Duct replacement cost in Casselberry, Florida
Duct repairs or replacement add roughly $1,500 to $5,000 to a Casselberry changeout, depending on how much of the trunk has to be replaced rather than patched. Duke Energy's duct test and repair rebate covers 50% of the test plus up to $200 of repairs, after a free Home Energy Check.
These are researched market ranges, not our prices and not a quote.
The dollar figures below come from published third-party cost guides — named and linked at the foot of the page — and from the City of Casselberry’s own published permit fee. They are here so you can tell whether a quote you have been handed is in the ordinary range for this work. They are not an offer, and no two houses in Casselberry cost the same to do.
What duct work costs in Casselberry
| Job | Researched range | What drives it |
|---|---|---|
| Duct repairs or replacement added to a changeout | $1,500–$5,000 | Florida statewide guide. Driven by how much of the trunk has to be replaced rather than patched. |
| Duct test and repair rebate, Duke Energy | 50% of the test + up to $200 | Single-family only, and only after a Home Energy Check. It comes off the number above. |
| Diagnostic visit | $75–$150 | A static pressure and leakage check is not a look-in-the-attic job. |
Why 1970s Casselberry ductwork is the limiting factor
Ductwork is the reason Casselberry quotes vary so much more than the equipment does. 57.1% of the city’s improved residential parcels were built between 1970 and 1989 and the median build year is 1977. In houses of that vintage the equipment has been replaced three or four times and the attic trunk very often has not. What that produces:
- Undersized returns. A single central return sized for a 1977 two-and-a-half ton system, now feeding a modern variable-speed air handler that wants far more air.
- High external static pressure. The equipment cannot move its rated airflow, so it does not deliver its rated capacity or its rated efficiency, whatever the SEER2 sticker says.
- Leakage into a vented attic. Supply air lost to an attic that reaches 130°F, and return leakage pulling that same air back into the house — which in a dewpoint-driven climate is a humidity problem, not just an efficiency one.
- Retrofitted runs in pre-1970 houses. 19.9% of the city predates 1970, when central air was frequently added after the fact rather than designed in. Those duct layouts are whatever fitted the attic.
Seminole County Property Appraiser CAMA extract (Parcels.csv, dated 2026-09-05). Improved residential parcels — single-family, townhome and condominium — in city tax district C1, City of Casselberry. n = 8,563.
The one rebate that pays for the diagnosis
Duke Energy pays a duct test and repair rebate — 50% of the cost of the duct test plus up to $200 toward repairs, per system, single-family only. Like every Home Energy Improvement rebate it requires the free Home Energy Check first. It will not pay for a duct replacement, but it will pay for finding out whether you need one.
Before you compare any number on this page, read the rebate order of operations. Duke Energy requires a free Home Energy Check completed within the previous 24 months before the equipment is installed. Replace first and apply afterwards and the claim is denied — on a strip-heat house, which is most of Casselberry’s 1970s and 80s stock, that is up to $1,000 thrown away.
Book the free Duke Energy Home Energy Check before you replace anything.
Duke Energy requires a free Home Energy Check completed within the previous 24 months to qualify for any Home Energy Improvement rebate. Replace the system first and apply afterwards and the application is denied — there is no retroactive path back.
It is a no-cost visit and it is the single most common way a Casselberry homeowner loses a four-figure rebate. If you are within a year of replacing, book it now, before you call anyone for a quote. Duke’s rebate line is 800.254.8535.
Cold in one room, clammy in another?
That is a duct symptom, not an equipment symptom. Replacing the box without testing the ducts reproduces the problem with a newer warranty.
Phone: (689) 308-3675 · Monday-Friday, 8:00 AM - 5:00 PM
Where the facts on this page come from
Every figure above is either a primary-source document or a named third-party cost guide. All of it was checked in September 2026. Fee schedules, rebate amounts and market prices change without notice — if you are about to spend money on one of these numbers, open the source and check it.