Ever since I started reviewing air conditioners back in the early 2000s, this is the question I get the most every time a heat wave hits. It used to be a no-brainer, with window ACs being the far superior choice. But in recent years, our Home Improvement & Outdoor Lab pros at the Good Housekeeping Institute have seen portable ACs narrow the gap, thanks to innovations like dual-hose design for more efficient cooling, and inverter technology to help cut down noise.
That said, in certain cases, one option is obviously the better fit. Here’s my current advice for anyone scratching their head in the AC aisle.
How we test air conditioners
We test air conditioners by first focusing on top brands and widely available models. Our research includes data from in-Lab testing with our engineers and at-home testing with testers. We looked at cooling power, ease of use and noise, plus we checked speed and consistency in cooling, ease of installation and filter maintenance. We also measured noise levels and airflow power using specialized tools.
Go with a window air conditioner if:
You want maximum cooling power, with minimum noise.
Though it’s true that today’s portable ACs are capable coolers, they still can’t compete with the best window ACs. That’s mainly because a window AC's heat-generating mechanical parts are located outside of the room that's being cooled. A window AC also uses outside air to cool its coils, while a portable AC relies on air from the room, which can pull in unconditioned air from other parts of the house.
In our tests, window ACs cool spaces more quickly and effectively than portable ACs, using less energy in the process. Though there are exceptions, window ACs overall are also quieter than portable ACs, again because their main engine is located outside the home.
LG 8,000 BTU Window Air Conditioner
Frigidaire 5,000 BTU Window-Mounted Air Conditioner
TCL TCL 8K Window Air Conditioner, H8W4MW
You have limited floor space.
Window ACs are extremely space-efficient, since they sit in the window, and not the middle of the room, like a portable AC. Besides taking up less space, window ACs don’t get in the way of the interior design. With a portable AC, conversely, it’s one of the first things you notice when you walk into the room.
You’re on a tight budget, or want to save energy.
While the cost of portable ACs has come down as they’ve become more common, in a BTU-to-BTU comparison (that’s British Thermal Units, or how cooling capacity is measured), window ACs are a far better deal. To illustrate that point: our best value pick among portable ACs costs roughly the same $300 as our best overall window AC. Many other top-rated portable ACs are in the $600 range.
Beyond the upfront cost, portable ACs are less energy efficient, so they’ll cost more to operate compared with a window AC.
Go with a portable air conditioner if:
You don’t have the right window to work with.
The best window AC in the world won’t do any good if you don’t have the right kind of window to place it in — specifically a large double-hung window, with a sash that goes up and down. Portable ACs, on the other hand, work with this conventional window type, plus most others, including horizontal sliders and casements. That's because portable ACs only need to be vented to the outside through a small hose, usually about six inches in diameter. You can even cut a hole in a wall or door and run the house through it, making the installation options practically limitless.
Whynter Portable Air Conditioner
De'Longhi PAC-UV Portable Air Conditioner
You want to cool various spaces.
As the name implies, portable ACs can move from room to room, given their wheeled design. That means they can be deployed to different parts of the home — say the family room during the day and the bedroom at night. You’ll need to have brackets in place to receive the exhaust hose, so it’s a bit of a project getting set up for this kind of portable cooling power. But it’s much easier than moving a window AC around the house throughout the day.
You live in a humid environment.
While any type of air conditioner will reduce humidity as it cools the air, portable ACs are especially good at it since their cooling process is specifically designed to pull moisture from the air. That's why you'll often see portable ACs marketed as a two-in-one solution that dries the air as it cools. Still, for the very best dehumidifying results, our experts say a dedicated dedicated dehumidifier is the way to go.
The bottom line
Consumer choice is always a good thing, and that's the case with air conditioners. Do window ACs have better engineering and overall cooling performance? Sure, that's why they've been around for close to a century. But portable ACs are a nice addition to the marketplace, providing a cooling option where there wasn't one before. As with any home purchase, consider all the factors when deciding between the two types of AC, then check our reviews to find the best model for your needs.
Having written thousands of product reviews and how-to articles on all aspects of home ownership, from routine maintenance to major renovations, Dan (he/him) brings more than 20 years of industry experience to his role as the director of the Home Improvement & Outdoor Lab at the Good Housekeeping Institute. A one-time roofer and a serial remodeler, Dan can often be found keeping house at his restored Brooklyn brownstone, where he lives with his wife and kids.
