Enervex Chimney Fans – What You Need to Know Before You Buy
An ENERVEX fan is a combination chimney cap and chimney exhaust fan that will correct draft problems in almost any chimney!
How Enervex Fans work
The ENERVEX FAN (formerly named Exhausto Fan) mounts atop the chimney, where it literally sucks the smoke from the flue. Even difficult drafting problems such as poorly proportioned corner fireplaces, seethrough fireplaces, backdrafting fireplaces, or odors from your chimney are solved with the ENERVEX Fan. ENERVEX fans are appropriate for masonry, aircooled, and solid pack flues as well as for woodstoves and fireplace inserts.
The ENERVEX motor is completely enclosed and maintenance free with aircooled, prelubricated, sealed ball bearings. It comes with a prewired junction box, a bird screen, and a speed motor control. Using the variable speed control, which is included with every Enervex fan, you can adjust the speed of the fan from the room where you have the fireplace. It also works as a ventilator: Turn it on when you need to refresh the air in the room, and the fan will pull out stale odors and cigarette smoke.
Description and Warranty
ENERVEX Fans are ULlisted, powerful, efficient, and very quiet. Made of extremely durable castaluminum and stainless steel, they have a six month moneyback guarantee, a twoyear warranty against defects in material and workmanship, and a 10year warranty against corrosion. The ENERVEX Fans are designed for minimum energy consumption, using about as much energy as a regular light bulb.
Choosing the Right Enervex Fan
ENERVEX Fans come in four residential models: Models RS9, RS12, RS14, and RS16, ranging from smallest to largest. The model Enervex chimney fan you need is determined by
 the size of your fireplace opening.
 the style of flue you have, and
 the area area of a flue,
The correct size Enervex Fan will correct any drafting problems at the lowest cost.
Measuring the area of your fireplace opening is easy: just measure the width and height of the fireplace opening, in inches, and multiply width times height to get the area in square inches. For example, 39″ wide by 30″ tall = 1170 square inches. NOTE: If you have a seethrough fireplace, add the square inches of the larger side and 1/2 the square inches of the smaller side to determine your “fireplace opening size.”
To determine the style of flue you have, you will need to go onto your roof and physically inspect the flue pipe where it leaves the chimney.
 It may be a clay (terracotta) pipe that is round, square, or rectangular.
 It may be a round metal flue pipe that is just a single pipe like stove pipe or a chimney liner.
 It may be a solid pack pipe (two concentric pipes with insulation between them and a covering over the insulation so you cannot see it).
 It may be an aircooled flue that has an inner pipe which is the actual flue, and either one or two air jackets surrounding the flue.
To determine the area of a square or rectangular flue pipe, multiply the inside length times the inside width. For example, a flue that measures 8″ by 8″ inside has an area of 64 square inches.
To determine the area of a round flue, measure the inside diameter, divide by two to get the radius, multiply the radius by itself and then by pi (3.14). For example, an 8″ flue has a 4″ radius. 4 x 4 = 16 x 3.14 = 50.24 square inches. For aircooled flues remember to measure the innermost pipe.
Now that you have the area of your fireplace opening and the area of your flue, find the right combination of flue type, flue size, and fireplace opening size on the table below:

 For woodstoves and fireplace inserts having a door opening size of less than 300 square inches.
 For 6″ diameter round flues with a fireplace opening of 400 to 599 square inches.
 For 7″ to 22″ diameter round flues with a fireplace opening from 400 to 899 square inches
 For square flues 5″x 5″ or 6″ x 6″ square with a fireplace opening from 400 to 599 square inches.
 For square flues from 7″x 7″ square to 20″ x 20″ square with a fireplace opening of 400 to 899 square inches
 For rectangular flues 6″x 10″, 7″x 11″, 8″x 12″, 9″x 13″, 10″x 14″, 11″x 15″, 12″ x 16″, 13″ x 18″, 14″ x 19″, or 15″ x 20″ with a fireplace opening of 400 to 899 square inches.


 For 5″ diameter round flues with a fireplace opening of 400 to 599 square inches.
 For 6″ diameter round flues with a fireplace opening of 600 to 899 square inches.
 For 8″ to 9″ diameter round flues with a fireplace opening of 900 to 1199 square inches
 For 10″ to 12″ diameter round flues with a fireplace opening of 900 to 1199 square inches
 For 14″ to 22″ diameter round flues with a fireplace opening of 900 to 2499 square inches
 For 4″ x 4″ square flues with a fireplace opening from 400 to 599 inches.
 For 6″ x 6″ square flues with a fireplace opening from 600 to 899 inches.
 For 8″ x 8″ and 9″ x 9″ square flues with a fireplace opening from 900 to 1199 inches.
 For square flues from 10″x 10″ square to 12″ x 12″ square with a fireplace opening between 900 and 1499 square inches
 For square flues from 13″x 13″ square to 20″ x 20″ square with a fireplace opening between 900 to 1999 square inches
 For 6″ x 10″ and 7″ x 11″ rectangular flues with a fireplace opening between 900 and 1199 square inches
 For 8″ x 12″, 9″ x 13″, and 10″ x 14″ rectangular flues with a fireplace opening between 900 and 1499 square inches.
 For 11″ x 15″ rectangular flues with a fireplace opening between 900 and 1999 square inches.
 For rectangular flues with a fireplace opening between 900 and 2499 square inches if the flue is one of the following sizes: 12″ x 16″, 13″ x 18″, 14″ x 19″, or 15″ x 20″.


 For 7″ diameter round flues with a fireplace opening between 900 and 1199 square inches
 For 8″ to 9″ diameter round flues with a fireplace opening between 1200 and 1499 square inches
 For 10″ diameter round flues with a fireplace opening between 1500 and 1999 square inches
 For 12″ diameter round flues with a fireplace opening between 1500 and 2499 square inches
 For 14″ to 22″ diameter round flues with a fireplace opening between 2500 and 3299 square inches
 For 7″ x 7″ square flues with a fireplace opening between 900 and 1199 square inches
 For 8″ x 8″ or 9″ x 9″ square flues with a fireplace opening between 1200 and 1499 square inches
 For 10″ x 10″, 11″ x 11″ or 12″ x 12″ square flues with a fireplace opening between 1500 and 1999 square inches
 For square flues from 13″x 13″ square to 20″ x 20″ square with a fireplace opening between 1500 and 1999 square inches
 For 6″ x 10″ or 7″ x 11″ rectangular flues with a fireplace opening between 1200 and 1499 square inches
 For 8″ x 12″ rectangular flues with a fireplace opening between 1500 and 1999 square inches
 For 9″ x 13″ or 10″ x 14″ rectangular flues with a fireplace opening between 1500 and 2499 square inches
 For 11″ x 15″ rectangular flues with a fireplace opening between 2000 and 2499 square inches
 For 12″ x 16,” 13″ x 18,” 14″ x 19,” or 15″ x 12″ rectangular flues with a fireplace opening between 2500 and 3299 square inches


 For 5″ diameter round flues with a fireplace opening between 600 and 899 square inches
 For 6″ diameter round flues with a fireplace opening between 900 and 1199 square inches
 For 7″ diameter round flues with a fireplace opening between 1200 and 1499 square inches
 For 8″ diameter round flues with a fireplace opening between 1500 and 1999 square inches
 For 9″ diameter round flues with a fireplace opening between 1500 and 2499 square inches
 For 10″ diameter round flues with a fireplace opening between 2000 and 2499 square inches
 For 12″ diameter round flues with a fireplace opening between 2500 and 3299 square inches
 For 14″ to 22″ diameter round flues with a fireplace opening between 3300 and 5000 square inches
 For 4″ x 4″ and 5″ x 5″ square flues with a fireplace opening between 600 and 899 square inches
 For 6″ x 6″ square flues with a fireplace opening between 900 and 1199 square inches
 For 7″ x 7″ square flues with a fireplace opening between 1200 and 1499 square inches
 For 8″ x 8″ and 9″ x 9″ square flues with a fireplace opening between 1500 and 1999 square inches
 For square flues from 10″x 10″ square to 20″ x 20″ square with a fireplace opening between 2500 and 3299 square inches
 For 6″ x 10″ rectangular flues with a fireplace opening between 1500 and 1999 square inches
 For 7″ x 11″ rectangular flues with a fireplace opening between 1500 and 2499 square inches
 For 8″ x 12″ rectangular flues with a fireplace opening between 2000 and 2499 square inches
 For 9″ x 13″, 10″ x 14″ or 11″ x 15″ rectangular flues with a fireplace opening between 2500 and 3299 square inches
 For rectangular flues with a fireplace opening between 3300 and 5000 square inches if the flue is one of the following sizes: 12″x 16″, 13″x 18″, 14″x 19″ or 15″x 20.”

Before installing, check local codes as some local codes prohibit the use of chimney fans on gas and oil furnaces. We strongly encourage you to have the 110V wiring installed by a certified electrician.
If you wish to install an ENERVEX (Exhausto) Fan on a round flue, you will need to purchase the appropriate adaptor.
 Order a SOLID PACK Adaptor if you have a solidpack flue, a stove pipe, or a chimney liner.
 Order an AIRCOOLED Adaptor if you have a double wall or triple wall air cooled flue.
Follow the printed installation instructions that come with the Enervex fan.