It got down to -7.5°F overnight and I was awoken twice by the simulator at 11:40 PM and 4:40 AM because it was having trouble maintaining temperature. With wind chill down to -30°F I elected not to mess with the HVAC until this morning. It is really frustrating how poorly I planned for the HVAC strategy – something to definitely learn from.
The simulator is heated using an external heat pump when the temperature is above 28°F outside. The compressor is disengaged automatically by the computer below 28°F but the fan continues to circulate the air. The problem is when the outside air is -7.5°F it acts like an efficient air conditioner – the coils absorb the heat from the air.
Instead I need to shut off the power to the external unit below 28°F and install an internal fan to circulate the air when running the convection heater.
I ran out there this morning to turn off the external unit and I am seeing a temperature rise but due to a couple technical glitches I have no historical temperature data since just before the new year.