The kitchen range hood has been quietly re-engineered over the last decade from a 200 CFM builder-grade recirculating cabinet vent into a 600–1,500 CFM externally-ducted professional exhaust that will happily depressurize a tight 2026 Westchester primary residence, backdraft a sealed-combustion boiler, pull carbon monoxide out of a wood-burning fireplace flue, and trip the newly-installed radon-mitigation fan into reverse — all within the first three minutes of firing a 60-inch Wolf dual-fuel range. Every meaningful primary-kitchen renovation drawing set produced in Bedford, Scarsdale, Rye, Chappaqua, Larchmont, Bronxville, and White Plains in 2026 now carries a matched, interlocked, tempered makeup air unit (MAU) — and the ones that don't are the ones we get called back to a year later to solve.
If you're planning a kitchen renovation this year and you're specifying anything more than a 400 CFM under-cabinet insert, this is the piece of your mechanical plan you cannot afford to hand-wave through. This guide covers the eight canonical 2026 makeup air programs, the IRC 2021 M1503.6 400-CFM code trigger and its Westchester enforcement, the ASHRAE 62.2 residential ventilation baseline your MAU sits on top of, the tempered vs. untempered vs. dedicated-heater decision math, ducting and dampering specs, common Westchester mistakes, and the realistic 2026 installed cost ranges from a modest Yonkers electric-heated inline MAU to a full Bedford glycol-loop hydronic tempered system on a 1,500 CFM downdraft-and-hood combined exhaust.
Why Makeup Air Matters More in 2026 Than Ever
Three shifts have made the makeup air unit its own line item on every serious 2026 Westchester kitchen drawing set. First, house envelopes have gotten dramatically tighter — the 2020 IECC and the 2024 amendments push new and gut-renovated homes to under 3 ACH50 in most of Westchester, with many performance-driven builds hitting 1.5 ACH50 or lower. A house that used to leak enough through window weatherstripping and rim joists to feed a 600 CFM hood no longer does. Second, the range hood arms race has real numbers behind it — a 48-inch Wolf DF484CG dual-fuel with a matched 1,200 CFM hood, a Miele HR 1954-3 with a 900 CFM insert, or a Thermador PRD486WDHU with a 1,000 CFM Bosch pro hood are all standard 2026 primary-kitchen specifications in a $2.5M+ Westchester renovation. Third, the AHJ (Authority Having Jurisdiction) enforcement has caught up — building departments in Bedford, Scarsdale, Rye, and White Plains are now routinely failing final inspection on hoods over 400 CFM without a documented, interlocked, and commissioned makeup air path.
According to the 2026 NKBA Kitchen Trends Survey, 71% of primary-kitchen renovations over $250K now specify a range hood at 600 CFM or above, up from 34% in 2019. Of those, IRC 2021 M1503.6 requires — not recommends — a mechanical makeup air system engaged whenever the exhaust runs.
Key reasons makeup air is having its moment in 2026:
- IRC 2021 M1503.6 requires makeup air on any hood exhausting more than 400 CFM
- New Westchester construction and gut renovations routinely hit 1.5–3 ACH50, eliminating the natural infiltration older houses relied on
- Sealed-combustion boilers, tankless water heaters, and direct-vent fireplaces can backdraft catastrophically under depressurization
- Wood-burning fireplaces will smoke into the room the moment a high-CFM hood fires
- Radon mitigation fans, mandatory in much of Westchester's Zone 1 radon geology, can reverse under negative pressure
- Untempered makeup air in a Zone 5A / 6A climate delivers 15°F outside air onto a chef's shoulders in January — the reason most first-generation MAUs get switched off within a season
Top 8 Kitchen Makeup Air Programs for 2026
- Electric Heated Inline MAU — The default entry-level 2026 spec. A Broan Model AMAK-AIS or Fantech MUAS 900 inline duct-mount fan-and-heater assembly, drawing 6–10 kW on a dedicated 40–60 amp 240V circuit, interlocked to the hood via a Broan HMASSK or Fantech PIC-C current-sensing relay. Delivers tempered air at 65–70°F even at 15°F outside temps. Good for hoods up to about 900 CFM.
- Hydronic Glycol-Loop Tempered MAU — The 2026 high-performance answer. A dedicated fan-coil unit fed by a glycol loop from the existing boiler manifold, with a Grundfos ALPHA2 circulator, a Taco X-Pump Block or a Caleffi 559 mixing valve, and a Belimo modulating actuator. Draws no electric load beyond the fan itself and delivers effectively unlimited tempered CFM. Standard on any hood above 900 CFM in a hydronic-heated Bedford or Scarsdale primary residence.
- Toe-Kick Motorized Damper MAU — The invisible-install approach. A Broan MD6TU or Fantech RVF motorized damper concealed inside the toe kick of the island run or the perimeter cabinet, interlocked to the hood switch, drawing untempered outside air directly into the kitchen floor plane. Only appropriate for hoods 400–600 CFM in shoulder-season climates — not defensible in a January Bedford kitchen without a companion heater.
- Transfer-Grille Interior MAU — The pragmatic small-renovation option. A pair of transfer grilles cut into a common wall between the kitchen and an adjacent conditioned space (living room, dining room, mudroom), sized to move 1 CFM per square inch of grille free area, with a barometric damper preventing reverse flow. Zero exterior penetration, but the source air must itself be replenished — works only if the adjoining zone leaks enough or has its own supply.
- Dedicated MAU with Integrated ERV Recovery — The Passive House-adjacent spec. A Zehnder ComfoAir Q600 or Panasonic Intelli-Balance 200 ERV cascaded upstream of the MAU heater, recovering 70–85% of the sensible heat from the exhaust stream before the MAU tempers the balance. The right answer on any tight-envelope Rye or Chappaqua build targeting sub-2 ACH50.
- Downdraft-and-Hood Combined Exhaust MAU — The island-and-cooktop scenario. A Wolf DD48 or BEST Cattura downdraft ganged with a ceiling-recessed island hood on a single interlock, exhausting up to 1,500 CFM combined and requiring a matched MAU sized to the peak simultaneous draw. Fantech MUAS 1200 electric or a dedicated 12,000 BTU/hr fan coil are the two mainstream 2026 answers.
- Rooftop RTU-Style MAU — The retrofit approach for older Westchester stone-and-plaster homes. A Greenheck LB, RV, or Modine Effinity roof-mounted makeup air unit with an insulated curb, a stainless spun-aluminum weathered damper, and a dedicated gas or electric heater section. Solves the problem for retrofits where no basement mechanical room exists — common on 1920s Larchmont Tudor and Bronxville colonial renovations.
- Zero-Duct Cross-Ventilation "Cracked Window" MAU — The code-non-compliant lie some contractors still tell in 2026. A homeowner is told the hood is "small enough" that opening a window when they cook satisfies the makeup air requirement. This is not code-compliant on any hood exhausting more than 400 CFM, it will not pass a Westchester final inspection, and it produces a raw 15°F January draft on the cook. Include this in the guide only to name it and warn against it.
The IRC 2021 M1503.6 Code Trigger: What Westchester Enforces in 2026
IRC 2021 Section M1503.6 is unambiguous. "Where one or more gas, liquid or solid fuel-burning appliances that are neither direct-vent appliances nor use a mechanical draft venting system are located within a dwelling unit, exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (0.19 m³/s) shall be provided with makeup air at a rate approximately equal to the exhaust air rate."
The New York State Uniform Fire Prevention and Building Code (2020 edition, amended 2024) adopts IRC M1503.6 by reference. In practice, every Westchester building department we work with in 2026 — Bedford, Chappaqua, Scarsdale, Rye, Larchmont, Bronxville, White Plains, Armonk, Katonah — enforces the trigger at exactly 400 CFM manufacturer-rated hood capacity, not at some reduced "typical use" number. If the nameplate says 600 CFM, you owe the building department a documented makeup air system.
What "makeup air at a rate approximately equal to the exhaust air rate" means in practice:
- The MAU nominal delivery must be within about 10% of the hood peak CFM at maximum blower speed
- The MAU must be automatically interlocked with the hood — a homeowner-operated switch is not acceptable
- The MAU air path must be tempered in Climate Zone 5A / 6A (all of Westchester) to avoid nuisance shutoffs and prevent condensation on adjacent framing
- The intake termination must be at least 10 feet from any exhaust termination, plumbing vent, or dryer vent per IRC M1503.4.3
Sealed-combustion appliances — direct-vent boilers, tankless water heaters with concentric intake-and-exhaust, direct-vent fireplaces — are technically exempt from triggering the requirement. Any atmospheric-vent boiler, natural-draft water heater, wood-burning fireplace, or unlisted gas log is a separate immediate red flag and often the reason a Westchester renovation goes from "MAU nice to have" to "MAU mandatory even at 300 CFM" per the AHJ's judgment call.
Tempered vs. Untempered vs. Dedicated-Heater: The Decision Math
The single most-regretted MAU decision in Westchester is specifying an untempered system in a Zone 5A climate. Fifteen-degree January air blowing across the cook's shoulders makes homeowners flip the makeup air breaker within a season and then run the hood without it — voiding both the code compliance and the safety envelope the interlock was designed to guarantee.
Untempered — Raw outside air, no heating element, no coil. Delivered at ambient. Appropriate only in shoulder-season climates or as a summer-only supplement in cooling season. Not a defensible 2026 spec for any Westchester primary residence.
Electric Resistance Tempered — 6–15 kW electric heating coil on a dedicated 40–60 amp 240V circuit, sized to raise incoming air from the design winter temperature (15°F for most of Westchester) to a target delivery of 55–65°F at the peak MAU CFM. Simple, reliable, expensive to run in a peak-electric-rate zone but only during actual hood operation. The right answer for hoods up to about 900 CFM in an all-electric or ductless-heat-pump-heated home.
Hydronic Glycol Coil Tempered — A fan coil fed by a glycol loop off the existing boiler, with a mixing valve and a modulating actuator. Effectively unlimited BTU delivery, no meaningful electric load beyond the fan itself, and orders of magnitude cheaper to operate on gas-fired boiler heat than resistance electric. The right answer in every gas-boiler or oil-boiler heated Westchester primary residence with a hood above 900 CFM.
ERV-Preheated + Tempered — A cascaded Zehnder or Panasonic ERV upstream of a smaller heater section, recovering 70–85% of the sensible heat from the exhaust stream. Reduces the peak heating load on the MAU coil by a factor of five and shrinks the electric or hydronic tempering requirement accordingly. The right answer on any Passive House-adjacent Chappaqua or Rye build.
Sizing, Ducting & Dampering: The Numbers That Matter
Nominal MAU delivery — Match hood nameplate at peak blower speed within ±10%. A 900 CFM Wolf VW45S hood on high pairs with an 800–1,000 CFM MAU.
Duct sizing — 8-inch round rigid galvanized duct is the minimum for 400–600 CFM; 10-inch for 600–900 CFM; 12-inch for 900–1,500 CFM. Flex duct anywhere in the intake path is a persistent noise-and-restriction failure mode and should be avoided outright. Duct runs above 25 equivalent feet require an inline booster fan.
Backdraft damper — Every MAU intake terminus needs a Broan or Fantech-branded backdraft damper at the exterior hood and a motorized isolation damper interlocked with the hood at the interior discharge. The two-damper strategy prevents winter infiltration when the hood is off.
Termination clearance — Minimum 10 feet from any exhaust vent (dryer, bath fan, HRV/ERV discharge), 10 feet above grade or 3 feet above snow line (whichever is greater in Bedford, Chappaqua, and North Salem), and 3 feet from any operable window per IRC M1503.4.3.
Interlock — A current-sensing relay (Broan HMASSK, Fantech PIC-C, or an air-pressure switch on the exhaust duct) that engages the MAU on hood start and delays MAU shutdown by 60–90 seconds after hood shutoff to fully evacuate the exhaust duct.
Delivery-point strategy — Discharge should introduce tempered air at floor level in the kitchen but away from the immediate cooking zone. A toe-kick grille under the perimeter cabinet run 8–12 feet from the range is the standard 2026 answer. Discharging directly at the cook or upward into the exhaust stream defeats both the tempering and the ventilation math.
Common Westchester Makeup Air Mistakes We Get Called to Fix
Every one of these has cost a Westchester homeowner between $6,000 and $40,000 to remediate after the fact in the last 24 months of our showroom's project history.
- 1,200 CFM hood installed with no MAU because "the house is old and leaky enough" — homeowner's sealed-combustion boiler backdrafts a CO event during the first Thanksgiving dinner
- Untempered toe-kick MAU installed under the range — homeowner disables the interlock in January and the hood is now running unmakeupped for the life of the kitchen
- MAU intake terminated three feet from the dryer vent — the kitchen smells like fabric softener whenever the dryer runs
- 10-inch duct for a 1,200 CFM system that needed 12 — the MAU delivers 800 CFM at nameplate speed and the hood pulls the balance from the flue
- Flex duct on the MAU intake run — the fan whines, the delivery drops 30%, and the system fails commissioning
- MAU wired to a wall switch instead of an interlock — the homeowner forgets to turn it on and the code compliance is theoretical
- No delay-off on the interlock — MAU shuts down at hood shutoff, the exhaust duct backdrafts through the shutter and the kitchen fills with 15°F air
- MAU commissioned to nominal CFM but never measured under actual house conditions — real-world delivery is 60% of nameplate because of duct static and elevation loss
Contractor Vetting: The Trades You Actually Need
An MAU is not a hood accessory — it is a coordinated mechanical, electrical, and building-envelope package that requires four trades to pull off correctly.
HVAC contractor — Sizes the unit, specifies the heater section, runs the duct, terminates the exterior hood, and commissions with a manometer and airflow hood. Ask for two documented Westchester references at the same CFM class and confirm they carry proper NATE or BPI certification.
Electrician — Runs the dedicated 40–60 amp 240V circuit for the electric heater section (or the low-voltage interlock and fan-only circuit for the hydronic version). Verifies the panel has capacity or specs the panel upgrade.
General contractor — Coordinates the exterior wall penetration through the framing, insulation, air barrier, and cladding without creating a thermal bridge or a rain-entry path. Insists on a 1-inch rigid foam surround and a proper mastic seal.
Building department — Should be brought into the conversation at the framing inspection, not at final. A pre-inspection meeting with the AHJ on any hood above 800 CFM prevents 90% of the surprises that show up at closeout.
Ask every contractor for:
- Three named Westchester references at the same CFM class
- Photos of at least one similar MAU install, commissioning report attached
- Written confirmation of the interlock spec, delay-off setting, and termination clearances
- A line item on the estimate for a post-install commissioning test with airflow measurement
Realistic 2026 Westchester Installed Costs
These are current showroom-verified installed-cost ranges from Vega Kitchen & Bath and our tradesman network across Bedford, Scarsdale, Rye, Chappaqua, Larchmont, Bronxville, and White Plains as of August 2026. All-in numbers, including unit, duct, damper, heater, electrical, and commissioning.
Toe-kick untempered MAU on 400–500 CFM hood, Yonkers or south-Westchester shoulder-season kitchen — $2,200–$3,400. Rarely a defensible spec but included for reference.
Electric-heated inline MAU on 600–800 CFM hood, straightforward exterior wall, White Plains or Larchmont — $5,800–$9,400. The default entry-level 2026 spec.
Electric-heated inline MAU on 900–1,200 CFM hood, complex duct routing, Scarsdale or Bronxville — $9,800–$14,600.
Hydronic glycol-loop MAU on 900–1,200 CFM hood, tapping existing boiler manifold, Chappaqua or Rye — $12,400–$18,900. The 2026 preferred spec on any hydronic-heated primary residence.
ERV-cascaded tempered MAU on 1,200 CFM hood in a Passive House-adjacent build, Chappaqua or Bedford — $18,600–$26,400.
Full glycol-loop tempered MAU on combined 1,500 CFM downdraft-and-hood, custom termination in stone façade, Bedford — $24,000–$38,500. The high end of the 2026 spec.
Retrofit rooftop RTU MAU into a 1920s Larchmont Tudor with no basement mechanical room — $22,000–$34,000 depending on roof access and gas-line proximity.
Full glycol-loop MAU with ERV recovery and Lutron RA2 Select scene integration on a 60-inch Wolf and 48-inch La Cornue paired range wall, Bedford — $32,000–$46,000.
Visit Our Showroom for Your MAU Spec
The single fastest way to get a defensible makeup air spec into your 2026 Westchester kitchen renovation is to bring your architect, your HVAC contractor, and your hood specification into our White Plains showroom for a coordination session. We keep current cut sheets for Broan, Fantech, Greenheck, and Zehnder MAU platforms, we've commissioned dozens of these systems in every Westchester zip code, and we can walk your team through the interlock, tempering, and termination decisions with real hardware in the room.
Vega Kitchen & Bath is at 285 Central Avenue, White Plains, NY 10606. Call us at (914) 350-3005 or email info@vkbd.llc to book a free 90-minute mechanical coordination consultation with our design and mechanical team.