Attic Fan Does Not Run On High Speed

The attic fan tends to makes a humming noise when it has a few blades and is running at a high speed setting.

Attic fan does not run on high speed.

Whole house fan will only run on high speed i have a whole house fan. The cost of electricity of running a standard attic exhaust fan is probably less thant 5 10 a year. When running at a high speed setting does the attic fan run hard or sluggishly. In order to get rid of the hum you need to either operate the fan at a low speed or replace the fan with a new one that has more blades.

Fans are rated by cubic feet of air per minute or cfm. You can fix this issue by turning down the settings or checking that the fan is getting enough air. If it is rotating slowly or not producing a lot of air in the high speed setting you may have a problem with the exhaust or intake. One major variable is the venting if you plan on running the fan on high speed most people do you need to make sure that there is at least enough exhaust venting for high speed setting.

Attic fans can sometimes start making noise whether it s humming rattling or making some other annoying noise. For years since we bought the house 10 years ago when we turned the fan on low it turned on high first before settling on low within a matter of a second or two. Parts can come loose or erode from high amounts of fan usage while turning the speed up to high can cause a persistent loud hum. A good rule of thumb is to provide one square foot of net free venting area for every 750 cfm.

Check the intake for any debris.