The Hidden Costs of AC Installation — Ask About These Before You Sign

Why two quotes for the same system differ by thousands

Homeowners reasonably assume that a 3-ton system from the same manufacturer should cost about the same from any contractor. When one quote comes in dramatically lower, the equipment is rarely the difference. The difference is which of the following are in the price, which are extra, and which are simply not going to be done.

Work through this list with any quote and the comparison becomes honest.

1. The permit and inspection

Air conditioning changeouts require a permit in Miami-Dade, Broward and Palm Beach, and an inspection afterwards. A quote that omits it is either adding it later or skipping it — and unpermitted work becomes your problem at resale, at insurance renewal, and if anything goes wrong. Ask directly: is the permit included in this price, and who pulls it? Full detail in what to expect from permits and inspection.

2. Removal and disposal of the old equipment

The old system has to be legally recovered — refrigerant reclaimed rather than vented — and hauled away. It is a real cost and it is occasionally left off a low quote.

3. Electrical work

New equipment may need a different breaker size, a new disconnect, or an upgraded whip. On older homes the existing wiring sometimes does not meet current code for the new unit. This is one of the more common “we found this on the day” add-ons, and a good contractor will have looked at your panel before quoting.

4. The pad, and hurricane tie-downs

A new pad is often needed, and in South Florida the outdoor unit must be secured against wind. In Miami-Dade and Broward — the High Velocity Hurricane Zone — equipment anchoring is a code requirement that the inspector checks, not an optional extra. Ask whether tie-downs and any required brackets are in the price.

5. The line set

The copper between indoor and outdoor units. Sometimes it can be reused after a proper flush; sometimes it must be replaced — particularly after a compressor burnout, or where the existing set is the wrong size for the new equipment. Replacing a line set through finished walls is real work. A quote should say which it assumes.

6. Duct modifications

If the new air handler has a different footprint or the existing plenum does not match, transition work is needed. And if the duct system is undersized — which is common in older homes — installing a modern high-efficiency system onto it will not deliver what was promised. Honest contractors raise this at quote time; it is not a pleasant conversation, which is why some skip it.

7. Condensate work

New drain lines, a proper trap, a secondary pan and float switch where the unit sits above finished space. In this climate that safety switch is not optional in any practical sense — see what happens when condensate goes wrong.

8. The thermostat

Some quotes include a basic thermostat, some include a communicating or smart one, some include none. With variable-speed and communicating equipment, the matched thermostat is not a cosmetic upgrade — the system needs it to do what it was sold for.

9. Access and physical difficulty

An attic air handler with a small hatch, a rooftop package unit needing a crane, a second-floor closet with a tight stair, a condenser in a side yard with three feet of clearance. These genuinely differ between houses and legitimately differ between quotes.

10. Code upgrades triggered by the work

Occasionally the inspection surfaces something — a return that does not meet current sizing rules, a platform that needs work, missing insulation on a section of duct. These are less common but they are real.

The questions to ask, verbatim

• Is the permit included, and do you pull it under your own licence?
• What is the exact model number of the indoor and outdoor units, and is there an AHRI matched rating?
• Is removal and disposal of the old system included?
• Does the price include a new pad and hurricane tie-downs?
• Are you reusing or replacing the line set, and what happens if it cannot be reused?
• What electrical work is included, and have you looked at my panel?
• What duct modifications are included, and have you assessed whether my duct system suits this equipment?
• What thermostat is included?
• What is your labour warranty, and will you register the equipment?
• What would trigger a change order, and what would it cost?

What a low quote usually means

Occasionally it means a genuinely lean operation with lower overhead, and that is fine. More often it means one of three things: the permit is being skipped, the system is being sized by guess rather than by load calculation, or the price will grow through change orders once the old system is out and you have no realistic option to stop.

The way to protect yourself is not to demand the lowest number. It is to make every quote itemise the same list, so you are comparing the same job. Pricing context is in the AC cost guide, and the instant estimate gives you a starting range in about a minute.