[Constantin]

I use a Webasto Airtop 5000 furnace. It runs on diesel and puts out 17,000 BTU/hr. Plenty to keep the boat warm in the spring and late fall. All forced-air systems are bound to make noise. Ensure adequate venting if you go the non-electrical route and be prepared to rely on shore power if you don''t. See more at vonwentzel.net