You can get a ball park estimate sufficient to create a realistic budget and set realistic payback expectations by using online calculators. These calculators enable you to enter your own data (for example, panel size and cost per watt) or to use the default values typical for your location.
The National Renewable Energy Lab (NREL) PVWatts calculator estimates the amount of energy production and dollar value of energy produced for grid-tied PV systems of specified size and orientation to the sun. The Solar & Wind Estimator provides a thorough financial analysis for solar water heating, pool or spa heating, and space heating/cooling systems in addition to PV systems. This analysis is based on energy bill savings and net system cost, after tax credits and other incentives are applied. The Solar & Wind Estimator also calculates the impact of loans if you intend to finance your system that way. It displays cash flow and your break-even point in graphical form.
Small changes in energy consumption habits can reduce the cost of renewable energy. For example, reducing household energy use by only 100 kilowatt hours a month has the same effect as buying 3-4 solar panels that produce 1,200 kWh annually, yet it costs nothing. Many PV owners began by replacing half the energy they use from the grid with solar power; then they reduce the other half with energy conservation. PV systems can be installed in stages to spread cost over several years.
Solar PV electricity is an appreciating asset. The value of your system will increase as future electric rates continue to rise. This investment will raise your home’s value, reduce peak loading on the grid, and support the local economy. PV prices have fallen by 70% over the last six years due to technological innovation and new financing models so the investment is more affordable than ever.
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