Heat pump and Solar at home anyone?

[Wannabecamperman]

We have just had a new 5 kW heat pump and all new radiators installed at home...... lovin it, lovin it, lovin it!

Also a mahoosive 7.5 kW solar array on the roof ......... lovin that too!

Now we can keep warm for tuppence and sell all the excess leccy to the grid

Anyone else gone down the green energy route?

Ya! I have solar (Renogy fixed and flexi panels, self installed) and a lithium (LiFePO4) solar generator plus extra battery bank, plus a Tesla with an Ohme home 7 kWh charger on an Octopus Energy intelligent tariff.

This means I get the 11pm - 5am nightly cost of just 7.5p per kWh, (under 2ppm to run the Tesla Model Y!) plus I can charge the battery bank overnight in the winter months when we use more than the solar produces. I have a heat pump too - in the Tesla haha, and love being able to heat the interior and even seats and steering wheel before getting in! Amazing bits of kit.

The next step is to have one for the home to replace the current Ideal Combi 30 gas boiler, however we spend only around £75 per month on gas in winter, including the standing charge, so it's hard to justify the outlay. Pleased you're enjoying it.

 

[chockswahay]

So then..... Solar is an easy thing to understand and in the grand scheme of things probably the most 'bangs per buck'. In our case we opted for an array twice the 'standard' size to maximise output in the leaner winter months and provide an excess in the summer. We just had our export approved last weekend and since then have exported 88 kW (£13.20) and imported 28 kW £6.16) so even allowing for standing charge at 66p/day we are still £2.20 up

When the spring/summer comes we anticipate exporting up to 800 kW/month.

Now as for Heat pumps, yes this is a different ball game altogether ...... in our case we recently bought a bungalow with dodgy old oil boiler and radiators. We had all new plumbing and radiators fitted to suit the low flow temperature of 40c at outside temperature of -3c. Since commissioning, the heating circuit has been on 24/7 and the average radiator temperature has been around 26c (!) and the room temperature around 20c. OK it has been mild recently but we have had chilly nights. The property has been super comfy and we have plenty of hot water...... all for an average of 3.5 kW per day. Actually the heat pump has used 64 kW electricity over 18 days and output 326 kW of heat

At the moment we have held back on batteries because the cost/performance/return is not good enough. I will review the situation after 12 months but expect to have either very low or zero energy costs.

For anyone who is inclined towards nerd/geek level interest in heat pumps you can have a look at this website and see what people are achieving (including me)

HeatpumpMonitor.org

heatpumpmonitor.org

 

[chockswahay]

How old is your house?

We may be moving from a 2016 new build property to a 1940's house considering a solar, a battery storage. Not sold on the heat pump yet.

Late 70's detached bungalow

 

[Asprin]

Solar panels and battery fitted, best thung since sliced bread. End ofNovember through to early February is a bit dull but with the battery buy in chaep between hours 02:00 and 04:00 during these months. Otherwise self sufficient on electric with surplus going to grid.

 

[pjm-84]

At the moment we have held back on batteries because the cost/performance/return is not good enough. I will review the situation after 12 months but expect to have either very low or zero energy costs.

This is the benefit of batteries - solar that I would normally export now goes back into the batteries ..... Data extract is from Mid Sept 2022 to now.

Grid to Home is mostly the car charging

 

[chockswahay]

Now we are in the brighter/warmer months our solar is really paying it's way....... no electricity bills since March and last month (May) we exported £175 to the grid.

Also now we have a small EV to run around in, the night rate for the whole house and the car is 7p/kW. Last night we charged the car, ran the washing machine and tumble dryer, heated up the domestic hot water..... 15 kW all for £1.05......... by mid morning the solar panels had already exported enough to cover that and will probably do another 20 to 30 kW before the day is out (and this is not the sunniest of days today)

It's a Win/Win

 

[Keith Smith]

We’ve finally got our heat pump installed. When planning started to get funny, (we are listed grade 2) wanting it a different colour and located in a completely unreasonable place, we were advised to get an architect to apply for us. He charged about £1,100 but they passed our application with no conditions and no hassle so well worth it. Getting the right installer is crucial, most of the people who quoted us knew nothing about heat pumps and they are doing installs which will never work efficiently.
We’ve just had a local firm call round to give us a quote for solar and batteries, going to get the architect onboard right at the start this time.

 

[Californication69]

Now we are in the brighter/warmer months our solar is really paying it's way....... no electricity bills since March and last month (May) we exported £175 to the grid.

Also now we have a small EV to run around in, the night rate for the whole house and the car is 7p/kW. Last night we charged the car, ran the washing machine and tumble dryer, heated up the domestic hot water..... 15 kW all for £1.05......... by mid morning the solar panels had already exported enough to cover that and will probably do another 20 to 30 kW before the day is out (and this is not the sunniest of days today)

It's a Win/Win

I’m seriously considering Aiko panels, around 18x514w and PW3, with myzappi 7kWh charger for future proofing.
It’ll only take 3 hours to charge Cali Ocean.
But at 7p, that’ll be 21 pence for 60 miles !
Just need to save £13k now.

 

[chockswahay]

I’m seriously considering Aiko panels, around 18x514w and PW3, with myzappi 7kWh charger for future proofing.
It’ll only take 3 hours to charge Cali Ocean.
But at 7p, that’ll be 21 pence for 60 miles !
Just need to save £13k now.

I tell you, it really feels like Octopus Energy PAY ME to drive our electic Mini Cooper! I can top it up overnight with (say) 10kw for 70p then next morning sell back the same 10 kW for £1.50 So I get paid 80p to drive the car.......... Get In!

 

[Christine Kirk]

We have just had a new 5 kW heat pump and all new radiators installed at home...... lovin it, lovin it, lovin it!

Also a mahoosive 7.5 kW solar array on the roof ......... lovin that too!

Now we can keep warm for tuppence and sell all the excess leccy to the grid

Anyone else gone down the green energy route?

Yep nearly 15 years ago , and it’s paid for itself twice over , plus we are still getting paid for electricity we supposedly export to the grid: RHI scheme which was an encouragement to install solar panels at the time. UFH also installed which was done to enable the house to be heated using a heat pump when the oil boiler needs replacement! One of our rental houses has been heated using an air pump for years and it does work well, plus is that there was a similar incentive scheme for its installation which is still paying!

 

[pjm-84]

I tell you, it really feels like Octopus Energy PAY ME to drive our electic Mini Cooper! I can top it up overnight with (say) 10kw for 70p then next morning sell back the same 10 kW for £1.50 So I get paid 80p to drive the car.......... Get In!

Octopus now want us to export directly back to them but originally it wasn't an option with an EV tariff so we left it at the deemed 50% of generation.

We're on GO so what would be the best tariff to adopt for the export?

 

[Mansfieldman750]

Now we are in the brighter/warmer months our solar is really paying it's way....... no electricity bills since March and last month (May) we exported £175 to the grid.

We have a 4kW solar array since 2011 so we are on a very high FIT - 74.37p/kWh, which is nice.
We generated 1372 kWh from 3 June - 1 September.
But only 320 kWh from 2 Dec 2024 - 1 March 2025.
We run up a big gas bill every winter for heating the house and hot water, can’t avoid it, if it’s raining the solars aren’t generating.
So I have 2 questions regards the heat pump :
Is the bungalow warm enough in winter ?
And if you don’t mind me asking, what was your electricity bill for the winter months, say 1 November to 28 February ?

 

[Wannabecamperman]

I tell you, it really feels like Octopus Energy PAY ME to drive our electic Mini Cooper! I can top it up overnight with (say) 10kw for 70p then next morning sell back the same 10 kW for £1.50 So I get paid 80p to drive the car.......... Get In!

Yes, I'm also on their Intelligent Octopus for the Tesla overnight charging and it's fab to get a full 250-300 mile range for a few quid. So much so, that I've now swapped my wife's car to an EV also, though the Tesla group 50 insurance meant that she didn't get a Tesla

 

[chockswahay]

Octopus now want us to export directly back to them but originally it wasn't an option with an EV tariff so we left it at the deemed 50% of generation.

We're on GO so what would be the best tariff to adopt for the export?

Just starndard export (currently 15p/kW)

 

[chockswahay]

We have a 4kW solar array since 2011 so we are on a very high FIT - 74.37p/kWh, which is nice.
We generated 1372 kWh from 3 June - 1 September.
But only 320 kWh from 2 Dec 2024 - 1 March 2025.
We run up a big gas bill every winter for heating the house and hot water, can’t avoid it, if it’s raining the solars aren’t generating.
So I have 2 questions regards the heat pump :
Is the bungalow warm enough in winter ?
And if you don’t mind me asking, what was your electricity bill for the winter months, say 1 November to 28 February ?

I can only get the figure for Nov, Dec and Jan at the moment but this was £229. The property was always warm 24 hours a day (heat never off). That is all heat, water and electricity during that time. This figure does not take into account the export during that time which was over £100.

I’m happy with the sums

 

[larrylamb]

I’m seriously considering Aiko panels, around 18x514w

Just had Aiko 7 x 645w panels fitted last month, 4.5kw . Pleased so far and a good price, £3500.

 

[Mansfieldman750]

I can only get the figure for Nov, Dec and Jan at the moment but this was £229. The property was always warm 24 hours a day (heat never off). That is all heat, water and electricity during that time. This figure does not take into account the export during that time which was over £100.

I’m happy with the sums

That’s fantastic. For the same period we were £266.78 for gas and £121.27 for electric.
Mind you we did get £238.03 back in FIT for Dec - Feb.

Anyone who installed solars in 2011 or 2012 is on a crazy high Feed in Tariff, linked to rpi for 25 years.

 

[Wannabecamperman]

That’s fantastic. For the same period we were £266.78 for gas and £121.27 for electric.
Mind you we did get £238.03 back in FIT for Dec - Feb.

Anyone who installed solars in 2011 or 2012 is on a crazy high Feed in Tariff, linked to rpi for 25 years.

True, but they paid and arm and leg back then also.

 

[pjm-84]

Cost me £7816 in 2012. I looked at solar in 2006 and it was £25k.

Pay back was 3.5years. Bar 32kWh, generation stands at 50MWh. If you average that between the tariffs over that period at 62p then its circa £31k FITs payment + £1k for 50% export. Plus also free use over that period.

I added storage batteries in 2022 as 90% of the generation was being exported

 

[Mansfieldman750]

This is the benefit of batteries - solar that I would normally export now goes back into the batteries ..... Data extract is from Mid Sept 2022 to now.

Grid to Home is mostly the car charging

View attachment 130075

I don’t understand that. Does it say your solar panels are only generating 2,300kWh per year ?
We are circa 3,500kWh. We are only 10 degrees off due south but that is a huge difference.

Should it read September 2023 not 2022 ?

 

[dspuk]

Just moved into (another) new build and they came with panels, as is the way now. 11 x 450W panels, the sort that are still a large panel but instead of tiles. Brand of everything is Growatt and while it "seems" to work fine the stock monitoring you get is worse than rubbish - basically a box in a cupboard that has a flashing red light. I was told if it was flashing fast, working well, flashing slow, not much sun. Useless.

Ended up buying an installer USB and putting in the loft with the inverter and that connects via RF signal to a lan box and after managing to hack the installer code on I could get the app working so I can now see the actual live yield, but not the use on the domestic side. Still awaiting the British Gas monitor and the DNO certificate so we can sell back.

Effectively all our day electricity will be free, unless running every appliance, and night we have to get from grid. Best day in the last month was 21KWh for the day and the worst 7.5. British weather.

Did look into a battery to be fully "off grid" but at 9K for the Tesla Powerwall 3, installed, I estimated about a 10 year payback - not worth it for me apart from bragging rights. May still do it one day!

So far though bills are promising and as soon as we can sell back to the grid should get even lower.

Having fitted the Cali solar in 22 has certainly helped me understand how it all works!

 

[pjm-84]

I don’t understand that. Does it say your solar panels are only generating 2,300kWh per year ?
We are circa 3,500kWh. We are only 10 degrees off due south but that is a huge difference.

Should it read September 2023 not 2022 ?

That's a 2 year period and generation is 6983kWh. Note these are read and recorded by the battery inverter and there is a degree of inaccuracy in the generation as can be seen by below.

 

[pjm-84]

Note 2025 will not read in total but will read monthly. Just a computer says bug

 

[Mansfieldman750]

Just moved into (another) new build and they came with panels, as is the way now. 11 x 450W panels, the sort that are still a large panel but instead of tiles. Brand of everything is Growatt and while it "seems" to work fine the stock monitoring you get is worse than rubbish - basically a box in a cupboard that has a flashing red light. I was told if it was flashing fast, working well, flashing slow, not much sun. Useless.

Ended up buying an installer USB and putting in the loft with the inverter and that connects via RF signal to a lan box and after managing to hack the installer code on I could get the app working so I can now see the actual live yield, but not the use on the domestic side. Still awaiting the British Gas monitor and the DNO certificate so we can sell back.

Effectively all our day electricity will be free, unless running every appliance, and night we have to get from grid. Best day in the last month was 21KWh for the day and the worst 7.5. British weather.

Did look into a battery to be fully "off grid" but at 9K for the Tesla Powerwall 3, installed, I estimated about a 10 year payback - not worth it for me apart from bragging rights. May still do it one day!

So far though bills are promising and as soon as we can sell back to the grid should get even lower.

Having fitted the Cali solar in 22 has certainly helped me understand how it all works!

Here is my faithful Bluetooth monitor which has been going strong since 2011. It’s dull in Mansfield right now.
The important figure is bottom right, which is the generation since 2011, and it’s all free to use ( but not more than is being generated at any given time )
I can hear the washing machine going onto spin right now, have to have a word with her. On second thoughts I’ll leave it.

 

[pjm-84]

Lol..... I have one of those. Its not intelligent to allow annual tariff change....... so you're plus 1120kWh over my Feb 2012 install.

Quick calculation for me equates to 3680kWh per year generation