ReedRichards

Well a heat pump on for a long period of time on a hot day would be a big clue. I'm not saying this rule is sensible but it is a rule you have to follow if you want to install a heat pump as a permitted development. Or you could ignore it - but might have to face the consequences. "MCS Planning Standards or equivalent" is a whole other can of worms.

The justification I have seen is that in summer your neighbours will have their windows open and will not want to be disturbed by the sound of somebody else's heat pump being used for cooling. In winter their windows will be closed so noise is not so much of an issue. Anyway (from https://www.planningportal.co.uk/permission/common-projects/heat-pumps/planning-permission-air-source-heat-pump ) So if you install a heat pump without planning permission, use it for cooling and a neighbour objects to the noise then you could try a retrospective application for planning permission but in view of the objection this might get turned down.

I would guess £100 to £200.

For an ASHP, cooling is not allowed without explicit planning permission. If you don't do cooling then an ASHP may be a permitted development.

My buffer tank has its own immersion heater, although it was never connected. I cannot see if there is one in this instance.

I got a provisional quote for boreholes when I was considering my options in 2019. The cost for two boreholes was estimated to be £17,000. Here is a comparison I made. I was effectively installing a completely new heating system with all new pipework as well as radiators. You'll have to ignore the RHI subsidythat was available at that time. ASHP GSHP Installation Cost £16,653 £23,528 RHI (No inflation) £10,255 £23,170 Difference £6,398 £358 Boreholes £0 £17,000 Property value enhancement £0 ??? Difference £0 £17,000 Running cost over 10 years £10,460 £8,270 Total £16,858 £25,628

Given that your heat pump is off anyway, you could make absolutely sure it is off by cutting its power and see if that makes any difference. Are you sure that the cleaner does not come early?

You didn't mention the E7 part first timer around. Having Economy 7, or a similar Electric Vehicle charging tariff, can really skew the normal economics of operating a heat pump. You can have a gas boiler that does WC and nobody objects if your heating system also has zones. Weather Compensation doesn't have to be as "hard core" as the Heat Geeks and their ilk would like it to be. When you start to sacrifice comfort for the sake of a bit more cost saving, where do you draw the line? Why not go the whole hog, put on your outdoor clothes and turn off the heating?

Weather Compensation is never necessary but it ought to save you money, surely? And it's certainly a complication because you need to work out how to set your water temperature based on what the outside temperature is. Bit just because @JohnMo didn't manage to do that doesn't mean that you won't. Weather Compensation works fine for me.

Isn't a combination of radiators and UFH simply the wrong thing to do? You are almost certainly going to need a higher flow temperature for the radiators so you don't get any economic benefit from the UFH. If you like UFH then install it throughout and save on running costs.

Surely the worst case scenario is that you use a fan heater to heat up the room quickly whilst the heat pump is providing background heating? But then why is the room colder in the first place if you have asked the heating to maintain a constant temperature? To me the central issue is whether the heating for the rooms housing the older person is compatible with the heating you want for the rest of the house. I like it cooler at night so I set back my heating. If I wanted part of the house at a constant temperature 24/7 then I would have to make that a separate zone. Hard core ASHP enthusiasts abhor zones because they tend to make running the ASHP a bit more expensive. So you pay a bit more to keep an old person comfortable; is that so terrible?

Then it seems ridiculous to get picky about the noise made by a heat pump; get the LPA to worry about the noise made by the planes. Long long ago I lived in Ealing and my building very occasionally found itself on the flight path of the planes going into Heathrow. You could not hear anything else at all when a plane was passing overhead.

So "near Stansted Airport" but not under the flight path?

I think somewhere back here is a post that says that the current Therma V generation controller does not work with the previous generation heat pump. Better check how long this ex-display model was on display.

That lack of modulation is not very good. if you need 4 kW output at, say, -5 C outside then you need 2 kW output at 8 C (assuming 21 C room temperature) and less than 2 kW at any higher outside temperature.

The most convincing argument for a buffer tank is if your warranty requires you to have one. My warranty obliges me to have a buffer tank. As someone who had his entire heat pump replaced under warranty after 3 years of service, I would caution against doing something that might void the warranty.

"Water Law" seems to be what is generally called "Weather Compensation" in the UK. Weather Compensation is unaffected by room temperature. But there is also "Load Compensation" where the heat source will work harder the further away the actual room temperature is from the desired room temperature set on the room thermostat. Load Compensation works very well maintaining a constant room temperature but it could reduce your heat pump efficiency by making it work harder when the room temperature needs to be increased rapidly. On the other hand, getting a room up to temperature quickly will boost your comfort so its swings and roundabouts.

Or you could conclude that it is allowing Octopus to install heat pumps for very little money, possibly for free.

I think that is it, essentially. But if the calculations are done rigorously then if you spend, say, 90 minutes per day heating your hot water then that leaves 22.5 hours to heat your dwelling and that might just tip you over the edge into needing a bigger heat pump than if it took 45 minutes a day to heat your hot water, leaving 23.25 hours for space heating. Or it might make no difference whatsoever.

Well it says "current " so it ought to be the current room temperature wherever your sensor is. That will be inside the control panel unless you can find a remote sensor somewhere else. But if that is right then it should change - unless your system is so well-balanced that it always maintains the current temperature at 20 (seems unlikely but possible).

Let's compare this with my installation: Annual heating energy (EPC): 15900 kWh Annual hot water energy(EPC): 2987 kWh Heat pump capacity: 12 kW External design temperature: -3.7 C Design Flow temperature: 50 C DHW design temperature: 55 C (max) My annual usage is: 5100 kWh So your heat load is over 25% bigger than mine and your 10 month usage is around 6000 kwH compared to my 5100 kWh in a year; that really doesn't seem too terrible from the economic point of view. And I bet you have room for improvement. The difference is that my system keeps us warm and provides all the hot water we need whereas yours does not. But again I think you will find you have room for improvement.

I already had a wood burning stove when my heat pump was installed. I'm sure that made no difference to my RHI application. But I only use my wood burner for the occasional damp day when we feel like a fire or in the event of a prolonged power cut. Be that as it may, your neighbour appears to be spending way too much to run their heat pump

That's not possible. The water will be heated to whatever temperature is set and then that heating will stop. If that fails there is a safety cut-out that will stop the hot water tank getting dangerously hot. It would only cost a fortune if you have left a hot tap running so the hot water flows away as fast as you can heat it. Also, hot water heating is normally given priority over space heating so you would have no heat in the house if your hot water was being heated all the time! So your system may be set to heat the hot water as necessary 24/7 but it will only actually heat the hot water when the tank temperature drops a certain number of degrees below the set temperature. You might be able to change this number but I don't know Midea units so i can't tell you how. For what its worth, in the hour before I get up I heat my hot water cylinder to 55 C with cheap rate electricity. Then during the day the set temperature is dropped to 44 C just to make sure the water in the cylinder doesn't get too cold if we use a lot of it. And at night it's off completely so the heat pump does not come on unexpectedly and scare the owls.

That's also what I do, 18 C overnight then gradually ramped up to 20.5 C by mid afternoon. In the 6 hours that my set temperature is 18 C the actual temperature rarely gets that low so effectively my heat pump is off for 6 hours overnight. I very much doubt that this has a significant adverse impact on my efficiency - and if it does it would be worth it not to get overheated in bed when trying to sleep.

I think it's a "retirement home", not a retirement home. It's a one and a half storey dwelling, detached I presume. That bill seems high even for a heat pump running with a COP of 1. At the very least, read the meter a few times a day to find out what is eating all that electricity.