Three weeks ago Ben and I went to a local meetup to hear a talk on several residential solar hot water heating systems. We were presented with information about three different systems and were shown data on the costs, efficiency, and temperature averages of the hot water (dependent on climate).
The cost range for the systems presented was between $2k and $6k, and the presenters agreed that the average non-batch closed loop system for a typical home costs around $6k. (I believe this includes a backup system.) The least expensive system that was discussed (~$2k) was a passive system, which was basically a solar oven collecting the water on the roof.
Each of the residents had different goals and budgets to work with, but all had a backup electrical system running in the case of several cloudy days in a row. Ben and I are both of the opinion that overall, people generally prefer hot water on-demand at any point in the day and in any amount, which is why they require a backup system. It would be nice to opt out of a such a system, not only because we balk at using fossil fuels for this project, but also because we’re embracing the changes in our daily routine that we will be necessary to make if our hot water is in limited supply.
The US Department of Energy explains the different types of systems pretty well and provides resources for further reading.
EERE Consumer’s Guide: Solar Water Heaters
Darrell Edgley was one of the presenters at the meetup. He is experimenting with all sorts of resource-saving methods at his home in Durham, NC, and records data from his solar hot water system daily. (Scroll down and click the “solar data” link.)
The information we took in from the meetup was valuable in that we were introduced to solar hot water heating and heard some good discussion on mechanical and cost differences between the three systems. I’ll be writing more about solar hot water heating once we begin to make some decisions on our budget for the water system.
You may want to consider putting tubing in for radiant flooring when the floor slab is put in place incase you want to use it in the future. You can also use the solar hotwater panels to heat the water for this purpose. Good luck!
Thanks for your comment Brian! We are considering radiant floor heating, yes. Haven’t done much research on it yet, though. I expect we’ll post about it when we do. :)