In the middle of November 2008, we had two Sunmate solar heating panels from Environmental Solar Systems installed on the south facing wall of our new addition. The photo taken in January 2008 shows the two panels. To the right, part of our solar greenhouse can be seen. The solar greenhouse has been on our home for nearly 30 years and it supplies between 30% and 50% of our heating on the original house. Thes Sunmate panels are about three feet wide by just over six feet tall and have a small muffin fan to circulate heat into the house.
In mid January on a day with full sun, the panels will begin providing heat about 9:00 am and will run until 2:30 or 3:00 pm. There is a period in the day of about 40 minutes when the panels will stop providing heat due to a shadow cast by a tree in our neighbor's yard. The exact time when the panels come on and shut off depends in part on the outside temperature. Even when the temperature is in the single digits, the panels will provide heat from about 9:20 am until after 2:00 pm. With the outside temperatures in the mid twenties or above, our furnace will not come on at all during the hours in which the panels are operating on days with full sun. Even when the sun is partially obscured by clouds the panels will provide some heat. Our large solar greenhouse does not provide heat until about 10:00 am, but continues to provide heat later in the day. It will heat the old part of the house a bit more than the panels heat the new addition. The old section of our house has only about R-7 insulation in the walls and has more north facing windows. With its large expanse of glazing, nearly 250 square feet, the solar greenhouse easily provides more heat than the small panels. But considering their size the Sunmate solar panels do an amazing job of providing heat.
Overall these panels provide a significant amount of heat reducing the time that our furnace runs. In addition, we have put insulated shades on many of our windows to further reduce our use of natural gas. These shades are described on the window_insulation page. Our main motivation in using solar heat is to reduce our use of non-renewable energy sources. A side benefit is any monetary savings from the reduced use of natural gas. Based on our current cost of natural gas, I estimate that it will take over twenty years before the panels save us enough to cover their cost. Of course, as the price of fuel goes up, the payback period will be shortened. During the heating season we have full or partial sun only about half of the time in our area. Thus, a location with more sun would see a shorter payback period. My only regret is not installing three panels, two for the family room and one for the bed room. This would have provided more heat on partially sunny days and days with temperatures in the teens or lower.
Check out the photovoltaic system that was completed in February of 2010
photographs by bernard
Solar Heating Panels
The two photographs above show the vents from one panel inside of the house. The vent on the left is the return and the one on the right delivers warm air to the house. In the photo on the left, you can see the wire going from an electrical outlet to the low voltage muffin fan. Between the right vent and the electrical outlet is a thermostat that may be set to turn the fan off when the room reaches the temperature set on it. There is a small disc thermostat inside the panel that is wired in series with the external thermostat. This turns the fan on when the temperature inside the solar panel reaches 110 F and turns the blower off when the temperature goes below 90 F. Output temperature varies between 80 and 125 F.
Two solar heating panels from Environmental solar Systems