Solar water panels are one of the cheapest ways to capture
free energy from the sun. We use this system to heat
both the domestic hot water and the radiant floor heating.
Radiant floor heating is that it adds important thermal
mass to the floor (see Passive
The design of the solar heating system was done by Peter
Millar (Building Energy Solutions, Reno, NV). Steve
Cupp (The Energy Source in Bishop, CA: 760-873-6165)
was an amazing local resource for used solar parts and
To power 80% of our Domestic Hot Water (DHW) and Space
Heating (SH) needs, we installed five 4ft. x. 8ft solar
collector panels (160ft2) and two 120gal storage tanks
(1.5*160ft2). We "staged" the two tanks so
that all the solar energy goes to heat one tank first,
then when it is hot, the other tank is heated. This
staging has two benefits: One is that on a cloudy day
you can at least count on one 120gal tank with hot water.
The second is that the hot water will recharge faster.
The basic concept is that 120gal of hot water is more
useful than 240gal of luke warm water.
Since our biggest demand for solar heating is in the
winter, we positioned the solar panels at a 60 degree
angle to maximize winter gain. We used this great solar
angle calculator: Sun
Backup heat for both the domestic hot water and the
radiant floor system are provided by a high efficiency
condensing propane boiler (Knight
Cooling in the summer is achieved simply by:
1) optimal placement of windows and overhangs
2) thermal mass in the floor
3) well insulated and tight envelope
4) a ceiling fan, and
5) cross ventilation
The effectiveness of these is maximized by "night
venting." This means opening the windows at
night and closing them during the day. Daytime ventillation
with hot air will only heat, rather than cool, the house.
To see the effect of night venting, check out this simulation.