Are ASHP the way to go?

Swipe

I may be missing something but how can you possibly run a heat pump solely from solar panels in winter?

Rodders53

Swipe said:

I may be missing something but how can you possibly run a heat pump solely from solar panels in winter?

You can't.  Re-read the posts where it was stated

the electricity we export for nine months of the year will pay for what we need to import for two or three months over the winter.

matt_drummer

Swipe said:

I may be missing something but how can you possibly run a heat pump solely from solar panels in winter?

You are missing everything really, you need to think big picture and not daily.

I generate 10,000 Kwh a year, so much in nine months of the year that I export a lot.

As my whole system is quite new I have to make some estimates.

I will export at least 5,000 Kwh a year, that will generate me £750 at 15p per Kwh.

In the winter when the sun shines less I will need to import some electricity, I will do that on my Economy 7 tariff at 15.11p per Kwh.

If I need to buy 1,000 Kwh for three months of the year it will cost me £453.30.

The electricity I exported in the other nine months will pay for what I import plus the standing charge.

It means I will pay nothing for my energy and it will all have come from my solar panels.

Of course, I realise that I had to buy the panels, the batteries and the heat pump.

But they will cost me littles more than what my energy costs would be for the next seven years . I have a bank loan over seven years, once that is repaid it will all be mine and free.

If I repay the loan earlier then I will save some interest and my payback will be even sooner.

I am spending what I would have spent anyway and after seven years have all this stuff.

Mstty

@matt_drummer how much electricity have you exported 1st Sept til today. 

I think from memory you have large battery storage to store it for ASHP use this winter.

matt_drummer

Mstty said:

matt_drummer said:

Mstty said:

matt_drummer said:

Mstty said:

Octopus standard installation £3000 

Just for reference given their generally good customer service this might be a good option.

Yes, but that's actually £8,000 before the BUS grant and if you had to pay VAT that's £9,600

And that's from Octopus Energy who are probably not looking to make the profit that a small local company would.

They also probably buy the equipment for much less.

I also know for a fact, as they are coming to survey my house on Monday, that they are not interested in anything other than straightforward installations at this time.

So, I would still love to know where you can buy an air source heat pump and all that goes with it for £3,000?

@matt_drummer

What was the outcome of the survey and the cost? 

I have had my survey today.

It took around four hours.

The heat loss calculation gave the result I was expecting, just under 7Kw.

I only need one radiator replacing, it's forty years old an in our hallway, all of the rest are big enough.

It all sounds good so I will keep this updated with what happens next.

Fingers crossed the quote won't cost an arm and a leg

In theory it looks like a standard install plus the radiator upgrade.

I may have some extra cabling as the heat pump will be a fair way from my consumer unit.

But, they haven't agreed to do it yet.

I will be very happy if I get anywhere close to the standard installation cost.

Mstty

matt_drummer said:

Mstty said:

matt_drummer said:

Mstty said:

matt_drummer said:

Mstty said:

Octopus standard installation £3000 

Just for reference given their generally good customer service this might be a good option.

Yes, but that's actually £8,000 before the BUS grant and if you had to pay VAT that's £9,600

And that's from Octopus Energy who are probably not looking to make the profit that a small local company would.

They also probably buy the equipment for much less.

I also know for a fact, as they are coming to survey my house on Monday, that they are not interested in anything other than straightforward installations at this time.

So, I would still love to know where you can buy an air source heat pump and all that goes with it for £3,000?

@matt_drummer

What was the outcome of the survey and the cost? 

I have had my survey today.

It took around four hours.

The heat loss calculation gave the result I was expecting, just under 7Kw.

I only need one radiator replacing, it's forty years old an in our hallway, all of the rest are big enough.

It all sounds good so I will keep this updated with what happens next.

Fingers crossed the quote won't cost an arm and a leg

In theory it looks like a standard install plus the radiator upgrade.

I may have some extra cabling as the heat pump will be a fair way from my consumer unit.

But, they haven't agreed to do it yet.

I will be very happy if I get anywhere close to the standard installation cost.

It does sound rather promising, I hope they come back with a very competitive quote as we are considering them for a bunch of flats we own in the family, we also own the building so no permission required.

Out of interest do you or anyone else know who Octopus got into bed with to make their ASHP I wonder what's under the hood.

matt_drummer

Mstty said:

@matt_drummer how much electricity have you exported 1st Sept til today. 

I think from memory you have large battery storage to store it for ASHP use this winter.

I can't answer that.

We moved to this house in September 2021 and it had a 4 Kwp system installed in 2014.

I receive the FIT payments and we are on deemed export.

I have no way to know how much of what we generated that we used, I know we imported 1,650 Kwh in 2022.

I have added another 6 Kwp of panels in the last month and 38 Kwh of usable battery storage.

Our existing panels generated 4,100 Kwh in 2022

I have estimated our generation for the year based on the new panels and the evidence so far is that they are performing better than I expected.

I will never know whether it fully works until I have some more time with it.

I do know that our gas usage last year was 12,500 Kwh.

If my boiler is 90% efficient that equates to 11,250 Kwh of heat.

I would expect to use 3,750 Kwh of electricity to run the heat pump at a SCOP of 3.00. 

I hope we can do better than a SCOP of 3.00, the house is very well insulated and doesn't lose heat quickly, I hope we can run a low flow temperature.

I haven't done this for monetary reasons, it helps to make it possible, but it has just become a bit of a challenge to make it work.

I am sure it will and if anybody is interested I will update this as I go along.

Now the solar and batteries are done I will start recording the data  from 1 April onwards (at a basic level) and see how close I was to getting it right!

ElwoodBlues

It depends where you live and how much you're at home. If you live in the south of the UK and are home most of the time (keeping the house at a constant temperature) then ASHP and underfloor heating might make sense. But if you live in a colder part of the country and the house is regularly empty then it's probably not such a good idea.

Reed_Richards

matt_drummer said:

In theory it looks like a standard install plus the radiator upgrade.

I presume you would also need a DHW cylinder upgrade, but perhaps that is part of a "standard install".

matt_drummer

Reed_Richards said:

matt_drummer said:

In theory it looks like a standard install plus the radiator upgrade.

I presume you would also need a DHW cylinder upgrade, but perhaps that is part of a "standard install".

It is part of the standard install, a 200 litre hot water tank

The heat pump, controls and hot water tank can be purchased in packs.