If you’re thinking about building a home that will comply to net zero construction in Vermont standards, no doubt you’ll have some questions about solar PV systems.
Only a few years ago the thought of having solar panels all over your roof was considered a weird or ugly thing to do. Not today. Having solar today is considered trendy, frugal, smart, and a way to insure you’ll retain market value for your home. Net zero construction in Vermont is quickly becoming the new norm.
How Many Solar Panels Do I Need?
We have a quick answer for that question: enough. Considering that solar is an investment, overkill is not as big of a problem as you might think.
For a net metering installation you really can’t have too big of an array, like this house in Massachusetts, because the excess energy you generate goes back into the grid. But within the context of not over-investing, we think the goal should be having an adequate system that will achieve net zero—yet with enough cushion to accommodate the varying energy usage habits of your family.
Sizing Your Array
Proper sizing of a solar PV system for net zero construction in Vermont involves two main considerations: Your family’s energy usage habits and building envelope efficiency.
Since a net zero solar-powered home is a super-insulated high performance home, calculating things like space heating and cooling for net zero construction in Vermont is not difficult. The only variable would be how long you need to leave a door open to enter or exit your home.
Since family habits vary, it’s important that whatever builder you chose knows how to interview you to assess your energy usage. Here are two main things we consider:
Energy Usage Considerations
- Do you have or plan to own an electric car? Can you power your electric car from a solar PV system? Yes. In fact, from the standpoint of solar, powering (charging) an electric car is no different than powering a refrigerator—but the car will take more power so it’s a bigger consideration. Here’s Tesla’s solution.
- Family habits. The greatest variable here is how many people will occupy the home? While each person won’t affect heating or cooling very much, each person will use things like hot water and water in general—causing a well pump to cycle more often.
Certainly, there is advantage to having your home oriented oriented toward the sun, and that your roof provides the space to accommodate the solar array — and that obstructions like trees won’t be a problem. Keep in mind that existing trees may continue to grow, so it’s important to see what could ‘grow into’ an obstruction a decade or two in the future.
Once your family’s energy usage is assessed, it’s a simple process to calculate how large your solar array should be. Aside from the obstructions noted above, each locale will see a fairly predictable amount of solar activu.
From there, the formula to determine array size is computed by dividing the total output needed by the average output of each panel. So again two simple questions come into play: How much does the sun shine and how much energy will I use?