How powerful a range hood do I need?
To power your range hood, you need at least 100 CFM for every 10,000 BTUs of your stovetop. For example, a 100,000 BTU stove needs at least a 1000 CFM range hood. For electric stoves, multiply the stove width by 10. So, for a 42” electric stove you want a range hood with at least 420 CFM.
For high-output gas ranges or cooktops, the minimum rate of 1 CFM of ventilation per 100 British thermal units (BTU) is recommended. For example, if your high-output burner output is 45,000 BTU, look for a range hood that provides 450 CFM to best clear the air. However, the higher the CFM, the louder the hood will be.
The HVI recommends taking a stove's BTU rating and dividing it by 100 to find a minimum level. For example, a stove with a 30,000 BTU rating would require a kitchen hood with a capacity of at least 300 CFM. A kitchen range hood should be able to cycle the air out of the entire kitchen 15 times per hour.
Be aware that it is also possible to have a hood that is too big and too powerful. You don't want to suck too much air from your kitchen; otherwise, you may require a make-up air kit to supply your kitchen with additional oxygen.
A range hood fan should move a minimum of 100 CFM of air for every 12 inches of stove width. This means that if you have a stove that is 30 inches wide then you need a range hood with a fan that rotates at least 250 CFM of air.
But if the size of your duct matches your ventilation power, your kitchen exhaust fan will do its job properly and quietly. A good rule of thumb for estimating duct diameter and CFM requirements is: 400 to 600 CFM = 6” to 8” duct. 700 to 900 CFM = 7” to 10” duct.
To meet the recommended CFM requirements, you'll need a range hood with 250 CFM. Island hoods – 150 CFM for every linear foot of cooktop. Due to the open nature of a kitchen island stove, you need extra power. As a general rule of thumb, for the same 30” cooktop, you'll need a range hood with 375 CFM.
Range hood dimensions most often measure 24”, 30” or 36” in width, but can span anywhere from 24” to 60” wide. It's best to install a hood that measures the same size as your cooktop to most effectively capture the grease, odors and smoke coming from any burner or element below.
For gas cooking surfaces or range, a minimum ventilation level of 100 CFM (Cubic Feet per Minute) per 10,000 BTU is recommended. However, the hood must have a minimum of 500 CFM of ventilation power.
What size range hood do I need for a 30” cooktop? With a 30” range, a 36 inch range hood is your best choice.
How much CFM do I need?
| Room Size: | CFM (At 2 ACH) |
|---|---|
| How many CFM for a 900 sq ft room? | 240 CFM |
| How many CFM for a 1000 sq ft home? | 267 CFM |
| How many CFM for a 1500 sq ft home? | 400 CFM |
| How many CFM for a 2000 sq ft house? | 533 CFM |
An OTR microwave won't be enough to effectively filter out the contaminants or strong odors produced by this type of cooking. Instead, you'll want to go with a high-CFM option such as a 2000 CFM Proline range hood to make sure the air is always clear and clean.
For every 10” of stove width, roughly 100 CFM is necessary. With frequent Asian cooking, though, you will be emitting more fumes than your average home does.
Keep in mind that the quietest range hood doesn't necessarily mean the most powerful. You could have a 200 or 300 CFM hood that's incredibly quiet. On the other hand, you could have an 1800 CFM hood that's quiet! Always compare the max CFM to the sone rating before deciding on a hood.
Clean the filters.
Range hood filters are key to ensuring your hood stays in great condition. Clean the filters every three to six weeks, depending on how much grease they accumulate. Without proper maintenance, grease and dirt will buildup and block the airflow.
Good CFM ranges from 4,000 to 5,000. Better ranges from 5,000 to 6,000. Best is over 6,000.
Measure the width of the area over the range or cooktop. Range hoods often come in 24", 30" or 36" widths. The hood should be at least as wide as the cooking surface, but preferably should be 6" wider.
- The size of the exhaust fan is the main criterion for selecting an exhaust fan for the bathroom (or kitchen). The airflow or amount of air exchanged per minute by the exhaust fan is measured in CFM (cubic feet per minute). ...
- The preferred location of the exhaust fan is near the shower area or the bathtub of the bathroom.
The suggested CFM requirements for cooktops: “Regular” gas cooktops output 40,000 BTU's. To calculate your gas stove's BTU, add the power of each burner and divide the total by 100. So a “regular” gas system would need a 300 CFM fan.
Remember, when choosing a range hood for your gas stove, go with a ducted hood. A ductless hood with charcoal filters doesn't have enough power to clean your air, and it won't move all the contaminants outside your home. If you made it this far, thank you so much.
How many CFM do I need for a 12x12 room?
One cfm per square foot of floor area is the average air quantity required for a room or entire building.
| Kitchen Range Width | Custom Hood Size | Range Hood Insert Size |
|---|---|---|
| 36" | 42" | 40" |
| 42" | 48" | 46" |
| 48" | 54" | 52" |
| 54" | 60" | 58" |
| Bathroom Size | Minimum Ventilation (CFM) Required* |
|---|---|
| Less than 50 sq. feet | 50 CFM |
| 50-100 sq. feet | 1 CFM per sqare foot of floor space |
| More than 100 sq. feet | Add the CFM requirement for each fixture: Toilet 50 CFM Shower 50 CFM Bathtub 50 CFM Jetted tub 100 CFM |
CFM = (fpm * area), where fpm is the feet per minute. To find the cubic feet per minute, substitute the FPM value with the area after the area is squared.
135 CFM is needed per square foot of space. So, a 100 square foot room would need 13.5 CFM. A 1,000 square foot room would need 135 CFM.
Your range hood should be six inches larger than your range. For great coverage, you can even buy a hood 12 inches larger than your range. Larger range hoods are always a great idea. With smaller hoods or hoods over electric stoves, you may be able to get by with a hood that is equal to the size of your cooktop.
In homes with naturally drafted fuel-fired appliances like a boiler inside the envelope, kitchen range hoods that exhaust more than 400 cu. ft. of air per minute require makeup air so they don't depressurize the home and draw combustion gases from the appliance into the living space.
One of the key features to look for in a range hood is the number of cubic feet per minute (CFM) the fan can move. It's a measure of the hood's power. A general rule of thumb is that you need 1 CFM for every 100 BTU's your range produces.
Good CFM ranges from 4,000 to 5,000. Better ranges from 5,000 to 6,000. Best is over 6,000.
For gas cooking surfaces or range, a minimum ventilation level of 100 CFM (Cubic Feet per Minute) per 10,000 BTU is recommended. However, the hood must have a minimum of 500 CFM of ventilation power.
What CFM do I need?
The rule of thumb is that you need at least 1 CFM per square foot of room area. To determine the square footage of your bathroom, multiply the length times the width. For example, if your bathroom is six feet wide and nine feet long, its square footage is 54. Therefore, it should have a fan rated for at least 54 CFM.
How many sones is a quiet range hood? A quiet range hood is about four to five sones, or about 50 dB at max speed. Lower speeds on quiet hoods can get down to just one sone! Most hoods range between seven and nine sones, depending on the quality of the materials and CFM.
