Why mobile home AC is different
- Ducts: they run under the floor or overhead. A HUD-backed study notes overhead systems are common in Florida, while under-floor ducts are common everywhere.
- Crossovers: double-wides need crossover ducts between sections. HUD says every connection must be sealed, and crossovers must be strapped up off the ground, with supports no more than 4 feet apart. See 24 CFR 3285.606.
- Space: many homes use a package unit, which keeps the whole system outside. Ask a licensed contractor what fits your home.
- Sizing: HUD says site-installed central air must be sized to the home's heat gain (24 CFR 3285.503). The old unit's size isn't proof that it was right.
Check the ducts first
- A HUD-backed study of homes in hot, humid climates found duct leakage and shell leakage have the most dramatic effect on a home's air pressure. It recommends limiting duct leakage to 5% to the outside.
- Leaky ducts waste cooling and can pull damp air into the floor and walls. A sagging belly, a loose crossover or a crushed duct can all be the cause. See underbelly repair.
- Two free fixes help: keep bedroom doors open if rooms don't have good return-air paths, and run exhaust fans only when you need them. See the study.
Signs you need service
- Weak airflow, or rooms at one end that never cool.
- A unit that runs all the time, or power bills that jump.
- Water pooling under the home. HUD says condensate must be directed beyond the home's perimeter.
- A musty smell when the system starts.
- A system that's short-cycling, icing up or tripping its breaker.
What Lakeland's permit records show
- City of Lakeland permits from 2014 to 2026 include about 74 AC jobs on mobile homes, most of them before 2021.
- Their median declared value was about $3,500, and half fell between roughly $2,900 and $4,300.
- Recent jobs have run higher: one 2026 package unit change-out was declared at about $6,500.
- Duct-only jobs were declared at about $2,500 on two 2024 permits.
- Declared values tend to run low, so treat these as a floor.
What it costs
HomeGuide puts a mobile home air conditioner at about $2,500 to $5,300, and a furnace, air conditioner and ductwork together at about $4,000 to $9,000. See HomeGuide's renovation costs. Unit size, efficiency, duct condition and electrical work drive the price. Get a quote that lists the model, the size and any duct repair.
Rules and efficiency
- Hire a Florida-licensed air conditioning or mechanical contractor. Check the license at myfloridalicense.com.
- Replacing a system usually needs a mechanical permit. Lakeland lists a separate mechanical application, and Polk's no-permit list covers only minor mechanical repairs. Your contractor should pull it.
- Federal minimums: new split-system AC under 45,000 Btu/h in Florida's region must meet 14.3 SEER2, and single-package AC 13.4 SEER2. See 10 CFR 430.32.
- HUD requires listed equipment. Fuel-burning appliances, except items such as ranges and dryers, must keep combustion separate from indoor air and vent outside (24 CFR 3280.709). Don't let anyone swap in equipment that isn't meant for your setup.
- In a park, moving or adding outdoor equipment is an exterior change, so ask first.
Storms and power
Secure a package unit to its pad, and keep plants and stored items clear of it. After a storm, check that the unit is level and the duct connection under the home hasn't pulled loose. If the home moved, have it looked at before you run the system. See leveling and tie-downs.
Questions to ask before you sign
- What size system does my home need, and how did you work that out?
- Will you test the ducts, and what will it cost to seal them?
- Is the equipment suited to a mobile home, and what's the model number?
- What's the SEER2 rating?
- Who pulls the permit?
- What's your license number, and what's the warranty on parts and labor?