Take the total cubic feet per minute of air flow cfm of the fan and divide by 750 2.
How much roof venting for 6000 cfm house fan.
Understanding whole house fan cfm.
You can only bring in as much air as you can discharge out of your attic vents.
We always recommend at least having 1 sqft of net free area venting for every 750 cfm in your system.
Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator.
Dangers of too much ventilation.
Whole house ventilation allows you to bring the cooler outdoor air through your windows home and attic space to thoroughly cool and ventilate both the home and attic.
A rule of thumb is you should have one square foot of net free venting area for every 500 cfm of airflow.
With a power switch or a thermostat installation an attic fan can be turned on to let hot air from the attic out.
However the utility of attic ventilation fans is actually quite a controversial topic.
Here is an example.
The qc es 6000 advanced whole house fan is a new take on the idea of whole house ventilation.
That translates to one attic vent 3 feet by 3 feet or two attic vents.
Roofing resources during covid 19 for contractors for homeowners.
The quietcool brand of whole house fans has taken america by storm.
A wind turbine catches the wind and spins a fan which pulls hot air outside.
If you need 6 000 cfm of air flow through your house divide 6 000 by 750 to get a minimum 8 square feet of attic venting.
Venting plays a huge part in how your quietcool whole house fan system works to its full potential.
Attic ventilation fans whether hard wired or powered by their own solar panels seem like a low cost and effective way to help keep your house cool.
The two main dangers associated with too much ventilation involve roof damage and increased utility bills.
The higher the cfm the more venting area is required to keep the system working efficiently.
Whole house fans come in a variety of sizes determined by the amount of air they circulate or whole house fan cfm.
So at 3000 cfm you ll want six square feet of venting.
The downside of attic ventilation fans.
For proper cooling and efficient operation any whole house comfort ventilator requires adequate unobstructed outlets in the attic through soffit vents grilles or louvers.
Airflow is measured in cubic feet per minute cfm.
To calculate the amount of attic exhaust area you will need divide the fan s capacity in cfm by 750.
This will give you the amount of net free venting in square feet required for the fan you select.
Determine how much net free venting your fan will require.
The process of thoroughly cooling the home and attic is called.