Hello, I am a new home owner and been doing a little research on my own to resolve this problem but thought I should ask the pros first. I have a 10 year old furnace with only 2 wires(R,W) running to my thermostat. I would like to get the cool air from my basement to the upper floor. My basement is finished and I cannot fish a new G wire without tearing into walls. Is it possible or safe to disconnect either R or W and use that wire to connect G to G? If not is there another option that safe and affordable. Thank you.

You can switch wires back an forth on your Thermostat to make the blower work. But after a few years it may start to do some ware and tare on your thermostat. If your furnace is easley accessible, add a blower switch at the furnace.

There are thermostats available (like the Bryant T6) that can manage fully featured systems using only 2 wires between the display module and the equipment control module. These were designed specifically for situations like what you have (limited availability of control wires).

You can switch wires back an forth on your Thermostat to make the blower work. But after a few years it may start to do some ware and tare on your thermostat. If your furnace is easley accessible, add a blower switch at the furnace.

Thanks for the info, I have been looking around on how to safely run a switch. Would someone be able to explain it here? Please?

Posting the brand/model# of the furnace would be helpful. One way to accomplish this: At the furnace, move the "W" wire to the "G" terminal. Turning the thermostat up will cause the furnace blower to run.

Thanks for everything, I simply switched the W to the G at the furnace. I only run the fan for a few hours a day so I don't burn out the fan motor. Thanks again.