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New building codes require what is called “make-up air” to be installed when a kitchen ventilation hood exceeds 400 CFM (cubic feet of air per minute). Many gas range and cooktop manufacturers recommend well over 400 CFMs for a ventilation hood especially when you exceed 4 burners on your appliance.
Do I need a makeup air for my range hood?
Your range hood pulls 1200+ CFM Even with a powerful hood, you may not require makeup air if it is installed in a large kitchen or well-ventilated space. However, if you live in a small space or the ventilation is not adequate, make up air is likely a good option for you.
Is make up air required?
In the US, the construction industry has long recognized the need for adequate makeup air for exhaust systems. Beginning in 2009 and in every version since, the International Residential Code (IRC) has required that makeup air be provided for kitchen hood exhaust systems with capacity of 400 cfm or greater.
Why is makeup air required?
Makeup air is needed in homes to replace air that is removed by mechanical devices, such as clothes dryers, kitchen exhaust fans, and bathroom exhaust fans. Makeup air is not the same thing as combustion air. Combustion air is needed to support combustion at appliances such as a furnace or water heater.
Is 400 CFM range hood enough?
We recommend purchasing a hood that is more powerful than 400 CFM, but the casual cook might be able to get by with 400. Most 400 CFM hoods are manufactured cheaply at big box stores, so they are not very durable.
Is a kitchen exhaust fan required by code?
California requires kitchen ventilation in all new construction and remodels, and even if your local authorities don’t require it, you should address it anyway. You can satisfy most local codes by installing a range hood.
How do you calculate air makeup?
Calculate the required volume. Divide room volume (Step 1) by total/1000 (Step 2). If less than 50, additional air is needed. If greater than or equal to 50, no additional air is needed.
What happens if you don’t have make up air?
What happens if you don’t have enough make up air supply? Without enough make up air, the building pressure becomes negative. When your exhaust hood is removing more air than you are replacing, it can cause everything from changes in the performance of your exhaust hood to excessive grease and smoke from your hood.
What is a makeup air system?
WHAT IS MAKE-UP AIR? Make-up air is designed to “make up” the air in your interior space that has been removed due to process exhaust fans. This type of HVAC solution pulls in fresh, tempered air from outside your building to replace existing air that cannot be recirculated.
How many CFM should a range hood have?
Wall-mounted & Under-cabinet range hoods – 100 CFM for every linear foot of cooktop. Most common types of cooktops measure 30 inches wide, or 2.5′. 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.
What CFM do I need?
The minimum CFM you need for your air compressor should be 1.5 times the total required CFMs of the tools. For example, if you need to run a spray gun of CFM 4 at 40 PSI, the CFM of the air compressor should be at least 4 x 1.5= 6 CFM.
How does a makeup air unit work?
Simply stated, a make up air unit pulls air in to your space from outdoors and conditions it to the indoor temperature, to replace air that’s pulled out by your kitchen exhaust equipment. Without it, you get back drafting, poor temperature control, negative air pressure and air quality problems.
What is a fresh air intake vent?
It does, but to make sure that the HVAC is receiving fresh air, a vent is needed. What is a fresh air intake vent? It is an open duct that goes from an outside vent that serves as a path for clean fresh air into the home. It often goes to the room where the furnace is or the basement.
Do kitchen fans bring in outside air?
Exhaust fans pull odors, and moisture, etc. from the house, and then venting them outdoors for removal. A motor is used in the fan to turn its blades, that work to pull air out of the space. The stale, humid, and contaminated air is propelled via the exhaust vent, exiting the house.
What is combustion air?
What is combustion air? Combustion air is a source of oxygen needed to burn fuel such as natural gas or liquid propane (LP). You can’t produce a flame in a furnace without proper combustion air. The image above shows the combustion air as a vent in the garage to pull air from the attic.
How many CFM can a 4 duct handle?
Reviewing the chart, a 4” pipe will convey 395 CFM at 4500 FPM. This means that a 4” pick-up on a machine will use 395 CFM from the filtering system; or, if you know that a machine will require approximately 400 CFM to remove the waste, you should use a 4” pipe for that purpose.
Is too much CFM bad?
Wasting Energy With Excessive Ventilation Increased CFM will not dry out the bathroom any faster, so the fan will still have to run for the same amount of time. However, since the airflow is higher a lot more energy is lost.
Can I use flex duct to vent range hood?
Can flexible duct be used for a range hood? No. Avoid flexible duct for your range hood, regardless of the CFM.
What do you do if you have no exhaust fan in kitchen?
Here’s what you can do to help mitigate the effects of your range-less kitchen, with specific advice culled from our readers: Use a window fan. Use a portable HEPA air filter. Use a fan in another room, like the bathroom. Get a grease splatter guard. Wipe down your kitchen cabinets frequently.
Does a range hood have to vent outside?
Range hoods do not have to be vented to the outside. You can purchase hoods without ductwork called ductless hoods. But, ducted range hoods are almost always preferred over ductless hoods.
Is an exhaust fan required over a stove?
Most residential building codes do not require a range hood above a stove or cook top, but you’d be wise to ensure your locale is not the exception. Even if it’s not legally required, you should think long and hard before forgoing a hood altogether.
