FHB Logo Facebook LinkedIn Email Pinterest Twitter Instagram Plus Icon Close Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Main Menu
Subscribe

In every issue you'll find...

  • Expert insights on techniques and principles
  • Unbiased tool reviews
  • Step-by-step details to master the job
  • Field-tested advice and know-how
Subscribe Now!
Subscribe
  • How-To
  • Design
  • Tools & Materials
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
  • Join
  • Log In
Main Menu Subscribe
FHB House Logo

The 2016 FHB House is energy-smart, connected, healthy, and durable. It’s small and sensible. Most of all, it’s a valuable model home, meant to educate designers and builders who aspire to create high-performance houses that are exceptional in their quality, comfort, and style.

Rhode Island 2016

Makeup Air for the Range Hood

A range hood won't work well in a tight house without make-up air.

By Mike Guertin
Article Image

My own house is pretty tight — about 1.5 ACH50 — and when I run the range exhaust fan, I can hear air whistle in through the door gasket. The FHB House is even tighter — 0.39 ACH50 — so I knew going in that we had to make provisions for make-up air when the range exhaust is operating. Make-up air needs to be introduced into the kitchen but not too close to the range hood itself or the air will be drawn directly into the hood and the air rising off steaming pots will spill into the room instead of being sucked into the hood. But on the other hand, I am reluctant to dump make-up air into the room where it may feel uncomfortable.

I opted to run a 6-in. duct through the first floor system, alongside the exhaust duct, and terminate it in the kitchen cabinet toekick space just to the left of the range.   There’s a space between the toekick and the bottom shelf of the cabinet, so air can freely flow out from the toekick area.exhaust2016-12-26 17.11

A 6-in. intake duct is a big hole in a tight house and one that I want to control to prevent heat loss.
exhaust2016-12-26 17.29So we installed an automatic mechanical make-up air damper (Broan). The 6-in. damper fits inline on the intake duct and has a small low-voltage motor that opens a gasketed damper valve. The motor opens the valve when air flow is sensed by a venturi switch mounted to the side of the exhaust duct.

 

 

 

 

 

 

 

 

 

 

 

 

exhaustIMG_4961The microwave / exhaust is ducted through a wall shared with a closet, so I installed a small snap-in access panel where the venturi switch in mounted. That way if there is ever a problem with the switch it can be easily accessed.

 

 

 

 

 

 

 

 

exhaustIMG_4962
Baseline Pressure
exhaustIMG_4971
Max depressurization before mechanical damper opens
exhaustIMG_4966
Negative pressure after mechanical damper opens fully and exhaust fan operates at high speed

To get a sense of whether there was any pressure differential inside to outside the house when the system was operating I used a manometer to measure the baseline pressure and compare it to the pressure differential when the exhaust was operating. The baseline pressure differential was about -0.4 Pa. When the exhaust fan was turned on and before the mechanical damper opened the pressure dropped to -28 Pa. This shows that the exhaust fan was depressurizing the house quite a bit for a few seconds while the damper opened. Once the damper was fully open the pressure difference settled at -7.6 Pa. So the exhaust fan put the house under a slight negative pressure.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

exhaustIMG_4986And how does the exhaust fan perform? To test it I put a flow hood over the exhaust vent to see how many CFM were exhausted. For a baseline I opened a door so the exhaust fan had all the makeup air it needed. The hood measured a flow of 101 CFM. Next I measured the flow with all the doors and windows closed and got a 87 CFM reading. This shows that there is some restricted makeup air flow that reduces fan performance. Still, even at 87 CFM, the range exhaust fan is evacuating plenty of air to keep most of the cooking fumes and moisture vapor from lingering in the house.

Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers.

Sign Up

Get home building tips, offers, and expert advice in your inbox

×
X
X

New Feature

Fine Homebuilding Forums

Ask questions, offer advice, and share your work

FHB House Logo

Sign up for FHB House eletters and get insider's access to the build, expert insights and special offers.

Sign Up
Rhode Island 2016 Videos Behind the Build: Vermont 2017 Behind the Build: California 2018 Behind the Build: Kentucky 2019 Behind the Build: Connecticut 2020

Navigate the Build

  • Introduction
  • Foundation
  • Framing
  • Windows and Doors
  • Insulation
  • Roof
  • Siding and Trim
  • Mechanicals
  • Interior Finishes
  • Kitchen and Baths
  • Outdoor Spaces
  • Completed Home

View Comments

  1. User avater
    user-5604481 | May 20, 2017 08:24pm | #1

    Hello, I was thinking of doing the same thing for make up air at my place but was concerned about bringing in cold air into metal duct and getting condensation and possible mold growth eventually. Do you believe this is something to be concerned about in a cold climate?

  2. User avater
    Mike_Guertin | May 25, 2017 07:53pm | #2

    Reply to user 56.....
    Condensation is unlikely on the inside surface of the duct in winter or summer conditions.

    Condensation could occur on the outside surface of the duct in the winter figuring that the cold incoming air would chill the duct. To avoid this problem I insulated the intake duct with R6 duct wrap insulation with a well sealed poly vapor barrier. The vapor barrier prevents interior warm air from contacting the surface of the metal duct in winter so there is little chance for condensation

  3. jonscholl | May 25, 2017 09:35pm | #3

    Why would you bother with make up air if you vent is only sucking out 101 CFM? That's tiny in comparison to todays 900 to 1200 CFM hoods. Doesn't code only require make-up air when the hood is over 400 CFM ? I understand that your manometer test showed a good impact from using the make-up air duct....but the energy penalty from bring in outside air doesn't seem worth it. I also notice that your exhaust vent is below your intake...both of which are located in a somewhat enclosed space....no concern about sucking back in the bad air you just exhausted?

    1. User avater
      Mike_Guertin | Jun 07, 2017 07:54am | #4

      The house is so tight (0.39ACH 50) that when the range exhaust fan is operating without the make-up duct open there is less than 30 CFM being exhausted. There just isn't enough air leaks in the house to provide the make-up air so in order for the exhaust fan to do its job we need to provide a duct for make-up air. There is an energy penalty whenever you operate an exhaust fan (bathroom, range) whether or not a dedicated make up air system is installed.

      You are right, the code doesn't require make up air for exhaust fans less than 400 cfm.

      The intake and exhaust are on the same wall and about 4 ft apart. The image doesn't show it but the area is actually pretty open. The deck ceiling above is only 5 ft. deep and the stone wall about 8 ft to open air. There may be a tiny bit of recycled exhaust air entering the intake. We were very limited when selecting locations for ducts due to the framing.

  4. User avater
    edarchitect | Jul 08, 2017 05:48pm | #5

    I like to bring in the make-up air as close to the burners as possible and never have it go past a person in the room. So, I deepen the countertop and bring it though a grille in the top behind the cooktop or a grille in the backsplash. Would be happy to send several pictures if you're interested.

  5. User avater
    VeritasContracting | Aug 27, 2017 10:54am | #6

    I have found from numerous makeup air installations bringing in makeup air into the return side of the heating and cooling system ductwork allows the unconditioned exterior air to be tempered before being introduced into the house. Added benefits, dedicated mechanical rooms are generally very accessible and access to the exterior from these locations is often unencumbered by finishes. We have successfully passed each and every code inspection using this method and it avoids bringing in very cold air in the winter and very hot and humid air in the summer into a room where you spend a lot of time.

  6. BobboMax | Oct 07, 2017 05:22pm | #7

    At 0.39 ACH50, how did you address general ventilation? I'm rebuilding a post-fire gut-to-the-studs 70s ranch house that's going to be difficult to seal- I'll be lucky if I get 4-5 ACH50.

    I'm intending to install a mini-split with baths and kitchen at opposite ends of the house. I'm thinking running those fans on a timer will probably give me plenty of ventilation, but I'm reluctant to rely on incidental make-up air, which could be coming from the crawl space or garage.

    1. User avater
      Mike_Guertin | Nov 18, 2017 12:14pm | #8

      We installed a fully ducted (intake/exhaust) ERV for continuous ventilation. The exhaust fans on timers (as you are planning) can work fine but they may draw in air from the crawl space or garage just as natural ventilation would.

  7. ACVP | Jan 29, 2018 04:36pm | #9

    Great solution. AirCycler sells this exact set up (pressure switch + damper). It's meant to be paired with their whole house ventilation systems, so the damper is typically located on the return side of the air handler.

  8. jcstratton | Feb 01, 2019 10:37am | #10

    Thanks for this great write-up of your solution. I'm curious, did you do another envelope leakage test after the damper was installed? Did the 0.39 ACH50 number change?

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

More Rhode Island 2016

View All
  • Makeup Air for the Range Hood

  • Finishing the Basement

  • A Look at the Finished Home

  • Range Exhaust

View All

Fine Homebuilding House - Rhode Island 2016 Sponsors

  • AdvanTech Logo
  • American Standard Logo
  • AMVIC Logo
  • Boral_CulturedStone Logo
  • Boral_Flag Logo
  • Boral_TruExterior Logo
  • CertainTeed Logo
  • Coravent Logo
  • Dryerbox Logo
  • DXV Logo
  • Flir Logo
  • Gladiator Logo
  • MAXUSA Logo
  • ProtectoWrap Logo
  • Roxul Logo
  • Sikkens Logo
  • Weyerhaeuser Logo
  • Integrity Logo
  • SoftPlan Logo
  • Tamarack Logo
  • TiteBond Logo
  • TrusJoist Logo
  • Whirlpool Logo
  • Zehnder Logo
  • ZipSystem Logo
  • Feeney Logo

Up Next

Featured Story

IBSx Roundtable: Behind the Siding—WRB, Drainable WRB, or Rainscreen?

Fine Homebuilding hosts a panel of building pros in a discussion of the various types of high-quality substrates that can be installed under siding to make a wall assembly more durable.

Featured Video

Video: Build a Fireplace, Brick by Brick

Get an overview of the process of creating a traditional-style fireplace that burns well and meets current building codes from experienced mason Mike Mehaffey.

Related Stories

  • How to Design Small, Smart Homes

  • Podcast 329: PRO TALK With Modular-Home Builder Jason Webster

  • Third-Day at IBSx: Pure Learning

  • More New Products at the Virtual International Builders’ Show

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Highlights

  • Fine Homebuilding All Access
  • Fine Homebuilding Podcast
  • Tool Tech

    Plus, get an extra 20% off with code GIFT20

  • "I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

    Get home building tips, offers, and expert advice in your inbox

    Sign Up See all newsletters

Video

View All
  • Podcast Episode 99 — Working with Wood

  • Podcast Episode 89 — Gross Stories

  • Make Up Air For Commercial Exhaust Fans in Homes

  • Gaggenau Lift Oven

View All

Kitchens

View All
  • All for Fun With Family

  • 1970s Revamp

  • Opening Up a Family Kitchen 16x9

    Opening Up a Family Kitchen

  • One Bad Kitchen, Three Good Designs 16x9

    One Bad Kitchen, Three Good Designs

View All

BOOKS, DVDs, & MERCH

Shop the Store
  • 2020 Fine Homebuilding Archive

    Buy Now
  • Fine Homebuilding Magazine Slipcase

    Buy Now
  • Musings of an Energy Nerd

    Buy Now
  • Code Check Building 4th Edition

    Buy Now
  • Shop the Store

Fine Homebuilding Magazine

  • Issue 297 - Feb/Mar 2021

    • Foundations for Success
    • Staircase Renovation
    • Ditch the Hose
  • Issue 296 - Dec 2020/Jan 2021

    • Insulating Glass Keeps Getting Better
    • Simple Way to Make Old Walls Straight and Plumb
    • Making Sense of Minisplits
  • Issue 295 - Kitchens & Baths

    • Condo Kitchen Reimagined
    • Row-House Remodel
    • Rise of the IAQ Monitor
  • Issue 294 - Oct/Nov 2020

    • Schoolhouse Reimagined
    • Tool Test: Folding Sawhorses
    • A Better Way to Build Tall Walls
  • Issue 293 - Aug/Sept 2020

    • A Practical Guide to Fall Protection
    • Installing Frameless Cabinets
    • Make Any Tablesaw Safer

Fine Homebuilding

Follow

Newsletter

Get home building tips, offers, and expert advice in your inbox

Sign Up See all newsletters

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Manage Preferences

Taunton Network

  • Green Building Advisor
  • Fine Woodworking
  • Fine Gardening
  • Threads
  • About
  • Contact
  • Advertise
  • Privacy Policy
  • Careers
  • Copyright
  • Terms of Use
  • Accessibility
  • CA Privacy Rights

© 2021 The Taunton Press, Inc. All rights reserved.

    Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Reader Projects
  • Magazine
  • Members
  • FHB House
  • Podcasts

  • FHB Podcast
  • ProTalk
  • Account

  • Log In
  • Join

    Podcasts

  • FHB Podcast
  • ProTalk
  • Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

    Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

    All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

    Shop the Store

  • Books
  • DVDs
  • Taunton Workshops

    More

  • FHB Ambassadors
  • Reader Projects
  • Podcast
  • Customer Support

    Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Sign Up See all newsletters

Follow

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 52%

Subscribe

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in