How to Get Even Heat Throughout a House

LESLIE: Joe in Pennsylvania is on the line, dealing with some heating issues. Tell us what’s going on at your money pit.

JOE: We have a furnace; it’s a propane furnace. It’s about five or six years old. It’s pretty good for heating the house but it seems like some of the rooms are hotter than (inaudible at 0:03:00) and some of the rooms seem to be cooler. And what happens is there’s no consistency, so I have a hard time with getting everything fluctuated so that everything stays even. And I don’t know how to adjust that so that it would heat the house evenly.

TOM: OK. So your furnace is kind of dumb in the sense that either it’s on or off, right? So that takes care of the furnace part of it. The problem here is with the duct system; it’s the distribution throughout the house.

This is a forced-air system, Joe?

JOE: Yes.

TOM: So, the duct system is what has to be tweaked here to get the balance just right. Now, the way you adjust the duct system is first by designing it properly, which may be the issue here. And that’s kind of hard to fix without adding additional ductwork to it or rerouting things that you have.

The second way you adjust it is by controlling the dampers – the duct dampers. Now, duct dampers are going to be mounted usually somewhere close to the furnace or at least at the very beginning of a duct line.

JOE: OK.

TOM: And it’s evidenced by a small handle on the side of the duct. And if you look at the nut and bolt that the handle is attached to, there’s going to be sort of a flat slot to it. If the flat is perpendicular to the duct system, it’s off. If it’s going with the duct system, it’s on. And you can adjust the flow with those duct dampers. And the third way you can control this is with the actual registers inside the room, whether they’re opened or closed.

Now, if those adjustments don’t change anything, the other thing to look at is the return air: where the return is pulling from. The best HVAC-system design has returns in every room. If you don’t have both the supply and return in the same room, you’re going to have a central return, usually a bigger register in the hallway near a bunch of rooms. And if you improve the airflow back to the return, that can improve the balance, as well. How much you do that? Well, it could be something as simple as undercutting doors.

But this is a balance issue; it has nothing to do with the fact that you have a furnace that’s a propane furnace. You know, it’s going to supply heat as it’s designed to do but the distribution is the issue. And it’s possible, also, that there could be fan adjustments to the fan speed that could impact this. But I think it’s over and above what you can do when we get into the fan work and the multi speeds and that sort of thing. That’s really a job for a service professional. But you could take a look for those duct dampers and see if they exist and see if you can tweak the airflow to make it a bit more comfortable.

JOE: Alright. I would be happy to do that.

TOM: Alright, Joe. Good luck with that project. Thanks so much for calling us at 888-MONEY-PIT.