SteamyTea

Or red sticky tape. Why not Bluetooth enabled light switches. If you are within a few metres if the room, it will turn the light on. To save multiple lights being on, it can scan for the strongest signal and turn the weaker signal lights off. Useful for people that like technology.

Regarding radiator sizing. It is the same calculation as working out heat loss through a window, door, wall, roof or even a DHW cylinder. It is the product of the power flow, surface area and temperature differences. There is a slight modification for convection currents, but they can generally be ignored in low running temperature systems. As a general rule, as something gets hotter, compared to the surrounding temperature, it needs a disproportionate greater amount of power (energy divided by time) to maintain that temperature. I have never done the calculations on a low temperature systems, but it might be useful.

Depends how deep into quantum physics you want to go. And phase change.

kWh and kW But think you meant kWh on the second one.

I may not have linked to the latest versions. It does rather, like most thing, depend on the size and insulation levels. Have a look at the manufacturers blurb about heat loss, then double it.

That will be around 3700 m3 of water. Taking a worse case scenario of the water being at 4°C, and allowing for a 2°C drop in temperature i.e. taking out half the energy, That will be about 15.5 GJ. So about 4.3 MWh, so quite a lot, just a little lower than the total energy required by my house for a year (but I have a stupidly small house). How is this pond refilled?

Better off with the more expensive to run storage heaters downstairs. You really need to do a room by room heat loss calculation otherwise it is all guesswork.

If it is a condensing boiler it may well stop condensing.

I have been wondering if I should get a small A2AHP, fit the internal unit in the loft, then pipe to the rooms. I only need a couple of kW of heating. Then I thought I could incorporate some MVHR into it. Being an 80s house, large, square or rectangular, louvred air vents would not look out if place.

I think the problem with A2AHPs is they look a bit strange in the inside. Your house layout is also important, they basically go though a wall. It is the problem I am having in trying to decide between a wet system and an air system. A wet system will use a lot of wall area for the radiators. There is no reason you cannot have a combination of both. As @ProDave said, old houses leak heat. My old Victorian terrace lost the lot in the 2 minutes it took to walk up the stairs.

Sorry, thought you had already had the beads in.

If the cold, outside air, is getting past the beads in the cavity, this negates the point of insulation to a certain extent. Are you going to render on the outside to improve this?

Where is this air coming from, and is it bypassing any insulation?

Never used LoopCad. Others on here have. Maybe you should start a topic about it and get it turned I to a tutorial. Could be useful to many people. May need some help from the mods to keep it tidy. I use Excel to calculate most things. By somewhere on here is a link to Jeremy Harris's heat loss spreadsheet. Here it is

Not really sure what you are trying to find out here. Have you done a heat loss calculation on your place yet? Or are you trying to do it with this radiator sizing we site?

If it uses MicroPython, it may well work with the existing BME280 libraries. I see there is some networking code on github for it. Oh, and some BME280 code. Micro electronics is just fantastic compared to mechanical engineering.

Whenever I see a fan heater on offer i.e. around a tenner, I buy it. I have a couple that are pretty quiet. But I agree, it is the biggest drawback of them. I find turning the radio up helps. The noise does act as a reminder that it is on. Had one heater that turned the fan off when up to temperature. Really annoyed me when I went out to work and came back to a very warm house. Not so bad when I left it on at night as I am on E7.

You can compare the usage between types. My guess is the fan heater will be the cheaper one to run.

Find out why such a difference. It may be that you like a hotter house, or you have an underperforming house. The EPC assessor probably used default values for when the house was built i.e. no insulation, single glazed windows, high air infiltration. Solar Thermal, is not only a 1 trick pony, it also needs servicing. PV does not. The electricity from the PV can be used for many different things, including warming up the sauna (though a simple, small greenhouse would almost get as warm). So rather than try and integrate two wet systems to work with each other, and in reality, there is little difference between an ASPH and a GSHP, let PV power the ASHP during the day. Or charge the car, that will give you the best return (compared to an ICE powered one). All this RE business is really playing with averages and probabilities i.e. Most likely time of maximum generation is between 10AM and 2PM, the weekly mean generation will drop in the winter, and rise in the spring, peaking in the summer. Take advantage of that, don't think that a box of electronics will make it produce more than it can. But work on the house first and reduce those losses, then look at what you can buy the kit for. Subsidies and grants have skewed the market.

Bypasses the thermal fuse?

Dead easy. Raspberry Pi Zero W, with BME 280, power off the ethernet (POE), connect to your router, or another router, either wirelessly or via USB to ethernet adapter, up to you. Then log data to a NAS (maybe a simple USB memory stick on the router) and read from that with the PC. (edit: always check that what is in the description is the correct article, I have a few BMPs rather than BMEs because of shifty traders)

Why, is it running cables, even very small ones that is the problem? Here is an idea, using cheap parts, to start logging data. https://microcontrollerslab.com/micropython-bme280-esp32-esp8266-temperature-humidity-pressure/

Don't negotiate a position on something they have to do anyway. Just carry on as normal, do what you think is best/right, and ignore them.

What I would do. Just take several readings across the diameter of the fan and take the average airflow.

Think of a number, say the value of your property, double it, then add your birthday as a laugh. This will be a big number. Then say to your neighbour, they can buy your place for this much money, and read the number out.