Solar Panels with Gas Boiler

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mcquilk

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About to start into a significant renovation where all options are open to me to redo electrics and plumbing. House is currently BER of F. I'm not mad on the idea of taking the insulation up to the point where a heat pump would be worthwhile, so currently looking at a combi boiler for the rads and hot water.

My question is - would it be worthwhile to get solar in to power the appliances only? As the combi boiler doesn't have a tank, it seems like it would be a real faff to get the solar to heat the water, so i'm thinking of just getting some PV panels in to power all appliances.

Would this be a common enough setup?
 
Similar set up here with a gas combi boiler and solar panels. The advice we got at the time was not to go down the “solar heating the water route” as we had the combi boiler. Works absolutely fine. House is now B2.

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We installed Solar Panels for power, still using gas for central heating.

While it's relatively early days, so far, we've no regrets.

As I'm sure you know, there's potential to heat water with an Eddie, or possibly charge an EV in the future, so more than just powering the house, to consider.

I'd suggest with starting by installing as many panels as you can (they are relatively cheap, in overall terms), then consider whether you'd benefit from installing a battery, or not. Other possibilities, thereafter.
 
Plus 1 to as many panels as you can. Ask for an inverter that can accommodate more panels in the future. The mistake we made was getting an inverter that could only handle the power generated by 8 panels. We now want more and are faced with getting a bigger inverter
 
rustbucket said:
Plus 1 to as many panels as you can. Ask for an inverter that can accommodate more panels in the future. The mistake we made was getting an inverter that could only handle the power generated by 8 panels. We now want more and are faced with getting a bigger inverter
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Good suggestion thanks. Didn't realise that inverter could only handle power from so many panels. I've a lot to learn yet
 
mcquilk said:
I'm not mad on the idea of taking the insulation up to the point where a heat pump would be worthwhile
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Can you expand on that a bit? I think you’d be much better off spending the solar panel money on better air tightness and insulation which will make the house more comfortable to live in, even if you don’t go for a heatpump. Although having swapped from an oil boiler to a heatpump I could not recommend it highly enough, the low slow heat is a far superior way to warm a home from a comfort perspective!
 
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Zenith63 said:
Can you expand on that a bit? I think you’d be much better off spending the solar panel money on better air tightness and insulation which will make the house more comfortable to live in, even if you don’t go for a heatpump.
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I'd second that, very good advice. Doing so will make a significant difference in the comfort and energy use of your home. Investing a lot up front in solar panels might save you a few quid over their lifetime, but they may end up costing you more.
 
Leo said:
I'd second that, very good advice. Doing so will make a significant difference in the comfort and energy use of your home. Investing a lot up front in solar panels might save you a few quid over their lifetime, but they may end up costing you more.
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in terms of return on investment, I'd be confident solar panels will perform a lot better than retrofitting. We've just had them fitted and I expect payback in under 10 years (possibly as low as 5 if energy prices stay high). I ran the numbers on external insulation and full retrofit and the payback was running into decades. Yes the house will be more comfortable but you'd get the same effect for less money by just turning the thermostats up.

Either way, whether you decide to get solar panels doesn't really have any relevance to what you're doing with your heating system, they'll pay for themselves either way.
 
shweeney said:
in terms of return on investment, I'd be confident solar panels will perform a lot better than retrofitting. We've just had them fitted and I expect payback in under 10 years (possibly as low as 5 if energy prices stay high). I ran the numbers on external insulation and full retrofit and the payback was running into decades. Yes the house will be more comfortable but you'd get the same effect for less money by just turning the thermostats up.
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A lot depends on the draftiness, heat retention and ventilation of the existing house.

I ran the numbers last year when energy prices were higher and break-even point for me was approaching 10 years and the calculations assumed zero maintenance or replacement costs over that time, nor did they factor in the opportunity cost of locking that money up.

If you are factoring in feed-in-tariffs, bear in mind other countries had eliminated them as numbers of solar installations rise to the point of becoming problematic in terms of grid management. We're likely a way off that yet here though.
 
Zenith63 said:
Can you expand on that a bit? I think you’d be much better off spending the solar panel money on better air tightness and insulation which will make the house more comfortable to live in, even if you don’t go for a heatpump. Although having swapped from an oil boiler to a heatpump I could not recommend it highly enough, the low slow heat is a far superior way to warm a home from a comfort perspective!
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Sure, maybe I phrased my comment badly. I'm not against insulating the place really well, which I absolutely think is necessary. I just don't trust a heat pump to be able to deliver. The level of air tightness required to enable a heat pump to work efficiently is perhaps more than I want to do right now, they work best with underfloor heating which I don't want, and I feel the expertise still isn't out there in terms od the installers. There's a lot of anecdotal evidence out there of people who have got a heat pump only to regret their decision afterwards.
 
shweeney said:
in terms of return on investment, I'd be confident solar panels will perform a lot better than retrofitting. We've just had them fitted and I expect payback in under 10 years (possibly as low as 5 if energy prices stay high). I ran the numbers on external insulation and full retrofit and the payback was running into decades. Yes the house will be more comfortable but you'd get the same effect for less money by just turning the thermostats up.

Either way, whether you decide to get solar panels doesn't really have any relevance to what you're doing with your heating system, they'll pay for themselves either way.
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Sorry for a simple question, but how did you 'run the numbers'? Is there a calculator somewhere?
 
mcquilk said:
Sure, maybe I phrased my comment badly. I'm not against insulating the place really well, which I absolutely think is necessary. I just don't trust a heat pump to be able to deliver. The level of air tightness required to enable a heat pump to work efficiently is perhaps more than I want to do right now, they work best with underfloor heating which I don't want, and I feel the expertise still isn't out there in terms od the installers. There's a lot of anecdotal evidence out there of people who have got a heat pump only to regret their decision afterwards.
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FWIW I think most of what you’re hearing is from people who don’t understand them or don’t like change. 60-70% of homes in Norway are heated with heatpumps, so they can deliver!

They work well with traditional radiators, they just need to be big enough, but they are generally oversized already so you might find only a couple need increasing if any. In my case it was only 1 out of about 25.

You don’t need to reach absurd levels of airtightness before a heatpump is an option. You should be aiming for that minimum level to avoid drafts and cold spots to make the house comfortable anyway. And FWIW there are diminishing returns on insulation, more balanced focus on airtightness will yield better results.
 
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Mcquilk, I think if you are doing a full renovation with plumbing and electrics that actually (with the heat pump grant) it will work out much better for you to get a heat pump now. But you've already said you don't want to do this, so I won't try to convince you, however let me say this. The government are going to gradually make oil and gas boilers, more and more expensive. Eventually we will all be on heat pumps.

Now is the perfect time for you to future proof your home, so that when you do eventually get a heat pump, it'll be much quicker and much cheaper. To that end, you should insist that all the main plumbing runs should be on 32mm pipe. You should size all the radiators so that they will work well with a heat pump. And finally, with a heat pump you do need a hot water tank, so consider going with a system boiler with a new tank, instead of a combi boiler.

Those upgrades are more than half the cost of putting in a Heat Pump.
 
To answer your original question, yes it's definitely worth getting solar.
I got solar 4 years ago and I still think it's the best thing I ever bought.
Now that you get paid for exporting your electricity, it actually doesn't matter that you can't divert your excess solar to do the hot water. In fact I get paid more to export (20c), than it costs to import at night (10c). So even though I have a hot water diverter, I don't use it. I export my excess to the grid and I use the cheap electricity at night to heat my water.
 
AJAM said:
To answer your original question, yes it's definitely worth getting solar.
I got solar 4 years ago and I still think it's the best thing I ever bought.
Now that you get paid for exporting your electricity, it actually doesn't matter that you can't divert your excess solar to do the hot water. In fact I get paid more to export (20c), than it costs to import at night (10c). So even though I have a hot water diverter, I don't use it. I export my excess to the grid and I use the cheap electricity at night to heat my water.
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Thanks. Appreciate the feedback. That's just what I wanted to hear. Sounds like solar is definitely the way to go.
 
AJAM said:
Mcquilk, I think if you are doing a full renovation with plumbing and electrics that actually (with the heat pump grant) it will work out much better for you to get a heat pump now. But you've already said you don't want to do this, so I won't try to convince you, however let me say this. The government are going to gradually make oil and gas boilers, more and more expensive. Eventually we will all be on heat pumps.

Now is the perfect time for you to future proof your home, so that when you do eventually get a heat pump, it'll be much quicker and much cheaper. To that end, you should insist that all the main plumbing runs should be on 32mm pipe. You should size all the radiators so that they will work well with a heat pump. And finally, with a heat pump you do need a hot water tank, so consider going with a system boiler with a new tank, instead of a combi boiler.

Those upgrades are more than half the cost of putting in a Heat Pump.
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This is a problem I have with heat pumps. Why would i get a heat pump and a boiler as well (one that is less efficient than a combi, at that)? Why not just get a combi boiler? Sure it'll be 20 years before they phase out gas to any significant extent?

Appreciate the suggestions you have on the piping though - setting myself up so I could, theoretically, get a heat pump in future is a great idea.
 
mcquilk said:
Why would i get a heat pump and a boiler as well (one that is less efficient than a combi, at that)?
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Might be misunderstanding you, but the heatpump would heat your radiators and domestic hot water, no boiler would be required.

Sure it'll be 20 years before they phase out gas to any significant extent?
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Doubt even in 20 years they’ll be banned from use, but the carbon tax is making them more expensive every year.
 
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