Q: Our dehumidification dry kiln has been working well for many years, but now we are faced with replacement of the compressor. The cost of freon is out of sight. It is apparently a gas that destroys the ozone layer, so the U.S. government has put a nice tax on it to discourage its use. What are our options for a less expensive kiln? We have two 30 MBF chambers now drying mostly 4/4 red oak green from the saw.

A: There are new gases for DH kilns that work fairly well. But they are also expensive. So, perhaps you might want to consider, for a minute or two, buying a steam boiler. After checking prices, fuel availability, and licensing and insurance requirements, you will probably discard this idea. Then you will have to go back to the DH kiln. Have your DH supplier give you the names of some mills using the new equipment and new gases and then check out their stories. Although the cost will be higher for DH kilns, they will still be very profitable. With red oak dried green from the saw, we need to carefully control the relative humidity and temperature, so the hot air kiln (no boiler) is probably not the best idea for you. You will probably need a small boiler for equalization and conditioning with any system that you choose.