Should you put your panels on tilt frames?
Tilt frames are used to get solar panels to the optimum angle and maximise power output.
Here is really common dilemma:
“I’ve got 3 quotes for solar: The first company says my roof is at the wrong pitch and wants to charge me hundreds of dollars extra to put my solar panels on tilt frames to optimize the amount of electricity I get. The second mob say it is fine to just put the panels flush on my roof and the third guy says that, yes my roof isn’t at the perfect pitch, but the best solution is to mount them flush to the roof and simply add an extra solar panel to make up for any reduced power output.
Now I’m really confused! Help!”
The problem here is that there are 2 extremes of solar installers:
At one end of the spectrum you have "The Solar Purist".
He is only happy if the solar panel is positioned for the absolute optimum power output – he is a perfectionist, highly technical, and has been in the industry since the dawn of solar, when solar panels cost 10 times what they do today. He thinks a few hundred dollars is a small price to pay to squeeze a bit more power out of those precious solar panels. And please, never, ever suggest to him that he uses a non-German inverter.
Then at the other end of the scale – you’ve got the “She’ll Be Right” Solar Installer.
He just wants to get the install done. If you’ve got a roof, and it doesn’t face south and it’s not completely shaded he’ll bang the panels on, and move on to the next job.
We believe that the best installation for your home is somewhere in the middle
The best solution to maximize return on your investment.
You need to consider the financial consequences for each option and then decide whether tilt frames are a good investment or not.
So let’s look at a typical scenario where tilt frames would be an option and see which of our 3 original options makes the most sense from an economic perspective:
To Tilt or Not to Tilt - that is the question
How to work out if tilt frames make sense or not:
Imagine you have a house in Nelson with a North facing roof that has a very shallow slope of 10° and you want to install a 3kW system.
The perfect tilt angle for solar panels is the same as the latitude of the install location. Nelson has a latitude of 41°.
So therefore the panels should be of the Latitude.
So if we follow those guidelines, we’d have to use tilt frames for all our solar panels right?
Panels at the perfect Angle:
If we crunch the numbers , then we can quickly work out that 3kW of north facing solar panels at the perfect angle of 41° will produce 12.0kWh per day averaged over 1 year.
If we value our electricity at 25c per kWh, then that earns us $1095 per year.
Panels at 10°
If we crunch the numbers for 3kW of North facing solar panels at only 10° then we discover that we get 11.6kWh per day which makes us $1058.
How much do tilt frames cost?
Assuming our 3kW system uses 195W panels, the extra cost of tilting 16 x 195W panels should be around $450.
So to make an extra $47 per year, we are going to be spending $450.
About a 9 year payback.
Whether you think this is a good investment is completely up to you. But your solar installer should give you the numbers so you can make an informed decision!
I personally wouldn’t bother, mainly because, if you use tilt frames on your roof, you can fit fewer panels on that valuable roof space.
Because you need to leave extra space between the panels so that one row of panels doesn’t cast a shadow on the row behind it. I also think that tilt frames are not so aesthetic to look at . But perhaps that is just me.
What about adding an extra panel?
The third option you have – is to make up for any lost power by simply adding an extra solar panel.
A few years ago, when panels were 5 x the price, this would have been an insane suggestion (and some old school solar installers still think it is a terrible waste!) but in 2012 it can make a lot of sense.
The cost of one extra 195W panel will be about $440. Installed flush to your roof, this 17 panel system will generate 13.0kWh per day and make us $1186 per year.
So your extra $440 investment is returning you an extra $169 per year compared to the 16 panel system mounted on tilt-frames at 41°.
I’d say that the extra panel is a much better investment that the racking.
Note: One thing that you don’t want is completely flat panels (angle = 0°). You want them to slope at least 10° so that the rain flows down the slope and helps the panels self clean.