Air Source Heat Pump?

[Exdro]

That (bolded part) doesn't sound very efficient. Heat pumps work best at lower temperatures. I had one fitted last year and the bedroom radiators upstairs are only pleasantly warm to the touch - certainly in moderately mild weather like we currently have. (Downstairs we have full UFH.)

Do you run your heat pump with weather compensation mode, i.e. the water temperature rises as the outdoor temperature drops? A lot of installers (mine included) leave the ASHP cranked right up to 50C or even 55C flow temperature so that people don't complain their rads aren't getting hot, but that's not the best way to run them.

That’s interesting info.Temp is set at 55 for rads and 45 for water. Immersion runs at Midday on Saturdays to raise HW to 60 while we are in cheap rate and the chance of solar is higher. Would be interested to hear what us best. Tx.

 

[Bob77]

That’s interesting info.Temp is set at 55 for rads and 45 for water. Immersion runs at Midday on Saturdays to raise HW to 60 while we are in cheap rate and the chance of solar is higher. Would be interested to hear what us best. Tx.

Well it depends on your heating set-up, I suppose. If it was swapped in for a gas boiler without changing the radiators then you might need to run at a higher flow temperature to get the heat you need. Best practice is to use larger rads and run them at a lower temperature, as heat pump efficiency drops off quite substantially at higher flow temps.

I have my hot water tank at 48C (60C once a week for Legionnaires), heating up overnight on cheap rate. Flow temperature for the central heating is currently 37C with a 10C outdoor temp. The colder it is outside, the higher the flow temp. From memory I think I have it maxing out at 50C when it hits about minus 5 outside.

Of course this is not practical in all cases. I was fortunate (if that's the word) in that I was basically gutting my house and could therefore put UFH in downstairs, and the rads were brand new and sized for the heat pump because they were replacing electric storage heaters.

I have had my ASHP (Daikin) for a year now, and am still experimenting. Last winter we still had building work going on, so the house had big holes in it - and the indoor unit had a faulty flow sensor so it wasn't working properly for the first couple of months.

What am I pondering is whether, if I get an EV and go for the Octopus EV tariff, I can effectively use the ground floor slab as a big storage heater by cranking the heat pump up overnight on cheap power. I still have Economy 7 (a hangover from the storage heater days) so I try to use as much of that as I can, but the Go tariff cheap rate ends much earlier in the morning, 5.30 IIRC.

 

[Exdro]

Well it depends on your heating set-up, I suppose. If it was swapped in for a gas boiler without changing the radiators then you might need to run at a higher flow temperature to get the heat you need. Best practice is to use larger rads and run them at a lower temperature, as heat pump efficiency drops off quite substantially at higher flow temps.

I have my hot water tank at 48C (60C once a week for Legionnaires), heating up overnight on cheap rate. Flow temperature for the central heating is currently 37C with a 10C outdoor temp. The colder it is outside, the higher the flow temp. From memory I think I have it maxing out at 50C when it hits about minus 5 outside.

Of course this is not practical in all cases. I was fortunate (if that's the word) in that I was basically gutting my house and could therefore put UFH in downstairs, and the rads were brand new and sized for the heat pump because they were replacing electric storage heaters.

I have had my ASHP (Daikin) for a year now, and am still experimenting. Last winter we still had building work going on, so the house had big holes in it - and the indoor unit had a faulty flow sensor so it wasn't working properly for the first couple of months.

What am I pondering is whether, if I get an EV and go for the Octopus EV tariff, I can effectively use the ground floor slab as a big storage heater by cranking the heat pump up overnight on cheap power. I still have Economy 7 (a hangover from the storage heater days) so I try to use as much of that as I can, but the Go tariff cheap rate ends much earlier in the morning, 5.30 IIRC.

We have an EV, Solar panels with 5KWh battery. All rads were updated and electric UFH (not from ASHP) in kitchen. EDF has cheaper rate from 2100 til 0700 each week night and from 2100 Friday through til 0700 Mondays. Not as cheap as Octopus but for a much longer period.