DIYrr

Noisy Bathroom Fan? Sone Ratings and the Attic-Vent Mistake

Q: Do I need a permit for a bathroom exhaust fan repair in Orange County, FL?

Depends on the scope. Orange County publishes no exemption for a like-for-like fan swap (its no-permit list is closed), so ask the county before treating a straight swap as exempt. NEW ducting, a new circuit, or a first-time install is mechanical/electrical permitted work, full stop.

Q: What does a bathroom exhaust fan repair cost?

DIY: $20–$400 for the fan unit itself, depending on type and features (basic fan-only models $20–$50) Hiring it out: $150–$550 installed to replace an existing bathroom fan; $250–$950 for a brand-new installation with venting through the roof or wall New-install price climbs when ductwork and exterior venting must be cut in — labor alone runs $200–$800. Published national figures (HomeGuide, checked Aug 2026) — local prices vary, and the free DIYrr planner pulls current retail prices for your exact repair.

Updated 2026-09-20 · Sources verified 2026-07-20

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Short answer: depends on the scope. Orange County publishes no exemption for a like-for-like fan swap (its no-permit list is closed), so ask the county before treating a straight swap as exempt. The full answer and its source are below, with the code requirements and mistakes that trip up Orlando homeowners.

The permit answer

Depends on the scope. Orange County publishes no exemption for a like-for-like fan swap (its no-permit list is closed), so ask the county before treating a straight swap as exempt. NEW ducting, a new circuit, or a first-time install is mechanical/electrical permitted work, full stop.
Source: https://www.orangecountyfl.net/PermitsLicenses/DivisionOfBuildingSafety.aspx

Orange County and the City of Orlando run separate permit offices with separate portals — and your mailing address alone doesn't tell you which one covers your home. Check which permit office covers your address →

Key facts before you start

Size by VOLUME, not floor area: Broan's current method is length x width x CEILING HEIGHT x 0.13, rounded up to the next ten (10 x 8 x 9 ft = 93.6 -> 100 CFM). The old '1 CFM per sq ft' rule undersizes the 9-10 ft ceilings common in newer Orlando builds. Over 100 sq ft, add per fixture instead: toilet 50, shower 50, bathtub 50, jetted tub 100. FBC-R M1507.4 floor is 50 cfm intermittent or 20 cfm continuous.
CFM sets the legal duct size, not what fits the hole. FBC-R Table M1506.2 caps 4" FLEX at 56 ft @50 CFM, 4 ft @80 CFM, and NOT ALLOWED at 100 CFM (4" smooth-wall: 114 / 31 / 10 ft). 3" flex is 'X' at every rating and 3" smooth is 5 ft max, so the 3" duct connector on budget fans (Broan 670/671/688/689) has to transition up almost immediately. Deduct 15 ft of allowance for EACH elbow. Exception: no length limit where the run meets the fan maker's design criteria or measured airflow is verified with a flow hood.
FBC-R M1501.1 verbatim: 'Air shall not be exhausted into an attic, soffit, ridge vent or crawl space' - the classic Orlando attic-dump defect that grows mold; M1507.2 separately bars recirculating bath air anywhere inside. Terminate at a roof/wall cap with a backdraft damper and, per M1506.3, not less than 3 ft from property lines, 3 ft from ANY building opening (operable or not), and 10 ft from a mechanical air intake unless the outlet sits 3 ft above that intake.
Central FL humidity: run the fan through the shower and >=20 minutes after. Panasonic WhisperFit DC condensation models sense relative humidity AND temperature and hold a built-in 20-minute delay timer, staying on past it while moisture is above the trigger point. Its Pick-A-Flow selector (50/80/110 CFM) is a code decision, not a comfort one - moving off 50 re-prices the duct run under Table M1506.2, and the 3" reducer in the box is unusable on almost any real run.
Noisy fan, free first fix: kill power, pull the grille, vacuum the blower wheel, motor housing and grille - dust imbalance is Broan's first-named cause - then tighten grille clips, brackets and mounting screws. Grinding, squealing or 'lawnmower' noise means worn bearings: replace the motor assembly, and swap the impeller at the same time. The motor is permanently lubricated and never needs oiling.
Before quoting a tear-out, check for a same-housing upgrade kit: Broan/NuTone QuicKit and Quick Install kits swap motor + grille from the room side with no rewiring and no new duct work (model label is inside the housing, in the corner nearest the outlet). Quote by sone as well as CFM - <=1.0 is refrigerator-quiet, 2.0 sounds about twice as loud as 1.0, 3.0 is conversation level. Install per Broan: over a tub or shower only on a GFCI-protected branch circuit, fan at least 5 ft above the floor, no switch reachable from the tub/shower, damper confirmed swinging free. Permits: Orange County publishes no bath-fan exemption - its mechanical application counts exhaust fans and alterations pull sub-permits, so confirm scope before any new circuit or duct run (EResQuestions@ocfl.net, 407-836-5550).

What it costs

DIY: $20–$400 for the fan unit itself, depending on type and features (basic fan-only models $20–$50)
Hiring it out: $150–$550 installed to replace an existing bathroom fan; $250–$950 for a brand-new installation with venting through the roof or wall
New-install price climbs when ductwork and exterior venting must be cut in — labor alone runs $200–$800.
Published national figures (HomeGuide, checked Aug 2026): https://homeguide.com/costs/cost-to-install-bathroom-exhaust-fan. Prices move — the free planner pulls current retail prices for your exact repair.

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Frequently asked questions

Do I need a permit for a bathroom exhaust fan repair in Orange County, FL?

Depends on the scope. Orange County publishes no exemption for a like-for-like fan swap (its no-permit list is closed), so ask the county before treating a straight swap as exempt. NEW ducting, a new circuit, or a first-time install is mechanical/electrical permitted work, full stop.

Are there specific building-code requirements for a bathroom exhaust fan repair?

CFM sets the legal duct size, not what fits the hole. FBC-R Table M1506.2 caps 4" FLEX at 56 ft @50 CFM, 4 ft @80 CFM, and NOT ALLOWED at 100 CFM (4" smooth-wall: 114 / 31 / 10 ft).

What tools or parts do I need to get right for a bathroom exhaust fan repair?

Before quoting a tear-out, check for a same-housing upgrade kit: Broan/NuTone QuicKit and Quick Install kits swap motor + grille from the room side with no rewiring and no new duct work (model label is inside the housing, in the corner nearest the outlet). (EResQuestions@ocfl.net, 407-836-5550)

What does a bathroom exhaust fan repair cost?

DIY: $20–$400 for the fan unit itself, depending on type and features (basic fan-only models $20–$50) Hiring it out: $150–$550 installed to replace an existing bathroom fan; $250–$950 for a brand-new installation with venting through the roof or wall New-install price climbs when ductwork and exterior venting must be cut in — labor alone runs $200–$800. Published national figures (HomeGuide, checked Aug 2026) — local prices vary, and the free DIYrr planner pulls current retail prices for your exact repair.

Related repairs

Sources

https://help.broan-nutone.com/en/bath-fans/How-do-I-properly-size-an-exhaust-fan-for-my-bathroom-288
https://codes.iccsafe.org/s/FLRC2023P1/chapter-15-exhaust-systems/FLRC2023P1-Pt05-Ch15-SecM1501.1
https://up.codes/viewer/florida/fl-residential-code-2023/chapter/15/exhaust-systems
https://broan-nutone.com/en-us/home/learn/what-are-sones
https://iaq.na.panasonic.com/ventilation/fans/whisperfit-dc-condensation
https://broan-nutone.com/en-us/home/learn/my-bath-fan-sounds-like-a-lawnmower
https://broan-nutone.com/getmedia/5de83f3d-e96a-4f2b-b52c-717e5f9009fc/Installation-Guide-670-671-688-689.pdf?ext=.pdf
https://broan-nutone.com/en-us/freshen-up-landing/fan-upgrade-kit
https://www.orangecountyfl.net/PermitsLicenses/DoINeedaPermit.aspx
https://www.orangecountyfl.net/PermitsLicenses/Permits/MechanicalPermit.aspx

This guide is general informational content, not professional or legal advice. Codes and county rules change — confirm permit requirements with your local building department, and use a licensed professional for electrical, gas, structural, or main-line plumbing work.

Built by Karhan Construction & Remodeling, an owner-led repair and remodeling company in Orlando — DIYrr is free whether or not you ever hire us.