Solar panel boilers

Can you use solar panels with a combi boiler?

The short answer is yes. Solar panels plus combi boiler are actually a great way to fuel a property and cut down on bills.

Five reasons to use solar panels with a combi boiler

  1. Lower electricity bills.
  2. Free fuel for your boiler.
  3. It provides a greener source of energy.
  4. You’ll be less reliant on rising fuel prices.
  5. You can run other electrical appliances at low cost or free too.

How it works

You may have seen panels installed on the roof of certain properties.These are thermal conductors that basically convert heat from the sun via photovoltaic cells to warm up fluid passing through them.

This will heat water which is stored in a hot water cylinder. This free, renewable electricity can then be used to provide power.

When you install solar panels you can choose between monocrystalline and polycrystalline. Each has different types of cells. As the name suggests monocrystalline solar panels have single crystal silicon while polycrystalline panels are made of up silicon fragments all melted together.

If you want to tell each one apart, monocrystalline panels are black and polycrystalline panels are a dark blue. The monocrystalline panels are more efficient but the polycrystalline are more cost-effective, however, before you do install solar panels you do need to assess whether it’s actually worth it as neither is cheap.

The times when most of us use hot water are in the mornings and at night, so because solar energy is gathered during the day the water that is heated up must be stored for later use in a  hot water cylinder.

Also the amount of solar energy available varies from day to day so it is also important to use the boiler to bring the water to a sufficient temperature on days when solar energy may not be in abundant supply.

Combining solar panels with an electric combi boiler

The combi boiler is a popular choice in the UK but not every type of combi is compatible with a thermal energy system. Some can accept pre-heated water, while others can’t. This is why when you are installing a new boiler, or looking to install solar panels you need advice from the experts.

Around 45 percent of combination boilers will in fact not accept water that has been heated beforehand, and others only accept water up to a certain temperature. Solar panel and combi boiler installation will include the following:

  1. Erecting scaffolding.
  2. Installing solar panel mounts.
  3. Installing solar panels.
  4. Wiring solar panels.
  5. Installing solar inverter.
  6. Bonding solar inverter and solar battery.
  7. Connecting the inverter to a consumer unit.
  8. Starting and testing solar panels.
  9. Plumbing solar water heater to boiler.


Solar thermal panels typically cost between £4,000 and £5,000 to install, including VAT (at 5%). For comparison, a conventional gas boiler costs between £1,500 and £4,764 to install, although the eventual bill will vary depending on how much work is required, parts needed, availability, where you live and who you employ to do the job.

Once installed, additional costs are minimal. Most systems use a small amount of electricity to run the pump but, in most cases, the pumping costs cancel out only about 8% of savings, and newer technology can typically reduce this to 3% or even zero. You’ll need to bear in mind the cost of maintenance, although it’s generally very low for solar water heating systems.

Pros and cons of solar water heating


  • Solar water heating can provide you with about a third of your hot water needs.
  • You could save between £55 and £95 per year on your fuel bills.
  • Systems need little maintenance and the costs of it are very low.
  • Most solar water-heating systems come with a five to 10-year warranty
  • Lowers your carbon footprint.


  • You’ll still need a boiler or immersion heater to make the water hotter, or provide hot water when solar energy isn’t available.
  • Not all boilers are compatible with solar water heating.
  • Solar thermal panels cost more to install than conventional electric and gas-heating systems.

At Range Heating we can answer all your questions about solar heating and our qualified engineers will be able to advise you on every aspect of the work.

It may be that you’re considering a  new boiler but are contemplating adding solar panels in the future, in which case we can recommend the most compatible boiler and we will take you through every step if you do decide to go ahead with your solar energy plans.

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