Reply #49: As a general rule, Solar water heatings work best if design as part of the home

[happyslug]

Retrofitting them can be costly. First is to make sure the roof is angled in the direction where the sun shine most of the day. Second the roof must be strong enough to take the weight of the water ANd the panel. If probably designed no pumps will be needed, water flows to its own level and unless the source of the water is low, the water will flow up to the panel and back into the tank. Problems can be if the water source is lower then your roof, then the water must be pumped up to that level. Most Cities have high tanks for water storage, but some may be low.

After you plan for the Solar water on the roof, you have to plan for storage of the heated water. This tank can be a conventional Hot water tank but the user must understand that the water can be hotter then needed (or colder then needed). If hotter some sort of mix with cold water is needed. This should be AFTER the water tank. Ideally some sort of gage that mixes the water to keep the temperature below 120 degrees Fahrenheit. If the water is to cold, the cold water source mix should be cut off and the water go through the secondary heating source to get the water temperature up. This can be done by a Computerized control system, controlling the temperature of the water by measuring the temperatures. Sounds complicated but is simple, two pipes into the Control unit (one cold one from the Water tank) then through a small tank-less water heater to heat the water up if that is needed.

Overall the system is doable, but at much higher costs then just installing a new tank or tank-less system. Can it work? yes, but you must understand increase cost of the whole system. I do not see if coming under $1500 dollars, thus no one is saying Solar when the original person put a limit of $800, but it is something to look at and the further south you are the better the system looks.

The big problem is most homes today are design to have a hot water heater. A tank-less system is a good retrofit for the tank-less system takes up about the same amount of room. Any other system, Solar or even a mix system with your Furnace (i.e. Hot water for your use AND to to heat the home) takes make retrofitting that is generally NOT cost effective. As I said above, probably can not do it for below $800.

When I first did research on Solar water heaters in the 1970s, they were popular in South Florida, do to the fact the area had NO NATURAL GAS SERVICE. Thus all water heaters were electric and electricity was high. You also did not have to worry about frozen pipes do to the temperatures. Most Solar Water Heaters were home made and cost effective. The problem was as you went north you had to worry about Water Freezing in winter AND the access to natural Gas as a heating source.

Today, Natural Gas prices are DOWN from hat they were just a few years ago. I expect that to change. As Natural gas prices go up I expect more and more people to opt for Solar Water heaters to save money. While the Capital Cost are much higher, the saving from having to use LESS heat from other sources of heat can be extensive. A solar system mixed with a Tank-less system can be a huge saving, providing you can do the above. Thus today you have sources for Solar Water Panels, something that really did not exist in the 1970s. If I was building a New home I would install enough to provide me hot water. I will also install a backup system so I have hot water at any time. Over time the system will pay for itself, but you first have to pay the much higher Capital costs.