Electric combi boilers / solar panels / eco heating solutions

The octopus gas tracker tariff price is excellent, and they have the best tariffs for solar panels and export prices.

We have a fairly efficient house, added solar and battery end of 2022 and an EV.

With 15p export, low rates at night, and even with more gas usage over winter, £50 a month has been enough to leave us with a gas and electricity surplus balance for 2023.

Wow. Thanks for the info. I'll look into it.

£50 a month plus a surplus! That’s very impressive indeed

If you do, if you could consider using my referral link, that would be really nice!
https://share.octopus.energy/blond-horse-546

Not a big surplus mind you, some of our balance is from referrals etc.

My usage:

£50 standing order
+£600

3596kwh elec imported at approx 10p/kwh (combination of tracker rate for part of the year, and 7.5p off peak rate)

-£360

2290kwh elec exported at 15p/kwh

+£343

7528kwh imported gas at approx 4p/kwh (gas tracker)

-£301

Standing charges at approx. £0.76 per day

-£277

Surplus of £5

Still helps to justify the cost of solar+battery installation. (6.6kwh system, 13kw battery)

I've roughly calculated that by having the solar + battery I'm saving £1800 a year. Approx 9 years to pay back the cost of the solar and battery system. Not great by itself, but with 2 EVs and the monthly savings on both cars fuel savings, means about 4 years to repay the cost.

A large 10kw+ battery filled with a low rate evening tariff probably would make the most difference.

How many charge cycles does the battery have?

I have a Tesla powerwall 2, the 10y warranty covers for unlimited cycles for solar self consumption, time of use load shifting, backup power. Up to 37.8Mwh for other uses, probably commercial related.
With 70% end of warranty capacity.

Our battery is warrantied for 10 years - I presume it will degrade over that time, but not to the point where it will invalidate that. They're constantly charging and discharging, so not sure charge cycles is a metric that matters too much...

Is there much energy wasted doing that? Or is it better for the grid to have more local electric near where it's needed at peak times rather than sending it further?

Has anyone had ‘heatgeeks’ out to do a survey?

As we are now definitely staying put here. I want to insulate our suspended floors, prior to this, I’d rather have the correct pipe work in place to save the aggro and difficulty in lifting them later on, as once the membranes are down it will be a mega pain. The heatpump will probably have to wait until next year, as solar this year, but I cannot do another year of freezing floors!

The survey is £350.00, which is not deducted from any future install. Has anyone had one and would care to elaborate on the usefulness, essentially I want everything I do in the next year to be future proof.

skint and cannot afford a full install now

Looks like OVO Energy partner with heatgeeks for their heat pump install work (possibly other insulation bits too). Can’t imagine they’d choose too much of a cowboy outfit as a big nationwide supplier?

Have come across them on YouTube where they do some install walkthroughs which I found interesting but definitely not an expert so couldn’t speak to their accuracy but they came across well/confident.

Surveys would be relevant for future installs as it'll be room size, radiator spec / heat loss calculations. It should give you a clear idea of heatpump size, radiator requirements, install location & considerations and system design. All those things shouldn't change over time.

However, what I've found though is that, from a BUS grant perspective, installers will want to survey themselves in case they get audited. They'll likely ask you to pay for their own survey even if you already have a super detailed one.

Basically, I would only bother with a survey in two cases:

1. You're ready to install and it'll be part of your install cost
   
2. You want to see if a heatpump is viable for your property and don't mind spending ~£300 to find out
   

Oooh useful thread - thanks @c.h.e.

I looked at it for a work project (I do development). They are really great bits of kit but do require a pretty good passivhaus rating to work efficiently enough and from what I remember, they didn't have huge capacity so were better for the new build flats we were building. That said i did go round an example of a retrofit flat with it installed and it worked well but they had done a full passivhaus job on the place.

This was 2 or 3 years ago though so maybe the tech has moved on

It seems we have some grants here for ASHP too so I am thinking about doing this. Going to try get a company to survey to see what the deal is.

Worth pointing out that Octopus via the Octoplus rewards page is giving out a free Greggs sausage roll and free regular drink every week.

Just had 5 Octopus vans show up..... for my heatpump install that was cancelled two weeks ago.

🫠

Free heatpump, result.

My house is all electric (ancient, never had central heating installed, off gas grid). I currently have a ruinously expensive immersion heater that is only needed for 3 hot taps (no bath, and shower is electric). What’s the best way to heat that much water? Presumably I can get some sort of central heater that heats it as you need it and pumps it to the taps, rather than storing hot water I don’t use much of. Like an electric combi boiler but only used for taps, not central heating.

[I am working on insulation, and I have the best storage heaters, which are terrible, but I’m not going to put a whole central heating system and heat pump in, I can’t afford it and I’d never see a return on it]

Smaller immersion tank that heats up on cheap electricity rate?
We heat our immersion tanks at night.

Maybe a heat battery. Sunamp are the ones I know about. I’m considering sunamp as we don’t have space for a water tank once our oil combi boiler goes.

The thing you're describing is called an instantaneous water heater, and they come in endless shapes and sizes, tanked and tankless.

(tankless ones use no power when the tap isn't running, but need a high amp electricity connection if you want more than a warm dribble)

You get small unvented water heaters, they are like 10L and take not long to heat up.

I have fitted a few in take aways or salons.

I think our electric shower is rated at 8kW. Makes you realise how much power it takes to heat water to a decent temperature very fast.

Would solar collectors/thermal be a plausible solution @t.o.?