How much hot water do you use, and what do you use to heat it?
A solar water heater will heat up to 70% of your home's hot water. The payback of a solar water heater varies based on what you are currently using to heat your water and how much hot water you use every day.
16% of the average Massachusetts home’s annual energy use comes from water heating alone—two-thirds as much energy as used for all electronics, appliances, and lighting! As a result, the amount of money you can save depends on how much hot water you use on a daily basis and what fuel you use to heat it.
A solar water heater will provide 50-70% of the average home’s hot water needs, replacing fuel that would otherwise be consumed in a conventional water heater. If you live in one of the 40% of homes in Massachusetts that use electricity, fuel oil, or propane to heat water, you’ll be able to save a lot of money on your energy bill from installing solar water heaters.
The average family of four can expect the following energy savings from installing a solar water heater:
Solar Water Heater Expected Savings*
| Fuel Type | Oil | Electricity | Propane | Natural Gas |
|---|---|---|---|---|
| Fuel Cost | $3.13/gallon | $0.157/kWh | $3.35/gallon | $1.38/therm |
| Annual Savings | $360 | $830 | $570 | $75 |
| Lifetime Savings | $7,200 | $16,600 | $11,350 | $1,500 |
| Years to Payback | 9.6 | 6.1 | 6.8 | 16.1 |
Your actual savings are likely to be different from the table above. In general, if you use more hot water than the average family, you will save more money with a solar water heater.
Don’t forget: energy prices are constantly fluctuating. While gas, oil, and electricity prices go up and down, sunlight is always free. The water heated by a solar water heater is virtually cost-free, with low maintenance costs over the system’s 20-30 year lifetime. As a result, solar water heating is a great way to lock in energy prices today and avoid the price swings associated with fossil fuels.
*Annual savings are average expected savings over 20-year lifetime. Assumptions for expected savings include: fuel prices of $3.13/gallon for oil, $3.09/gallon for propane (Massachusetts winter 2014/15 average, MA DOER), 15.72 cents/kWh for electricity, and $1.38/therm for gas (Massachusetts averages from 2011-2014, EIA) and escalators ranging from 0.8% to 2.1% EIA Annual Energy Outlook 2015, Reference Case for New England); solar fraction of 70%; three collectors installed at $12,000 (average from MassCEC Commonwealth Solar Hot Water Rebate database); and use of all available incentives, including a 0% interest Mass Save Heat Loan (see here for more information on SHW incentives).