Frequently Asked Questions
Commonly asked questions related to solar power.
Photovoltaic (PV) systems work by converting light emitted from the sun into electrical current. It’s the same technology found on pocket calculators, just on a larger scale. Modern systems do this by using crystalline silicon (c-Si) solar cells made of multicrystalline, and monocrystalline silicon. These cells are housed in panels that output direct current (DC) electricity, which is converted into alternating current (AC) electricity by an inverter. The current is then sent to your existing electrical panel where it is distributed throughout the home.
The DMV has a great climate for solar power, receiving nearly the same amount of sunlight per year as places like Jacksonville or Atlanta (who are known for their torrid climate). Other important considerations include the layout, orientation of your roof (with moderate-slope southward facing roofs being optimal), and items that may obstruct sunlight getting to the panels (trees, adjacent buildings, etc.).
If your home is located in Northern VA you can use the Northern VA Solar Map to get an idea of your potential to benefit from solar. Click here to access the map. If you are located in DC, Virginia, or Maryland you can use Google’s Project Sunroof to research your home’s solar potential. Click here for a link to Project Sunroof.
Today, solar energy costs less than traditional electricity in many markets. While the greatest savings occurs from an upfront purchase, many customers are able to reduce their monthly electrical cost even after the price of financing. Actual savings will depend on several factors including utility rates, electrical usage, and available sunlight.
The Federal Solar Tax Credit is an incentive that allows you to claim a tax credit for 26% of the total cost of installing your solar power system. If the credit exceeds your total tax bill, your taxes for that year will be completely eliminated, and the remaining credit can be applied to future tax bills. To take advantage of this incentive, simply fill out this form, and submit it with your federal tax return.
No, nor do we recommend them. For customers wanting a zero down option, financing represents a much better value.
Although solar systems are expandable, installations should be done in one stage whenever possible. Splitting the average solar system into two separate installations increases the total cost by more than $11,000. There are a variety of solutions for things like unknown usage (new construction, recent purchase), future usage (electric vehicle, hot tub, etc.) or limited budget that should be explored before resorting to splitting a system.
Net metering is a stipulation that requires utility companies to give you credit for any excess electricity your system produces. For example, a home that consumes 30 kWhs of grid electricity during the night, and produces an excess of 30 kWhs of solar electricity during the day would register as having used no grid electricity at all. The value of net excess generation over a billing cycle can be applied to future months.
When properly installed, a PV system will last 25-35 years. During that time, most systems require little to no maintenance.
Very minimally. We have answered this question in greater depth here.
According to the Database of State Incentives for Renewables & Efficiency, homeowners’ associations are not allowed to prohibit the installation of solar panels.
We also dive into this topic on our blog post here.
Yes, we would be happy to provide a solar quote for your new construction project. We need four things in order to do so:
- Energy usage report: You can use this Home Energy Calculator, download the results to a PDF and attach it to your email reply
- Number of solar eligible roof faces: this includes any roof face with between a 90°-270° orientation with no shading obstructions
- The dimensions, slope, and orientation of the roof faces from #2
- House plans
Read this blog post for more in depth information on going solar during/after a new home build.
It depends where you live.
In D.C., net excess generation (NEG) is credited to customers’ accounts at the full retail rate (in dollars). It can then be used to offset any future charges on that account. However, the credit is never paid out.
In Maryland, NEG energy credits (in kWh) are rolled forward month to month to be used for future use. If credits still exist after a 12-month period, they will be paid out at the generation rate.
In Virginia, NEG (in kWh) are rolled forward month to be used for future use. If credits still exist after a 12-month period, they can be rolled over to the next 12-month period, up to a limit.
In both Maryland and Virginia, it is not a good idea to design a system that produces significantly more electricity than is used. This is not necessarily the case in D.C., where the incentives are so substantial that NEG can provide a positive investment even if the energy credits are never used.
Standard Test Conditions (STC) refer to the fixed set of conditions under which solar panels are tested and named (e.g. a 300W panel). The three factors are temperature of the cell (25°C), solar irradiance (1000w/sq. m) and mass of air (1.5 atmospheric units) and they approximate what a panel would produce at the equator at noon during equinox. Because these are extremely ideal conditions, they can generally be considered the maximum a panel could produce. Because these factors are constantly fluctuating, the actual output of panels with different amounts of sunlight exposure in different parts of the world during different times of the day will almost never reach STC. This is also the reason why properly designed systems will have greater solar panel capacity than they will inverter capacity (see next FAQ).
Homeowners reviewing solar system specifications may notice that the aggregate capacity of their inverters in alternating current (AC) is less than the aggregate capacity of their solar panels in direct current (DC). The reason for this is that solar panel nameplate ratings are based on generic laboratory conditions rather than real-world, site-specific conditions. Because laboratory conditions almost always exceed real-world conditions and because inverters are more efficient when operating close to capacity, a properly designed solar system will have an inverter capacity less than the solar capacity. Matching the capacity of the solar panels and inverters (DC/AC ratio = 1.0) prevents the inverters from operating at maximum efficiency and results in unnecessary additional cost for the customer.
The vast majority of solar systems in the US are grid-tied systems, which are required to shut down when the utility power goes out to avoid back feeding power into the grid while it is being repaired. Energy storage systems can provide emergency electricity when the grid is down but are generally regarded as inferior to other technologies that serve this purpose.
The reason that the figure from your solar monitoring is different from the export figure from your utility meter is because the first measures how much energy your system produces while the second measures how much energy is being exported from your home. The two numbers would only be the same if the home was not using any electricity. As an example, if your system is producing 9000 watts of power and your home is consuming 9000 watts of power, no electricity would be flowing through your meter.
The widespread use of EPC agreements (where one company sells a system and another designs and installs it) and subcontracting (where one company sells and designs a system and another does the physical installation) in the solar industry causes skepticism among homeowners about who will actually be designing and installing their system. We are a fully licensed solar and electrical contractor. We design and install all our systems in house without the use of subcontractors.
Probably not. Although many installers love to use these as a quote differentiator/up-sell item, they cause ventilation short circuits. Attic ventilation is a more delicate science than many people realize and adding additional vents inhibits the proper function of a home’s existing ventilation system.
A typical solar power system in our area will offset 122 tons of carbon dioxide over its lifetime, and produce enough electricity to eliminate the need to burn 221 tons of coal.
You can request a free quote here.