Cheap solar panels now have an efficiency of over 20%. I wander if it makes sense to just use those and install a DC resistance element in the hot water cylinder.

Thanks so much. Very well done. On the air purge valves. After a couple of weeks when you think the air is gone are you closing them to prevent pressure loss? My system doesn’t have a water makeup supply, it’s just a simple garage floor heat. Do you lose pressure over time?

Hi Benjamin. What do you think of heating a (electric) hot tub using solar vacuum tubes and instead of a complicated glycol system with risks of overheating the glycol etc... just heating the water directly and implementing a drainback system that returns the water to the tub and evacuates water from the collector? I'm in Canada, so freeze prevention is important, but low maintenance is also key.

Great Vid : I have purchased a home that has a glycol heat exchange drain back system about 20 years old. The system runs when power is applied and seems to work, it reached about 140 degrees and shuts off after a while it starts again when temp is about 100 degrees. The problem is it is not connected to the hot water tank all pipping has been cut off not sure why ? I am attempting to hook it back up and this vid is great for this process. I have been told that a gas water heater may be the reason for the disconnection ? any help would be appreciated.

Slides available?