Get step-by-step tips on troubleshooting a cold area of a home with forced air heat. Learn how to check for duct blockages and promote proper air flow before you call an HVAC contractor for your forced air heating system.
LESLIE: Alright. Daniela is freezing. What’s going on? How can we help you, besides giving you a sweater?
DANIELA: First, I want to say thank you for taking my call. Your show is full of a lot of great information.
The reason why I’m calling is that we rented a home that was built about five or six years ago. For some reason, the second floor is always freezing cold; I mean, like, your fingers are numb-cold.
TOM: What kind of heating system  do you have, Daniela?
DANIELA: We have forced air.
TOM: OK. And do you have a central return duct upstairs where, you know, like in the hallway or something, where the air goes back into the system?
TOM: Hmm. OK. So it’s just one zone, right?
DANIELA: It’s one – no, it’s two zones, actually.
TOM: So you have two separate heating systems, then? One for the upstairs and one for the downstairs?
DANIELA: Yeah. We do have two and that’s what is kind of confusing because I’ll keep the heat downstairs around 72 and upstairs around 71 and it’s still – you know you need like three blankets to go to sleep.
TOM: Hmm. Well, it doesn’t sound like the upstairs duct system is correctly installed. I would look to that first. It’s real important that you don’t have any blockages in those ducts, that they have good airflow and also that it has a clear path back to the return duct. Now, if the return duct is in the hallway and you close your doors when you sleep, then you’re not going to be able to get the air back. That’s why you have to make sure that when you have that kind of system that the second floor doors are actually undercut by about an inch to an inch-and-a-half so you have a place for the heat to go back and be reheated or recooled, depending on whether you’re in the heating or air conditioning system .
TOM: But I would take a look at the duct system. If I were you, the first thing I would do is check airflow at every register to make sure nothing is disconnected or not flowing. I’d check airflow at the return; you can do that very simply by holding up like a tissue when it’s running. It should seemingly suck right back in and almost stick to the return duct. I’d take a look at all the doors and make sure that they’re undercut so you have good airflow back.
Those are the basics. If you still have an issue after that, I’d have an HVAC contractor come in to also check to make sure that the fan speed is correct; that you’re pushing enough heated air throughout that system.
DANIELA: OK. Well, that’s great. I will do that. Thank you very much.
TOM: You’re very welcome. Thanks so much for calling us at 888-MONEY-PIT and we hope we’ve helped warm you up, Daniela.