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Solar Thermal Homeowner Guide
Solar thermal utilises solar radiation to create free, emission-free hot water for any household. Solar thermal can:
- Provide free, clean energy for your home
- Vastly reduce household consumption of fossil fuels
- Be integrated into an existing heating system
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Renewables Hub
How does Solar Thermal work?
Solar thermal panels work similarly to a pipe laying in the sun. The outside surface of the pipe absorbs sunlight, which heats the inside of the pipe. Solar thermal works on the same principle:
- The solar thermal collectors absorb sunlight, which heats up the heat carrier fluid inside.
- A pump transfers the fluid to the heat exchanger in the solar storage.
- The thermal energy is transmitted to a storage tank, which can be used to heat water for the household.
What’s the difference between Solar PV Panels and Solar Thermal?
Solar PV panels absorb sunlight and convert it into usable electricity using silicon-based technology, which can then directly power your home or be stored in a battery storage system for later use. The electricity generated is extremely versatile, and can be used to power virtually anything in your house.
Solar thermal panels are used to heat the water in your home, rather than generate electricity. It is more space efficient than solar PV panels, and also more efficient when it comes to collecting heat from the sun. Solar thermal panels tend to be cheaper, requiring less initial investment.
If you’re struggling to decide whether solar PV panels or solar thermal is best for your home, it will likely come down to circumstances, budget, and whichever your household will gain the most value from.
Solar thermal is generally considered more effective overall - however the tradeoff is that it’s far less versatile, as hot water generated by solar thermal is generally less useful than the electricity generated by solar panels.
Households using a lot of electricity during the day may get the most benefit from solar PV, and if you have a hot water heater cylinder then a solar diverter can be fitted wich would divert excess electricity to your immersion heater.
Solar thermal however is a simple technology which can offer real benefits to households with high hot water usage, with the added benefit of homeowners being able to turn on the tap and feel the generated hot water.
All in all, both systems can provide serious benefits to households, and both have the potential to save money and cut carbon emissions.
What types of Solar Thermal are available?
Solar thermal systems as a whole work very similarly to each other, however there are two types of solar collectors available - evacuated tube collectors and flat plate collectors.
Evacuated tube collectors
Evacuated tube collectors work by absorbing solar radiation from the sun, then utilising a vacuum to insulate the absorbers to virtually negate any heat loss whatsoever. They then transfer it from thermal energy to a fluid.
Advantages of evacuated tube collectors
- Provides the best performance available
- Requires less overall roof space for a similar output to flat plate collectors
- Produces higher temperatures than flat plate collectors
- Can be rotated to catch more of the sun’s rays
Disadvantages of evacuated tube collectors
- More expensive than flat plate collectors
- More expensive upkeep costs (although the extra upkeep charge may be negated by more efficient heat collection)
- Not as robust as flat plate collectors
Flat plate collectors
Flat plate collectors generate energy via a black absorber surface that faces the sun. The absorber is designed to collect as much radiation as possible, reflecting only a small amount of energy.
Instead of the perfect vacuum insulation you get in evacuated tube collectors, flat plate collectors use more traditional insulation such as polyurethane foam to insulate the heat they gather. Whilst this is less effective, it is much easier to manufacture and therefore cheaper.
Advantages of flat plate collectors
- Cheaper to buy than evacuated tube collectors
- Easier and cheaper to maintain and repair
- Long life and very little to go wrong
Disadvantages of flat plate collectors
- Less efficient than evacuated tube collectors
- Requires more roof space for the same output
In terms of looks, flat plate collectors look akin to solar PV panels, whereas the tube array from evacuated tube collectors makes them look similar to column radiators. The vast majority of installs are currently with flat plate collectors due to their simplicity and ease of installation.
How much does Solar Thermal cost?
Solar thermal systems typically cost between £3,000 and £5,000, for an average UK three-bedroom house. This depends on several factors when it comes to installation, including whether you get flat plate or evacuated tube collectors.
Fortunately, once the initial expense is out of the way, a solar thermal system will start reducing your carbon emissions and energy bills straight away.
How much money will Solar Thermal save?
Naturally, the amount of money you can save with solar thermal depends on a variety of factors. The size, efficiency, and type of solar thermal system you have are the main factors, as well as how much hot water your household uses.
According to government research, solar thermal panels can cut hot water bills by around 50% on average. Yet with gas prices rising, this amount could increase going forward.
Does Solar Thermal work in the winter?
Solar thermal systems do work in the winter, however they may not be quite as effective.
During the winter, the days are shorter and the sunlight is typically weaker - meaning you won’t get quite as much value from solar thermal systems. The Energy Saving Trust estimates you’ll get about 25% of your hot water supply from solar thermal during the winter.
In spring and autumn, you can expect solar thermal to make significantly more of a contribution towards your hot water usage.
In the summer, solar thermal will likely meet your household’s hot water demand by itself, generating between 90-100% of your hot water requirement.
Is Solar Thermal worth it?
Solar thermal panels are a good way for households to minimise bills and reduce carbon emissions in the long run. They’re relatively hassle-free too, requiring only occasional cleaning to keep them relatively clean.
The average person uses between 90-150 litres of hot water each day, and an appropriately sized solar thermal setup will be able to cover around 60% of your hot water requirements each year (based on an average family of four).
This can result in significant savings, so if you can afford the initial investment, and have the necessary roof space - solar thermal is certainly worth considering.
Our Stock
Renewables at City Plumbing leads the way when it comes to efficient, renewable heating systems. We stock a vast range of solar thermal systems from leading suppliers and can identify and recommend the best systems available to help you save money and cut household emissions.
Talk to Our Team of Renewables Experts
With our expert knowledge of the latest Energy Efficient Technologies, an unrivalled product range and nationwide branch coverage City Plumbing Supplies are at the forefront of the transition to net zero carbon.
- We advise across a wide range of technologies
- We work with an extensive range of manufacturers to offer agnostic solutions
- Fully indemnified design service covering multiple technologies
- Energy Efficiency Technical Sale
Call us on 0330 016 8850 or email us at renewables@cityplumbing.co.uk
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