We used to heat our 1930's, well insulated, underfloor heated (with upstairs rads) home with a gas boiler set at 55c flow temp.
Since we had an Mitsubishi Ecodan 8.5KW heast pump fitted in March 2021-June 2021, by an incompetent company - Hero Renewables, we struggle to get anywhere near a comfortable room temperature. Since the installation Hero Renewables had been on BBC's Rip Off Britain and have thankfully ceased trading.
Outside, a very chilly -6C inside a very chilly 12C! I know we are in a cold snap with the weather, but last year we struggled when it went below 0C.
The pump is continuously on and we are hitting record daily electricity usage everyday since last week
Are we expecting too much?
I am so glad we kept the dirty coal fire!!
I am starting to decide which rooms we can sacrifice for the greater good, which is quite difficult when it is a full house.
I am thinking that the heat pump was undersized for the property, and we can either get a larger heat pump, but, someone will have to do some hard selling for me to be convinced that a larger pump will solve all our problems with cold rooms and extortionate electricity costs, or, go back to a gas boiler
I am waiting to hear back from Mitsubishi to hear what they suggest
Do you have any heat loss calculations for your home? Do you have a buffer tank or low loss header in your system? Is your system operating in weather compensation mode? How much energy are you using? How does that compare with your previous gas consumption?
What was the design flow temperature for this retrofit? That’s the key. And yes, it will run continuously when it’s -6 outside. The system was probably designed for -2 or -3.
And yes, heating a house continuously at those temperatures costs money. Be that gas, oil, electricity or coal. At the moment, oil is probably the lowest cost per kWh delivered into the property.
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.
sorry to hear this - we are having similar issues unfortunately! Ours has only been in 2 weeks so trying to exercise my consumer right to reject as it’s within 30 days - really wish I didn’t bother switching from gas! Been nothing but a nightmare.
Since the installation Hero Renewables had been on BBC's Rip Off Britain and have thankfully ceased trading.
What did they say about them on the show? Did you experience the same problems as discussed on the programme?
With regards to your issues, there is certainly a way to go with fixing this as 12C is quite the deficit, but I've seen some good improvements on this forum so there's no harm in trying before making a decision on upgrading or going back to gas.
For starters in addition to Derek's questions, can you tell us a bit about the positioning of the unit outside? Is it in open space or surrounded on one or more sides? How far from the sides is it? How long is the pipe run from the pump to the house? What's the insulation on the pipework like?
Then on your install itself, did you keep 55C as the design flow? Did your installer recommend changing any rads to meet this and did you do so? Can you see statistics on your unit regarding heat delivered and information from sensors? I would be interested in hearing the difference in temperature between incoming and outgoing water and the flow rate of the water at a time when you think it's going flat out to see if it's working to full capacity.
A flow temp of 55C makes for an expensive system to run, but if your installer matched that up with the power of your rads at 55C from a heat pump then that's not a blocker on the output power of the heat pump, just the electricity used.
Finally, have you implemented any basic easy wins on insulation? Eg draught proofing, adding a bit of loft insulation, secondary glazing where you only have single glazing?
@editor Here goes Mars. I've put the screens in sequence into a pdf. Hopefully it views okay. You do need to be able to access your FTC Service menu (between screen 1 and 2) - the default password should be 0000 (unless the installer changed it).
@editor Here goes Mars. I've put the screens in sequence into a pdf. Hopefully it views okay. You do need to be able to access your FTC Service menu (between screen 1 and 2) - the default password should be 0000 (unless the installer changed it).
