[RE-wrenches] Dealing with snow

penobscotsolar at midmaine.com penobscotsolar at midmaine.com
Fri Aug 14 13:48:19 PDT 2009


Hi August,
   Here in Maine we get pretty decent amounts of snow. There isn't any
foolproof way to keep your panels clear without doing it manually
because we sometimes get sticky, half ice, half snow type of
precipitation, but here's some of the things we do.
>
>
>
> 1. Do you typically mount arrays flush to the roof? If so, I'm assuming
> that roof pitches are generally designed to handle the various snow load
> and snow-shed scenarios depending on how much snow the area sees?

  We do typically flush mount, providing the roof pitch is the typical
10-12 pitch. If it is less we have used tilt up racks, but that
seriously cuts down the available usable array sq.footage. The roofs
here are built to handle snow loads exceeding what we would normally
get, but you will still often see people on less than 10 pitched roofs
cleaning them off in the middle of Feb.


>
> 2. Does the height off the roof matter? In other words, is it better to
> mount low to the roof or higher above the roof. Does snow wedge under the
> array?

We have always mounted as close to the peak as possible. I have seen
arrays, not installed by my company, in which the snow has built up over
time on the top of an array mounted too far below the roof line/peak. The
snow melts and refreezes and quickly becomes a liability to the
effectiveness of the array, at least. We have moved the entire array to
the top of the roof line and the clients no longer had that problem. Of
course, for customers that rely on a roof rake to remove snow from their
array, moving the panels to the highest point on the roof essentially
removes that option.


>
> 3. Are there products out there designed to help shed snow?

   We have used Rain-X. It does seem to help. Occasional re-application is
necessary. Beside that, I haven't used any other option. Maybe a solar
powered electric heater :-) would work?


   With pole or frame mounts that are adjustable we tend to tilt them up
to 80 or 85 degrees to facilitate snow shedding.
>

   I'm sure you'll hear a lot more from other NE wrenches, amongst,
geographically, others.

Daryl DeJoy
NABCEP Certified PV installer
Penobscot Solar Design




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