Range Hood Duct Size Calculator

FAQs

What size duct should I use for a range hood? The recommended duct size for a range hood is typically 6 inches in diameter.

Can you use 4 inch duct for range hood? Using a 4 inch duct for a range hood is generally not recommended as it might not provide sufficient airflow for effective ventilation.

How many CFM do I need for a 36 range hood? For a 36-inch range hood, you would ideally want a minimum of around 250-400 CFM (Cubic Feet per Minute) for adequate ventilation.

How many CFM can a 6 inch duct handle? A 6-inch duct can handle approximately 150-300 CFM depending on factors like duct length and layout.

Is flexible duct OK for range hood? Flexible duct can be used for range hoods, but it’s important to use high-quality insulated flexible duct to minimize air leakage and maximize efficiency.

Is 400 CFM enough for range hood? A 400 CFM range hood can work well for standard cooking setups, but for larger kitchens or heavy cooking, higher CFM may be more effective.

How many CFM can a 4 inch duct handle? A 4-inch duct is generally not suitable for range hoods, as it might handle around 100-150 CFM at best, which is insufficient for effective ventilation.

What is code for venting range hood? Venting codes can vary by location, but typically range hoods should be vented to the outdoors to prevent indoor air pollution.

Is it OK to use semi rigid duct for range hood? Yes, semi-rigid duct can be used for range hood venting, as long as it meets local building codes and is properly installed.

Is 400 CFM enough for 36 range hood? 400 CFM should be sufficient for a 36-inch range hood in most standard cooking situations.

Can I use a 36 inch hood with a 30 inch range? Using a 36-inch hood with a 30-inch range is acceptable and allows for a bit of extra coverage.

Is 350 CFM enough for range hood? 350 CFM can be sufficient for a range hood, but it depends on the specific cooking habits and kitchen setup.

Does increasing duct size increase CFM? Yes, increasing duct size can potentially increase CFM by reducing air resistance, but other factors like the fan’s capacity also play a role.

Does length of duct affect CFM? Yes, longer ducts can lead to increased air resistance, which can impact CFM. Proper duct sizing and minimizing bends are important to maintain CFM.

What is the rule of thumb for HVAC duct sizing? A common rule of thumb is to aim for a duct velocity of around 800-900 feet per minute (fpm) for efficient HVAC duct sizing.

Does CFM matter for range hoods? Yes, CFM matters for range hoods as it determines the ability to effectively remove smoke, odors, and grease from your kitchen.

What are the disadvantages of flexible ductwork? Flexible ductwork can be prone to air leakage, has higher pressure drop, and might not be as durable as rigid ducts.

Is flexible ducting better than rigid? Rigid ducting is generally more efficient and has fewer airflow restrictions compared to flexible ducting.

What CFM is quietest for range hood? Range hoods around 300-600 CFM can provide a good balance between performance and noise level.

How do I increase the CFM on my range hood? To increase CFM, you can consider using a more powerful fan or improving the ductwork to reduce air resistance.

How many CFM do I need for a 30 gas range? For a 30-inch gas range, around 250-400 CFM is typically recommended for effective ventilation.

How far can a range hood be vented? The maximum venting distance can vary, but it’s generally recommended to keep the duct run as short and straight as possible to maintain airflow.

What kind of ductwork for kitchen hood? Rigid metal ductwork, such as galvanized steel or aluminum, is often recommended for kitchen hood ventilation.

Can I use rectangular duct for range hood? Yes, rectangular duct can be used, but it’s important to ensure the equivalent diameter provides the necessary CFM capacity.

Can I use 5 inch duct for range hood? A 5-inch duct might be better than a 4-inch one, but 6-inch is the more standard size for range hood ventilation.

Is it code to have a range hood for a gas stove? Ventilation requirements can vary, but it’s generally recommended to have a range hood for gas stoves to remove combustion byproducts.

Is it code to have a vent over a gas stove? Local building codes often require a ventilation system, like a range hood, over gas stoves to ensure safety.

Can you use PVC pipe for rangehood ducting? Using PVC pipe for range hood ducting is not recommended due to its potential to release harmful fumes when exposed to high temperatures.

Can I use semi-rigid flexible aluminum duct for range hood? Yes, semi-rigid flexible aluminum duct can be used for range hood venting if it meets local codes and is installed properly.

Which is better duct or ductless range hood? Ducted range hoods are generally more effective at removing pollutants compared to ductless ones.

Is 36 inches too high for range hood? A range hood should typically be installed around 28-36 inches above the cooktop, so 36 inches is within the recommended range.

Is 900 CFM good for a range hood? A 900 CFM range hood is powerful and suitable for larger cooking setups or professional kitchens.

How wide should a hood be for a 36 range? A hood width of 36 inches is appropriate for a 36-inch range.

Can a range hood be too big? A range hood can be too big if its CFM rating is significantly higher than what’s necessary for your cooking habits and kitchen size.

Should range hood be as deep as range? The range hood should ideally be as deep as the range or slightly wider to ensure effective coverage.

Should range hood be bigger than range? A range hood can be slightly larger than the range to provide better coverage, but it shouldn’t be excessively larger.

Is 390 CFM enough for range hood? 390 CFM can work for smaller kitchens and light cooking, but for more extensive cooking, you might want a higher CFM.

Is 400 CFM enough for Indian cooking? Indian cooking often involves strong spices and high heat, so a higher CFM, around 600-900, might be more appropriate.

What is a good CFM airflow? A good CFM airflow depends on your kitchen size, cooking habits, and the type of range you have. Generally, 300-600 CFM is suitable for most homes.

Is it better to undersize or oversize ductwork? It’s generally better to slightly oversize ductwork to ensure proper airflow and minimize pressure drop.

Is it bad to oversize ductwork? While slight oversizing is generally better, significantly oversizing can lead to reduced air velocity and potential energy inefficiency.

What happens if ductwork is undersized? Undersized ductwork can lead to reduced airflow, poor ventilation, and strain on the fan, reducing the overall effectiveness of the system.

How do I know if my ductwork is too small? If your range hood is struggling to remove smoke and odors, or if the airflow seems weak, your ductwork might be too small.

What is the rule of thumb for CFM per square foot? A common rule of thumb is to have around 1 CFM per square foot of kitchen area, but this can vary based on cooking style and equipment.

Do you want higher or lower CFM? For effective range hood ventilation, higher CFM is generally better, but it should be balanced with noise considerations.

What is the 2 foot rule for ducts? The 2-foot rule suggests that for every 90-degree bend in a duct, you should have 2 feet of straight duct to maintain proper airflow.

How do I know what size duct to use? Calculating duct size involves considering factors like CFM, duct length, and static pressure. HVAC professionals often use duct sizing software.

How many CFM do I need for a 12×12 room? For a 12×12 room, you would want around 120-240 CFM of airflow for effective ventilation.

What is code for venting range hood? Venting codes can vary by location, but range hoods are often required to be vented outdoors to prevent indoor air pollution.

Is 450 CFM enough for range hood? 450 CFM can work for moderate cooking, but for more extensive cooking or larger kitchens, higher CFM might be better.

What are the 4 rules for flexible ducts? Four important rules for flexible ducts are: keep them as straight as possible, avoid sharp bends, minimize sagging, and use appropriate supports.

What is the life expectancy of a flexible duct? Flexible ducts can last around 15-25 years, but this depends on factors like installation quality and environmental conditions.

What is the alternative to flex ductwork? The alternative to flexible ductwork is rigid ductwork, which can be made from materials like galvanized steel or aluminum.

Can I use semi rigid duct for range hood? Yes, semi-rigid duct can be suitable for range hood venting if installed correctly and meeting local codes.

What is the most efficient duct shape? Round ducts are generally the most efficient in terms of airflow and pressure drop.

How often should flexible ductwork be replaced? Flexible ductwork should be replaced if it’s damaged, leaking, or has significantly deteriorated. Proper maintenance can extend its lifespan.

What size duct is the same as the CFM for a range hood? There isn’t a direct correlation between duct size and CFM. Duct size affects air resistance, which in turn impacts CFM.

Does higher CFM mean quieter? Higher CFM can sometimes mean more noise due to increased air movement and fan speed, but fan design also plays a role in noise level.

Is 6 Sones loud for a range hood? 6 Sones is considered moderately loud for a range hood. Quieter range hoods are often rated around 1-3 Sones.

What CFM is quietest for range hood? Range hoods in the 300-450 CFM range often strike a good balance between performance and noise level.

Why is my hood vent not strong enough? Several factors could contribute, including incorrect duct sizing, excessive duct length, bends, blockages, or a fan with insufficient CFM.

How many CFM do I need for a 30 range hood? For a 30-inch range hood, around 250-400 CFM is generally recommended for effective ventilation.

What size of hood fan for a 30 inch stove? For a 30-inch stove, a hood fan with around 250-400 CFM is suitable for most cooking needs.

Is it OK to vent your range hood into the attic? Venting a range hood into the attic is generally not recommended as it can introduce moisture and odors into the attic space.

Can I vent my range hood out of the side of my house? Venting a range hood out of the side of your house is possible, but you should follow local codes and ensure proper installation to avoid issues.

Can I use 4 inch duct for range hood? Using a 4-inch duct for a range hood is generally not recommended as it might not provide sufficient airflow for effective ventilation.

What is standard duct size for range hood? The standard duct size for range hoods is typically 6 inches in diameter.

Is it OK to use flexible duct for range hood? Flexible duct can be used for range hoods, but it’s important to use high-quality insulated flexible duct to minimize air leakage and maximize efficiency.

Can I use a 3 inch duct for range hood? Using a 3-inch duct for a range hood is not recommended, as it’s likely too small to provide adequate airflow.

How many CFM can a 5 inch duct handle? A 5-inch duct can handle around 125-250 CFM depending on factors like duct length and layout.

How many CFM will a 6 inch flex duct carry? A 6-inch flex duct can carry approximately 150-300 CFM depending on various factors.