One of the issues to consider when adding a range hood, or replacing one, is whether it will cause depressurization problems in the house. If the exhaust flow of a range hood (or any other fan) causes high levels of house depressurization, there are some possible negative consequences:

  1. Backdrafting or spillage of vented combustion appliances, including fireplaces and woodstoves
  2. An increase in radon entry from the soil
  3. An increase of air entering the house from attic spaces or wall cavities
  4. Drafts from the outside

The bigger the fan and the tighter the house, the more depressurization that is likely to occur.

Have you encountered this in your work? Have you seen instances where a newly installed range hood requires some monitoring or the provision of make-up air? What levels of depressurization have you seen created?

Back when I was testing houses in the eighties and nineties, we saw several houses exceed 20 Pa of depressurization. Are we seeing that today?

The gradual disappearance of natural draft appliances (those with chimneys) and the availability of consumer carbon monoxide alarms have reduced some of the dangers.

We would be interested in hearing about your experiences.

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Luke, are you suggesting a passive or powered supply duct?

I've seen both work with success, really it comes down to duct design/placement. It would depend on the location of the supply duct's entry point as well as duct sizing, length, type, etc.

One emerging option is a passive opening (with power damper) near the range hood AND a separate fan powered supply duct linked to the heating system's return plenum. The passive supply duct handles the majority of makeup air and the powered supply duct dumps air into the return if it senses a state of negative pressure.

Also, you can have your central ERV system offset it's incoming/outgoing fans until a pressure balance is reached. However, again your ERV is never going to account for an oversized range hood entirely. AND the more you offset the ERV air streams, the less efficient the unit will become.

Maybe install a passive 5" supply duct located underneath the stove with power damper to open whenever the range hood is running. AND an ERV that offsets based on negative pressure? A combination of the range drawing in air during cooking and the ERV balancing the remaining pressure imbalances. That could be a combination solution.

Luke, the depressurization caused by an overpowered fan (e.g. 600 cfm)  in a kitchen cannot be compensated by a relatively small passive duct. The fan is creating a high static pressure to drive the exhaust out of the house. The resulting house depressurization will be lower than the pressure in the duct that a fan creates and that depressurization is the pressure that will drive the flow in the passive duct. Your passive duct would have to be much bigger than the fan ducting to come anywhere close to matching the exhaust.

Because of those size limitations, and because passive ducts do not provide acceptably comfortable air in winter conditions, most practical solutions for very large fans in houses require powered and tempered make-up air. I imagine that problems due to smaller fans might be compensated by a properly designed passive duct.


re: hood flow rate and make up air recommendations, see my slides from NAPHN 2018 (p. 34  +) and the Tools section (aww Broan's online tool for MA system design), at

150 CFM might work in a super tight house with wall/corner hood installation, powererd MA, and side extensions or a very hi Capture Efficiency Hood (HVI ratings may come out this year). But I would tend to go toward 300 CFM for hi emission cooking, with split MA registers.

re: ERV boost with a hood, the Dutch researchers (Jacob et al. at TNO) are testing this out in multifamily settings. Stay tuned.

I saw an interesting article on cleaning make-up air which referenced the hardware found in hydroponics shops. If you really want an effective carbon filter with a supplemental balancing fan, here is a description of where to find one:

This article references Canadian sources but I am sure equivalent American ones exist.


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