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Hot water from the roof.
Collectors that absorb heat rather than light, and carry it straight into your hot water cylinder. Fitted across Chertsey and Surrey.
A simple system, and an old one
Solar thermal has been on British roofs since the seventies. There are three moving parts and one of them is a pump.
The collectors absorb heat
Flat plates or evacuated tubes on the roof. They are after warmth rather than light, so they work on a bright but cool day.
A pump moves the fluid
A small circulating pump pushes a glycol mix from the collectors down to the cylinder. That pump is the only electricity the system uses.
A coil heats your water
The fluid gives its heat up through a coil inside the cylinder and goes back to the roof cooler. The water in the tank is never mixed with it.
The boiler tops up what is missing
From roughly March to October it does most of the work on its own. In midwinter it preheats and the boiler finishes the job.
What gets fitted
Collectors
Flat plate panels or evacuated tubes on the roof, sized to the household rather than the roof area.
A twin coil cylinder
One coil for the solar circuit, one for the boiler. If your existing cylinder is single coil it gets replaced.
Pump station and controller
A small unit near the cylinder that runs the pump only when the roof is hotter than the tank.
A temperature readout
Collector temperature, tank temperature and whether the pump is running. Most people watch it for a fortnight and then stop.
Where it works best
- Houses with a cylinder already
- The cheapest version of this job. If the cylinder is twin coil, half the work is already done.
- Families and high hot water use
- The more hot water you draw, the more of the collector output goes to use rather than sitting in the tank.
- Alongside a heat pump
- Solar thermal takes the summer hot water load off the heat pump entirely, which is when a heat pump is least efficient at it.
- Roofs that solar PV has already filled
- Collectors take up far less room than an array, so a small south-facing dormer or garage roof can carry them.
Will it work in your house?
Solar thermal has one hard requirement and it is worth establishing first. Two taps.
What sort of boiler do you have?
Is there a hot water cylinder?
Solar thermal heats water in a cylinder, so the cylinder is the requirement rather than the roof. Everything else is straightforward by comparison.
Yes, and it is the straightforward version
You already have the cylinder, which is most of the work. Twin coil and we connect straight to it; single coil and it gets swapped.
How the job runs
What you have now
Your cylinder, your boiler and your roof. That is enough to say whether it is straightforward or not.
The quotation
Collectors, cylinder if it needs changing, and the full price with 0% VAT.
Survey
Roof access, the pipe route down to the cylinder, and where the pump station goes.
Installation
Collectors, pipework, cylinder and controls. Two days if the cylinder is being replaced.
Commissioning
Filled, pressurised, balanced and handed over with the controller explained.
And then we are still here
A solar thermal system wants very little, but not nothing.
Your paperwork, on the day
Commissioning record, Benchmark entry, the pressure and glycol readings, and the manufacturer documentation.
Two years, in writing
Two years in writing, transferable if you sell, and insurance-backed.
A glycol check
The heat transfer fluid degrades slowly and wants checking every few years. It is a short visit.
One number, not a call centre
You ring the people who installed it, and we attend within five working days.
Two things people ask about next
Both have a page of their own.
The questions we get asked most
Is this the same as solar panels?
No. Solar PV makes electricity. Solar thermal makes heat and puts it straight into your hot water. Different technology, different job, and they can share a roof if there is room.
Do I need a hot water cylinder?
Yes. The system heats stored water, so a combi boiler on its own will not work. If there is no cylinder, one goes in as part of the job.
Will it work in winter?
It generates all year but the useful contribution runs roughly March to October. In midwinter it preheats the water and the boiler finishes it.
Is there VAT on solar thermal?
No. Solar thermal is zero-rated until 31 March 2027, the same as solar panels and battery storage.
Is there a grant?
Not for solar thermal on its own. The zero VAT rate applies, and if you are putting in a heat pump at the same time the Boiler Upgrade Scheme covers that part.
How much roof does it take?
Far less than a PV array. Two to four square metres covers most households, which is why a garage roof or a dormer often does the job.
How long does it last?
The collectors have no moving parts and carry long manufacturer warranties. The pump and the heat transfer fluid are the parts that want attention over time.
Often worth doing at the same time
Same team, same survey, one visit where it makes sense.
Book a free survey for solar thermal
Tell us about the property and we will come and look at it. No charge, and the figures come in writing afterwards.
- A proper survey, and the figures in writing
- Any grant you qualify for, applied for by us
- No charge, whether or not you go ahead
- Weekdays 8am to 5pm, on 01932 550828
Tell us what cylinder you have.
Your cylinder and your roof are most of the answer. Send us a photograph of the airing cupboard and we can tell you a great deal before visiting.