Costs
Duct replacement cost in Longwood, FL
Published Orlando-metro guides add $2,500–$6,000 for duct replacement on top of a changeout. In Longwood that is a live question on most jobs: 66.5% of the city's 4,962 residential parcels were built 1970–1989, so the attic runs are often original. Researched third-party ranges, not quoted prices.
Published ranges
What duct work adds
These are researched market estimates, not a quote
Every money figure on this page is a published third-party range, compiled in September 2026 from the pricing guides listed in the sources at the foot of the page. They are here so you can sanity-check what a contractor offers you before you sign, not so you can hold anyone to a number they did not write. The one exception is the City of Longwood permit fee, which is the City's own published figure and is linked to its fee schedule.
| What is being priced | Researched range | What moves it |
|---|---|---|
| Duct replacement, added to a changeout | $2,500–$6,000 | Duct replacement, added to a changeout rather than instead of one. |
| The changeout it is added to | $7,500–$10,500 | What Orlando-metro guides call typical for a 1,500–2,500 sq ft home — the band Longwood's 1,594 sq ft median living area sits inside. |
Why this comes up here
1979 median build year, and what that means in the attic
Duct is where Longwood quotes diverge. The Seminole County Property Appraiser's records for tax district L1 put the median build year at 1979, with a quarter of parcels built by 1973 and three quarters by 1987. In that era the air handler generally went in the attic, the supply runs were flex, and the return was a single central grille. Fifty years later the flex has sagged, the outer jacket has opened at the boots, and the whole system is sitting in an attic that reaches 130°F in August.
The result is a house that cools unevenly and a system that runs longer than it should to hit the same temperature. Putting a new, correctly sized system on top of that duct means paying for capacity you then leak into the attic — which is exactly the case for testing before you buy rather than after.
- Parcels built 1970–89
- 66.5% of 4,962
- 25th percentile build year
- 1973
- Median build year
- 1979
- 75th percentile build year
- 1987
- Duke duct test and repair
- Up to $450 back
Money back on the duct work
Duke pays toward duct testing and repair
Duke Energy publishes a duct test and repair rebate of up to $450 back for Florida single-family homes, alongside up to $1,000 for HVAC replacement and up to $800 for attic insulation, per its 9 June 2025 news release. Like every Home Energy Improvement rebate it sits behind the Home Energy Check, and the check has to come first.
Duke Energy requires a free Home Energy Check completed within the previous 24 months before it will pay any Home Energy Improvement rebate, and the work has to have been recommended by that check. Replace the system first and apply afterwards and the claim is denied — there is no retrospective route. Duke also requires that the whole home is heated and cooled electrically, that the installer is a licensed and insured air conditioning contractor, and that the work is approved by a licensed city or county inspector. On a Longwood job that last condition is the City permit and the passed mechanical final, which makes the permit a rebate requirement and not just a legal one.
Two things that catch people out
Attic access, and the $7,500 line
Two Longwood-specific notes. First, if the air handler is in the attic the City's mechanical permit application has a checkbox for it and makes attic access a condition of inspection — duct work that blocks the access hatch creates a failed inspection. Attic air handlers in Longwood. Second, adding duct replacement to a changeout is usually what pushes the contract past $7,500, which is the point at which a Notice of Commencement stops being optional.
There is a second reason the total matters. Longwood requires a Notice of Commencement recorded with Seminole County, with a certified copy delivered to the City at application or before the first inspection, and states that if no NOC is on file when an inspection is scheduled “the inspection will not be completed and all work must remain open.” A mechanical permit to repair or replace an existing heating or air conditioning system valued under $7,500 is excepted, per §713.135(d), Florida Statutes. Read those two numbers together: the typical Orlando-metro changeout of $7,500–$10,500 straddles the $7,500 line, so on a mid-size Longwood job whether you have to record a document at the county courthouse can come down to whether the duct work is in the contract.
Sources
- Airborne Tech Service, Orlando AC replacement cost guide (third-party pricing guide). https://airbornetechservice.com/ac-replacement-cost-orlando/
- Seminole County Property Appraiser CAMA extract (Parcels.csv, dated 5 September 2026), tax district L1 — Longwood; improved residential parcels, DOR codes 01 and 04. https://www.scpafl.org/
- Duke Energy news release, 9 June 2025 — expanded Florida home improvement rebates. https://news.duke-energy.com/releases/duke-energy-expands-home-improvement-rebate-program-to-help-florida-customers-save-energy-and-money-this-summer
- Duke Energy, Home Energy Improvement — HVAC Replacement. https://www.duke-energy.com/home/products/home-energy-improvement/hvac-replacement
- Duke Energy Florida rebate application portal. https://www.dukeenergyrebates.com/florida/#/home
- City of Longwood Mechanical Permit application. https://www.longwoodfl.org/DocumentCenter/View/4604/Mechanical-Permit-application-PDF-
- Florida Statutes §713.135 — Notice of Commencement, including the §713.135(d) exception for HVAC repair or replacement under $7,500. https://www.flsenate.gov/Laws/Statutes/2026/713.135
- City of Longwood Fee Schedule (Resolution 26-1724, effective 1 July 2026). https://www.longwoodfl.org/702/Fee-Schedule
Figures are dated. Permit fees, rebate amounts and code cycles change — re-check the primary source before you rely on a number here.
Test the duct before you size the system
On a 1970s Longwood plan the duct decides how much of the new system you actually get to keep. That is worth finding out before the equipment is ordered.