We’re a bit behind on our posts, but we’ll try to get back on track with this one from our winter experience with our solar thermal unit. The Velux system that we have has a nice feature that lets you read the temperature of the collectors on a display in the systems room. During the cold snap earlier this year when daytime temps barely rose above freezing yet the sun was shining brightly, the collectors were still registering temps in the 145 degree range, i.e., more than enough heat to maintain the 120 degrees that we have the water heater thermostat set at. Even when the daytime temps are low, the collectors are still able to harness the heat of the winter sun.