Heat pump thread

My sister’s new ASHP install was costing her a tenner a day this last week.

Easily done! I turned ours on during the cold spell last week and it was closer to £13 for a days electric.

Don’t make such big changes, go for a couple of degrees and leave it for a few days, ideally in cold weather.

For those of you who’ve had an ASHP fitted, did they make much mess? Also how many fitters were on the job?

Sorry I haven’t read the whole thread.

We had 4 fitters (4 vans) on site for 4 days then 2 for 2 days. They had messed up during their survey day so basically replumbed the whole house. They expected 5 days max. Weren’t too messy although I had to take up carpets later to improve the way they had refitted the boards and I have to patch some walls where they channeled out to fit additional rads, that was expected so no complaints. Our house was almost all 8mm microbore so had to be ripped out, we expected the inconvenience so no problem. If you have larger bore piping it may not be necessary but you may need additional radiators after the heat loss calcs are done.

It all depends on who is fitting it. If I was doing it, there’d be little mess, and what there was would be cleaned up every day. I work on my own, so take longer fitting it, changing from a gas boiler to a ASHP would take me, typically, 5 days, with a few rads changed too. If its a full pipework change, easily 10 days work.
I’ve read reports of others doing it in 2 days.

Octopus are now offering in our area. It gave me a flat rate of £3000 after the grant, regardless of what extra work needs doing.

On the one hand this is great, but I am planning to change the rads myself and I’m fairly sure I won’t need anything else. I’d that’s the case I don’t want to pay the flat rate. I think I’ll contact some local installers. I want to get it to come in under the £7500.

Don’t make such big changes, go for a couple of degrees and leave it for a few days, ideally in cold weather.

Have you requested the weather to do the same ?  We can be +5 and -15 on consecutive days .

Is it really like having a storage heater again ,?

Just starting my third winter with an ASHP, still like it :-)

I’ve been planning to replace rads, I did the central areas of the house last year, now I want to do the living spaces. I’ve been working on making them slightly wider and double panel which will roughly double the area. This will make the current boiler much more effective and efficient. However the rule of thumb seems to be that for a heat pump you want 2.5x the area.

However, I think that the original rads were oversized when run at 80C, because the house was really warm. Even as they are I can run the boiler at 55C or even 50C when it’s mild and 60C when it’s cold. That’s a dT of around 40C. If I halved that, that would mean a flow temp of 40C in the coldest conditions we see would be enough to heat the house – therefore suitable for a heat pump. However there’s a couple of caveats to that calculation. The radiator isn’t the same temperature all the way across, so by doubling the area you’re not really doubling the heat output. However I’m more than doubling the area, but how much heat is output depends on the flow rate, so I’m not really sure how much extra heat I’ll be able to get.

The other thing to consider is that even at 55C in mild conditions the heating warms the house in say, 30 mins, and then stops for an hour or so. So in theory a heat pump could run at even lower temps for longer or even continuously, and still heat the house. And at the lower temps it could be very efficient and therefore cost less than gas (which is what I want).

I don’t want to replace these rads and then have to do it again for a heat pump install in the future. But the rads I am choosing now are the biggest I think I can fit in the spaces we have so.. dunno.

Coincidentally Octopus just called me back to follow up on the quote I requested. She said that they would come and do a survey to verify what you actually need, and if rads didn’t need changing that would knock the price down. She also said I could send photos of possible locations for it.

This is great service from Octopus, they have an actual knowledgable person contact you and provide follow-up through the process rather than a call centre drone. You don’t have to commit after the survey which is great.