Angle for solar roof ?

[ElectricTundra]

Safe assumption that the ideal angle for Tesla roof is the same as standard panels? So for south facing then Lat * .76 + 3.1 for a starting point for ideal roof slope? Tiles won't lay flat though so add a bit of extra slope to correct for that? 5°?

 

[BerTX]

It makes very little difference, actually. Not worth worrying about or trying to correct for. I have a fixed array that is NOT on a roof, and every year I think about re-working the support structure to make it adjustable for the seasonal change in sun angle. Every year I do the calculations and decide it isn't worth it.

Maybe next year...

 

[swaltner]

Yes, the optimal angle should be the same between Tesla Solar Roof and standard solar panels. It would be something to discuss with your architect/builder if you are in the planning stage for a new house, but as #BerTX said, it's probably best to be ignored for a house that already has the roof structure installed.

 

[ElectricTundra]

I'd think the louvre grids would make angle a much bigger issue.

 

[FlyF4]

I guess I would be more concerned as to whether the Tesla solution is worth the much higher price (long break even point) and has as good of efficiency as tried and proven modules on the market for years. I'd love to see some efficiency numbers and watts per square meter. I don't think I would ever buy into something that new and unproven. That's just me.

 

[miimura]

I guess I would be more concerned as to whether the Tesla solution is worth the much higher price (long break even point) and has as good of efficiency as tried and proven modules on the market for years. I'd love to see some efficiency numbers and watts per square meter. I don't think I would ever buy into something that new and unproven. That's just me.

IMHO, the W/m^2 doesn't matter. What matters is the cost of the comparable roof with solar panels vs. the total cost of the solar roof with the same production as the solar panels. Then you can decide if the cosmetics justify any cost difference. In my case, people can't even see my roof from the street, so cosmetics don't matter.

 

[ElectricTundra]

@FlyF4, generally yes, but for us the extra cost is somewhat minimal since we're building a new house so its the diff between whatever we'd have normally used and the Tesla product. Based on what we know so far the Tesla product looks like a good, though agree it's slightly risky, option for us.

My wife has also stated that we'll get solar panels on our roof when she dies or infinity, whichever comes first. She really dislikes how they look.

 

[FlyF4]

IMHO, the W/m^2 doesn't matter. What matters is the cost of the comparable roof with solar panels vs. the total cost of the solar roof with the same production as the solar panels. Then you can decide if the cosmetics justify any cost difference. In my case, people can't even see my roof from the street, so cosmetics don't matter.

yes agree. Many companies will specify the watts per sq meter with cost to make comparison easier. For me, the wattage per sq meter did matter because I had limited space and wanted a particular size system.

 

[ElectricTundra]

I got to have a conversation with one of the folks who developed the solar film louvres that I believe Tesla are using. There are two versions; fixed and variable. The variable version would be able to vary their angle to match the angle of the sun or perhaps better, provide an angle that enhances the amount of sun that hits the cells. At some angles the louvres would act as reflectors so rather than open parallel to the sun's rays would be at an appropriate angle of incidence. Potentially, the variable louvres could increase a panel or shingle efficiency by up to 30%.

The downside though is that as the louvre angle changes the appearance also changes. So what looks like textured shingles in August may look like solar cells in January.

I got the sense that the variable version is not yet ready for prime time and could be several years out yet. I was also unable to determine from our conversation how much impact the louvre's (assuming fixed) will have on efficiency and if mounting angle is more critical with them than with standard panels.

 

[Topher]

Simplest angle: Angle of your existing roof.
For a new house, simple angle: due South (sun-ward) at the angle of your latitude.
For anything else do the actual math for your latitude, typical weather, actual orientation of your house, etc.

Examples: Further from due South, requires lower angle. Early morning fog moves optimal orientation further West. Peak electricity use patterns move optimal Westward, if you can take advantage of that. Heavy snowfall moves tilt angle steeper.

I'd think the louvre grids would make angle a much bigger issue.

Probably not for optimal angle, but possibly for acceptable angles.

Thank you kindly.