Click on the questions below to find out the answers to these commonly asked questions.
I have a 2,500 square foot home. How large a system do I need and how much will it cost?
Will I need batteries for my solar system?
If I install a solar electric system, does that mean I don't need the local utility company?
What kind of payback can I expect from my investment in a solar PV system?
What kind of maintenance is involved?
Can my solar PV system be used to heat my pool?
What if we move within the next 3 to 5 years, what happens to our investment?
I’ve heard that the energy required to create a solar cell exceeds the amount of energy that cell will produce over its lifetime. If this is the case, what’s the point?
Who can I talk to about installing a solar system in my home or business?
I have a 2,500 square foot home. How large a system do I need and how much will it cost?
Assuming you want to offset as much of your annual electric bill as possible, the size of your system is more a function of your annual electric bill rather than the size of your home. People have different energy consumption habits, so a 2,500 square foot home could spend $1,200 a year or $3,000 a year on electricity. The type of home you have, the kind of appliances you run, your home's location, orientation etc all have a bearing on how much electricity you consume.
To illustrate, a well placed, well-designed 3.0 kiloWatt solar PV system in& Arizona might generate approximately $900 worth of electricity a year. The same system in New Jersey might only generate $500 a year worth of electricity. It should be noted that despite the significantly reduced output (due to less sunlight hours per day) in NJ, current state incentives make the economics of installing a solar PV system in NJ more attractive than in AZ (see www.dsireusa.org for a list of incentives available by state).
The two other factors which realistically determine the size of system most people install are: the amount of useable space to install an array (the solar panels/ modules) and the homeowner's budget. If both these factors are not a consideration, the system can be designed to eliminate as much of your electric bill as possible throughout the year.
Will I need batteries for my solar system?
Generally speaking, there are three types of systems: basic grid-tie systems, grid-tied systems with battery back-up, and stand-alone (off-grid) systems.
A basic grid-tie solar system does not require batteries because if your system produces more electricity that your house is consuming at a given point in time, the surplus power will be fed back into the utility grid, causing your electric meter to run backwards! This gives you a credit on your electricity account which you can then draw against in the evening, or whenever you are using more electricity than your system is producing.
A grid-tie system with battery back-up behaves in a similar way under normal conditions, but the system also employs batteries which are used in the event of a power failure. In a battery-backed system, the batteries are kept fully charged by the solar array and inverter and the "surplus" power is used by the home (any surplus beyond that is fed back into the utility grid). The main difference between this system and a basic grid-tie system is that a battery-backed system is designed to switch over to battery power once a grid failure is detected. The system is also designed to isolate itself from the grid to prevent "backfeeding" of surplus power in the event of a grid failure. In contrast, basic grid-tie systems are designed to shut down when there is a grid failure for safety reasons (to prevent backfeeding), even if the sun is out and they can be producing power.
A stand-alone, or off-grid system, is typically installed in a remote location where access to regular electrical service is impossible, or prohibitively expensive.
If I install a solar electric system, does that mean I don't need the local utility company?
Although it is possible to take yourself off the grid, it makes a lot more sense (economically and practically) to remain part of the grid and be able to sell your surplus energy back to the utility. The ability to buy and sell electricity from/ to the utility is called "net metering". This is one of the major advancements in energy policy that allows solar PV system owners a reasonable time-frame for payback on their investment (see question on Payback)
What kind of payback can I expect from my investment in a solar PV system?
Depending on where you are located, the simple payback (i.e. the time it takes to pay off your solar PV system based on today's electricity rates with no inflation factored in) on a PV system ranges from approximately 8 to 16 years. These are based on the net cost of a system after incentives. Keep in mind however, that the real payback will vary for each system based on your individual circumstances. Factors such as your tax bracket (for state taxes), cost of electricity (including distribution and other charges) and the rate at which electricity prices increase over the next 30 years will all have a bearing on the final payback of your system.
It is important to keep in mind that once you have made your investment in a PV system, the electricity will will generate is essentially "free" for the next 25-30 years (the approximate lifetime of your system). The amount of electricity generated each year will also be fairly consistent so it will be relatively easy to predictthe "market" value of the power you generate. What may be more difficult to predict is the change in the price of electricity over this extended time period, but don't worry, ANY increase in the cost of electricity will automatically make your investment more attractive!
What kind of maintenance is involved?
Typically, maintenance consists of keeping the surface of the PV modules (panels) clean since dust and dirt collected on the surface can reduce system performance. To do this, simply hose down the surface of the modules once or twice a year, depending on how quickly dirt collects on their surface. Modules that are mounted at a 5 degree angle or greater will have the benefit of natural cleaning action from rain and/or snow.
Can my solar PV system be used to heat my pool?
The short answer is yes. However, since PV systems produce electricity (which can in turn be used to heat water), we recommend that you look into a solar hot water system if heating water is your main concern. Using electricity to heat water is inefficient, particularly since the payback on a solar hot water system is typically less than half that of a PV system.
What if we move within the next 3 to 5 years, what happens to our investment?
Studies using historical data from the California home resale market indicate that homeowners who install a PV system should at the very least recover their investment. Unlike other home improvements such as additions, new bathrooms or kitrchen remodels, installing a solar PV system has a tangible benefit: it lowers your electric bills. This lower operating cost for your home translates into real value for the buyer and is reflected in the resale price.
In addition to recovering your investment, you will now have helped promote solar energy to a new user who may not have otherwise considered installing a system. Many rebate programs will allow you to install a new system on your next home!
I've heard that the energy required to create a solar cell exceeds the amount of energy that cell will produce over its lifetime. If this is the case, what's the point?
This is one of the myths associated with solar PV (photovoltaics). While this may have been the case at one time, today's manufacturing processes insure that a solar cell will "pay back" the amount of energy required to manufacture it within 1 to 4 years depending on the type of cell.
Who can I talk to about installing a solar system in my home or business?
If you are thinking about installing either a solar PV (electric) or solar thermal (hot water) system in your home or business, send us a note by clicking on the Contact Us section (at the top right-hand corner of the page) with your phone number and address. Someone will get back to you within 2 business days.
 Back To Top |
