Evacuated Tube Solar Panels: The Advantages and Disadvantages

Evacuated tube solar panels are the most expensive kind of solar hot water panels. They have an efficiency rating of up to 90%, so they generate more heat than other types of solar panels.

How do evacuated tube solar panels work?

An evacuated tube includes a smaller glass tube that is kept in a larger tube. The air is pumped from the space in between the inner tube and the outer tube, which creates a vacuum thermal insulation layer. This layer decreases the amount of heat lost from the solar collector.

The inner glass tube is coated using a selective light absorber made from a material like aluminium nitrate or titanium nitrate oxide. It helps increase the absorption of solar radiation. An absorber plate runs through the internal glass tube. Usually, this is made from copper and absorbs heat and moves it to a heat transfer fluid.

Once the transfer liquid gets hot, this evaporates and changes to vapour, which rises towards the top of the panel and the heat is moved using a heat exchanger to a different liquid. The process then starts once again after the transfer liquid condenses and travels down the evacuated tube.

Given that evacuated tube solar panels are the most expensive, you may be unclear if they actually are best for you. Look into the advantages and disadvantages to help you choose.


They produce a lot more heat compared to other systems

Because the panels are often 90% efficient, you can generate a lot more heat with evacuated tube systems compared to flat plate collectors. Although they are more expensive, you can heat a lot more hot water, which should save you additional money.

evacuated tube solar panels on stand

You’ll save up to £60 per year on your gas costs

If you have gas heating, you should see a reduction of £60 every year on your home heating costs. Solar energy is free to generate, therefore you will see a difference in your bills within a few months.

Save 270kg CO2 in comparison to gas

Thermal solar panels are a great way to cut your carbon footprint. They produce heat from the sun, the specific renewable reference point, so you can do your bit to reduce the usage of non-renewable fuels while helping to reverse global warming.

Obtain hot water throughout each season

Regardless of the Britain’s cold winters, it is possible to get some great free hot water from your solar panels throughout every season.

Get an average of £349 every year from the Renewable Heat Incentive (RHI)

If you get your system installed by an MCS-registered expert, you might be able to make money for producing hot water with your solar panels through the government’s Renewable Heat Incentive (RHI). A 2m2 solar system, which is generally sufficient for a 2-individual household, may earn you £200 per year from your RHI, while a 4m2 system will earn you up to £345.


You may need a back-up heater

Through the winter season, you may not be able to get your hot water to your preferred temperature. This means that you’ll need a back-up heating system, which will obviously cost you money on electricity and gas.

Solar thermal panels are not suitable for use with combi boilers

Combi boilers offer instant hot water, and don’t have a separate hot water cylinder. They’re not suitable for solar hot water systems, so if you want a solar thermal system you will need to replace your boiler. This could drive the cost up by a minimum of £1000.

Emily Rivers

Emily Rivers is the Customer Experience Manager at Quotatis. She informs customers of the latest developments in a range of products so they can make the best choice for their homes and ensures they get the best out of our service.