What matters most when picking an RV air conditioner
The best RV air conditioner for you depends on three things: how much cooling power you need (measured in BTU), where you'll mount it, and what your RV's electrical system can handle. A rooftop unit works for most travel trailers and motorhomes, but some rigs need a portable or window unit instead. Your power budget matters just as much as cooling capacity—a 15,000 BTU unit draws roughly 1,500 watts when running, which will overload many RV electrical systems if you're also running other appliances.
The most common choice is a rooftop air conditioner because it saves interior space and cools efficiently. But if your RV has a low roof, limited roof space, or an older electrical system, a portable or window unit might be your only option. Before you buy anything, measure your roof opening, check your RV's amperage capacity, and decide whether you want one unit or two.
Key Takeaways
- Rooftop air conditioners are standard for RVs but require a 15-amp or 30-amp electrical hookup and draw 1,500 to 3,500 watts depending on BTU size.
- A 13,500 to 15,000 BTU unit cools most travel trailers; larger motorhomes often need 15,000 BTU or dual units for adequate cooling.
- Portable and window units work in RVs without roof space or with limited power, but they take up interior room and cool less efficiently than rooftop models.
- Installation requires cutting an opening in your roof or wall, sealing it properly to prevent leaks, and running electrical lines—tasks many owners hire out rather than do themselves.
- Maintenance includes cleaning filters monthly, checking refrigerant levels yearly, and inspecting seals before each season to catch leaks early.
Rooftop units: the standard choice for most RVs
Rooftop air conditioners are the most popular option because they don't use interior space and they pull air from outside rather than recirculating warm cabin air. Models like the Dometic Brisk Air, Coleman Mach, and Atwood are designed specifically for RVs and come with mounting brackets, ducting, and thermostats built in. Most rooftop units range from 13,500 to 15,000 BTU for travel trailers, with larger motorhomes using 15,000 BTU or installing two units.
Installation means cutting a rectangular opening in your roof (usually 14 by 14 inches), running the unit's electrical cable to your breaker panel, and sealing everything with RV-grade caulk to prevent water leaks. If you're not comfortable with roof work, an RV service center can install one for $500 to $1,500 depending on your location and whether your electrical system needs upgrades. The unit itself costs $800 to $2,000 new, though used models are often available for $400 to $800.
Rooftop units require either a 15-amp or 30-amp shore power connection. A 13,500 BTU unit typically draws 1,500 watts, while a 15,000 BTU model draws closer to 1,800 watts. If your RV has only a 15-amp service (1,800 watts total), running the air conditioner means you can't use your water heater, microwave, or other high-draw appliances at the same time. A 30-amp service (3,600 watts) gives you more flexibility.
Portable and window units for tight spaces
Portable air conditioners sit on the floor and vent hot air through a window or roof vent, making them useful if your RV has no roof space or if you're renting and can't modify the structure. Window units mount in a side window or vent opening and work similarly. Both are cheaper upfront ($300 to $800) and require no permanent installation, but they consume interior space and are less efficient than rooftop models because they recirculate some warm air.
A portable unit typically needs a 15-amp outlet and draws 1,000 to 1,500 watts depending on size. Window units draw similar power. The trade-off is comfort: a portable unit cools a small bedroom or dinette area well, but won't cool an entire motorhome effectively. Many RV owners use a portable unit as a backup or supplement to a rooftop unit during extremely hot weather.
Installation is straightforward—plug it in and run the exhaust hose out a window or vent—but you'll lose that window or vent to the hose. Portable units are also louder than rooftop models and require regular filter cleaning to maintain cooling power.
Understanding BTU, watts, and electrical limits
BTU (British Thermal Units) measures cooling capacity. A higher BTU number means more cooling power, but it also means higher power draw. The relationship is roughly linear: a 13,500 BTU unit draws about 1,500 watts, while a 15,000 BTU unit draws about 1,800 watts. Some high-efficiency models draw slightly less, but not by much.
Your RV's electrical system is the real constraint. A 15-amp service provides 1,800 watts total; a 30-amp service provides 3,600 watts. If you're plugged into shore power at a campground, you have access to that full amount. If you're running on battery and an inverter, your inverter's capacity is the limit—most RV inverters are 2,000 to 3,000 watts, which means you can run an air conditioner but not much else simultaneously.
Choosing the right BTU size means matching it to your RV's size and your power budget. A 20-foot travel trailer usually needs 13,500 to 15,000 BTU. A 30-foot motorhome often needs 15,000 BTU or two units. If you have only 15-amp service, a 13,500 BTU unit is your practical maximum; anything larger will trip your breaker when you try to run other appliances.
Installation: roof cutting, sealing, and electrical work
Installing a rooftop air conditioner involves four steps: marking and cutting the roof opening, mounting the unit, running electrical cable to your breaker panel, and sealing everything to prevent leaks. The roof opening is usually 14 by 14 inches for standard RV units. You'll need a reciprocating saw or jigsaw, a drill, and a level to do it correctly.
After cutting, you mount the unit's base ring to the roof frame using the brackets and fasteners that come with it. Then you run the electrical cable (usually 10-gauge or 8-gauge wire) from the unit down through the RV to your breaker panel, where you install a dedicated 15-amp or 20-amp breaker. Finally, you seal the roof opening with RV-grade silicone caulk or Dicor tape to prevent water from leaking into the RV during rain or when driving through car washes.
Many RV owners hire this work out because roof work is risky and a bad seal can cause expensive water damage. An RV service center typically charges $500 to $1,500 for installation, depending on whether your electrical system needs upgrades. If your RV's breaker panel is full or your wiring is too small, you may need an electrician to upgrade it first, which adds $200 to $500.
Maintenance and seasonal care
RV air conditioners need regular maintenance to run efficiently and last. Clean or replace the filter monthly during cooling season—a clogged filter reduces cooling power and makes the unit work harder. Most RV units have a washable filter that you can rinse with water and air-dry, or a disposable filter you swap out.
Check the refrigerant level once a year, ideally before the cooling season starts. Low refrigerant means the unit won't cool well and may damage the compressor. A service center can check this with a pressure gauge and add refrigerant if needed, usually for $100 to $200. Inspect the roof seal around the unit before each season—caulk cracks or gaps with RV-grade silicone to prevent leaks.
If your air conditioner isn't cooling as well as it used to, the most common causes are a dirty filter, low refrigerant, or a clogged condenser coil. Clean the filter first. If that doesn't help, have a service center check the refrigerant and inspect the coils. Addressing these issues early prevents bigger problems later.
Comparing rooftop, portable, and window options
| Type | BTU Range | Power Draw | Cost (Unit) | Installation | Best For |
|---|---|---|---|---|---|
| Rooftop | 13,500–15,000 | 1,500–1,800 watts | $800–$2,000 | Roof cutting, electrical work | Most travel trailers and motorhomes |
| Portable | 8,000–12,000 | 1,000–1,500 watts | $300–$800 | Plug and vent hose | Rentals, limited roof space, backup cooling |
| Window | 5,000–10,000 | 800–1,200 watts | $250–$600 | Mount in window or vent | Small RVs, single rooms, rentals |
Frequently Asked Questions
Can I run an air conditioner on my RV's battery and inverter?
Only if your inverter is large enough. A 13,500 BTU air conditioner draws about 1,500 watts, so you need at least a 2,000-watt inverter. Even then, you'll drain your battery quickly—most RV batteries can't sustain that draw for more than an hour or two. Shore power is the practical way to run an air conditioner for extended periods.
What's the difference between a 13,500 and 15,000 BTU unit?
A 15,000 BTU unit cools about 10 percent faster and handles larger spaces better, but it draws about 300 more watts. For a 20-foot travel trailer, 13,500 BTU is usually enough. For a 30-foot motorhome or if you live in a very hot climate, 15,000 BTU or dual units are worth the extra power draw.
Do I need to winterize my air conditioner?
If you store your RV in winter, you don't need to do anything special—just make sure the roof seal is intact so water doesn't leak in. If you use your RV year-round, run the unit occasionally during cold months to keep the compressor lubricated. Some owners cover the rooftop unit with a protective cap during storage to keep debris out.
How long does an RV air conditioner last?
Most rooftop units last 10 to 15 years with regular maintenance. Portable and window units typically last 5 to 10 years. The compressor is the most expensive part to replace; if it fails after the warranty expires, replacement often costs $800 to $1,500, so many owners choose to replace the whole unit instead.
Can I install an air conditioner myself?
If you're comfortable with roof work, electrical wiring, and using power tools, you can do it. The hardest part is cutting a straight opening and sealing it properly to prevent leaks. Many owners hire an RV service center for the installation to avoid roof damage and may support the electrical work is safe and up to code.