Ok, I just installed the Thermguard fan controller and here are my observations:
1) Reason I got it: Details: Baby countryside corn stove, 2500 square foot house. Minnesota. The reason I bought the Thermguard was because my house had cold rooms causing the furnace to go on even when the corn stove was running and parts of the house were 80 degrees. Previously I disconnected a cold air vent on one end of the house and added a fan that would blow warm air from the basement up to that end of the floor above through that vent. That barely worked and was noisy. Next I thought about turning the furnace fan on low 24 hours a day. But, I thought this would cause too much wear. The goal was to circulate the warm air from the corn stove so the basement (where the stove is located) wasn't 80 degrees while the rest of the house was 55-65.
2) Installation: The Thermguard unit was conveniently small and easy to hook up. Just 2 wires connect to the fan wires on the thermostat. I checked the colors of the wires at the thermostat, then installed the unit downstairs by the furnace to those wires. In my situation there was a slight problem: The central air switch was using one of the fan wires on the thermostat. This caused the AC to go on when the Thermguard turned the fan on (the instructions said this could happen with some thermostats). I shut down the circuit breaker for the AC, but there was still a hum in the AC box when the fan went on (I assume a relay was being switched, but couldn't trigger the AC because while the system had power to the relay via the thermostat, the AC didn't have power to turn on). So, I simply disconnected one of the 2 thermostat wires going to the AC (between furnace and AC box - I will add a switch to the wire later). This stopped the humming in the AC box and stopped the AC from going on. Obviously this meant I didn't need to shut off the circuit breaker for the AC. I then followed the steps for setting the unit up. I started with the default timing of 5 minutes on in every 1/2 hour.
3) Results: The results were immediate. Almost instantly the temp evened out throughout the entire house. Yes, it was still warmer down in the room with the corn stove, but luckily I had a cold air vent right next to the stove to suck in the warm air. An unexpected result was that we needed to turn down the feed on the corn stove and open some windows because the house got almost too warm to sleep at night. It is obvious the Thermguard will easily pay for itself in the first month or 2 of operation since I doubt my furnace will be going on until January when the temps get 20-30 below zero. And I have no connection with Thermguard, just like products that actually do what they say they will do and do it simply and effectively.
