Hi,
I had drastic freeze up problems in my class C fresh water system. The living quarters would be at 21 C (70 f) and it still froze. I tried putting a 1500 watt electric heater under the sink, while running the water heater. No dice!
Then I replaced the return air grill for the furnace with twin window fans. They draw 27 watts--and slightly pressurize the heating ducts. It is enough to prevent freeze up at -27 c (-16F)
The generator runs were to warm up the rear bedroom before stopping, not for direct freeze prevention.
