Ask Your Question

Angie's List Answers is the trusted spot to ask home improvement and health questions and get answers from service companies, health providers and consumers. For ratings and reviews on companies in your area, search Angie's List.

Top 30 Days Experts
Rank Leader Points*
1 kstreett 240
2 Guest_9020487 110
3 Guest_9190926 105
4 GoldenKid 100
5 ahowell 95
6 KnowledgeBase 95
7 skbloom 80
8 Guest_98024861 70
9 Guest_9311297 70
10 Guest_9400529 70

*Updates every 4 hours

Browse Projects By Category

Question DetailsAsked on 8/10/2017

Central air blowing hot air in four rooms, cold air in five rooms?

Inside unit is located in the attic. It looks pretty standard & has 9 ducts (4 on each side & 1 on top) on the opposite side of where the supply duct is located. The ducts on the left & the 1 on top are the ones blowing cold, 4 on the right blowing hot. It seems it's pulling in heat from the attic since in the morning, the air seems warm vs hot.

Called the local AC/Heat company & the tech was stumped when he came out. 20 minutes later he said the board was "burnt" & a heat strip needed replaced, adding that it was actually pushing heat out while the AC was on.

The thing that doesn't make sense to me is... if the ducts all share the same supply of air after being cooled/heated, why isn't the air "warm" in all of the ducts vs half hot/half cold?

Do you have the same question? Follow this Question

1 Answer


Sounds like maybe a two-chamber air handler - some have two heating coils, some have two blower fans for larger size units - so if the heating strip (sounds like this is a heat pump) was on in one side that would explain about half the ducts running hot, especially if they were actually "hot" rather than just warm.

Though I would question replacing the heat strip, if it was heating OK - unless he found one of two was heating but the other one (running off same board) was burned out as well as the board having failed and running heat when the demand was not there for it.

Another alternative - air handler has an access hatch open or supply duct detached on that one side so it is pulling hot attic air into the air handler and through the ducts - which could be as hot as 130-140 degrees in the hot of the day. If the temperature on the 4 "hot" ducts varies with time of day, from coolest in very early morning (before any solar heating occurs) and highest typically in post-noon to late afternoon, then it pulling in attic air is more likely the case. Could be as simple as a duct joint coming apart because the heat has caused the duct tape to peel free, or a flex duct got hot enough that the plastic stretched out and weakened and the duct tore through on the suction side of the air handler.

Another possibility - if you have two zones in the air handler and the thermostat for one has failed/lost power or accidentally been bumped to HEAT/FURNACE so is calling for heat for that zone, which in a typical two-zone 2-story house could explain about half the ducts running hot. Easily checked with a volt-ohm meter or circuit continuity checker to see if the thermostats are calling for heat or cooling.

Here is another prior similar question with answer - though might or might not be as applicable because it relates to a central air furnace/AC system whereas yours, with the heat srips, sounds like a stand-alone AC with auxiliary heating or a heat pump with supplemental electric heating.

Answered 3 years ago by LCD

Related Questions

Terms Of Use
Privacy Policy