Panasonic

The Home Ventilating Institute (HVI), a trade association representing the manufacturers of 95% of the residential fans in North America, recommends that a bathroom exhaust fan be selected that is capable of providing eight air changes per hour (ACH). Most building codes only require a minimum airflow of 50 cfm from a bathroom, with a capacity of providing five ACH. HVI also recommends that the kitchen ventilation fan (not the rangehood) be sized to provide 15 ACH and in other rooms be sized to provide six ACH. Panasonic feels that the designer should use the more optimal ventilation rates recommended by HVI. The following tables reflect the HVI sizing guidelines and assume metal duct and a reasonable roof jack or weather cap. If flexible or semi-rigid duct is used, add ten feet of duct run for your fan selection calculation to allow for the higher static pressure created.

Table A:	Bathroom fan sizing and selection (to achieve 8 ACH as per HVI)
Table B:	Other room fan sizing and selection (except kitchens and baths. Including spaces such as living rooms, utility rooms, large closets, etc.) (to achieve 6 ACH)
Table C:	Kitchen fan sizing and selection (not rangehood flow) (to achieve 15 ACH)

Table A: Bathroom fan sizing and selection (to achieve 8 ACH as per HVI)

Bathroom	Rigid metal duct length from fan to cap
Sq Ft	10 feet	20 feet	30 feet	40 feet
50	05VQ2	05VQ2	05VQ2	07VQ2
60	07VQ2	07VQ2	07VQ2	07VQ2
70	07VQ2	08VQ2	08VQ2	08VQ2
80	08VQ2	08VQ2	11VQ2	11VQ2
90	11VQ2	20VQ2	20VQ2	20VQ2
100	20VQ2	20VQ2	20VQ2	20VQ2
140	20VQ2	20VQ2	20VQ2	20VQ2
180	20VQ2	20VQ2	35VQ2 or 11 + 20VQ2	35VQ2 or 11 + 20VQ2
240	35VQ2 or 11 + 20VQ2	35VQ2 or 11 + 20VQ2	35VQ2 or 2-20VQ2	35VQ2 or 2-20VQ2
300	35VQ2 or 2-20VQ2	2-20VQ2	2-20VQ2	2-20VQ2

Assumes eight foot ceilings.
Duct diameter is four inch for 05/07/08/11VQ fans, six inch for 20/35VQ fans.
If flexible or semi-rigid duct is used, add ten feet of duct run.

Example:
Eight foot by ten foot master bathroom = 80 square feet
Twenty feet of four inch metal duct from the fan to the gable end cap
Enter Table A at 80 square feet and go across to 20 feet of duct.
The recommended fan is the FV-08VQ2 fan or the FV-08VQL fan/light combo
If flexible ducting is used, such as aluminum flex or insulated plastic flex, add ten feet to the duct run and go over to 30 feet of duct. This means that the fan should be upsized to the FV-11VQ2 fan or the FV-11VQL fan light combo.

Table B: Other room fan sizing and selection (except kitchens and baths. Including spaces such as living rooms, utility rooms, large closets, etc.) (to achieve 6 ACH)

Room	Rigid metal duct length from fan to cap
Sq Ft	10 feet	20 feet	30 feet	40 feet
50	05VQ2	05VQ2	05VQ2	07VQ2
60	05VQ2	05VQ2	05VQ2	07VQ2
70	07VQ2	07VQ2	07VQ2	07VQ2
80	07VQ2	07VQ2	07VQ2	07VQ2
90	07VQ2	08VQ2	08VQ2	08VQ2
100	07VQ2	08VQ2	11VQ2	11VQ2
140	20VQ2	20VQ2	20VQ2	20VQ2
180	20VQ2	20VQ2	20VQ2	20VQ2
240	20VQ2	20VQ2	35VQ2 or 2-20VQ2	35VQ2 or 2-20VQ2
300	35VQ2 or 2-20VQ2	35VQ2 or 2-20VQ2	35VQ2 or 2-20VQ2	35VQ2 or 2-20VQ2

Assumes eight foot ceilings.
Duct diameter is four inch for 05/07/08/11VQ fans, six inch for 20/35VQ fans.
If flexible or semi-rigid duct is used, add ten feet of duct run.

Example:
Twelve foot by twenty foot family room = 240 square feet
Twenty feet of six inch metal duct from the fan to the gable end cap
Enter Table B at 240 square feet and go across to 20 feet of duct.
The recommended fan is the FV-20VQ2 fan.
If flexible ducting is used, such as aluminum flex or insulated plastic flex, add ten feet to the duct run and go over to 30 feet of duct. This means that the fan should be upsized to the FV-35VQ2 fan or two FV-20VQ fans should be used to get the total flow needed.

Table C: Kitchen fan sizing and selection (not rangehood flow) (to achieve 15 ACH)

Kitchen	Rigid metal duct length from fan to cap
Sq Ft	10 feet	20 feet	30 feet	40 feet
50	11VQ2	11VQ2	20VQ2	20VQ2
60	20VQ2	20VQ2	20VQ2	20VQ2
70	20VQ2	20VQ2	20VQ2	20VQ2
80	20VQ2	20VQ2	20VQ2	20VQ2
90	20VQ2	20VQ2	20VQ2	35VQ2
100	20VQ2	35VQ2	35VQ2	35VQ2
140	35VQ2	35VQ2	35VQ2	35VQ2
180	2-20VQ2	2-20VQ2	2-20VQ2	2-20VQ 2
240	20+35VQ2	20+35VQ2	2-35VQ2	2-35VQ 2
300	2-35VQ2	2-35VQ2	2-35VQ2	2-35VQ2

Assumes eight foot ceilings.
Duct diameter is four inch for 11VQ fans, six inch for 20/35VQ fans.
If flexible or semi-rigid duct is used, add ten feet of duct run.

Example:
Ten foot by ten foot kitchen area = 100 square feet
Ten feet of six inch metal duct from the fan to the gable end cap
Enter Table C at 100 square feet and go across to 10 feet of duct.
The recommended fan is the FV-20VQ2 fan.
If flexible ducting is used, such as aluminum flex or insulated plastic flex, add ten feet to the duct run and go over to 20 feet of duct. This means that the fan should be upsized to the FV-35VQ2 fan.