2manytoyz wrote:My question on thise fans would be at what static pressure are they producing that airflow. A 5" flex duct only carries about 50 cfm at .5 in/wc if the static rating for those fans is near that then you will potentially shorten the life of the fan considerably. I do residental and commercial hvac for anliving and a 5000 btu unit (.417 ton unit) by industry norms needs about 167 cfm. Am i missing something that is radically different with using this type of unit as I am planning a similar design for my camper.
Brian
How long a run are your numbers based on? my guess is 100ft. Mine are only 5ft long, so a much higher CFM would be expected. The A/C units cost about $100 and they last for years under the short term conditions like these. If static pressure is shortening their life expectancy its not enough to show up under these conditions. According to the manufacture of mine the fan puts out between 111 and 136 cfm. I suspect that fans in these units are designed to push pretty hard, given that they have to suck across a pretty tight coil and then blow the air across the room.
Tom