The goal is to keep temperatures up in my garage which I am using to heat my greenhouse in Iowa via insulated ducting buried underground a short distance between the two structures.

The greenhouse was already in full production when I installed the ducting so burying it under the beds wasn’t an option. Instead. the duct pops up in the greenhouse like a submarine periscope and is fitted with a centrifugal fan that is controlled by a speed control and thermostat.

It’s cold here in Iowa and it’s unlikely that the air I’m piping in there will be hot enough to offset the lack of insulation and intense cold I’m dealing with. If I can get just one Bhut Jolokia (Ghost Pepper) to ripen in December this year, then I’ve done something pretty remarkable. The leaves are dropping off the hottest peppers now but the kale, chard, celery, greens, and herbs are loving it.

Version 1

Too much mass on the sides, not enough up above. Lower bricks aren’t hardly getting warm and outer side bricks are much cooler than the inner ones. I want hot bricks exposed to open air.


Version 2

Much better though still too much mass in some places. I’m going for all bricks HOT after 6 hours of firing the stove.

Version 3

This one could be the one! All the bricks are very hot after burning the stove about 6 hours. I may even add an additional brick or two against some of the surfaces that are too hot to touch.

Next step is to bring the ducting right up next to the wood stove and possibly even attach the duct to a cavity in the themal mass around the stove or attach it to a heat reclaimer like the magic heater. This will require an additional 30 feet of 6″ ducting which I will most likely need to insulate in order to make sure that it’s able to deliver that warmth all the way to the green house.