Solar thermal installation – your questions answered

How do I know if my property is suitable for a solar thermal system? Just how hot is the water generated? We’ve answered your most frequently asked questions here, but don’t hesitate to get in touch if there’s anything else you’d like to know.

How does a solar thermal system work?

Solar panels on your roof capture heat from the sun and use it to heat a solar fluid called glycol. The hot glycol is pumped through your domestic hot water cylinder to heat the water within – for a more detailed explanation, see How solar thermal works.

How do I know if my property is suitable?

If you’ve got an unshaded roof offering at least 4m2 – 6m2 of space, that faces west, south-west, south or south-east, the chances are your property is perfect for solar thermal panels. The best way to find out  is get in touch and we’ll come out and assess your property, free of charge. You’ll also need space for a hot water cylinder – in an airing cupboard, or loft space perhaps.

I don’t have a south-facing roof – is that a problem?

Solar thermal systems harness the sun’s heat, not its light, so unlike a solar PV system, you don’t necessarily have to have a south-facing roof. West, south-west, south or south-east will all work well. North-facing roofs unfortunately aren’t suitable.

How much will a solar thermal installation set me back?

The cost of your solar thermal system depends on how much hot water you want to generate and your home’s hot water storage capacity. To give you an idea, a typical system of 2-3 solar panels and a 200-300 litre domestic storage cylinder will cost between £1,500 and £3,500 – but don’t forget that the government’s Renewable Heat Incentive means you will earn money back for every unit of heat your solar thermal system generates. Get in touch for a free, no-obligation assessment and we’ll give you a more accurate quote based on your exact needs.

How much money can I expect to save?

How much you’ll save depends on how your home currently heats its water, but you can expect to see savings of up to £200 a year on your energy bills, which represents a saving of up to 70% on your hot water costs. It’s not just about what you’ll save though – your solar thermal system will also generate an income for your farm, business or home via the Renewable Heat Incentive. Because of this, you could be better off with solar thermal – for more information on savings, visit the Save with solar thermal page.

Does the Renewable Heat Incentive apply to solar thermal installations?

Yes. Under the government’s Renewable Heat Incentive scheme, solar thermal systems installed by an MCS-accredited installer will receive a payment from the government for every unit of heat they generate. The rate you’ll receive depends on whether you’re a business or homeowner. The commercial RHI pays 10p per kilowatt of heat generated, every year for 20 years, guaranteed, while the domestic RHI pays 19.2p for 7 years (figures accurate as of 1 October 2014).

How much CO2 will I save each year?

Exactly how much CO2 you’ll save depends on how you currently heat your water, but you could reduce your carbon footprint by up to half a tonne by installing a solar thermal system.

Will I need to buy a new boiler too?

No – if your existing boiler is working well and you’re happy with it, our solar thermal systems will happily work alongside it.

I have a combi boiler – can I still have a solar thermal system?

Yes – we’ll need to install a hot water storage tank – in a cupboard or loft – but solar thermal systems work well with combi boilers.

Just how hot is the hot water generated?

Solar thermal pre-heats your water from mains temperature – 6 degrees – to between 35 and 45 degrees. Your boiler or immersion heater does the rest, taking it up to the desired 60 – 65 degrees. This is a considerably more energy-efficient and cost-effective way to heat your water than asking your boiler to do all of the work from 6 degrees.

Can you use solar thermal to heat swimming pools?

You can, and indeed we’d argue that you should. On top of the environmental benefits, a solar thermal system is a far more cost-effective way to keep your swimming pool temperature between 25 and 28 degrees than fossil fuels, particularly in the summer. The estimated payback period if you use your solar thermal system to heat your swimming pool is 3 to 6 years.

Do Lime-Circle solar thermal systems come with a warranty or guarantee?

Yes – as well as the manufacturer’s own guarantee (which you can rely on, as we only use the best parts), we’ll also cover your whole installation for two years against any installation defects that are Lime-Circle’s fault. We take great pride in the quality of our craftsmanship though, so we’re pretty confident you won’t need to take us up on this guarantee. It’s just for your peace of mind – you shouldn’t have to contact us again until you’re ready for your first year’s free service.

Will a solar thermal system still generate hot water in the winter?

Over the cooler months, your system will still pre-heat your water, but you’ll need a supplementary heat source like a boiler or an immersion heater to get the water temperature up to the desired 60 – 65 degrees. This is still far more cost- and energy-efficient than your boiler heating water from 6 degrees.

Will I need planning permission for my solar thermal system?

If you live in England or Scotland and your home isn’t listed or in a conservation area, you won’t usually need planning permission, as domestic solar thermal installations are classed as ‘permitted development’. If you’re unsure, get in touch and we can advise you on whether you’ll need to seek permission. If you live in Wales or Ireland, you will need planning permission.

How long does it take to install a system? How disruptive is it?

We aim to have installed your solar thermal system and left you in peace within 3 to 4 days, depending on how many panels we install on your roof. You’ll typically be without hot water for a day while we plumb in your new system – we obviously try and do this as quickly as possible. Other than this, disruption is minimal. All of our engineers are conscientious and will your home exactly as they found it.

If my business or family grows, can the system be expanded to keep up?

Yes – if you find your property needs more hot water for any reason, we can return and add more solar panels to your system to heat more hot water.

Do solar thermal systems need much maintenance?

Solar thermal systems are, happily, quite low maintenance – your solar panels do need to be kept clean to work effectively, but the good old British weather does a good job of that. We are one of the East Midland’s only solar thermal installers to offer a free solar aftercare service – we’ll come back for the first two years to thoroughly clean your solar panels, and check the fixtures and fittings to make sure everything is working as well as it should be. The glycol in your system will need replacing roughly every 5 years – this is an inexpensive job though.

What happens if I move house?

It’s up to you – if you would like to take your system with you, we’ll happily come to your house, remove it and reinstall it at your new pad. However, a MORI survey shows that, because people are willing to pay £10,000 more for homes with environmentally-friendly modifications, estate agents typically increase the prices of houses of eco-homes, so if you decide to leave your solar thermal system behind you won’t be out of pocket.