I've just moved into a house in Albuquerque. We notice that the vents in the two baths actually blow "cool" air when the heat is on. Apparently, they are at the end of ducts. Is there anything that can be done to resolve this? Is there a pressure adjustment that is perhaps too low, or is the furnace not burning hot enough at the source?

We plan on contacting a heating specialist, but thought I'd try to get an idea here, first.

BobL

Not quite enough information to diagnose the problem.

Not quite enough information to diagnose the problem.

What other information would be helpful? Don't really know anything about Heating systems, so don't know what to provide.

BobL

If the furnace is at the far end of the house and you have a long run of uninsulated duct, you may need to insulate it. The type of ducts and the temperature rise of the air going through the furnace could help.

Thanks for some direction, labman.

The temperature rise "75-100 degrees external static"
Approximate distance from furnace to back duct - 40ft
Ducts are cement ducts in the foundation.
Furnace as 128000 BTU Natural Gas

A couple of things to add... we had a duct-scope during the purchase process, so there are no obstructions. Also, regarding the distance... there are vents that are a few feet beyond these two that have warm air coming out. However, I think that these two vents are at the end of the ducting.

BobL

Could be you are talking about return air ducts? If so they atre not supposed to be hot.

Nope. These are vents in the floor in each of the bathrooms.

BobL

Knowing that the ductwork is in a concrete foundation is helpful to know. Now, it would be good to know if this is a perimeter loop duct system or octopus. Also what are the differen t temperatures at the registers. If the furnace ran solid for 10 minutes do the duct warm up some? I know you probably don't have a velocimeter, but air flow velocity and CFM would also be helpful to know. If this is a perimeter loop system in the slab I know of little you can do to correct the problem, it was probably a bad design from the start. There are duct booster fans that can be installed but this would not be a sure fix, and the price would be high.

Thanks much. I don't know what the duct system is, either, but all of the vents (except these two) are at the perimeter of the house.

Would a new furnace improve the situation? This one is old, and we had previously discussed replacing it with an AC (heat and cool) system. If so, should I look for something with a higher output BTU, stronger fan, or...