Residential Dehumidifiers for Kiln Drying

You need an industrial model to dry wood the homeowner version is not built for it. November 8, 2007

Question
I purchased a small bandsaw mill and have a pretty hefty stack of wood I want dried. I've built a small kiln and am ready to add the dehumidifier. I've looked at the Ebac and Wood-Mizer dehumidifiers and those are out of my price range, but do have an Aprilaire 1700 whole house unit available if I want it. My kiln is 12'L x 8' wide but only 6' H with 7" thick walls insulated and sealed well. I've read where the Aprilaire has to be set up by a professional installer. Are they really that hard to wire?

Forum Responses
(Sawing and Drying Forum)
From contributor D:
An Aprilaire dehumidifier would not last long in a kiln environment. If you are leaning toward doing something on a very small scale, you could buy a regular home dehumidifier. They also will not last very long, but you will not have as much invested. Residential dehumidifiers do not operate at temperatures high enough to be effective for all species of lumber. If you are drying green lumber or some species that need a higher temperature, you might be better off with a simple heat and vent system.



From Professor Gene Wengert, forum technical advisor:
There is a big difference between a house AC unit and a DH unit for a kiln. Both are heat pumps, but the DH unit has coils that will stand up to the acids in wood. Also, a DH unit has controls for drying.


From the original questioner:
I was assuming the Aprilaire was a DH that attached to the existing furnace duct. I would mount it outside the kiln since it has in/out 8' ports. If that's not a good choice, I was also looking at the Ebac Triton and using an external RH control, but of course I would use a moisture tester periodically. Also I don't think I would be drying more than 400bf at any given time.


From contributor D:
The fact that the dehumidifier is outside the chamber makes no difference, because all the air inside the dehumidifier is from the kiln (or should be).