Solar energy has long been used by man to heat water. At its most primitive, this was done by simply putting water in a pot and leaving it in the sun. This basic concept is known as solar thermal water heating. As you might imagine, modern systems are a tad more sophisticated, but some can still be damaged by freezing problems.
There are three big expenses when it comes to powering your home. Basic electrical needs for your lights, computers, televisions and such is one. Heating or cooling the home is the second. Heating the potable water you use is the third and can constitute a third of your utility bill. Solar thermal water heating is one way to combat the water heating expense.
Heating water takes a lot of energy. Fortunately, there is plenty of it in sunlight. If you don’t believe me, just consider your car. What happens if you leave it in a parking lot on a sunny summer day? The interior heats up to the point that you can barely sit down or touch anything. This is a form of passive solar energy where heat is the end result.