What to Know About Wall Air Conditioners

Want to cool your home in an efficient and cost effective way? Through-the-wall air conditioners can be a good choice to keep you and your home cool.

Willis Carrier, an American engineer, invented the first modern air conditioner in 1902. Since then, design refinements have led to many amazing air conditioner innovations, including through-the wall air conditioners. Not as popular as window-mounted units, through-the-wall air conditioners come with some unique challenges and noteworthy advantages.

What Is a Through-the-Wall Air Conditioner?

Through-the-wall air conditioners are self-contained cooling appliances installed permanently in a building’s exterior wall. Designed to span from the inside wall surface to the outside, these units maximize efficiency by creating an airtight seal when properly installed. And, once installed, they never need to be removed, except for servicing or replacement.

How Do Wall Air Conditioners Work?

Like all modern air conditioners, through-the-wall units work by blowing air over coils containing coolant gas, while expelling warm air outside. Through-the-wall units are typically rectangular, fitting in a precisely framed hole in an exterior wall, within a specially made containment sleeve. The fit of the sleeve and the hole around the unit provides an airtight seal, maximizing cooling efficiency.

Let’s compare the advantages of wall ACs to other types of cooling units. Window ACs often need to be removed at the end of the cooling season and don’t achieve a perfectly airtight seal. They also obscure the view through the window. Portable air conditioners have the same issues and reduce the floor space in your home.

Ductless mini-split air conditioners are powerful, but often much louder than through-the-wall machines. Mini-splits also require large condenser units to be installed outside. Through-the-wall units are known for their quietness compared to other types of air conditioners, with some models running at less than 50 decibels.

Types of Wall Air Conditioners

When shopping for through-the-wall air conditioners, keep these key differences in mind as you make your choice:

120 vs. 220 volt

Almost all modern air conditioners, including through-the-wall models, are designed to run off regular 120-volt electrical outlets. A few larger models require a 220-volt electrical outlet, which means you’ll need to upgrade if there isn’t a 220-volt outlet nearby. If you’re unsure about any of this, consult an electrician before buying an air conditioner that needs a 220-volt outlet.

Fixed sleeve vs. slide-out sleeve

All through-the-wall air conditioners come with metal containment sleeves that hold the units in place. These sleeves can be permanently fixed to the unit or removable. The air conditioners with removable sleeves are easier to service or replace, provided you find a new unit that fits your old sleeve.

Some (but not all) air conditioners with removable sleeves are designed to work in windows as well as exterior walls. Be sure to check the owner’s manual before attempting to install a through-the-wall unit in a window.

Packaged terminal air conditioner

Typically larger and more powerful than most through-the-wall units, most packaged-terminal air conditioners (PTACs) offer robust heating as well as cooling capabilities. Often used in hotels and hospitals, PTACs are more expensive than standard through-the-wall units, but can save you money in the long run if you plan to heat as well as cool your home.

Some PTACs come with cords and can be plugged into regular outlets. Others need to be hard-wired into your home’s electrical system.

How To Choose a Wall Air Conditioner

With more options than ever before, choosing the best wall air conditioner might seem daunting. It doesn’t have to be. Here are the main things to keep in mind:

  • Cost: This varies a lot. Small, simple wall air conditioners can cost as little as $400. Big, powerful, feature-packed units can easily be $1,500 or more. Between these two extremes is a well-populated middle ground.
  • Size: This refers to the unit’s physical size (how much wall space it takes) as well as its cooling capacity, and is typically expressed in British thermal units (Btus) per hour. Bigger spaces require an air conditioner with a higher Btu rating to keep the space cool. For an exact analysis of cooling capacity needs for a given room size, check out the chart under “Buying Guidance.”
  • Energy Efficiency: If saving on electricity matters to you, look for a unit with variable speed controls and energy saving modes. Also, watch for units with the Energy Star label. These units are at least 10 percent more efficient than comparable models.
  • Controls and Features: Decide if features like heating, fan-only mode, touch and voice controls, remote control and variable speed matter to you. Shop accordingly.
  • Sleeves: If you’re replacing an existing wall air conditioner but keeping its removable sleeve, be sure to buy one that fits the old sleeve perfectly. Many sleeves and air conditioner units come in standard sizes so brand swapping does sometimes work.

Wall Air Conditioner Installation and Maintenance

Most through-the-wall air conditioners are simple to install. If you’re a capable DIYer with the tools and guts to cut a large hole in your wall, frame a precisely sized opening, then fix the drywall on the inside and siding on the outside, there’s probably no need to hire a professional.

But if your installation requires wiring or you’re worried about cutting into water pipes in your wall, hiring an electrician and appliance installer is wise. Expect to pay $700 to $800 for a medium-sized wall AC installation job.

As for maintenance, expect to oil the motor and change belts once a year. Check and clean or change filters once a month, or as needed. Inspect the coils annually, cleaning as needed. These timelines are general — always follow manufacturer instructions for exact maintenance timing. If you’re uncomfortable with any of these jobs, call in a professional.

Robert Maxwell
Robert Maxwell is a writer, videographer, photographer and online strength coach based in Northern Ontarion, Canada. He grew up on a rural self-sufficient homestead property where he learned the skills to build his own home from the ground up, do all his own vehicle repairs, and work with wood, stone and metal to find practical DIY solutions to many everyday problems.