Finding reliable information about solar panel installation on roof

We had a proposal for solar panel installation done by Company A, who told us our home was a good candidate. 11 solar panels on 1/2 of our south-facing roof would cover 100% of our electric energy needs. There are no trees in the way. We would pay around $9500 after a 25% federal rebate and 26% New York state rebate. Then they did some more measurements and said that the pitch of our roof is 47 degrees and they can’t install on a pitch over 45 degrees.

Company B told us that the 47 degree pitch isn’t an issue, that they’re OSHA certified, that a company that says they can’t do that pitch is one that doesn’t want to have to pay for the extra training and certification to be able to handle that pitch. They gave us a proposal and price very similar to the one from Company A. Their reviews on Google reviews are 4.8 out of 5.

Company C looked at our house on Google street view and said right off that they can’t do it. They could see that the pitch is over 45 degrees. They warned us that any company that told us they could do it would be taking too much of a risk and that the panels could fall down and/or pull our roof down. Their reviews on Google reviews are 4.9 out of 5.

The fact that 2 companies out of 3 won’t do it is giving us pause. Thoughts on finding reliable information about this would be much appreciated!

Kind of a dumb suggestion - but how about finding an industry professional that doesn’t have a dog in this show to help you sort out the wisdom of the 47% pitch? Maybe, a building inspector or architectural engineer?

Maybe try to contact the companies that manufacture the panels–they should know under what circumstances their products can properly be used.

Thinking back to this post:

And using my questionable math skills … @jdc 's roof seems to me to be pitched at just shy of 42 degrees.

The implication in his post is that the panels aren’t the problem so much as the buttressing of the roof structure in order to reinforce it against possible lift-induced damage.

So … yeah … you may need to reach out to a panel manufacturer and an architect, structural engineer, knowledgeable roofer, or other professional.

ETA: I doubt I did the math right (I’m tired), but the point may still stand :wink:

Found an online calculator for this: JDC’s roof appears to have a ~42% grade or be at a 22.6* pitch – JFTR.

How about contacting your electrical authority or whoever is offering the state rebate?

5/12 pitch is 22.62 degrees.

When we had solar panels installed, we asked the electrician to move the inverter up above head height on the wall. Refused. Above head height would indicate that a ladder or platform had been used. Ladder or platform use would require ‘working at heights’ certification, and ‘risk assessment’ per OHSA ‘working at heights’.

Different regulatory regime here, but entirely plausible that workers aren’t willing to work on surface steeper than 45 degrees.

Years ago, I worked in accounting for a solar company and sat in on a couple of Solar 101 seminars. I’ve forgotten far more than I remember, but a couple of basics I remember is that every location has an optimal angle for solar collection and the panels have to be mounted on racks for heat dissipation.

Depending on where you’re located, the optimal PV panel angle varies as explained here: Note that Portland’s optimum pitch is 46 degrees, so your roof would be ideal in that location. If you’re in a location where 30 degrees is the optimal angle, you’d have to angle the panel so high on one side, that it becomes an airfoil.

As stated above, there’s also the safety issue. As I recall, there was a limit to how steep a roof pitch the installers could work on. Also, homes in Hawaii are limited to two stories and I believe 25’, There was a limit to how high off the ground the installers could work.

Because I processed refunds, I’d see installations rejected by the design engineers for these and other reasons that the salesperson ignored in their quest to make the sale. The most common issue was the salesperson overstating how much electricity could be generated, sometimes proposing additional panels at wacky angles and far less than optimal locations, just to boost the numbers.

I remember this being discussed in the seminars. The standalone inverters had to be installed at standing level. which lead to other issues such as placement and number of inverters. Again, the engineers would express their frustration at what the salespeople proposed.

Thanks @Didi44 for the PV panel angle link. It says that our optimum pitch would be 41 degrees.

@susan the rebate comes as a tax credit. This is the webpage for our state’s solar authority; I’ll send them an email Solar Program (NY-Sun) - NYSERDA

@aruvqan that’s a helpful comment. The project needs to be approved by our local village authority which is notoriously nitpicky about granting permits. (We had an addition on the back of the house years ago and according to our contractor they’re stricter than surrounding municipalities) So I hope that they’ll veto it if it sounds unsafe to them:

“The Village of XX is proud of its outstanding efforts via the Building Department to oversee environmentally safe and code regulated building practices in the village. It helps maintain an aesthetically pleasing quality of life for residents … through stringent policies on occupancy, zoning, and planning.
Residents who are planning to conduct any work on their home that may include plumbing, electrical, and any construction or renovation in or outside of the home should contact the building department to obtain necessary permits and code inspections.”

I coordinated installation of 146 panel PV array on our Church and the roof pitch was quite steep, possibly close to 47 degrees. Installer used regular racking and structural engineer we hired separately (because he had handled engineering of large renovation of the Church, and had a head start in knowledge of the building) approved the design, certified the roof could handle the load. A steep roof probably produces more dramatic avalanches of snow, so installing snow breakers at the eaves might be a good idea if there are paths or anything delicate below the array. I am guessing the third company just doesn’t want to work on such a steep roof. Our crew rented a large scissor lift to bring up all the materials and the crew. Curiously the roofing company that re-roofed the two half roofs prior to the job did not use a lift and the workers humped every bundle of shingles up the 40 foot ladders. Everbody harnessed up for their work, which was comforting,

Thank you @jdc that’s reassuring to know!
Churches are big energy consumers I’ve heard and often not built with energy efficiency in mind so solar makes sense.

Do you mind telling me the name of the church so I can look at it on google maps and compare the angle? PM me if you want to keep it relatively private. Or I’ll PM you a picture of our house.

800 Highland Ave. Needham MA

That they say it’s a 47 degree pitch, gives me pause. I mean, who does that? I have a 12/12 roof on part of my house that makes it 45 degrees.

Really, from what I just see driving around here, that should be no problem at all. A pain to install perhaps, but If it’s facing south, I think that just about ideal.

Its only convenient that a slightly less sloped roof there at your latitude is just right for your latitude, that the panel can be mounted without an angle adjusting frame… they are mounted on frames the world over…

You need a steeply pitched roof to deal with snow…

So you have the complication of adding snow and ice weights onto the frame requirement. The ones who reject the job aren’t carpenters or roofers to fix , be sure about, the roofing system so as to handle the snow load … when the solar panel reduces the pitch… snow might build up. Its easier to add a steeper solar panel, knowing the steeper pitch is going to be enough.

Its a bit arrogant of them to say that its impossible,its just outside the work they want to do. (whether thats purely want or they shouldnt do it , is irrelevant to you. )


Our village did approve the construction plans and the installation happened 2 days ago. It took 2 men from 8 AM to 3 PM (including a lunch break) to put the frames on the roof, pull the panels up the ladder, attach them to the frames and then put “critter gard” mesh around the sides to keep squirrels and birds out. They were both securely harnessed.

It doesn’t look like the frames adjust the angle at all. The lead installer was a young-looking guy who turned out to be 36 and has been doing it for 10 years. I asked about the steep angle (which looks very comparable to the roof of the church linked by jdc) and how 2 companies had said the angle was too steep for them to work with. He said that it wasn’t really an issue and that the install would have happened even faster but they were moving more slowly because it had rained overnight.

An electrician worked on the other side of the roof to do the electrical panel connections and conversion and add a couple of boxes and meters. He was done in under 4 hours.

This sounds similar to what happens in the UK. If you come here and drive around, you will see plenty of ugly developments, but also a great many pretty villages and town high streets.

My mother lived for years in a small town in The Cotswolds and was not even allowed to paint the front door a different colour, lest it spoiled the ambience. At least it stopped Mc D, Costa, or Mr Rich Banker from building some ‘monstrous carbuncle’ in the high street.