Why does my house smell like a dead animal when the air conditioner runs in the summer and how do I fix it?

Question

We only get this smell in the summer when the air conditioner is running. I am suspecting something is wrong with the drain pain in the furnace. We have corrected a poorly installed drain line but the smell continues.

Answer 1

Your suspicions are well-founded. The fact that the odor is limited to the cooling cycle simply means that there is a connection between the moisture collected in your evaporator coil and the odor.

There may be a substantial amount of fungi (mold) that has established itself on your evaporator coil, drain pan, blower wheel and return-air plenum. It can lay relatively dormant during the dry times (heating and no operation) and begin prolific growth when exposed to moisture. When fungi grows, it can release gases called mycotoxins which are malodorous and potentially harmful.

The repair of the drain line indicates that there was a back-up, and the resulting moisture may have caused an unresolved mold issue. Beyond that, it is possible your drain pan is currently plugged or cracked, and dripping water under your air handler.

There are some parallels between the organisms that work to decay dead animals and the fungi that is probably "off-gassing" in your air handler, so I am not surprised at your description, although I doubt you will find a critter.

What you need to find , though, is a good a/c mechanic you can trust to give you an honest evaluation of your equipment. Depending on the age of the equipment (12-15 years is a good run) you may want to consider replacement. Good luck, and I'm only a key-stoke away!

Answer 2

If your AC shares ducting with your heating, and the smell only is present when the AC is working, I'd say your "poorly installed drainline" is nto the only thing that is poorly installed.

It may be mold, or even algae has built up inside your AC's innards. Mold usually smells musty, and algae smells like something dead.

Whoever installed the system should come back and fix it right.

You might get the health department to come and inspect, and give advice.

Answer 3

Assuming this is Central Heat and Air, you should get the smell both seasons , heat or cool if its in the Ducts- the air travels the same in either case- You sould have a condensate drain and it should not drip in a pan, but rather a Sewer line- only time water goes in that pan is when the main Drip line is clogged. clean it and inspect the pan for a dead rodent, who may have gone there to drink.

Answer 4

There might be a dead animal in the duct work. Start with having a company clean your ducts it might be mold. Also have a tech check for proper operation of your AC maybe the drip pad is gathering water and mold is infesting your house.

Answer 5

do you change the air filters?
if not, then that could be the problem...also having your air ducts cleaned about once a year will rid your house of unpleasant smells and bacteria. (this type of cleaning will also help keep respiratory problems at bay)

Answer 6

Might have soemthign dead under the house, Pay the nabor kid 5.00 to go unerthere and look around :)

Answer 7

You obviously have a dead critter in the system. You'll need to check your ducts ( take them apart ) and see whats crawled in and died

Answer 8

Change your filter and also have your furnice clean every six months. along with your air ducts