How to measure shading for solar panel instalation

olbas_oil

My  2 storey house has roof pitches facing (nearly) East & West. Jutting out from the house is a long single storey extension (living space and garage).


I think the South facing pitch on the extension would get the most sun, particularly if I placed the panels at the far (West) side. There's so little sun at this time of year that I can't make direct observations on how much shading there is from the main house. The websites I have seen just allow compass directions, but take no account of shading from nearby structures. Is there an app/website that would give me a better idea?
    

zeupater

Hi

Before you get into the technicalities, have a think about your expected usage profile ...

Are you always up and using energy at sunrise/morning vs evening/sunset ... I know it sounds odd, but most don't consider that the energy they use is normally skewed towards the afternoon & evening, more than morning ...

Next, how long is the 1 storey part of the property (ie could you have S facing panels on the W of the roof to minimise shade) use and how many panels are you looking at in total - also, are you looking at using 2 or 3 roof planes (E/W/S) ... importantly, is the roof gabled or hipped?

Anyway, it's probably the best time of year to look at the worst shading conditions at the moment, so if you're worried about potential shade why not wait for the next sunny day (Wednesday?), grab a camera and take a picture every couple of hours or so to check what actually throws shadows across the roof .... could be neighbours, trees, hedges  TV aerials etc ...

HTH - Z