Insulate the ductwork or warm the crawlspace?
I work in an old church that has been repurposed that has a forced air heat system. The ductwork capacity is large and when the heat kicks on the initial blasts are pretty cold. A work colleague thought it would be better to put some type of register off the ductwork to heat the crawlspace than to insulate the ductwork. The crawlspace is about 2500 square feet and has a vapor barrier with spray foam insulation on the exterior walls. The thought was that heating the crawlspace would help the furnace work less hard to get warm air pumped into the building. Thoughts?
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