Marvin

Hi @Jwenty This is a very difficult question to give a good reply to. I believe that there is no alternative but to go through all the major variables that affect the result in detail. In my humble opinion, if you are not prepared to do this, as this is a lot of information, you are stuck with general assumptions. For an example of details to consider, in order to reply people here would require clarity on some items already mentioned: Are you comparing the 9000kWh of gas with the output of the ASHP or the input? What is the expected COP of the proposed ASHP? You calculate down to -2C: Interesting that your in Bristol. As you know ASHP's work best running low and slow: The lowest temperature recorded in Bristol in the last 20 years I think was minus 7 or minus 8C although that is not an all day temperature. A big source of heat loss in winter is to do with refreshing the air in the building. Are you aiming for a MVHR or is it trickle vents, and an airbrick for the wood burner? The devil is in the detail. Oh, and yes we fitted an ASHP to our renovated bungalow that has AIM (Airtightness, insulation, MVHR) and now APE (Air Source Heat Pump, PV and EV.) to a high standard. Marvin

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.sgn.co.uk/sites/default/files/media-entities/documents/2019-11/SGN-Excavation-Guide-160216.pdf&ved=2ahUKEwiWifXm8Pn2AhXTTsAKHZA4BfQQFnoECAQQBg&usg=AOvVaw0scq1RZq_KBVOXFbxgRoAd

Best to go AIM where possible: Airtight, insulation and Mechanical ventilation if you can without loosing the heart of your build. Good luck. M

Hi @fletcher5555 Good luck with your project. Ask plenty, learn lots, save time/money. Marvin.

Don't get jealous of these rates they f**ked up, and if I leave it they will only send me a HUGH bill sometime in the future....

Clearer photo hopefully.

Just looked at last months bill! It says I'm on a fixed rate until 22 Dec 2023. Can anyone beat this:

@Barryscotland Like this. PV left. Mains right.

Sounds good, but don't forget a cowl of some sort to stop the rain from entering.. Check that the flat roof joists are not in the way, Watch out that service runs avoid the pipe area ( cable runs for instance) Good luck M

this sort of thing re positions of inlets and outlets

I think inlets also need to be furthest distance from the outlet, so, furthest from the internal door in the bedrooms.

+1 Couldn't that cause the LG to overheat? Or is it going into a buffer tank immersion?

Hi @Matt540 I have learnt yet another thing! Thanks @Temp and @JohnMo 👍👍👍. I will now use this info to check my system!

Damn, Some standing charge!😮

Hi @Matt540 The buffer tank is, designed to avoid short cycling. A cycle begins when the ASHP starts the heating the circulating water, and continues until the return water temperature meets the ASHP "hot enough" set temperature, and then turns off until the water temperature becomes lower than the "turn on" set temperature. The importance of this is that in tests its noted that an ASHP needs to get going before it reaches its best performance (COP) and then when turning off it does the same in reverse. Because of this the ASHP should aim to heat for at least 10min. The problem of Buffer or no Buffer is to do with the quantity of water in each individually controlled emitter zone. We have a buffer and radiators which have TRVs ( TVRs because we get north south solar gain problems). If we didn't have a buffer tank, and only one radiator was to work, the small amount of water in the system (ASHP to one radiator and back) would heat up quite quickly causing the ASHP to short cycle thus being inefficient. So to answer your question in my opinion the reason some use buffers and some don't is dependant on what the ASHP is connected to. It appears that radiators with no TVRs may work and large areas of UFH may work. However as @JohnMo says buffers usually have the option of an immersion to give additional heat in exceptional circumstances like if the ASHP breaks down (assuming like me you have a pump circulating the water from the buffer to the emitters) or a very cold spell. Hope this helps Marvin

And it starts. Notice the £160 standing charge per year! A mere 80% increase. For what? And what's your letter say?

Last time I saw silly prices was in about 2004. One terrace two up two down house which was completely derelict, with not even any plaster on the walls and the rear 2 story extension a good 4 inches away from the rest, sold at auction for the same price as the terrace 9 further along which had been completely done up and was for sale. I knew what that meant then, and I do now. M

5.12kW for us.

Slow cooker runs during day and then ready at 6pm. Even if main oven was less energy overall, too much at 6pm to be produced by PV.

Trickle energy. Yes. Just the 1 at lunch time then.....

Slow cookers are good. Trickle energy....

Low!

Car fully charged. Hot water 🔥 🔥 🔥 House warm. Washing done Dishwasher done Batteries charged. Makita all charged. Phones charged. Laptop charged. chargeable batteries charged Now 3.5kW going to grid....

True @bobberjob we're all waiting for better batteries at a lower price to make the off grid practical. (Yes there are some exceptions) Our 5.12kW PV produces all the power we need in a year, just not when we need it..... However for us we have APE (ASHP, PV and EV) and are driving around for about 3p a mile at the moment and cooling in the summer powered by the PV as well, so some benefits. M

Good point!