Buyer’s Guide to Solar Water Heaters
Get a basic overview of the most important factors to consider when buying a solar water heater.
Capturing the heat of the sun is one of the oldest and simplest technologies for generating hot water. In fact, the first patent for a commercially produced solar water heater was granted in 1891. Today’s generation of solar water heaters have been fine-tuned to do an ever better job of capturing and storing the heat of the heat of the sun and are about 80 percent efficient at turning sunlight into usable energy. Depending on your hot water usage you could generate 40 to 80 percent of the hot water you need with no energy costs using a solar water heater.
If you are interested in buying a solar water heater for your property, there are a few important things to know:
Passive vs Active Solar Systems: The first decision you will have to make is whether to purchase a passive or active solar system. The difference is in whether the system requires electricity to move the heated water or not. Obviously the best energy savings comes from using a passive system, but this will restrict you in your placement of the collectors and reservoir tanks. Passive systems are also more reliable simply because they have fewer moving parts.
How to Size Your System: The general rule for sizing a solar water heater is to have 20 square feet of collector area for the first two people in the household and 8 square feet for each additional person. For the reserve tank, a good benchmark is about 18 gallons per person.
How to Site Your Collectors: One of the biggest myths about solar water heaters is that your collectors have to be sited perfectly in order to be efficient. This would require a southern exposure with an appropriate tilt matched to your site’s latitude, something the roofs of many homes can’t provide.
The reality is, the difference in performance between a collector that is sited to mathematical perfection and one that is sited with a merely good tilt and exposure is pretty small. Collectors can be as much as 45 degrees off of due south and only see about 3.5 percent reduction in output, or have a tilt as much as 30 degrees off and only see about 9 percent reduction in output.
How to Maximize Your Energy Savings: One final question you may have to answer when buying a solar water heater is what to do for backup hot water. Backup water is not an absolute necessity, but it will be helpful if you ever have guests or otherwise use up more hot water than the solar heater can produce. The best bet for backup water is to choose a tankless hot water heater because it only turns on when you need it.
Want More Advice?
If you would like more advice about choosing the right solar water heater for your specific property and needs please call The Stanley Louis Company at 800-217-6527.
