Simple electric furnace repairs can cost as little as $125, while more thorough gas furnace repairs might cost as much as $2,550. The average cost of repairing a damaged furnace is roughly $385.
The cost of furnace repair is highly dependent on what has to be corrected. A thermostat, for example, can cost anywhere from $125 to $400 to fix. The cost of replacing or upgrading your thermostat to a smart one might be upwards of $750.