Insulating Return Air and Blower Compartments


Old 01-09-09, 01:55 PM
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Insulating Return Air and Blower Compartments

Can anyone recommend specific sound insulating material I can install in the return air and blower compartments of my 25 year old Luxaire furnace and the best way to adhere the material.

I considered rigid foam insulation ordinarily used for home insulating, but want to maximize the sound deadening effect.

When retrofitting an existing furnace can the installed material break apart with the blower in use, and is there a possible fire hazard?

Any feedback would be greatly appreciated.

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Old 01-09-09, 02:24 PM
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Because air is forced at a good deal of velocity over a period of many years, and because insulation breaking away can plug up a furnace and prevent it from operating, the questions you raise are good ones.

I'm not familiar with any good ways of retrofitting ductwork. Usually ductwork is insulated when it's built, an the relatively rigid insulation panels are cut to size and held in place with steel rivets.

Someone else may have methods that will work that they will suggest.

Also, with existing ductwork you will be reducing the effective size of the duct which will increase the resistance to air flow and the velocity of the air circulated. For a furnace with marginal ductwork (not unusual) this could cause problems.

Air conditioning (if any) might cause more issues.

I'm afraid I can't be of much help, but I can add additional issues to worry about!
Old 01-09-09, 02:36 PM
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25 years old!!! If it needs insulating might be time to replace.
Old 01-09-09, 07:46 PM
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As a furnace designer, I don't recommend adding insulation inside the furnace casing at all. THAT IS CHANGING THE FURNACE DESIGN. Not only would that void any warranties it could be, in effect playing Russian roulette. Since finding this site a month ago I have been horrified (I really don't think it is too strong of a word) at the number of times I have read posts where largely untrained people intend to modify furnaces or defeat safety devices.

People, don't you realize that furnace in your home can kill you! Fire is only your friend when it is under control. Otherwise it is a wild beast wanting to consume you! I guess the general public has no idea how much blood, sweat, and tears goes into taming that beast in the design phase. I know times are rough but please don't make them rougher by putting your home or the very life of your family in jeopardy. Unless you are 100% confident that you know what you are doing, contact a professional. Would you consider removing our wife's gall bladder yourself to save some money? This poster isn't one of them but I swear I have seen some posts here that make just about as much sense.

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