# Insulation in cold air return?



## Caulkmaster (Oct 11, 2010)

Hi, all - I just bought a house from the '40s which uses ducts that are built into the support beams, Opened up cold air intake to clean it before turning on heat, and saw that it was full of insulation. That's not good, riight? Or does the filter on the heater remove any air contaminants?


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## havasu (Oct 11, 2010)

I have limited knowledge myself on this topic, but will throw in my two cents anyway. This would be better left for a professional with lots of knowledge in duct work. Many ducts from that era contained asbestos, and you don't want to disrupt it without proper safety precautions. It may be possible to reline your original ducts or reroute them, but get a professional opinion from someone in person.


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## classic (Oct 20, 2010)

if this is loose insulation in an unlined return, the return suction pressure has pulled the insulation in from the attic or walls. This means that your return trunk is not airtight and your efficiency has dropped. Vacuum the insulation out. Seal it if possible

If it is blanket type insulation, it was origionally attached to the walls of the return line, and this is blocking return air from getting back to the unit

If these ducts are nuninsulated they are VERY inneficient.


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