Best Window Air Conditioner — Buying Guide

Window air conditioners are the most popular cooling solution for apartments and rooms without central AC. They're affordable, easy to install, and effective for single-room cooling. Here's what to look for and our top pick for small rooms.

Who Should Buy a Window AC?

A window AC is ideal if you:

• Rent an apartment and can't install a mini-split
• Need to cool one or two rooms, not a whole house
• Want a permanent installation that doesn't take up floor space
• Are on a budget (window ACs are significantly cheaper than split systems)

What to Look for When Buying

• BTU rating: 5,000 BTU for up to 150 sq ft, 8,000 BTU for up to 350 sq ft, 10,000 BTU for up to 450 sq ft, 12,000 BTU for up to 550 sq ft. Don't oversize — a unit that's too large will cool too quickly without removing enough humidity, leaving the room feeling clammy.
• EER rating: Energy Efficiency Ratio. Higher is better. Look for 10+ for good efficiency.
• Noise level: Check the dB rating. Units below 50 dB are suitable for bedrooms.
• Window compatibility: Most window ACs fit standard double-hung windows. Check the minimum and maximum width of the included window kit against your window opening.
• Filter type: Washable filters are more economical than disposable ones long-term.
• Controls: Mechanical controls are simpler and more reliable; digital controls offer more precision and often include a remote.

Top Pick: Amazon Basics 5,000 BTU Window AC

For small rooms up to 150 sq ft, the Amazon Basics 5,000 BTU Window Air Conditioner is a reliable, no-frills option that does exactly what it needs to. Key features:

• Quiet operation: Designed for low-noise performance, suitable for bedrooms and home offices
• Washable filter: Reusable mesh filter saves money on replacements and is easy to clean
• Two modes: Cool and fan-only
• Adjustable window kit: Fits standard double-hung windows
• Mechanical controls: Simple, intuitive dials — no complicated menus
• Compact size: Doesn't protrude far into the room

It's not packed with features, but for a small bedroom, studio apartment, or home office, it's an affordable and dependable choice.

How to Install a Window AC

1. Open the window and place the AC unit on the sill, centered in the opening
2. Extend the side panels to fill the gap between the unit and the window frame
3. Lower the window sash onto the top of the unit
4. Secure with the included brackets and foam strips to seal gaps
5. Plug into a dedicated 115V outlet (most 5,000–10,000 BTU units use standard plugs)

For a detailed walkthrough, see our guide on how to install a window air conditioner.

Window AC vs Portable AC

For most situations, a window AC is the better choice if your window type is compatible. If you can't use a window unit, see our guide on the best portable air conditioners.

Maintenance Tips

• Clean the filter every 2–4 weeks during heavy use
• Cover the outdoor portion in winter to protect from ice and debris — use a waterproof AC cover
• Check that the unit is slightly tilted toward the outside so condensate drains properly

A window AC is one of the most cost-effective ways to cool a room. Choose the right BTU for your space, install it correctly, and keep the filter clean — it'll serve you reliably for years.