Electric combi boilers / solar panels / eco heating solutions

I’m sure you will check, but for your NE panels, generation will be very low. Check very carefully before going for those as they’re unlikely to be cost effective for a long time.

Was going to be about 10 year payback time for us which was the product warranty period, matching what @Howard says above, but our quote was about £12k last year for 6 panels (SSE facing) + 9.6kWh battery. Not worth it. If that spec got down to about £6-7k then I’d probably jump.

Just out of curiosity I googled 420W panel from CEF which has a local branch.

https://www.cef.co.uk/catalogue/products/5260431-420w-black-white-frame-gapless-solar-panel

Just over £100 but could be hopeless as I have no idea on premium brands.

I'm calculating around 8 years payback at the moment. It's tough because return to grid and energy tariffs are all over the place.

Costs are as follows:

1. ASHP (inc a couple of replacement rads, hot water tank, inverter, install etc) - £2,700
   
2. Solar (12 panels, 7.2kw battery, install etc) - £9,450
   
   

Estimated annual electricity usage - 14,000kWh
Estimated usable generation - 4,500kWh
Estimated annual electricity saving with Solar / battery - £1.3k (ish)
Estimated annual gas saving with ASHP - £?? probably a slight increase but that's more about ditching gas than saving money

I'll need to see how to manage the ASHP practically with the cheaper overnight energy rates, battery storage etc to see if it can save money vs gas.

Currently looking like the solar install will be by Christmas but ASHP won't be until May.

This is the current Solar Together price list for Herts - about £8.5k for what you want. 40% YoY price drop...

Seriously considering just loading up on panels on the house roof as well as garage (currently planned) as they're so cheap and I'd rather install all at once.

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I just fitted Homely to manage our ASHP. The installer app updated the other day and now has a button to “add inverter” - could be battery / solar integration

Interesting thanks. Maybe I’ll look into it again then if prices have dropped that much

From when I calculated it was about 4.5-5y payback on just solar, and 7-8 years with battery system.

We have a solar water diverter so using gas when gas rates are cheaper, and intend to heat the tank at night with cheap electricity if gas rates go higher than electric.

If you plan to move home in the next 7 years then solar + battery is unlikely to be worth it financially, as I don’t think solar panels are priced into property sale values.
Might make it more desirable for purchase though going forwards, as lower bills and lower energy performance ratings might become more important purchase requirements.

return to grid and energy

I thought this was not a thing? i.e. it was at 1 point but they stopped it?

I'm going nowhere. We'll definitely still be living here come payback timeline.

There is also a consideration of increase in house value that isn't insignificant should we decide to move (we're not).

At one point it was something insane like 50p per kWh.

It still exists but it's nowhere near that. Something like 7-12p per kWh.

Octopus has various electricity sale tariffs.
They still have a fixed export tariff which is quite generous at 15p /kWh sold.

Also they have various smart tariffs which have a dynamic buy sell price, which can work out really well if you have a lot of battery storage.

Because of the 15p/kWh sale, it worked out cheaper to pay for gas and sell the spare electricity instead. Not the most environmentally friendly option, but better financially.

Estate agent literature doesn’t really mention the solar panel benefits or price them accordingly at the moment.

Also online house valuations and desktop valuations don’t take into account renovations or added solar panels / improved energy efficiency into their calculations yet.

To add insult to injury they're suggesting to replace 10 radiators (!) so it's £3k after the BUS grant for us. Maybe just get a combi (when the boiler breaks in a few years) and let the next owners handle it in a few years?

This sounds more hassle and money than you'll be saving. Get a decent new combi and some smart controls, and leave the rest to someone else to worry about.

The combi quote from BG (yuck) came in at £4,300 for a 30kW Vaillant 830 (rear flue requirement limits us to Vaillant apparently?) and in the meantime I learnt that we don't need to cap off gas (as long as it's not used for heating) and can keep the gas-hob range cooker. So all in all the costs would be about the same (£3k + £300 for planning + £500-900 for structural eng stuff + chimney block) of course we'd need to repaint some walls where the new radiators are shorter and thicker.

The loft insulation top-up doesn't seem to be in the requirements list, granted it's a good thing to do and we should do it anyway and we will, but nice that we're not held up to that before the works can go forward.

Sure but even if it's just likelihood to sell at asking price / more viewings etc, there's clearly not a negative to selling your house by having solar / ASHP or any other cost saving or climate positive tech.

100%, I know for me, I would definitely favour cost saving/climate positive tech in a future house move.
Not sure it’s a value adding home improvement yet though.

It’s is still a thing but they pay absolutely fuck all and shaft you.

So for the same money they can install a ASHP and all new rads. Honestly I don’t know how they are doing it!

Material alone would be a fortune.

I’m very sceptical about this grant stuff as anything previously related to grants is cut every corner and as soon they are out you’ll never get em back

Preach. The company that installed ours swiftly went bust. If only they’d hung around for the £7.5k grant instead of just £5k

Luckily I’m a hands on kinda guy and could probably now add ASHP engineer to my CV.

This scheme like every other scheme is open to huge fraud.

Companies fit, close and restart.

If they would open it up to everyone, it wouldn’t just help the smaller installers but the quality and level of work would go up huge. These companies that install 9 times out of 10 are fuckin crap because they don’t give a fuck and as soon as the money drys up they are out!

Update on our two projects:

ASHP

1. Final cost is £2700 for a 7Kw Daikin ASHP, new water tank (and relocation from centre of house to garage), removal of boiler, swap out of three radiators.
   
2. Install looking like being May next year though (!)
   
3. Having arguments with a daft person at Octopus who doesn't understand that AC units are not ASHPs in the Govt definition and so this install does not require planning permission. The local planning officer I chatted with this week described the request for planning permission as 'aggressively unusual'
   
4. Trying to work with them to split the system as we have wet UFH on the entire ground floor. Running that at 40 deg and the rest at 50 deg would mean a 3.48 COP upstairs and a 4.02 COP downstairs rather than 3.48 everywhere so some money / energy to be saved
   
   

Solar / Battery

1. We can fit 9x415W panels the rear (SSW) elevation of our garage so we're now discussing adding a further 9 to the other side for all day generation as panels are so cheap vs cost to install in one go
   
2. Probably going for 7.4Kwh battery but looking at potentially 9.6 to maximise overnight usage for AC / hot water & heating
   
3. Installation looking like January now
   

Why not just oversize the rads and run everything at 40 degrees? General advice is not to zone.

and relocation from centre of house to garage

Wave goodbye to ever washing your hands with hot water again.

They are replacing 3 rads. I assume this is cost saving from Octopus. Easier to run at 50 degrees than pay out for 7 more radiators.

I guess if they pass that cost on, it would take a long time to recoup 7 radiators at .50 COP

I guess. Not something I do anyway so…

I’d rather have the large airing cupboard for child stuff storage and not the noise of the cylinder right next to her bedroom.

Ours is silent. Assume you have a pump or something, they can be noisy.