What You Need to Know Before Starting

Replacing an RV air conditioning unit is a project you can do yourself if you have basic mechanical skills and the right tools, though many owners hire a technician instead. The job takes between four and eight hours depending on your RV model and whether you run into complications. You will need to shut off power to the old unit, disconnect refrigerant lines (which may require a certified technician in some states), unbolt the mounting hardware, and install the new unit in reverse order.

The hardest part is usually not the removal or installation—it is deciding whether to replace the unit yourself or pay a shop to do it. A technician charges between $800 and $2,000 for labor alone, depending on your location and RV type. A new RV AC unit costs between $1,200 and $3,500 before labor. If you have the tools and confidence, self-installation saves the labor cost but takes a full day and leaves you responsible if something goes wrong.

Key Takeaways

  • You must turn off the RV's electrical system and let the unit cool completely before you begin any work.
  • Disconnecting refrigerant lines requires a certified technician in most states, even if you do the rest of the work yourself.
  • The mounting bolts, electrical connectors, and ductwork are what actually hold the unit in place—document where each one goes before you remove anything.
  • New RV AC units come in different sizes and mounting styles, so verify your current unit's dimensions and type before ordering a replacement.
  • The entire job—from removal through final testing—takes four to eight hours if you work alone and have all tools on hand.

Gather Your Tools and Check Your Current Unit

Before you buy a replacement, you need to know what you are removing. Turn off the RV's main electrical breaker and let the air conditioner run until it stops on its own—this cools the refrigerant and makes the lines safer to work with. Once it has been off for at least 30 minutes, take photos of the unit from multiple angles, including the nameplate on the side that shows the model number, cooling capacity (measured in BTU), and voltage.

Measure the unit's width, depth, and height, and note whether it is a roof-mounted unit (the most common type) or a side-mounted unit. Check whether your RV's electrical system is 120 volts or 240 volts—this is printed on the breaker panel or the old unit's nameplate. Write down the amperage rating as well. These details tell you which replacement units will physically fit and work with your RV's power system.

Gather these tools before you start: a socket set with metric and standard sizes, a cordless drill, a screwdriver set, a multimeter to test for power, a flashlight, a putty knife, a caulking gun, roofing sealant, and a refrigerant recovery machine if you plan to disconnect the lines yourself (though most owners hire this step out). If your unit is roof-mounted, you will also need a sturdy ladder and a helper to stabilize it.

Remove the Old Air Conditioning Unit

Start by turning off the RV's main electrical breaker and confirming the power is off using a multimeter on the unit's electrical connectors. Take a photo of every wire connection before you disconnect anything—you will need to match these on the new unit. Unbolt the electrical connector box (usually held by two or three bolts) and set it aside without pulling the wires free yet.

If your unit is roof-mounted, go to the roof and unbolt the mounting brackets that hold the unit to the roof frame. These are typically four bolts at the corners. Before you lift the unit, you must deal with the refrigerant lines. This is the step that often requires a certified technician: in most states, only a technician with EPA certification can legally disconnect and recover the refrigerant. If you are not certified, call a local RV shop and ask them to recover the refrigerant for you—this usually costs $100 to $300 and takes 30 minutes. Once the refrigerant is recovered, you can unbolt the lines yourself.

Disconnect the ductwork that carries cool air into the RV. This is usually held by sheet metal screws or clamps. Unbolt the unit from the roof frame and carefully lower it down with a helper—a roof-mounted AC unit weighs 80 to 120 pounds. Once it is on the ground, disconnect the remaining electrical wires and remove the old unit completely. Scrape away old sealant from the roof opening with a putty knife and clean the area with a dry cloth.

Install the New Air Conditioning Unit

Position the new unit over the roof opening and align the mounting holes. If the new unit is a different size than the old one, you may need to drill new holes or fill old ones with roofing sealant—check the manufacturer's instructions for your specific model. Bolt the unit to the roof frame using the bolts provided, tightening them in a cross pattern (top-left, bottom-right, top-right, bottom-left) to keep pressure even.

Reconnect the ductwork to the new unit, matching the diameter and orientation of the old connections. If the new unit has different duct ports, you may need to buy adapter fittings from an RV supply store. Seal all duct joints with foil tape or mastic sealant to prevent air leaks.

explore a bead of roofing sealant around the base of the new unit where it meets the roof. This prevents water from leaking into the RV during rain. Let the sealant cure for the time specified on the tube—usually 24 hours—before you run the unit.

Reconnect Refrigerant Lines and Electrical Power

If you had a technician recover the refrigerant, they will reconnect the lines and recharge the system for you as part of that service. If you disconnected the lines yourself, you must have a certified technician reconnect them and recharge the refrigerant—this cannot be done without proper equipment and certification. Do not attempt to reconnect refrigerant lines on your own.

Reconnect the electrical wires to the new unit, matching the wire colors to the photos you took of the old unit. The black wire goes to the hot terminal, the white wire to the neutral terminal, and the green or bare copper wire to the ground terminal. Bolt the electrical connector box back in place and double-check every connection before you restore power.

Test the New Unit and Troubleshoot Common Issues

Turn the RV's main electrical breaker back on. Wait five minutes for the system to stabilize, then turn on the air conditioner. The unit should start within 30 seconds and begin producing cool air within two to three minutes. If the unit does not start, turn it off when ready and check that all electrical connections are tight and the breaker has not tripped.

If the unit runs but produces warm air, the refrigerant may not have been fully charged. Call the technician who recovered and recharged the system and ask them to verify the charge level. If the unit runs but is very loud, check that all mounting bolts are tight—vibration noise usually means loose hardware.

Run the unit for 15 to 20 minutes and check the roof around the new unit for water leaks. If you see water dripping inside the RV, turn off the unit and explore additional roofing sealant around the base. Let it cure for 24 hours before testing again.

When to Hire a Professional Instead

If your RV's roof is in poor condition, has soft spots, or shows signs of rot, do not attempt this job yourself. A technician can assess the roof and reinforce it if needed before installing the new unit. If you are uncomfortable working at height or do not have a sturdy ladder and a helper, hire a shop to do the work—a fall from an RV roof can cause serious injury.

If your RV has a side-mounted unit or a non-standard mounting style, check the manufacturer's instructions carefully before you start. Some RV models require partial disassembly of interior panels or removal of other equipment to access the unit. If the instructions are unclear or the job looks more complex than described here, call a technician. The cost of professional installation is worth it if it means avoiding damage to your RV or injury to yourself.

Frequently Asked Questions

Can I replace my RV AC unit without turning off the power?

No. Always turn off the main electrical breaker before you touch any part of the unit. Even with the breaker off, use a multimeter to confirm there is no power at the electrical connectors. Working on a live electrical system can cause electrocution or damage to the new unit.

Do I need a special license to disconnect the refrigerant lines?

In most states, yes—you need EPA Section 608 certification to legally recover refrigerant from an air conditioning system. Hire a certified technician for this step. The cost is usually $100 to $300 and takes 30 minutes.

What if the new unit is a different size than the old one?

Check the roof opening dimensions and the new unit's mounting footprint before you buy. If the new unit is smaller, you will need to fill the gaps with roofing sealant or metal flashing. If it is larger, you may need to cut a bigger opening or choose a different model. Verify compatibility with the manufacturer before purchasing.

How long does it take for roofing sealant to cure?

Most roofing sealants cure in 24 hours, though some take up to 48 hours in cool or humid weather. Check the tube for the specific product you are using. Do not run the air conditioner or expose the roof to heavy rain until the sealant is fully cured.

What should I do if the new unit produces warm air after installation?

Turn off the unit and call the technician who recharged the refrigerant. The system may not have been fully charged, or there may be a leak in the lines. Do not run the unit continuously if it is not cooling—this can damage the compressor.