“Is my roof suitable for solar panels?” You have probably asked yourself this question if you’ve been considering a photovoltaic system for your home.
source: Luma Solar
The good news is that you can install solar panels on almost any roof, as long as they have a suitable racking system.
For example, you can use clamps if you have a standing seam metal roof, or penetrating mounts for shingle and tile roofs. Ballasted mounts are also viable if you have a flat roof, although this is less common in residential settings.
Having an asbestos roof is one of the main factors that can limit the use of solar panels. While the installation is technically possible, most solar contractors will decline this type of work due to the health risks involved.
The fibers released when drilling asbestos can be extremely hazardous if inhaled, and this is not only a health risk for installers, but also for anyone living in the home. Asbestos can stay in your body for years without symptoms, and then cause severe lung issues without warning.
Even if you have an asbestos-free roofing system, you need to consider three important things about solar panels:
- Solar panels are very durable. High-quality photovoltaic modules can last for more than 25 years, which is great because you get over two decades of clean electricity. However, this also means you need to remove them in case of a roof replacement.
- Solar panels are large and heavy. Typically, a 60-cell solar module for residential use will measure around 65” x 40”, while having a weight of around 40-50 pounds. The newer solar panel designs with 120 half-cells have roughly the same weight and dimensions. There are also modules with larger designs, and their weight increases accordingly.
- Solar panels can generate high voltage and current. This becomes a risk factor if you have a flammable roofing material like cedar. If this is your case and the roof is old, you can upgrade to a roofing material that is more compatible with solar panels. Fireproofing is also an option, but it only makes sense if your roof will have at least the same service life as your solar panels.
For instance, if your solar power system has 20 modules, you’re adding between 800 and 1,000 pounds of equipment to your roof structure.
Removing the solar panels for a roof replacement and then reinstalling them can be an expensive procedure. This also involves the risk of damaging components, and most solar manufacturers will typically void their warranties if your modules are dismounted and reinstalled.
To avoid the situation, the best solution is making sure that your current roof still has a service life of at least 25 years.
Even if your current roof still has a few years of service life left, an early replacement is recommended if you plan to install solar panels.
Going solar is a long-term investment, and your home must have suitable conditions to get the maximum benefit from that asset.
Alternatively, you have the option of solar roof shingles or tiles. You can get a new roof and solar electricity at once, without dealing with two separate projects and installation crews.
You have probably heard about the Tesla solar roof by now, but there are many other high-quality options to choose from.
How to Simplify Your Solar Panel Installation
The complexity of installing solar panels depends on your roofing system and material.
If you’re looking for simplicity and a quick installation, there are two main options: Using a standing seam metal roof or installing solar shingles or tiles with built-in photovoltaic cells.
There are several mounting options for solar racking systems, as mentioned above, but standing seam roofs have a major advantage: you can use clamps and avoid penetrating mounts completely. This is a simple design change that brings multiple benefits:
- Since there is no need to drill your roof while installing solar panels, the risk of water leaks is minimized.
- You may get better warranty conditions for your roofing system, since solar panels are installed with no modifications.
Water leaks should not be an issue when working with professional solar installers, regardless of the mounting type.
However, roof repairs are much less likely if there is no drilling involved in the first place. Standing seam metal roofs are characterized by their durability, fire resistance, and watertightness.
A qualified solar company can deliver a professional installation on any type of roof. However, you should avoid flammable or fragile roof materials whenever possible.
You will need fireproofing treatment when using flammable materials like cedar, and this increases the cost of your project.
If you have a fragile roofing material like clay, consider that even experienced solar installers may break a few tiles in the process.
The installation becomes a bit more complex, since penetrating mounts are necessary in both cases, but you don’t have to deal with flammable or fragile materials.
Asphalt shingles and synthetic roof tiles are both durable, and they can be manipulated with ease while installing solar modules.
Installing Solar Panels on Low-Pitch and High-Pitch Roofs
If you hire professional installers and your racking system is of high quality, your roof pitch should not be a limitation for using solar panels. However, there are some design considerations if your roof slope is very low or very high.
The shear force on the racking mounts increases along with the pitch, and this must be considered by solar installation companies during the design process.
Working on a high-pitch roof is also riskier since falls are more likely when working on a steep surface. Qualified solar installers can handle any roof, but a lower pitch typically makes their job easier.
The orientation of solar panels affects their electricity production, and this effect is more pronounced on a high-pitched roof. Keep this in mind if you’re considering one for your home.
- In northern hemisphere countries like the US, south-facing roof sections get the most sunshine throughout the year, while north-facing sections get the least. You will want to avoid north-facing solar panels on a high-pitched roof, since this will drastically reduce their productivity.
- In both the northern and southern hemisphere, east-facing solar panels generate more electricity during the morning, while west-facing panels are more productive during the afternoon.
- If you have east-facing and west-facing modules on a high pitch roof, this effect will be evident when measuring their electricity output.
Most home designs in the US have pitched roofs, while flat roofs are more common on commercial buildings.
However, if you happen to own a home with a flat roof design, a ballasted mounting system also becomes an option for your solar panels. In such a case, there are no clamps and penetrating mounts, and the solar array is held in place with weight alone.
Getting a Solar Roofing System: A Viable Alternative
A solar roof can be a great option if you’re building a new home or need a roof replacement for an existing property. Instead of dealing with two separate installations, you can simply purchase a roofing system with built-in photovoltaic cells. This has many advantages:
- The cost of a solar roof is often lower than the combined cost of a new roof and a solar panel system. Solar roofs can seem expensive when compared with solar panels alone, but they are cost-effective when you need a new roof anyway.
- There are many solar roof designs available in the market, which means you can pick one that matches your overall home design.
Solar roofing is a great option for homeowners who prefer designs that use shingles or tiles.
Normally, if you want to use solar panels on shingle or tile roofs, you need to install penetrating mounts through the roof. – This procedure must be carried out very carefully, or you could be dealing with water leaks in a few months.
Another viable option is to use BiPV solar tiles or shingles: you will save on wiring and installation costs, and there is no need to drill holes in the new roof.
Just like electric vehicles, solar roofs tend to get associated with Tesla. However, there are many other providers that also offer great products.
Some solar roof providers only offer complete replacements, covering your home with a combination of solar and non-solar shingles.
The solar shingles are used for roof areas that get maximum sunshine, while the normal shingles are used for all other areas.
Solar roof providers will often design both shingles with identical or very similar appearances, which means your photovoltaic cells become invisible from ground level.
There are also solar roof providers who offer partial upgrades, which means their solar shingles and tiles are compatible with roofing materials from other providers. This is an advantage if your roof is still in good condition, since you can upgrade only the areas that get plenty of sunshine.
Luma Solar, SunTegra, SunPower, CertainTeed offer solar shingles/tiles that can be used for partial upgrades. Keep in mind that the product offering and designs available will vary depending on the provider.
If you need a new roof and are also considering solar power, the simplest options are a standing seam metal roof or a solar roofing system. Asphalt shingle and synthetic tile roofs also allow solar panel installation with relative ease, although you will need penetrating mounts.
Clamps alone are enough when you have a standing seam metal roof, and a solar roofing system eliminates racking completely because PV cells are built in.
Flammable roofing materials like cedar should be fireproofed before installing solar panels, and fragile materials like clay should be handled with care to minimize the number of broken tiles.
You should definitely avoid asbestos due to the health risks involved, and you probably won’t find a solar installer willing to do the work in the first place.