ReedRichards

I looked up previously that the phase change temperature of the usual material in a Sunamp box is 58 C. So to get it to change phase in a reasonable amount of time you need water hotter than that, maybe I think some of the very latest heat pumps can manage 65 degrees, mine won't without the help of an immersion heater and that's inside my hot water cylinder so wouldn't work for this application.. The thing to look at in the spec. is what COP you should aspire to for a 65 C output (and some averaged outside temperature).

I've always been a bit puzzled by those air vents. If they are "automatic", why do you need intervene manually and loosen the screw?

But isn't @oranjeboom wanting a heat pump to work with a Sunamp they already own? If so, it's unlikely to be a "special".

Isn't the phase change temperature of a standard Sunamp a bit too high for an ASHP? It certainly used to be; perhaps a newer ASHP capable of a higher temperature output would be okay?

I am suspicious of ECO4 installations because you tend to just get what you are given. In your case you have been given a sophisticated Daiken controller and a very unsophisticated Honeywell room thermostat. It's likely that your very basic room thermostat overrides your sophisticated Daiken controller, the heat pump is on when the room is below the set temperature and off when the room is at or above the set temperature.

Over the last 4 years the price of heating oil has varied between about 25p per litre and about 100p per litre. It would be much better to tell us how many litres of heating oil you used to use each year because the actual price you paid could have varied wildly depending on when you bought.

I don't think this is true. I replaced an oil boiler with a heat pump in December 2020 and at that time the running costs were quite close, assuming my heat pump gave me 3 kWh of heat for every 1 kWh of electricity, as an average over the year . Since then the price of electricity has increased by about 100% and the price of heating oil by 50%. So unless your old oil boiler was particularly old and inefficient or unless your ASHP achieves a particularly high efficiency I think an oil boiler would be cheaper to run at the moment. But all that extra insulation should make your home cheaper to heat whatever you use. And if you could have measured your daily oil usage you would have found you used a lot of oil in cold weather, just as you are using a lot of electricity now. My heat pump has a weather dependent set point. In my particular case that would make the set point 39 C when the outside temperature is 3 C. When it gets colder outside the set point get progressively higher. This keeps me nice and warm inside, about 20 C as a 24 hour average. But it will cost me more than if I had left the set point at 39 C and shivered through the recent cold spell.

Surely with weather compensation you absolutely need all your radiators balanced, @HughF? Otherwise some rooms are permanently too hot and others permanently too cold? If your radiators have TRVs you're not supposed to use them with weather compensation, certainly not the "hard core" weather compensation that the likes of Heat Geeks would advocate. Or do you leave all the doors open and have fans to distribute the air around your dwelling?

Not necessarily. A lot of heat pump systems have a buffer tank to make sure there is always a sufficient volume of water. In a 4-port buffer it's possible that there is some mixing between the water entering your heating system and the water returning from the radiators. If that happens then the water that enters your heating system isn't as hot as the water that leaves your heat pump. But I would not expect the difference to be as great as 7 degrees. Is the flow temperature measured as 40 degrees or is that what it is supposed to be?

When my flow and return pipes were first installed above the kitchen they were quite noisy, almost a resonance. But after they were insulated that noise ceased.

Maybe it's time to revive my idea of converting a room into a giant microwave oven and then just cooking yourself very gently; it's the perfect solution to warming the person and not anything else. Pot plants in the room might suffer, however.

All radiative heating follows an inverse square law if the heat source is small, meaning if you move twice as far away from the heat source you will get one quarter of the heat you were getting. Spreading the heat source over a wide area like a wall should significantly reduce this, although the adjoining bits of wall and floor might get quite hot. And presumably quite a bit of heat will go to the other side of the wall. As others say, direct electrical heating is expensive to run.

I find it very hard to believe that any piece of AI situated in my house can get better information on the weather than I can. Yesterday as I was going out my phone was telling me that there would be rain in 10 minutes. We went for a short walk, had a coffee, went for another walk and watched the sunset and it started to rain as we were driving home at least 2 hours later; and the rain was actually a short shower. I think the smartest thing a Homely (or similar) could do in my house would be to see how often the house got a bit too cold or a bit too hot because it got the weather predictions wrong and decide to give up trying.

I think Heat Geek have a lot to answer for in raising aspirations that can be very difficult to achieve. But if you are trying to anticipate the weather (and solar gain) tomorrow or the day after then surely you can do that manually once a day. My heat pump lets you shift the weather compensation curve up and down by 1 degree increments up to 5 degrees either way and I think this is quite a common heat pump feature. Surely that is as good as any automated system could achieve, particularly where I live where the weather forecasts are unreliable.

I'm afraid I have no idea how you would do this but if your heat pump already offers you a linear weather compensation curve then you will never be that far wrong. So I wonder if the cost of "improving" the weather compensation would justify the benefit?

I read elsewhere that octopus will not quote for a LWT lower than 50 C. This could adversely affect your running costs if your house can do better.

Presumably you can check the new wire and add extra insulation if necessary?

So why are we all talking about a 5 Kw heat pump (say) instead of a 1 to 5 kW heat pump and quoting the minimum output power as well as a maximum?

You can bet if it performs badly that will be well-publicised. Promoting heat pumps as drop-in replacements for fossil fuel boilers seems like shooting yourself in the foot.

My understanding is that Heat Geek is a training/accreditation company. An installer pays them a sum of money, undertakes a training course, or several, and then gets to call themselves a Heat Geek. I presume those trained installers undertake to work to certain standards but I don't know if they suffer penalties if they don't maintain these standards.

The point that is so frequently brushed aside is actually quoted in the article Heat pumps using propane may be more efficient and able to reach higher temperatures but they will always be more efficient if you can keep them operating at lower temperatures.

I presume you also only insure your car for Third Party, Fire & Theft, because you can afford to replace it. And no need to insure your house and contents. Insurance, after all, costs money. What I was referring to was a free warranty that came with something I would have bought anyway. Not an extended warranty, just the basic one. All I had to do was to avoid doing anything that would void it.

I have an LG heat pump. My installer tells me that not installing a buffer would void the warranty. Better check that Samsung don't impose the same condition. My 7 year warranty came in very handy after 3 years.

For the information of anyone following this thread, I found a website with a recent installation manual here: https://www.lg.com/uk/support/product-support/cs-HM121MR.U34/ . This includes installer settings for both Series 3 and Series 4 versions of the Therma V.

I found the manuals for my model of heat pump here: https://www.lg.com/uk/support/product-support/cs-HM121MR.U34/ . I don't think the actual manual is specific to the 12 kW version that I have.