When not to install solar !

[Gazap]

Just getting into solar and after a little advice.
When surveying a roof for solar panels at what point do you decide the panels should not be installed ? percentage of hard shading/soft shading, distant building that obscure direct sunlight in winter < 20 degrees angle but ok > 20 degrees, any help would be much appreciated, thanks.

 

[dansk]

Just getting into solar and after a little advice.
When surveying a roof for solar panels at what point do you decide the panels should not be installed ? percentage of hard shading/soft shading, distant building that obscure direct sunlight in winter < 20 degrees angle but ok > 20 degrees, any help would be much appreciated, thanks.

When the panels are too big for the roof

 

[Gazap]

And the correct answer is ........?

 

[Gazap]

quote " your survey needs to ensure there are no obstacles in the depth of winter when the sun is only 15.5 degrees up in the sky.If there are obstacles that are blocking visibility of the sun, you need to try and find another location."
This cant always be the case , as we live in built up areas ! any thoughts on this ? And what would you say was acceptable.

 

[SolarCity]

It's a judgement call that comes with experience I suppose. The SAP calculation should give a rough guideline on how economical a system will be.

 

[Gazap]

SAP calculation would be based on having access to full sun throughout the year, but what if there are obstacles in the Winter months periods that stops the direct sunlight, how would this be calculated and what is classed as acceptable or is it just a finger in the air job ?

 

[SolarCity]

Depends on how thorough you want to be. You could measure everything up and model it in 3D using a package like PV SOL Expert. Or you could use a solar scope so that you can check the suns path throughout the year.

 

[Gazap]

Is there an alternative software to PV SOL Expert as very expensive £1000 +

 

[SolarCity]

Is there an alternative software to PV SOL Expert as very expensive £1000 +

I've not seen a decent alternative that provides the features that we require. I'd say it is well worth the money. It is the time that you need to invest in learning how to use the software that is expensive if you are a busy person.

 

[SRE]

I wasn't keen on buying PVSOL - another expense, more training, not enough time - I wish I'd done it earlier! It's saved me loads of time and opened up options for different panel and inverter combinations that I just wouldn't have time to do otherwise. Biggsolar and others convinced me that I should have it and I use it regularly for shading now too. We provide the customer with the with and without shading figures so they understand how much of an impact the shading has and it's up to them to decide whether it's economically viable after that. Haven't cracked the financial side of it yet I've been too busy but I'm hoping to sort that out soon too.

I didn't buy the Expert version, just the pro but it does shading, just not as pretty as the expert version. Well worth the expense and time.

 

[bigbob1]

If your measuring up a house you have to remember to leave 500mm either side of the panels and don't have them sitting in the gutter! could be diffrence between 994 panels or 800 panels.
South facing 35 degrees no shadng.
SAP calc upto 20% shading does nothing to the calc.
North East/West does appear on sap calc, is customer happy with returns? ( i wouldn't be but some people have as i found out the other day n/e facing roof's and the s/e side is tiny, they really want solar just an 11 year payback as opposed to 7 year)

Tree's generally lose there leaves in the winter?

Bungalow's sat in the middle of a load of houses is where you have to start really thinking about shading. There fine in summer but winter you could be shaded for 3-4 hours a day as the sun moves through s/e to s/w.

When you get rolling you should start thinking about software, which will take up all your time using if your trying to grow a business, on top of visits, quotes, e-mails/letters, designing ordering (spending 2 hours working out shading!). Or you can always find a supplier that will do it for you!! they are out there, postcode few pics they do it all for you, i know eco solar equipment in oxford will do this for you if you buy there gear for the job (there goes your margin!).