We are looking into converting from FHA to FHW. One BIG problem that not mentioned much with forced hot air are the air ducts. They are major subways for rodents, chipmunks and whatever animal that can crawl into them for free heat and comfort. If one dies in there, you can imagine what your are breathing. The cost to get rid of these squatters is $200 and up annually, not to mention the stress hearing them eating away your house inner walls. DO what is best for you, but we are CONVERTING!