Custom ductwork for wood burning furnace - where can I get it

Alright, I have the furnace in the basement, have figured out how to install the chimney and have it available and ready to go. Problem is the ductwork. I called a friend/client to get an estimate for the ductwork for the installation, and the estimate was $1,900. I cannot sawllow that number for just tying the furnace into the existing ductwork, which consists of reducing a 24" x 24" supply line and 24" x 20" return line to fit into the current ductwork. We are talking about 3 to 4 feet of ductwork here for each line to hook them up into the existing system.

My problem is finding somebody to bend the metal to make it work. Anybody have any suggestions for a supplier in Maryland? Better yet, is this something I can do on my own as far as bending the sheetmetal is concerned? Just trying to get the furnace installed right now and will deal with the AC install come the spring time.

inevitabLEE said:

6" & 8" flex duct is around $1/ ft and easy to work with.

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Yeah, the flexible ductwork is not going to work because I have to go from the furnace, with a 24" x 24" hot air opening to a 22" x 16" ductwork opening and from the furnace supply line of 24" x 20" to a supply duct opening of 20 1/2" x 10 1/2". All the ductwork for the house is already present. Just a matter of sitting the furnace right below it and attaching the current ductwork to the furnace.

inevitabLEE said:

Most HVAC shops have their own tin shop. I had my furnace plenum custom built for around $100. It stands about 30" off the top of my furnace .If I understand it's just a glorified plenum. Should be easy.

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Yep, you are understanding correctly. As I look into this some more and do some research, it is the plenums that I need for both the supply and return sides. One is 24x24 and the other is 24x20 on the furnace. They need to be reduced to fit into the current ductwork. I would gladly pay $100 for this stuff. Even $200. Just need to find a place that can make it for me. The install is going to be somewhat easy after that. Time consuming, but straight forward.

backdraft damper - I am assuming that this goes on the supply side only. Please correct me if I am wrong. Also, where in the supply line does it go? Is it the first thing to go on the furnace, or does it go on top of the plenum? Will the HVAC shop be able to set this all up for me and incorporate the backdraft damper on the plenum?

laynes69 said:

A backdraft damper keeps the movement of air from the woodfurnace from backfeeding into the central furnace. It separates the operation of each unit when installed in parallel. You have to be careful with the placement, place it in the wrong area and you will hold heat into the woodfurnace during an outage. You could talk to your local hvac and see what they recommend. They should be able to build something for your needs.

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Alright, life just easier. There is only a single furnace, the wood burning furnace. It has a natural gas backup as part of the furnace, but it is a single unit with two firing chambers, but only a single supply plenum and single return plenum. So, it does not look like I need a backdraft damper. Thanks for mentioning Yukon for the plenums. They look like just what I need for this job.