Solar technology converts the sun's energy to electricity, transfers it to a liquid or air, or stores it in a solid mass like stone. Increasingly, buildings are also sited and designed to absorb the sun’s heat through “passive” solar strategies.
Solar energy systems come in all shapes and sizes: from solar photovoltaics (or “PV”), which produce electricity (that can be used to heat and cool your building), to passive solar (for heating buildings with sunlight), to solar thermal (to provide hot water). For more information about solar thermal, visit the Solar page in the Hot Water section of this website. Solar PV and passive solar are described below.
- Photovoltaics (PV): Modern solar photovoltaic panels convert the sun’s energy into electricity. PV panels are made out of thin wafers of silicon—the same basic building block of beach sand. Sunlight hitting the PV panels causes the electrons in the silicon wafers to move around rapidly, creating an electrical charge that is captured, then typically converted to alternating current (AC) and used to power homes, businesses or whole communities. In Vermont, solar panels produce most of their potential power during the summer months. When considering solar PV, you may hear some of the following terms for ways to obtain electricity:
- Net metering - This allows you to receive a direct credit from your utility for power your system generates; your solar generation can be used to offset your energy consumption
- Purchase or lease options - Many solar installers offer you the option of buying your system, leasing it over time, or leasing with a later option to purchase it. Terms will vary.
- Off grid - Your location is not connected to the local electric utility and the power you generate will be used on site only
- Passive Solar: A passive solar home collects heat as the sun shines through south-facing windows and retains it in materials that store heat, known as thermal mass. Concrete, brick, stone, and tile are commonly used, since they have the advantage of doing double duty as a structural and/or finish material. To be successful, a passive solar home design must include basic elements that work together, including properly oriented windows, proper material and amount of mass, a way to distribute the heat, and control strategies to maintain comfortable temperatures. Regardless of whether your home was originally designed to be a passive solar home, you can use the sun’s warmth during winter days by opening south-facing curtains or drapes. In summer, closing the drapes during the day will help keep the house cooler.
- When paired with batteries, solar PV may be able to provide you with renewable energy and a back-up power source if the utility supply is interrupted
- Passive solar uses no additional fuel to help keep your house at a comfortable temperature year-round
- Not all roofs face the correct direction for solar, and some roofs require maintenance and preparations to allow for the weight of the solar arrays. If you have an issue with locating your solar system on your roof, it may make sense to consider a ground-mounted solar system for your property.
- Technology improvements are making solar PV cheaper and more flexible when it comes to siting requirements
Some Next Steps
Solar PV may potentially reduce your energy costs, depending on the incentives available at the time you “go solar.” However, most people believe it’s important to “right size” a solar system. So, before going solar, you will probably want to consider having a professional energy assessment to identify ways in which you can save energy. Then you may want to scale your solar system to the amount of energy you need to produce after having done all cost-effective efficiency work and considering the potential for higher electricity use in the future. This approach typically enables commercial and residential customers to save the most energy and money overall.
The Department of Public Service published “A Vermonter’s Guide to Residential Solar,” which homeowners may find helpful. That guide, along with other renewable energy resources, can be found at the Department's Resources page:
Visit the pages below to learn more about Heating & Cooling: