Solar Hot Water Systems Can Heat Up Your Savings
If you’re not quite ready to make the investment into a solar PV array for your home, a solar hot water system can save you money with fewer upfront costs. If you already have solar, or are planning to install a solar system, you can save even more with a solar hot water system to replace your propane-, natural gas- or oil-powered conventional hot water heater.
There are several types of solar hot water heaters. A solar installer can help you decide which type of heater is best for your home and your budget. But because most people don’t like to speak to home contractors without understanding some of the lingo, here’s EcoOutfitters‘ quick-and-easy guide to solar hot water. Use this as your starting point to understand your options before you “go solar” in a whole new way.
Passive and Active Solar Hot Water Heaters
Solar hot water heaters are divided in to two broad categories: active and passive units. An active unit uses circulating pumps and controls to keep the water flowing. A passive unit doesn’t. Isn’t that easy?
Both types of units have some similarities. Components include a storage tank (or two) and solar collectors. In two-tank systems, water is pre-heated by the solar components prior to being shuttled in to a second tank where the back-up heating system will finish heating the water to the desired temperature (if necessary.)
Passive Solar Hot Water Heaters
You’ve probably guessed that passive solar hot water heaters are the less expensive choice. Two types of passive solar water heaters are used in homes; they are identified by the type of solar collectors they use.
A flat plate collector are made from insulated boxes with a dark absorber plate under glass or plastic covers. A variation of a flat plate collector is used in solar water heaters for pools.
Integral-collector storage systems, or ICS systems, collect water in black tanks or tubes within an insulated, glazed box (to help attract and absorb the sun’s rays.) The solar collector preheats the water and then it travels to the backup water heater tank. The glass pipes can freeze in cold weather, so these solar hot water heaters are used more frequently in the southern states and places like Arizona and Southern California where temps rarely, if ever, hit freezing.
Active Solar Water Heating Systems
Active solar hot water systems come in two forms. Direct circulation systems use pumps to circulate household water through the collectors for heating and then through the home. In areas that don’t experience freezing temperatures, this system represents extra cost savings.
In most parts of the country, however, you’ll need a non-freezing heat-transfer fluid within the tubes and pumps, which runs through the collectors and a heat exchanger. From there, the heated water is distributed through the home. This keeps cold water out of freezing atmosphere, preventing damage to the system. The water never circulates, it stays within the heat exchanger and storage tank, so this is called an indirect circulation system.
Why Solar Hot Water is Not Like a Solar PV Array
Solar hot water heaters are examples of passive solar energy. The sun’s warmth directly heats the water (or the heat-transfer fluid in the case of indirect circulation systems). In a solar PV array, the solar panels capture the sun’s irradiance, which is then converted, by means of technology we explain in this post, to actual electricity that’s fed back in to the grid or used to power your home.
A solar hot water heater is an energy efficient home improvement you can make for about 1/2 the cost of a typical solar PV array, and you can save money year round. There are also, like solar PV arrays, some tax credits and rebates available for solar hot water systems, although not to the same extent in most states.