My house was built in the 1950s, so the fireplace has a design where area surrounding the actual fire area is hollow. The idea is that the fire heats up the surrounding hollow area from which the air is expected to be brought back into the room. The design has a wide, short vent above the fire area and two square (about 9"/22cm wide/high) vents, all three of which are vents for this hollow area. I was told by our chimney cleaner that forcing air into the two lower vents would blow the hot air into the room from the upper vent, thus heating the entire room and more. I'll be damned if it doesn't work. The problem is that the only fans that I have to force air into this vent are cheap, heater fans. (I obvioulsy only use the fan-only function.) But these don't put out nearly enough air to make a difference. I spoke with a few people at Home Depot about fans for those two vents, and they had absolutely no clue what I was talking about. So, I'm still looking for high-volume fans to force more of the hot air out of the fireplace area. Hell, I've even considered getting some appropriately sized fans from the local electrical shop and building enclosures to keep my 3-yr-old's fingers away from them. Is there any place that sells fans meant specifically for this purpose, or is this type of fireplace design long since relegated to histry?