Who’s Caved and Switched the Heating On Already?
@editor Not yet mine is still off. I have been monitoring the house (happy Wife requirement!) now the OAT (10C to 19C range at the moment) has started dropping but the house is still hanging in there at 22C. As mentioned, a pain in height of summer! 😀
5 Bedroom House in Cambridgeshire, double glazing, 300mm loft insulation and cavity wall insulation
Design temperature 21C @ OAT -2C = 10.2Kw heat loss, deltaT = 8 degrees
Bivalent system containing:
12Kw Samsung High Temperature Quiet (Gen 6) heat pump
26Kw Grant Blue Flame Oil Boiler
4.1Kw Solar Panel Array
34Kwh GivEnergy Stackable Battery System
Central heating still switched off and will be until October. The Octopus Cosy account has built up a good credit over the summer, but I have over a tonne of sycamore windfall from the spring storms in the wood stores. Perks of village life is free hardwood from services rendered to help clear it from where it fell. It has seasoned beautifully in a south facing setting with the warm and dry summer we've had. I'll be lighting the stove for a few hours in the evenings now for a month or so. The cat is very grateful 🙂
I have 3 women in the house, 2 little ones, so my heating came on and off about a month or so ago. The moment we had 10c on 2nd of August to be precise. We had no Summer this year, my solar generation has been better in March April and May than June July and August:(
Mine went on today. IAT has dropped two degrees over the past few days.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
In the last week, the external temperature in south Manchester has varied between just under 10C and 19C. We certainly have had the heating turned on 24 hours of the day and don’t consider it to be caving at all. The logic is simple to me. I like the temperature to be 20C. I don’t care which month of the year it is, I always want it to be at least 20C.
We installed our new toy in August, so I have been impatient to play with it. I have been slowly edging the weather compensation curve downwards to optimise performance. The heat pump has been doing a great job of keeping the downstairs internal temperature at, or very close to, 20C. Upstairs is settling at around 21C.
My wife and I frequently observe how comfortable it is with consistent temperatures throughout the house.
Grant Aerona 290 15.5kW, Grant Smart Controller, 2 x 200l cylinders, hot water plate heat exchanger, Single zone open loop system with TRVs for bedrooms & one sunny living room, Weather compensation with set back by room thermostat based load compensation
We've been running our Ecodan system, installed in June, using the Havenwise app from the start, and it had basically been doing hot water only heating until the last week or so, when we've started to notice occasional heat coming from the radiators at times, which is the first opportunity we've had to experience heat pump controlled heating around the house.
MELCloud still reports that the pump is spending over 75% of the day idle, but the time spent providing heating is now higher than that for hot water for the first time since it has been installed.
We're now playing around with the scheduling to get the settings right for the house, which has so far involved going from a target temperature of 20C, up to 21 and, as of yesterday evening, back down to 20 again when we collectively decided it was a bit 'toasty' in the early evening. The MELCloud thermostat is located halfway up the stairs, away from any radiators, so we're monitoring the individual room temperatures using cheap digital temperature displays purchased from Amazon to see whether we need to touch the fully open TRV's in any of the rooms at any point.
Sad as it sounds, it's quite exciting to actually feel the system doing its thing for the first time. It's surprising how little heat seems to be produced by any of the radiators, but they're obviously doing what's required when needed. It's noticeable too how little solar generation there's been on the generally cloudy days so we're actually started to use grid power towards the end of some days, confirming my instinct that increasing the battery storage from the current 10.5kWh capacity would definitely be a worthwhile investment at some point.
130m2 4 bed detached house in West Yorkshire
10kW Mitsubishi Ecodan R290 Heat Pump - Installed June 2025, currently running via Havenwise.
6.3kWp PV, 5kW Sunsynk Inverter, 3 x 5.3kWh Sunsynk Batteries
MyEnergi Zappi Charger for 1 EV (Ioniq5) and 1 PHEV (Outlander)
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