View Single Post
Old 08-01-14, 05:13 AM   #11
Mikesolar
Master EcoRenovator
 
Mikesolar's Avatar
 
Join Date: Aug 2012
Location: Toronto
Posts: 958
Thanks: 40
Thanked 158 Times in 150 Posts
Default

Quote:
Originally Posted by Exeric View Post
There may be a third option, but it would depend on your future plans. It also has the disadvantage of there not being a fuel backup if your electric grid went down. Many people are trying to go as electric as possible because they can subsidize their electricity use with PV power. This would have the same effect as zeroing out the future expenses for water heating. That's if New Mexico is a grid tied state?

I personally plan on going that route. I've already bought an electric Marathon water heater which is a fiberglass design and is supposed to last a lifetime because it doesn't have the usual rusting out problem. They are about a thousand dollars. I think it is wise to think not only about the grid going down and causing cold showers. Cold showers can also be caused by mechanical failure. Solar hot water heaters have a very poor track record in this regard. Also regular metal water heaters last only about 10 years and then rust out. So a Marathon fed by PV is a very viable option compared to what you are considering. Of course, PV can be used for a thousand other things also which makes it more flexible even than cheap natural gas.
This is and issue. As solar PV gets less expensive, SDHW looks less viable especially with the mechanical issues of an improperly installed system. I have a number of 25 year old systems still working fine and some failing after 5-6 years. I won't install tube systems anymore because a higher percentage fail and they fail faster as well.

I have found that the best SDHW systems are ones that are PV powered (20w panel) and have no other controller to muck up (which is what has failed in 40% of the systems I see). They also are not SUPER efficient, generating high temps like a tube does. Doax made a system that I think could work well for many years.

Mikesolar is offline   Reply With Quote