Solar PV on West facing roof?

monster · Post by **monster** » 26 May 2011, 14:45

Can anyone advise me?

We have a due west facing, unshaded roof, with solar thermal, that performs very well.

When I looked into having PV added, a well known local supplier, told me it was only worth it on SW,South or SE roofs and therefore not to bother....

Does anyone else have a due west facing roof with PV - is it really a dead loss?

The front of the house is east facing, but in a conservation area, so an east and west array may be difficult.

Views please - thanks

RenewableCandy · Post by **RenewableCandy** » 26 May 2011, 15:17

Just down the road from chateau Renewable is a large, West-facing roof (on a newly-built house) adorned with 20 solar PV panels. So someone thinks it's worth it.

There's a little radar-type diagram published by the CAT which implies that due E or W you get between 70 and 80% of the energy you would get with the same kit on the same slope facing due South. Whether or not you reckon that's worth it, is another matter.

I've also noticed there is an E-W difference thus: here in Yorkshire we get sunnier afternoons than mornings (Haar mist from the North Sea comes in on cloudless mornings). Whereas across the Penines they may get brighter mornings but the rain's more likely in the afternoon (West wind in from a warm sea).

2 As and a B · Post by **2 As and a B** » 26 May 2011, 15:31

A friend in the area is getting solar PV on a west facing roof. He's pretty thorough and cautious (multiple quotes, spreadsheets, risk analyses, and so on) so I should think it is worthwhile. But it isn't installed yet...

JohnB · Post by **JohnB** » 26 May 2011, 16:58

My roof is roughly WSW facing, and the company that does free installations I contacted said it wasn't suitable, so presumably they didn't think they'd make enough money from it. I seem to get most sun in the afternoon, which is when the sun falls on this side of the house.

2 As and a B · Post by **2 As and a B** » 26 May 2011, 18:06

Pitch/inclination is also important.

Here's a chart from the Homesun website:

http://www.homesun.com/faqs/roofs-and-installation/

Our roof is WSW-facing but the pitch is something less than 30 degrees (by my calculations). The sun was on it by 7am this morning and would be on it until dusk. The other side gets the early morning sun and still had the sun on it, albeit at nearly zero degrees, around 5pm yesterday. Amazing really! Of course, the roof doesn't get that long in the sun during the winter with the sun being lower and the days shorter.