SteamyTea

Not really. A larger store will mean greater overall losses and 4 kWp is pretty small. To heat 500lt of water by 30°C will take about 17 kWh of electricity, add in some losses, about 25 kWh. On E7 that will be about £2.50 a day, on gas about £1. You could put in a dedicated ASHP and reduce electricity costs down to about the same as gas (and have a much lower carbon footprint), some of that power can be supplied by the PV though. Water saving showers and a timer may be better.

In some ways it focusses the mind and what to spend money on. Many spend more on a kitchen and bathroom than insulation and airtightness, which means they spend more on a heating system. Ideal time to reappraise the building materials choices from the ground up.

London tends to be 1 to 1.5°C higher temperature than the surrounding counties (though it does depend where in London as it is a very large place). So ASHP a good idea, and they can cool. Also the air quality is pretty poor. So MVHR should be fitted (put the inlet pipe up as high as possible). So there may be, depending on the space available and the cash to spend, a case for forced air heating as that can combine the two. It is only larger pipework really.

Ideally you want an ASHP oversized as this reduces the airspeed though the external heat exchanger. This keeps noise levels lower and improves the CoP (lot of air, cooled a little, rather than a small amount of air, cooled a lot). Modulation is really to do with matching the airflow with the thermal extraction to the temperature (and RH) differences needed. Modulation ASHPs also tend to draw a lower current when starting, which stops the lights dimming.

You may also find that the oil burner was heating the house up from a lower temperature, this could also give the impression that it is 'heating quicker'. But comparing a 30 kW and a 12 kW heater will probably make the biggest difference. After efficiency losses, the ASHP is about half the output.

If you are happy with the finish on the surface, crack on.

https://forum.buildhub.org.uk/topic/14636-ecodan-cooling/ Running backwards is not really the right term to use. This caused a lot of confusion with heat pumps.

When the pump modulated the pressure in different areas of the circuit varies. PV/T stays as a constant though.

You can go to https://ec.europa.eu/jrc/en/pvgis And get a fairly good estimate of output. Think there is weather info there, but the Met Office now has lots you can download for free (after I paid hundreds to get some).

That should be nice battery, but a battery of mice is formidable. https://www.bbc.co.uk/sounds/play/m000q3pn

Both. 100⁰C water is the universal solvent.

Anything with a Peugeot XUD engine would still be going. Landrovers should be classed as EVs, the body panels and the rivets make a mice battery.

You could try a wallpaper steamer.

Not sure what you mean, PV?

Only mechanically. I like the look of them, though they are cramped inside, but then so was the Discovery. A farming mate of mine had one, I was always having to go around to fix it, then he got a Disco, that was just as bad. He ended up with a couple of Troopers, had little trouble from them.

Good stuff.

No idea what your weather is like at the moment, but here (West Cornwall) it is is 9°C and 99% humidity. Good test for MVHR (wish I had it, got window open as I am cooking).

Welcome. First things first, a rough drawing, with dimensions of your house would be useful. If it is similar to my old Victorian terrace, the thermal loses where dreadful. Knowing what I now know, I could have put it right when I gutted the place, hard to do after the event. Really comes down to how much you want to spend, and how much work you do yourself.

Won't the MVHR keep the condensation risk very low?

It will be a combination of the power that the ASHP puts out, the CoP it is trying to run at (if this is a settable parameter), the power the radiators can deliver at and the temperature differences between the indoor air temperature and the radiators, and the overall heat losses of the building. It may also be a mismatch between the ASHP, buffer and radiators. And that is before variable weather is taken into account, this can affect the CoP and the building losses. A cold but sunny, still day will be very different from a blustery, rainy day. Usually combustion boilers have a greater power output as a ratio of mean power needed, this can mean they may heat up a building faster, but they do it at the cost of efficiency.

Do it properly with GRP. Then forget about it for 40 years.

Anyone want to buy a time-share apartment, off plans, in Spain. This sort of thing is not new.

Airtightness and insulation, then you can probably swap the GSHP to a much cheaper ASHP. And look at your DHW usage, water does not need to be stored above 60°C all the the time and a shower does not need to use 150 litres of water

Hard to tell, but usually it is a filled polyester resin used to cast these. So a polyester car body filler would work fine. Then CT1 @pocster's favourite, o the fittings.

GRP it.