Most efficient panels for a small space

Hi all,
I have had a few people quote for solar panels and I have been surprised they have always said the best solution is to put them on my pitched west facing roof. Attached is a photo showing the roof layout. The west facing pitch roof is long so can contain more panels, and as it is pitched it is more straight forward to put on the roof. However, as it is due west I understand it is approximately 30% less efficient, and you can also see the roof suffers shading both from the chimney (which in the photo is casting a shadow), and late in the day there is potential shading from the neighbours roof.

In my head it potentially makes more sense to install a system on the flag south facing roof which measures 3100mm x 5400mm, where there is only going to be shading from the neighbours house at the end of the day (and optimizers wouldn’t help as the whole system would end up in shade).

I wonder if anyone has any advice on what would be the most efficient panels that I could mount on this south facing roof given the size limitation? I wondered whether there are new panels on the market that produce more electricity, or whether there may be some coming on the market soon that are worth holding out for? The bottom line is I want a system that is about to produce 4 kwh in a day, and with a battery to approximately match that capacity

Many thanks

Hi @Lewes

Have you played around with the panel layout yourself, you can use our Photonik solar design tool for this. You can put panels on your south and west roof and see what generates more energy overall. Yes, your south roof will be more efficient (assuming northern hemisphere), but you’ll get more energy overall on west. Why not use both roofs?

Here’s an example of a similar roof. The difference in efficiency in this example is less than 20%. You can see overall generation is higher on the west roof, but payback period is longer. It really depends what you are optimising for.

You can add estimated shade derating as well, and see how that changes the equation.

Specifically to answer the question of most efficient panels, you can see here:

After looking at your roof layout, installing the solar rooftop system on the south-facing roof (3100mm x 5400mm) may yield better efficiency despite potential shading and to do so look for high-efficiency panels to maximize output. Keep an eye on emerging technologies for more efficient options, ensuring your system meets the goal of generating 4 kWh daily, paired with a matching-capacity battery.