Frequently Asked Questions about Solar

Should I go solar?

Maybe. We’re big fans of solar (obviously) but that doesn’t mean it’s right for everybody. While there are options such as community solar that allow potentially anyone to benefit, you’re more likely to see a financial return on investment if some or all of the following criteria apply to you:

• You own your home, and plan to live in it for at least as long as your calculated payback period.
• Your roof is unshaded or minimally shaded throughout the day.
• Your electricity prices are above the US average, which is around $0.13 per kWh.
• You have the cash to purchase a system, or have a good credit rating with which to secure financing.
• You live in a state with favorable incentives.

Of course, there are many non-financial benefits to solar. To name a few, solar energy is better for the environment, contributes to lowered costs and increased electrical grid resiliency , and contributes to a rapidly growing part of the economy that employs more than 250,000 people in the US .

I think I live too far north for solar to work.

The Solar Nerd actually lives in Buffalo, NY. Depending on the year, our 4.6 kW array produces around 80-90% of our total power needs. While snow does cover our solar array for a couple weeks a year, it’s during a time when the sun is low in the sky, so our overall power generation for the year isn’t greatly affected. I could go up on the roof with a long, slippery ladder in the dead of the Buffalo winter and brush the snow off, but I would probably break my neck in the process. Not worth it for a few extra kilowatt hours.

The United States is further south than people often realize. For example, the city of Burlington, Vermont is at about the same latitude as sunny Monaco .

Solar radiation is affected by both climate and latitude. Our solar calculator uses your zip code to account for both so that we can estimate your power generation.

How do I pay for solar?

Check out The Solar Nerd guide to solar financing.

How much does home solar cost?

If you haven’t already, use our solar cost calculator to very quickly get a ballpark price estimate that is tailored to your climate, roof configuration, and available incentives and rebates.

When you’re ready to go further, use our solar quote program to get competitive prices from qualified local installers.

What are the components of a photovoltaic system?

Our Solar 101 guide describes the various parts of a system such as modules, inverters, and racking systems.

How long do the components of a photovoltaic system last?

A PV system consists of semiconductors, electronics, and aluminium mounting. Unless you have a ground mount system with a tracking system (which is rare in residential applications) there are no moving parts involved.

Because of this, the components are robust, and manufacturers are able to offer very long warranties, typically in the range of 20-25 years for solar panels, inverters, and mounting systems. It is possible for components to last even longer than this. It wouldn’t be surprising for a system to still be in operation after 40 years.

Panels do degrade over time and produce slightly less electricity each year as they age. Our solar cost calculator factors in this degradation as a 0.9% decline in output every year.

What effect will solar panels have on my roof?

Part of the installation process is a structural engineering analysis to ensure that your project will meet local building codes. The analysis will ensure that the roof load, accounting for the weight of the panels and racking, are within the total pounds per square foot (psf) limit of your structure.

In some regions, wind uplift and snow loads are considered as well.

Your roof will remain watertight due to the use of flashing and sealants under the mount points.

One perhaps unexpected benefit is that solar panels, which are separated from your roof by an air gap, may help keep your house cooler in summer months due to shading effects, according to one study . This may also prolong the lifespan of roofing materials underneath by protecting them from UV light and reducing thermal extremes.

What are the enviromental benefits of solar?

Solar photovoltaic cells turn sunlight directly into electricity. No fuel is consumed, and no emissions are produced during operation. When taking into account the full lifecycle of the technology, including manufacturing and the supply chain, solar produces around 1/10th the carbon emissions of high efficiency combined cycle gas turbine power plants, and about 1/20th the emissions of coal, according to an IPCC analysis.

But it takes energy to manufacture solar panels, which might be sourced from coal or gas!

A meta-study by Brookhaven National Laboratory in 2009 concluded that the energy payback period for solar, which is the amount of time that it takes for a solar panel to produce as much energy as was required to manufacture it, is between 1.0 and 2.7 years, depending on the technology of the panel. Given that panel efficiencies continue to improve, we should expect this number to be lower today.

In contrast, fossil fuel power plants never achieve energy payback in the same way that wind and solar do, because they require a continuous input of mined or extracted fossil fuels.

I’ve heard that solar panels contain toxic metals.

Solar cells are made with silicon, which is entirely non-toxic: glass, for example, is composed of silicon.

Varying amounts of heavy metals can be found in solar cells, depending on the technology. Most home solar will use monocrystalline or polycrystalline cells, which may contain a small amount of lead used in the solder used to join wiring.

Thin-film panels, which are less common in residential solar, are often based on cadium and telluride. However, cadium is a waste product of mining, and the production of thin film solar uses this waste and does not contribute to any marginal increase in cadium production.

In any case, these materials are sealed behind a durable glass and alumnium frame that is designed withstand severe wind and hail. There is no toxic hazard to the homeowner. On a per-watt basis, solar is responsible for far less heavy metal pollution than coal burning, which is a major source of mercury emissions.

Solar panel recycling is not yet very widespread because panels last for a long time, and there is not yet a large waste stream. However, recycling is feasible and is being done by some companies, and will become more widespread in the future as the current generation of panels nears the end of their useful life.