Why is my electric bill suddenly high in Altamonte Springs
If nothing in the house changed, the AC is almost always the reason: an aging system running longer to do the same job, a dirty coil or duct leak forcing longer cycles, or a system old enough that its efficiency has dropped well below what it was rated at. In a city where most housing dates to the 1970s and 1980s, that is the single most common explanation.
What is most likely wrong
Ranked by probability| Cause | How common | What it looks like |
|---|---|---|
| 1. Aging equipment running longer to hold the same temperature | Most common on older systems | Bill creeps up over a season or two rather than jumping overnight; system runs more hours per day than it used to. |
| 2. Dirty coil or clogged filter forcing longer run times | Common | Comparable weather to last year, but noticeably longer or more frequent cycles. |
| 3. Leaky or uninsulated attic ductwork losing conditioned air before it reaches the room | Common on original 1970s-80s duct | Some rooms harder to cool than others; attic noticeably warm near the duct runs. |
| 4. Refrigerant undercharge from a slow leak | Less common | Gradual decline in cooling alongside the bill increase, not a sudden jump. |
What you can safely check yourself
Before you call- Compare the bill to the same month last year, not to last month — Florida's summer load swing is enormous on its own.
- Check the filter and the outdoor coil for visible dirt or debris.
- Note whether the system runs noticeably longer per cycle than it used to, or almost continuously on a normal afternoon.
- If accessible safely, check attic duct connections near the air handler for obvious gaps or disconnected sections.
Where the licensed line is
A run capacitor holds a lethal charge even after the power is off. Refrigerant handling requires EPA Section 608 technician certification, and in Florida this work requires a state-licensed air conditioning contractor under Chapter 489, F.S.
Verify the licence of any contractor you hire at the DBPR licensee search.
Why this happens in Altamonte Springs
Local pattern72.4% of Altamonte Springs' 13,253 residential parcels were built between 1970 and 1989, the highest share of that era of any city in Seminole County. A system on a house that age has typically been through two or three changeouts, but the ductwork running through the attic is frequently still the original run — and an efficient new condenser pushing air through forty-five-year-old, leaking duct does not deliver the efficiency it is rated for.
Before replacing anything, book Duke Energy's free Home Energy Check. It is the one diagnostic that both tells you where the house is actually losing energy and is the mandatory first step toward any Home Energy Improvement rebate.
Book the free Home Energy Check
Duke Energy requires a free Home Energy Check completed within the previous 24 months before it will pay ANY Home Energy Improvement rebate. It is free and it is the gate.
Get the quote and confirm the equipment qualifies
The rebate tier depends on the efficiency you install and on what you are replacing. Strip heat to a heat pump is the largest published tier; replacing a straight air conditioner with another one is the smallest.
Have the work done by a participating contractor
The installer has to be in Duke's participating-contractor program, and the permit still gets pulled and inspected the normal way.
Apply after installation, within the window
The improvement must be completed within 24 months of the assessment.
The order that gets you denied
Replace the system first, then apply for the rebate. There is no retroactive Home Energy Check. This is the mistake, and it costs up to $1,000.
Seminole County Property Appraiser CAMA extract (Parcels.csv, 5 September 2026), tax district A1 — Altamonte Springs. 13,253 improved residential parcels: single-family, townhome and condominium. Apartments and manufactured homes excluded.
Duke Energy publishes these amounts. The page they come from is not scoped to a single state — its body also references the Carolinas, Ohio, Kentucky and Indiana. The Florida application portal confirms the program and the Home Energy Check prerequisite apply to Duke Energy Florida, but no Florida-scoped statement of these specific dollar figures was located. Rebate amounts change. Every figure here is dated, and Duke Energy on 800.254.8535 is the only authority on what is payable today.
What the fix typically costs
Researched ranges| What is being priced | Researched range | What moves it |
|---|---|---|
| Diagnostic tune-up to find the loss | $75–$150 | Orlando-market diagnostic or dispatch fee. After-hours calls commonly $150–$250. |
| Full changeout, if the equipment itself is the cause | $6,500–$11,000 | Full central system replacement quoted for the Altamonte Springs area, varying with home size, efficiency, duct condition and permitting. Labour is commonly 30–50% of the total and runs at the top of that band in older homes. |
Sources: Smart Home Air & Heat, Orlando repair-cost ranges (August 2026), Clear Comfort Orlando's own published prices, and for the expansion valve the Angi Orlando aggregator estimate (May 2026), the only source found for that part. Compiled September 2026. Not this business's prices.
Two things reduce the number before you ever price a repair: a maintenance plan catches the dirty-coil and low-airflow causes before they show up on a bill, and Duke Energy's duct test-and-repair rebate (see duct in this city) pays toward finding attic duct loss. If the honest answer is that the equipment itself is simply old, compare the numbers on repair or replace.
Related questions
FAQWhy did my electric bill suddenly go up?
If nothing in the house changed, the AC is almost always the reason: an aging system running longer to do the same job, a dirty coil or duct leak forcing longer cycles, or a system old enough that its efficiency has dropped well below what it was rated at. In a city where most housing dates to the 1970s and 1980s, that is the single most common explanation.