Find a Solar Panel Installer you can trust in Llanerchymedd.

Tesla’s top-of-the-range battery storage system is still one of the most expensive on the market. It has a huge 13.5kWh usable capacity and can even keep you up and running during a power cut. But how long does a Tesla Powerwall battery last? And does this mean it’s worth investing in one?

The Tesla Powerwall 2.0 comes with a 10-year warranty. But Tesla says that it should last way beyond this – at least 5 years longer. The standard warranty says that it should work at 70% capacity for the full 10 years – so if it loses more than 30% of its storage capacity within that time, it should still be covered.

While the Tesla Powerwall does last a long time, it has a large capacity that most average households won’t require, and it’s a costly option. After installation, the Powerwall 2.0 will set you back between £6,500 and £9,000, so ideally you want it to last past its 10-year warranty.

Before you splash out, consider the size of the solar panel system you want to install or you already have. Will it generate enough electricity to make it worth storing in the Powerwall? If not, are you expecting to upgrade your solar panels to a larger system in the future? If you are, then it might be worth investing in a Powerwall. It might also be better to wait until you come to upgrade your solar panels – the solar battery price trend is going the same way as solar panels, so they will probably continue to decrease in price as more people adopt the technology.

There are a few trusted companies in the UK that make solar panels. While there are other solar thermal panels out there that are made by Chinese and American companies, we’ll focus on the brands with a longstanding presence in the UK since these are the panels MCS-registered solar companies are likely to recommend to you.

Viessmann, Worcester Bosch, Solar UK and Dimplex make some of the best solar thermal panels in the UK. Dimplex and Viessmann offer both flat plate and evacuated tube solar panels, while Solar UK only offers evacuated tubes. Worcester Bosch’s Greenskies range are all flat plate collectors. Viessmann’s panels come with a 5-year warranty, while Worcester Bosch and Dimplex offer extensive 10-year warranties. However, Solar UK offer a comprehensive 25-year warranty and guarantee that the panels will deliver the same level of performance for 25 years!

We’d recommend choosing evacuated tube solar thermal panels because they are the most efficient. While there won’t be much difference between evacuated tubes and flat plates in the summer, in the winter evacuated tubes are much better at taking heat from the sun than flat plates. Since our winters are long and cold with few daylight hours, we think it makes sense to go with evacuated tubes. However, if your priority is looks over maximising efficiency, you might want to choose flat plate collectors since they sit flat on the roof and look more like solar PV panels, whereas the evacuated tubes will stick out.

Yes – solar thermal can be used for central heating. Solar thermal panels work by collecting heat from the sun, either through evacuated tubes or flat plate collectors, and transferring that to a heat transfer liquid that heats your hot water. This can then be used to preheat your central heating.

You’ll need a hot water cylinder to store the water that your solar thermal panels heat up. It’s likely that you’ll need an immersion heater or boiler to heat the water further so you can use it for your central heating, and as a back-up during the longest winter months since the solar panels won’t be able to generate as much heat.

In our opinion, it’s best to use your solar thermal panels for hot water rather than your central heating. That’s because you use hot water all year round, whereas you probably won’t have your central heating on in the spring and summer, when the panels can generate the most heat. For central heating, air- or ground-source heat pumps are a great renewable option, and you can even power them with electricity from solar PV panels if you want to be as eco-friendly as possible.

How much energy a solar panel produces depends on its manufacturer and exposure to the sun. A good-quality solar panel typically has a power output of about 300 watts per hour, but this can vary from about 240 to 360 watts. How much energy your solar panel will produce per day depends on how many hours of unshaded daylight it’s exposed to.

Here’s an idea of how much energy you could expect a large commercial solar panel installation to produce in a year.

Solar panel system size, No. of solar panels, Annual electricity output

11kW, 44, 9,350kW

20kW, 80, 17,000kW

30kW, 120, 25,500kW

40kW, 160, 34,000kW

50kW, 200, 42,500kW