 8.5KW Ecodan, UHF downstairs retrofitted so little thermal mass, Rads upstairs.
Design Temp was std 50°C at -2°C.
Really managed to dial in the WC curve this winter currently set at 32°C flow at 3°C and above any lower flow temp leads to awful cycling even with everything run as a single zone.
Ecodan can't modulate down any further.
Bottom end of curve set at 45°C at -10C.
Currently, its -5°C and flow temp is running at 40°C house is steady at 21.5°C downstairs, 20°C upstairs
I don't setback overnight its just not worth it during the winter, so the heat pumps runs space heating continually apart from an hour for DHW overnight.
Yesterday being the coldest so far the heat pump used around 40kwh, the past week has been between 30-40kwh depending on OAT.
Running costs if I was on a std tariff then heating in Dec would have cost £150. Jan will probably be over £200 over the year I think it would be on a par with gas prices.
We are on the backstop rate and we’re running about £70-85/week in electric at the moment.
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
@hughf - yes and no. Yes if I put on extra layers of clothing, no if I don't. I'm old enough to remember getting dressed in bed as a child as we had minimal heating in those days, I just view the current inconvenience as one of those things.
Midea 14kW (for now...) ASHP heating both building and DHW
I'm lovely and warm (22 degC +/- 0.5) but the bills are going to hurt. On track for £210 this month. Still cheaper than a modern gas boiler overall, but the very coldest past few days are individually worse than gas. What I'd give for a Passivhaus!
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
My 5kW Samsung is running at full capacity. COP about 2.6
House-3 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
10kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
This past month has been cold. My weather station says the average temperature in the past 30 days is 1C. In that period I have been averaging electricity costs of £9/day to keep 180 square metre, timber frame exposed location house at 19/20C. I do set back for 6 hours at night to 15C and recovery is within an hour if not too sub zero and two hours if minus 3/4 C.
Flow temps rarely get above 36C and large K2/3 rads just warm to touch. All in all very satisfied with 14kW Ecodan.
Down to -6 last night. Yesterday running fixed flow@31 deg I used 29kwh for heating/dhw. Kitchen 22, othere areas 21/20. Running 9am-11pm. Very happy compared to up to 60kwh some days my first winter ,zoned with installer settings wc.242sqm ufh.
@cathoderay quite a lot of short cycling there, have you managed to put your finger on the cause?
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
