Inconspicuous solar hot water heater in your roof

Interesting idea. I would consider using copper rather than PEX however. I would think the heat transfer would be better with copper. Additionally, in many climates you don't even need a glycol loop. Modern controllers have an antifreeze cycle that will circulate water through the collector pipes as needed to keep them from freezing. My simple copper flat plate collector doesn't freeze at +10f. Much colder and I would drain it. Most parts of the country don't really get those temps for very long each winter.

Icarus

 

It is interesting that PV solar is "sexy" but DHW is a much cheaper, much more efficient way to use solar energy. I am also a great fan of PV solar, but if you have the location for PV you should start with DHW. DHW has way more bang for the buck.

Icarus

 

That is a great idea. My roof is not suitable for PV because of some mature shade trees, but I installed a ridge vent when I reroofed the house back in 2000.

 

Solar hot water is much more shade tolerant than PV. A single simple shadow from a utility wire for example reduce the output of an entire SERIES string of Pv by up to 90% (or more) depending on how the string is wired.

Solar hot water won't be effected by that little shadow at all. So even locations that for a variety of reasons may not be suitable for Pv might make great sites for DHW. Additionally, solar hot water is much more forgiving of being in less than ideal exposure angles.