My walls in the upstairs bathroom are extremely hot. Don’t know if it is plumbing or HVAC. The bathroom is over the utility & HVAC system downstairs. Can you shed some light?

-Carol

Carol, you should try to measure how hot “extremely hot” is and see if there is anything that changes the temperature such as the time of day, or if any appliances are running such as the furnace or hot water tank. Your domestic hot water lines should not cause the walls in your upstairs bathroom to get noticeably hot -even if your hot water pipes are placed directly against them. It’s possible that it could be some electrical problem, but I think with more than one wall affected, that would be unlikely. Your HVAC (Heating, Ventilating, and Air Conditioning) being directly below the bathroom could be a culprit. Whether your HVAC system is new or old, there could be something wrong with its vents. But what I think it most likely is that you may have a vent from your HVAC system, hot water tank, or other appliance going through the wall up to the roof. These vents are often installed without enough clearance around them as they go up to the roof (e.g. too close to a wall in your bathroom).

-Brian