Originally Posted By: dvalley This post was automatically imported from our archived forum.
I have two questions that I need answers for right away please?
1.) Can A/C ductwork be run through a chimney chase in order to bring air conditioning to upper units in a multi-family? I'm thinking not!
2.) I had recommended to my client to have all branch ductwork in basement insulated because condensation was dripping from them. The seller had stated that the HVAC contractor had told him that these should not be insulated because condensation had to go somewhere. I told my client that these wouldn?t be condensating if they were insulated. Am I right or wrong? Does all ductwork need insulation or is it just the mains?
Originally Posted By: gbeaumont This post was automatically imported from our archived forum.
Hi Dave,
1) I can see many potential issues with this firstly if the chimney is in use by anything else there is an abvious issue, secondarily to get a duct into a chimney (even if its abandoned as a chimney) would entail breaking into and out of it to run the duct, so there is in all likely hood a fire bocking issue.
2) insulation in unconditioned space: vapor retarder required on cooling ducts conductive to condensation (IRC 1601.3.4) obviously if cold air is being blown trough a duct the duct wall will be at the internal duct temperature, if the air outside the duct is 80 odd degrees and 90 odd % humid as it is here today, you will get condensation forming on the duct, so insulating the one from the other is a good idea.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
Thanks Gerry,
I should have mentioned that the chimney is not being used for combustion at any point in the house. It?s abandoned.
The fireblocking would not be an issue on this specific chimney. My question is that if this ductwork is run into the chase, don't we have serious condensation issues with the mortar?
Originally Posted By: Robert Chebook This post was automatically imported from our archived forum.
Hi David,
Im new to this site and found your post while checking it out. Im not a Home Inspector (yet) but Ive been a tin knocker (sheet metal mechanic) for about 10 years. First of all using a Chimney as a chase is dangerous because first it weakens the structure when you remove bricks to enter and exit the chimney. And secondly like you mentioned condensation will drot out the motar from the inside also weaking the structure. The only way to do it safley would be have an expert remove the chimney making sure the opening is suported properly and then running the duct through the space, costly, but Ive seen it done.
Also any time there is a difference between the air in the duct and the air temp out side the duct it should be insulated. Condensation will do nothing but rot out duct and destroy the unit itself if it flows that way.
Hope Ive been of help and sorry I was so long winded