Age & Condition of Roof
If your roof is damaged and needs repair, or if it’s old and will need a replacement within the next few years, it’s best to fix it before going through with a solar installation. Even assuming you got it approved and found installers who would go ahead with the installation despite your roof’s condition, you’d have to pay the extra costs to dismantle the system and re-install the solar energy system when you address these issues down the road.
Also, because solar panels increase the amount of weight on your roof, it must be structurally sound enough to sustain that weight. If you own a modern home it is very likely to be structurally sound enough to sustain the added weight of your new system. However, if your home is older, especially if it has been re-roofed 2-3 times, it might not sustain the added weight load of a solar energy system.
There are several roof types. Some are great for solar (see Viable Roof Types photo); while others, not so much. Common roof types include composition shingle, rolled comp, tar & gravel, wood shake & shingle, slate, concrete tile, clay tile & metal. Some less popular roof types include EPDM, PVC/TPO, plastic and foam, too.
Some roof types will always be disqualified for solar; and even though you will see solar on homes on some roof types (see Not Always Viable Roof Types photo), you could be disqualified from putting solar on your roof if you have one of the following roof types … depending on where you live, local installers and other guidelines:
- Tar & Gravel
- Wood Shake / Shingle
- Composite tile
- Asphalt covered metal
- Corrugated curved metal
- Corrugated trapezoidal metal
- Asbestos shingles
Aerial imagery might not always be able to determine one roof type from another. So, if you work with a solar rep remotely (which, is becoming the new norm) they will probably need photos of your roof at a couple different angles to be able to look at your roof to determine what type it is, as well as condition, design, layout, available area, azimuth, sun direction and identify complex angles.
A question that needs to be asked is, “do I get enough sun to go solar?” To determine if your roof gets enough sun, you need to look at which direction your roof faces and the azimuth of your roof, also. Ideally, you get most solar energy production from the south facing part of your roof. Depending also on the azimuth of your roof, east and west are secondary. Generally, north does not produce enough energy to be viable.
The suns’ rays do not hit the roofs that are too flat or too steep or that have too much pitch, at the best angles. The standard or ideal azimuth range is between 60 and 300 degrees.
Size of Available Area on Roof
Some homes have one to many complicated angles and this impacts the layout of the roof, which determines in part, how much available space there is to install solar panels. The roof on your home might be an open gable or box gable roof, or it could be flat, dormer, hip, hip and valley, gambrel, mansard, dutch gable, or a half dozen other less popular roof styles. Besides the impact of having a roof that’s so cut up (too many dormers, hips, valleys, etc) that there is not optimal space available for and adequate number of solar panels, there are also setbacks to factor in.
Most areas that enforce the fire codes, such as the ones shown below, will generally require 36” pathways from eave to ridge and along the ridge. When you factor in the regulations along with the limitations the layout of the roof can impose, there might not be enough room on your roof to install enough solar panels to generate enough energy to power your home.
- CFC – California Fire Code
- IFC – International Fire Code
- NFPA – National Fire Protection Association
- NYS – New York State Fire Code
Shade and/or Other Obstructions
Solar panels are like sun sponges. The more light they get, the more energy they produce in return. The amount of power your solar energy system can generate is dependent on sunlight. 100% Solar access = 0% Shade! As a result, your solar panels will produce slightly less energy when the weather is cloudy, and no energy at night. Each module should, at a minimum, be above 60% solar access.
So, if there are trees or other obstructions in your yard, or trees in your neighbor’s yard which block the suns’ rays from your roof, you might be able to get by with trimming back the trees or removing the obstructions in your yard, or getting the neighbor’s trees trimmed back. However, sometimes there are too many obstructions, or the obstructions shade too much of your roof; and they cannot be removed.
In addition to not placing panels under overhanging trees, placing panels directly next to chimneys or dormers will potentially create “hard threats” (threats that cause year-round shading). So, those areas need to be avoided also.
Sometimes you can remove the shading or obstructions and that’s great. Sometimes, you can’t address the shading and obstructions currently, but have a plan and timeline to get it taken care of. That’s something to look forward to. Otherwise, your roof may not qualify to go solar.
There might be another option to go solar, even if your roof is not able to produce enough solar energy. Depending on your location, the local installers and whether there is adequate space on your property, a hybrid or ground mount system might be a possibility. You’ll want to talk with a capable solar rep about that option, if you are in this situation.
You Don’t Own the Roof
One of the first scenarios that is characteristic of this is when you own your home; and are also part of a HOA, which may own the roof, or rights to the roof. The HOA might also have rules in place to make it very difficult for you to go solar. With HOAs, it really depends on where you live and the language of your HOA’s governing documents.
Also, you could be leasing or renting a house. Or, it could be that you live in an apartment, you’re renting, or you’re living with family; which essentially means that you don’t own a roof to install panels on.
If you don’t own the roof, you can’t go solar in the traditional sense. But, for some of the other reasons your roof might not qualify, you are best advised to talk with a professional solar rep to see what options might be available for you.
16 Important Questions to Ask a Solar Rep Before You Say YES to a Solar Energy System on Your Roof!
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