We have an A/C (and heat) unit in the attic with force air ducts going to the ceilings in the rooms. I was in the attic today when the A/C turned on. I felt cold air come on my leg when I was near the unit. I looked carefully to see that air is leaking near the copper tubes coming out of the unit near the evaporator area.

I took pictures and marked the area where cold air seemed to be coming out in red. Is that normal? Should I somehow seal it with perhaps rubber seals sold in the market or improvise something?

Thanks for your help.area where air is leaking

wider picture of furnace where air is leaking

  • What is that large white pipe? I hope that's not the exhaust. Please tell me that's the combustion air intake! Jul 11 '20 at 7:27
  • @supertanker13 I have no idea what that is. Is there a way to find out? I an a novice.
    – Guraaf
    Jul 13 '20 at 0:05
  • Did you ever get this resolved? If so, please give a check-mark to the answer that helped you the most, or write up your own answer explaining what you did to get it fixed and give yourself a check mark. That will help others with this kind of problem know that this has a resolution and is a good place to look for their answer.
    – FreeMan
    Aug 14 '20 at 11:25

I would pack a chunk of insulation in there , I usually use a soft putty that stays soft incase the unit requires servicing but air leaks in an I heated space add up to $ quickly. I bet you can find a chunk or 2 in an attic.


I would pack some good rubber foam in the space. Some strength is needed because vibration movement between the copper tube and steel shell can wear through the copper. It is good to stop the air leak but important to prevent rubbing wear.

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