Solar Water Heating: Overview

Solar in the US

What Size Solar Hot Water System Do I Need?

Sizing a solar water heating system for your home is fairly straightforward. Since it is a supplemental heating system for which you will have some sort of a backup heat source, there is no danger of running out of hot water. As mentioned previously, an 80 gallon tank is recommended for households of three people or fewer. For 4-6 people, a 120 gallon tank is more likely necessary. Allow 20 square feet of collector area for each of the first two family members. Expansion from that point is based on system location. Add eight square feet for each additional family member if you live in the Sun Belt. If you live in the northern US, allow 12 to 14 additional square feet per additional person. For example, for a family of five in Massachusetts, you could use a 120 gallon tank with about 80 square feet of collector (possibly two 4’ x 10’ collectors).

Heating water with the sun is a very do-able and cost-effective option. Installation complexity will depend on the plumbing runs necessary for your system. Be sure to consult a plumber who is familiar with solar water heating systems before you purchase anything. If you do plan to install the system yourself, please review some of our other articles to learn more. Even better join us in Massachusetts when we host solar water heating professionals like Bob Ramlow for an informative class.

Do-it-yourself rating –[5 hammers out of 5] requires a professional for all but the handiest person.
What you need to know to install a solar water heating system:

• Basic plumbing & soldering
• Basic calculations for friction loss in pipe runs
• Planning pipe runs
• Locating due South

References:
Solar Water Heating: Comprehensive Guide by Bob Ramlow
Solar Water Heating Systems: Home Edition by Tom Lane
Dept of Energy Consumer Guide to Solar Water Heating