I have been thinking about lowering my blower speed on my furnace so its not so loud. Currently I use the fan on terminal (G) to activate my blower. I also use the w terminal for my propane backup with a seperate thermostat. I know changing the heating mode speed could cause the heat exchanger to over heat when using propane but I think I can change the (G) terminal speed sperate from the propane(w) terminal speed. Im aware I would have to change it back in the summer since A/C uses the G terminal to activate the fan. Also, how much heating ability would I lose by lowering my fan speed? Would the increased air temperature offset the reduced air volume? I know lots of questions. Bottom line is I simply want to reduce the drafts in the house and get a more even slow distribution of heat. But I also don't want the blower to run 24/7 because its to slow to heat properly, a happy medium i guess.