Electric combi boilers / solar panels / eco heating solutions

No regrets. I can afford this but it is frustrating. It’s still better to generate some power.

Anyone have solar panels and doesn't think its shit?

I don't see how HW solar saves £37 per year!

Over winter, in northern Scotland, it doesnt contribute much as the days are short and the sun doesn't climb that high. But it can still contribute a bit.

However it's halfway through a fairly cloudy April day and my old serpentine collector is running 12C to 15C hotter than the bottom of the cylinder.
The incoming cold water was 8C this morning and the bottom of the tank is already at 35C

It won't do it all today, but I'll probably be able to completely switch off the immersion again in a month or so. At the new energy prices, that could be saving £2 per day

i did the calcs recently for 5kw solar panels on our semi - the calculator thing reckoned we'd be 650 quid worse off financially over the lifetime of the panels.

fair enough there is a carbon saving, but i think there are better savings to be made from not eating meat, driving less, and not flying.

If PV cost £600 to install, not £6k, I reckon they'd be on to a winner. Why are they so pricey?

The big expense for us though has been insulating the whole house. All external walls have been insulated internally. Luckily we have space to make the rooms a little smaller.

How / what have you done? It would be very interesting to see.

What about floor and roof?

We have had 2 rooms done with insulated plasterboard. Seem to recall it's about 4cm thick?

Out local council is doing the Solar Together scheme, and we have been quoted for solar panels - £7,500 for 4.2kWh, and indicted savings of £445 per year

If you have really good insulation doesn't your house get really hot in summer? Mine internally already reaches 35-45 if I'm not there to open windows.

Insulation works both ways though - It prevents your house heating up so much in the first place.

I added a whole bunch of insulation to the eaves of our loft conversion, and shaved 2 or 3 degrees off the temperature during Summer.

I've not ever retrofitted, but we had one in our new build flat that we bought 5 years ago. It was really fantastic. Clothes dried indoors on the rack within hours, and we almost never turned the heating on.

However, house plants were not super happy with it, as they all tended to dry out very quickly.

will dig out a few photos and further deets and share dude

Nice one - thanks

We are having solar panels and battery installed in May. We are high usage (bill is currently £300 a month!) so hould get pay back quicker than most.

System to consist of following ;
6.24KWp (16 x 390wp Panels) system complete with all electrical components/Labour/roof access
All associated isolators and control wiring
SOLAR-EDGE 5.0KWp Inverter and 16 X Power Optimizers
All relevant warranty’s – certification, Building control and Western Power notifications
1 x 10KWh Solar-Edge Battery complete with all electrical wiring and components

We also have the system that turns on our immersion heater when there is excess generation. Estimation is 6.36MWh per year.

Are dual fuel (gas/electric) combis a thing?

Seems all the Solar/PV options focus on having a tank of warmish water that you'll then use to lessen what a normal gas combi needs when you demand hot water.

If you've got a battery then wouldn't it be an option to have a combi use electric when the battery has charge, and gas when it's empty. Or is it just that it makes for a complicated/expensive boiler if done that way so there's not enough of a market for it?

No but you could use the leccy from the solar to heat an immersor in the tank and then when the combo or system boiler fires up it only needs to heat it from a higher temp.

What your describing ive never heard of as thats not really the way a boiler works.

Labour costs, insurance, warranties? Panels are the least of the cost.

That's a big battery. I was quoted 11 panels through Solar Together (Kent) for about 5k with the option of a 3kwh battery for another 2.2 house spending units. Do you think you'd ever top a 10kwh battery out?

Sadly yes! We use 11mwh per year, with some Seymour’s peak usage at times! Also plan to switch to electric car for next year, so will help with that too

Bugger, I completely missed this (I ran a marathon at the beginning of the month and then got Covid so haven't been terribly attentive)

A few tl;dr observations/ brain splurge...

Electric heating bad. Very expensive to run and in the case of electric UFH a nightmare to repair or replace if there are problems.

Heatpumps good. Very good. There is no more efficient way to convert purchasable energy to heat energy than a heat pump installation and this narrative that's been doing the rounds in the media recently that "heat pumps are now cost comparable to boilers" is a load of shite. I've been installing HPs for the last fifteen years and in most instances you can expect a payback of 3-5 years. That's an actual payback as in the the amount of money you will have saved on running costs will have paid for cost of the installation.

Solar panels are good but you need to really know what you're doing with the spec and installation if you want to use solar thermal as a standalone heat source... it is possible but I'd rather have a HP myself and know that you'll have dependable heating and hot water all year around. Solar as an add on to HP is a great choice and I know Viessmann for example have been really focussed on allowing their controls integrate the systems to maximise efficiency which is very good.
EDIT: I'm referring to solar thermal, PV panels are great in most instances and make great sense with HP as you don't need to worry too much about storing your energy as electricity when you can pump it into heating and DHW, another argument in favour of a good size buffer tank...

If you are considering a HP and the installer says you don't need a buffer tank walk away, they're idiots. There are a number of reasons why your HP installation should have a buffer and not having one is a bad idea, also with buffers the bigger the better so if you have the space for a big one then get one, you'll reduce the number of starts on your compressors which will prolong the life expectancy of the machine and also allow you to maximise use of night rate electricity.

Wet underfloor heating is the best for heating distribution, there are also some very good capillary tube heating distribution systems available these days too. Radiators are ok with HP these days but it's certainly advisable to upgrade to more efficient aluminium radiators that will allow you to run a lower operating temperature.

As previously stated by others absolutely do go nuts with insulation where available and I also wouldn't rule out retrofit wet UFH in a lot of instances, it might cost a wedge at the moment but why not cool the jets on that fancy kitchen and then upgrade that in a few years when you've reaped the benefits of your efficient and cheap to run heating system... mechanical works are almost never something that's easy to upgrade down the line without major disturbance.

I'll try and answer any more specific questions people have if anyone wants to ask anything, I've been working in the HP industry for fifteen years and we've won a bunch of industry awards so I do know what I'm talking about for once...

I'm also currently upgrading our own flat with an air source heat pump installation, upgrading some of the radiators and also adding in some retrofitted UFH in the bathroom so it really is all achievable and I'd even argue there are a fair few elements that a competent DIYer can do to keep costs manageable.

:)

There's a lot of stuff about heat pumps, solar, etc in recent a to b magazine issues

https://www.atob.org.uk/

They seem quite pleased with their setup.

Dream setup for our place - maybe in 10 years time (fitted new boiler in 2020 as couldn't face major renovation required to get the place efficient enough for ASHP)

• insulate floors
  
• insulate some external walls (terrace, so not too bad)
  
• fit underfloor wet heating throughout
  
• re-fit loft conversion with more effective insulation
  
• ASHP on the back, under the deck
  
• solar panels on the garden office roof feeding the immersion heater
  
• additional panels on the flat roof if possible
  
• storage battery somewhere
  
  

Gonna be wallet crushing

It's certainly a big commitment but sounds like a good plan!
The one thing I'd say is if you're going to get an ASHP anyway you'd be better off to let the ASHP do the DHW and direct the Solar PV to running the ASHP instead of an immersion. Every 1kw of energy you put into the immersion will give you approximately 1kw of DHW heating but if you put 1kw into the ASHP you'll be getting c.3-3.5kw of DHW heating...

I am considering solar panels and battery soon.
With expected increases in energy prices, and a plug in hybrid and electric car in the next 1-2 years, its making some sense.

Getting some quotes on east/west split 16-20 panels at approx 400w each.
6kw inverter
Tesla powerwall 2 13.5kw battery
Car charge point

So far it seems to be around £16500 or so for the above.

Very rough calculations suggest that if we manage to save 6mw a year on purchased electricity at 40p a kw, then I would recoup costs in about 6 years and 10 months.

Also thinking of adding a solar suplus connected controller for the immersion heater.

Aiming to find a reputable firm that offers 0% finance. 0% finance makes a lot of sense while we have high inflation.

How are you finding your Solar-Edge system?

We’re comparing this with cheaper alternatives, as we have a fairly simple shade free roof, though we are planning both sides of an east west roof.

I like that you can upgrade the warranty to 25 years on the inverter.