SteamyTea

Then get a stick, beat into him that airtightness and properly fitted insulation are important. Then beat him again. And again. And again just in case. Tell him that if you don't get an airtightness number of below 0.5 ACH, then you will send him your electricity bill every month. Then beat him again.

Not that big, it is the 1m size that will limit the amount of insulation. Can you make it 1.5m?

Yes, this is why older houses tend to use a lot of energy. They leak air and the insulation levels are very low.

The actual physical size of the house is irrelevant, it is how much energy it uses and the peak power needed (that kWh and kW thing again). It is usual to oversize ASHPs as they produce a better CoP (the performance multiplier) that way. Think of it as a car, gently cruising along a deserted road the fuel economy is quite good, but accelerate up a hill and it drops significantly. In car terms it is know as the specific brake fuel consumption and often larger engine cars produce better fuel economy (it is to do with the cylinder area to power ratio).

Yes. That is down to decent insualtion. I added extra to mine as when I changed it I had to get a like for like replacement. Some people have gone down the Sunamp DHW storage system as the losses are very low, but they cost a lot more than a cylinder. If you are not totally committed in your house design yet, consider fitting the cylinder in a larger cupboard so that extra insulation can be added.

You got it.

No, I am on E7. So resistance heating. The grey columns shows my usage (two charts up), but if I had an ASHP, the heating time could easily be shifted by 10 hours.

Yes. That is the top of the tank temperature, the median temperature is lower, but I can take a shower with 35°C water quite happily.

I could do it, and have the qualifications to back it up. But it is not worth doing it. Not as if I could charge you £1500 consultancy fee. what you need to do is break down the system into each element, then see what is the most efficient and the least efficient, then aggregate the lot and compare prices. It is what spreadsheets were made for.

How hot do you think stored water needs to be? Here are my temperatures, and I don't run out.

You been left on your own again, weekends are so peaceful without you.

Just fit them, roof intergraded systems cost about the same as tiling a roof. Once fitted, you can play with the wiring later. Much harder to play with pipes later.

That is Nick's view. The way I see it is that if the ASHP is set up right, it is going to produce around 2.5 times the input energy, even for DHW (this is not true for a badly set up system). So say your PV is producing 500W for an hour, or even a 100W, you can multiply that by 2.5. So 1,200W or 250W. You can take that energy input away from any imports. So say your ASHP needs 1500W of energy, and your PV is delivering 500W, you are only importing 1000W. That is better than using all of it for the DHW, and paying full price to run the ASHP, even of the CoP goes up a little. Having said that, I do think that there may be benefits in having 2 ASHPs, one for space heating and another for DHW, but the installation costs are too high.

Have you ever logged your actual energy usage by the hour, then seen what you can shift to the times that PV will most likely be producing. Something like this:

That offer will vanish, relying on an energy supplier to off a cheap deal for years is not going to happen.

You would have to match the load to the generation. The trouble is the generation is constantly varying, your load, while it is on, is constant. So sometimes, your generation may be producing 2 kW, and your load is only 1 kW, the difference leaks out though the wires to the grid. If it is the other way around 1 kW generation and 2 kW load, then all the generation will go to the load, plus the extra 1 kW will be drawn from the grid. This is why people use diverters. They try and match the load to the grid. But if your load is greater than the maximum generation at any time, then it will draw from the gird. And in the summer, when your load is low, most of your generation will be exported.

Sounds about right. But remember that is energy, the kWh, not power, that will be a lot lower most of the time.

Something like this? You can get it all from PVGIS

Those cheap deals will be pulled from the marketplace. Heat your water from a heat pump, you know it makes sense. Here is a quick and dirty chart

I have always stuck with variable tariffs, has not been unknown for EDF to drop my unit price. Fix the heating. I am about to push the button on buying an A2AHP to replace my main storage heater. It has taken a price of 12p/kWh to do this, at 10p/kWh it was not worth spending £350.

Octopus has taken over Avro's customers. That is going to cost them.

Stop speculating and start calculating. https://photovoltaic-software.com/solar-tools/voltage-drop-calculator-dc-ac

kW is power kWh is energy

A diesel generator.

Yes, but then integrating the battery storage into your home wiring may be a challenge. Yes, it is what diverters do, but it is still a grey area about allowing a larger than a nominal 4 kWp system be limited by the inverter (you can search for the thread about it, it is on here somewhere). Alternatively ask your DNO if you can connect a larger system. I don't have PV, but with batteries, it is all about load time shifting. It is similar to using E7. Now my E7 price has just gone up to 12p/kWh, so if the amortised cost is lower than that, then it is worthwhile. But you need to take into account what else you could have done with that cash i.e. put it towards an electric car, you will loose all of your capital either way, except the EV may have some value in a decades time.