We have added 24 solar panels to our house. We have 12 on the front roof, 4 on the garage roof, and 8 on the rear roof. The front panels are facing SSE and the north ones NNW. Since these were installed on the 13th June there has been loads of sunshine. All the panels, split into three strings of 8, are generating well.

When I was researching which solar to buy I had a few tell me that the rear panels were not worth the money. Well, in any installation the solar panels are almost *the* cheapest part of the purchase. Scaffolding costs as much as half the cost of the total panel purchase. The inverter and batteries are the most expensive and there are other items you can add, like a backup/EPS unit to allow you to keep running when the grid has a power cut.

So far the rear panels, which are 33% of the capacity, are producing 24.4% of the solar. The front and garage are producing 38.8% and 36.8% respectively. North facing panels are definitely worthwhile.

Since the install the system has generated 1,430 kWh (saving 26.32p per kWh, £376.38 so far) and exported 1,130 kWh (earning 16.5p per kWh, £186.45 so far).

You do need to get an inverter that can a) use the majority of the electrical power generated by your panels, b) that will allow your typical maximum household demand to be satisfied by the solar, c) than can charge your battery and draw down from it to the typical maximum household demand.

If you are buying a battery then it should be sized to cater for your standard daily consumption. [Find your electricity bill, look for your annual kWh consumed, divide by 365 = minimum battery size.]

In peak summer you will burn zero grid kWs. You will run your house 100% from solar (and battery overnight) and have excess solar to sell back to the grid. In the winter you can run the house from the battery overnight and into the morning and dark evenings and the solar will contribute to an extent. Getting a good tariff is vital.

Paying your DNO for the G99 request to allow a bigger inverter than the 3.6kW a G98 request permits is a must. Any solar provider trying to sell you just a 3.6kW inverter ad a 5kWh battery is probably looking for the quickest sell and is not looking at your specific needs.

There are lots of tools to help you decide what any setup for you would look like and what your savings would look like. Here are two I’ve used:

• https://garydoessolar.com/utilities/dailymodellingutility/   This is a useful site to model your costs and savings for different inverter and battery options.
• https://globalsolaratlas.info/detail?c=51.44569,-0.906871,19&s=51.445917,-0.907346&m=site  This is a useful site to model your solar generation modelling.
• Most advertised Solar providers (those that pop-up in your facebook and instagram) who offer a modelling tool, just use it as a method of collecting your data to call you back and push the sales process.

Doing solar correctly is also about getting onto a good tariff with your supplier that maximises your savings from using solar and maximises earnings from export to the grid.

For many the various Octopus Energy fits the bill, but for me E.ON Next provides me the best rates. Especially when combined with the longest and cheapest off-peak rates for EV charging. Why run my dishwasher (or any other appliance) in peak times, using my 26.32p of saved solar, when I can sell that 1kWh to the grid at 16.5p and wash the dishes at 6.7p overnight. Charging the house battery overnight is also more cost-effective than charging it with solar power.

Solar is worth it. However, you need to look at the available space for the panels, as well as what shading you have that would disrupt your solar absorption. I have some shading on my garage roof from a nearby tree (no, councils will not chop or trim a tree just to give you more solar radiance) so I have some optimisers on these panels (and on this string as a whole) to ensure that I get the best out of that string of panels.

Do the maths. Then look for the right system that covers your needs. Then find the right installer than will give you what you need not just what they have to sell, and that will do a good job of the installation and is a company with a good background and not just a roofer and a sparky out to make a quick deal [remember the G98 warning!].