The biggest factors to consider when working out how many solar panels you need are:
- The amount of roof space you have to fit solar panels on
- Appliances you run / how much energy you use each day
- How much money you can get as a Feed-in-tariff
- Whether you might get a solar power battery system later
How much roof space do you need for a solar power system?
Modern solar panels (written in 2019) are usually 2m x 1m and produce approximately 300W each.
So if your roof is 15m x 5m on the North face, you could fit at least 2 rows of 13 panels. This would be 26 solar panels and if they are each 300W it would be 7.8kW!
This is usually more than enough solar power for your home.
What if my roof is shaded?
Shading from trees and other obstacles can reduce your solar power system output! This will affect your solar savings potential. It is always best to avoid shade wherever possible, but if you can’t avoid it then you need to manage it.
Some shade management strategies for home solar power systems:
- Trim back any trees which are shading the best roof areas for solar panels
- Relocate any antennae or other roof obstacles where possible
- Cut down stink pipes if possible
- Install solar panel optimisers or micro-inverters – although this increases the cost of your solar power system, it will ensure optimal performance where shading is inevitable.
What if my roof doesn’t face North?
Solar panels produce more energy the more sunlight they get. But it’s very common to have solar panels facing East and West. This reduces the average output by around 10% – 15%. South-facing panels will also produce energy, although usually 15% – 25% less than optimal North facing solar panel systems.
Is it still worth it if I have a small roof?
If you can only fit a small solar power system on your roof, it’s still worth getting solar panels. Although you won’t save as much money as you would with a larger system, you should still be able to see a 3 – 4 year Return On Investment. Which means you’ll still make a good amount of savings for the outlay.