Exact Solar

Use the sun's energy to heat your water.  A properly sized solar water heating system provides about 75% of your annual domestic hot water needs. 

Typically between a quarter and a third of your energy expenditures goes to water heating.  Depending on what you currently use to heat your water, a solar water heating system could pay for itself in less than 5 years -- an incredible 20% return on your investment.

The US Department of Energy has an overview.

Attention PA residents:  Pennsylvania's Sunshine Grant Program has started accepting applications.  Rebates of 25%, up to $2000 are now available.

(diagram from "This Old House")
A solar water heating system consists of:

• (a) Solar Collectors are typically located on the roof or ground mounted on a rack.  They transfer the thermal energy from the sun to a heat transfer solution.  Collectors can be flat plate or evacuated tube. 

• (e) Storage Tank is a super-insulated hot water tank that stores the sun's energy for later use.  Water in the tank receives the sun's energy from the heat transfer solution through a heat exchanger.  In some cases, your existing hot water tank can be used.

•  (d) Automatic Control turns the (c) Pump on and off when necessary -- the system works completely automatically, nothing for you to do.

The size and design of a solar water heating system is dependent upon the number of people it serves.  A typical system for a family of four would consist of two 4' x 8' collectors and an 80 gallon storage tank.  Depending on the complexity of installation, costs generally range from $7500 to $8000.

In addition to the Sunshine Grant, there is a federal income tax credit of 30% of the cost of the system available to reduce the effective cost of a solar water heating system (there is no longer a cap on the tax credit). For budgetary financial analysis, click on the Financial Calculations link.