ReedRichards

The inverse square law gets you. Radiation, infrared or otherwise, radiates out from the source. If 500 W of heat hits you when you stand 1 metre away from the source you will get 125 W at 2 metres away, 55 W at 3 metres etc. This actually applies to a small source like a light bulb, a panel heater won't be quite as bad, but the fatal flaw with the type of product @Galvin1972 is plugging so hard is that you have to locate yourself close to the heater if you want it to heat you and not just other objects in the room.

But at the moment you can get a better rate for exporting your solar electricity and heating your water with the heat pump (with a CoP of 2 or more). And it's even cheaper if you can use a night-rate/EV tariff when heating your water with the ASHP.

Are you sure your cooling actually has an effect? On another thread, you suggested that because it was 30 C outside and 22 C (or so) inside that it did, but I achieve exactly the same with no cooling whatsoever. I presume this is because the thermal mass of my house keeps the inside temperature nearer the average outside temperature rather than following all the outside peaks and troughs. We also use window blinds to limit solar gain.

Would it be such a sacrifice to trade-in your existing car for an EV? I'm on the EON NextDrive tariff and it meshes very well with my other electrical items, ASHP, solar PV with battery.

Sorry to interject myself into this topic but I'm now wondering how programmable these A/C units are, when used in heating mode. Can you programme different temperatures at different times and on different days of the week, as you can with a central heating programmer?

I had been looking at what was on offer on the Appliances Direct website. The units there seem to be predominantly R32s, I had not realised that there were a few R290 units as well. Hence my question about F-Gas certification.

I'm wondering about getting one of these units myself but don't I strictly need an F-Gas certified installer to put it in?

Every autumn, field mice take up residence my loft to spend the winter; I have no idea how they manage to get in. I trap and remove them but it's a constant battle for a few months. They like to chew on the pipe insulation but have never touched the foil-covered type; I use Kingspan Kooltherm. The downside to this is that it takes a long time to install, making it a DIY job rather than something you could afford to pay a tradesperson to do.

When trying to heat my water with excess solar electricity I tripped the over-temperature cut-off on my immersion heater on many occasions. But I was always able to remove the cover, press the little rod-like button and it reset. Why was yours no resettable in the same way?

That's your suggestion, I think, not something the OP said. How about a volumiser if you don't like buffers?

Yes, it would work but the heat pump is more likely to cycle if it is only heating part of your house.

A section of my central heating was badly designed so that return water from zone 2 can flow backwards through a radiator in zone 1. I tried a double check valve but that made a lot of noise whenever water was being pumped through it. So I moved on to a single check flap valve which is silent except when it closes; closure causes water hammer in some pipes buried in a wall. I think the problem is that these pipes were not secured so move and bang against a beam. I tried fitting a hammer arrestor (a flomasta bell-shaped type) but it only worked for a week. What I seem to need is a flap valve with a slow-close mechanism. These appear to be used in North America for basement sump pumps but they are hard to come by here and anyway they don't look to be up to the standards required for central heating with pressurised water. I can't find anything that seems to be appropriate for use in domestic plumbing. Any suggestions?

They are typically no more noisy that the flue from a condensing boiler but they are subject to restrictions on noise, unlike boilers.

If the water coming out the shower had dropped to 30 C I'm sure your kid would have let you know! The only logical explanation I can think of is that the sensor is right at the bottom of the tank, for some unknown reason. That's pretty much was @jothis saying.

No, it's terrible, but I am struggling to think how an installer could get this wrong.

I don't think any specialised equipment is needed, just a lot of time and patience. If you can't get your house up to the desired temperature then whatever output temperature is being called for is set too low (for that particular outside temperature). Eventually you should be able to map out what output water temperature is needed for the range of outside temperatures you encounter. Then you set your weather compensation ("Water Law") parameters to match that.

Well it looks like it's Load Compensation as well as Weather Compensation if it boosts the output to get the house up to temperature. Heat pump manufacturers seem to delight in inventing their own terminology for processes that are well-establish and named for gas boilers. And no two heat pump manufacturers use the same terminology, as far as I can see.

I remember the days when you got 1000 W multiplied my time (In hours) for your kWh. At only 100 W no wonder the energy companies are raking it in!

I switched from oil to a heat pump and up-sized the radiators at the same time. Almost all oil boilers are just on/off so if you just oversize the rads but stick with an oil burner you will heat the house more rapidly and increase the frequency at which your oil burner cycles. That's neither good for efficiency nor good for the longevity of your oil burner.

For some heat pump manufacturers, their 12 kW model is just a software limited version of their 16 kW unit. In such instances there is no disadvantage in opting for the larger output one - except that they may charge you more for it!

Your piece of what?

My calculated heat loss was 8.94 kW and I have a 12 kW heat pump. I live in a timber-framed bungalow built in 1980. The most the my heat pump has ever used in a day that I recorded is just under 60 kWh. By @JohnMo's figures that would have cost me £15 for that day. However my average usage is about 16 kWh per day for both heating and hot water. Something that you need to understand about heat pumps is that it's the seasonal average that hits you in the pocket; you shouldn't get hung-up on worst case scenarios and costs.

You should always take the average temperature of the radiator, so measure the inlet and outlet water temperatures and take the average of the two. The temperature of the water entering the bathroom radiator should be the same as the water temperature entering every other radiator. Your weather compensation curve would give you an output water temperature of 39 C when it's 10 C outside and 30 C when it's 20 C outside. The temperature of the water entering the rad should be almost the same as that of the water leaving the heat pump so the implication is that it was about 12 C outside when your plumber made his measurement. Does that sound right? If the plumber had come when the outside temperature was below 0 C then he should have fond that the water entering the rad was at about 48 C.

Thanks. I have room for an outside unit so the comment about in and out vents for the all-in-one makes me think that the outside unit is preferable. They are cheaper too. And quieter (inside the room) do you think?

We have a workshop at the back of our detached garage that needs to be heated and I was wondering about these electricQ air-to-air heat pumps . E.g. https://www.aircondirect.co.uk/p/1681860/electriq-12000-btu-wall-mounted-heat-pump-air-conditioner-with-smart-app?gQT=1 or possibly one of the cheaper split units. It's a small space, about 5 m x 2m, but badly insulated because the walls are a single layer of brick, covered by plasterboard. We sometimes need to run a dehumidifier in there so the dehumidification action of the heat pump is a plus. But are these reliable, or is there a better manufacturer for something sub £1k?