With temperatures climbing into the triple digits, running out to buy a window air-conditioning unit might seem like a simple way to beat the heat.

But while these air conditioners can help keep you cool, experts say you should consider other options.

“I wouldn’t want to pay the electricity bill on a standard window unit,” said Colin Taylor, senior manager of climate programs at CLASP, a nonprofit focused on appliance efficiency.

A basic window unit typically has a lower initial cost than other models and is relatively easy to install, but they guzzle energy, straining electricity grids, and can contribute to the planet-warming emissions driving extreme heat.

Here’s how standard window air conditioners stack up against other cooling options.

Energy use

Basic window units use a standard compressor, which has only two settings: on or off. This means the air conditioner will run at full speed until it’s able to cool down a room to the set temperature before shutting off. When the space starts to warm again, the heat triggers it to kick back on.

“They are the least efficient technology available,” said Ana Maria Carreño, senior director of climate programs at CLASP. “That shouldn’t be an alternative that is sought for a long-term solution for space cooling.”

There are better technologies out there, she and other experts say, including:

— Inverter window air conditioners. Inverter air conditioners can vary the speed of the compressor according to demand for cooling. For example, once the desired temperature is reached, these air conditioners decrease the speed of the compressor’s motor instead of shutting off completely and having to run at full speed when it becomes warm again. This helps to save energy and maintain the room’s temperature.

One peer-reviewed study published in 2020 found that inverter units could save up to 44 percent of electricity consumption compared with a non-inverter air conditioner. The more energy-efficient technology could also cut carbon dioxide emissions by nearly half, the study said.

These window units are “substantially more efficient,” Taylor said. “Anyone rushing out to buy a product should go for the inverter unit.”

— Mini-split air conditioners. They are among the most energy-efficient and affordable options, Taylor and other experts said. As the name suggests, these air conditioners are split into two parts: an outdoor condenser or compressor unit and an indoor air-handling unit. Mini-splits also use inverter technology. A typical mini-split should consume about half as much electricity per unit of cooling delivered compared with a standard window unit.

“This is a technology that is very efficient,” Carreño said.

Cost

Prices for any air conditioner type will vary based on size.

An 8,000-BTU standard window air conditioner — one of the most commonly available sizes that can usually cool a room ranging from 250 to 350 square feet — could cost around $250. Similar-size inverter-style units can be more expensive, with some models going for $300 or more.

One benefit of window units is their easy installation. They don’t require much technical support and don’t have the same installation cost that would come with a mini-split, Carreño said. On top of higher installation costs, which are typically above $1,000, mini-splits are also pricier than window units.

“But I think when you compare the cost of running it in the long term, you will get better savings with a mini-split,” Carreño said. Over time, she added, mini-splits are “going to result in better comfort for the user and less costs on the electricity bill.”

Staying cool

Opting for a mini-split, however, isn’t always possible. For instance, window units are useful for people who can’t install permanent equipment, such as renters, said Matt Malinowski, buildings director for the American Council for an Energy-Efficient Economy, a nonprofit group.

If you are considering a window unit, Malinowski suggested looking at models certified by Energy Star.

It’s also important to make sure your air conditioner is the right size for the space you’re trying to cool. General BTU ratings, which indicate an air conditioner’s cooling capacity, can be a good starting point, according to Consumer Reports. Units with a capacity of 5,000 to 6,500 BTU are typically enough to cool 100 to 250 square feet, or the size of a smaller bedroom or home office. But ceiling height, the size of your windows and doorways, how much shade or sun the room gets, and how many people are inside could all affect the amount of cooling power you’ll need.

To help maximize the energy efficiency of your window air conditioner, experts recommend reducing leaks around the unit and taking additional steps to seal your home so the cool air isn’t lost. You should also turn off the air conditioner if you’re not going to be in the room.

Avoid cranking down your thermostat, Taylor said. Setting the thermostat low will also not cool your space faster.

“Especially the traditional fixed-speed units, it’s either on or off,” he said, “and it’s going to be on full speed until it hits that set temperature.”