Window ACs have been around for a long time. While they were invented in the 1930s, they became affordable for the general public in the 1960s.

There is a range of sizes and brands of window ACs. You might want to consult a guide to help you choose the right one.

Lucky for you, we are here with a comprehensive guide that helps you select the right window AC. So, read on to find out.

What to Know Before Buying Window AC?

Window ACs are popular for their cooling efficiency. There are still some things that you need to know when you’re purchasing a window AC:

1. Cooling Capacity

Whether you’re investing in a split AC or a widow AC, you need to be mindful of the unit’s cooling power. This cooling power is measured in BTUs and is selected based on room size, sunlight exposure, and occupancy. An undersized unit may struggle to cool the space, while an oversized one might cool too quickly without removing enough humidity, leaving the room feeling damp.

2. Window Dimensions and Type

Before purchasing, measure your window's width, height, and depth to ensure the unit fits properly. Most window ACs are designed for double-hung windows that slide up and down, but there are models suitable for slider or casement windows as well.

3. Energy Efficiency

Window ACs typically consume more energy compared to a split AC unit. However, the energy efficiency of the AC also depends on the model and the technology it uses. Look for units with an Energy Star certification, as they consume less electricity and can lower your energy bills. Also , look for features like programmable timers and energy-saving modes which can allow you to save up on energy too.

4. Installation and Maintenance

Proper installation for window AC is crucial for optimal performance. Ensure the unit is level so it drains correctly, and use the provided installation kit to seal any gaps, preventing air leaks. Regular maintenance, such as cleaning or replacing filters, keeps the AC running efficiently.

5. Electrical Requirements

Check your home's electrical system to ensure it matches the AC's requirements. Most units under 15,000 BTUs operate on standard 115V circuits, but larger units may need a 220V outlet.

How to Size the Right Window Air Conditioner?

Selecting the correct size for your window air conditioner is crucial for effective cooling and energy efficiency. An undersized unit may struggle to cool your space, while an oversized one can cool too quickly without properly dehumidifying, leaving the room feeling damp.

To determine the appropriate cooling capacity, measured in British Thermal Units (BTUs), start by calculating your room's square footage. Multiply the room's length by its width to get the area. For instance, a 10-foot by 15-foot room equals 150 square feet. According to Energy Star guidelines, a room of this size typically requires a 5,000 BTU air conditioner. Here is an estimate of the BTUs for some standard room sizes that you can refer to when selecting the size of your window AC:

Because these are just recommendations, adjustments to the BTUs might be needed based on certain conditions. These conditions include the sunlight exposure of the room, the number of people occupying it, and other elements that might generate heat:

• Sunlight Exposure: If the room receives abundant sunlight, increase the capacity by 10%. For heavily shaded rooms, reduce it by 10%.

• Occupancy: Add 600 BTUs for each additional person if more than two people regularly occupy the room.

• Kitchen Use: Kitchens generate more heat; therefore, increase the capacity by 4,000 BTUs when installed in a kitchen.

How to Choose the Right Window Air Conditioner Dimensions?

Window air conditioners require a space in the wall for a fit. If the AC does not fit properly, you cannot expect it to perform well. Plus, if the AC does not fit, there’s also a chance that it might fall off, causing a safety hazard.

So, it is essential that before purchasing, you measure your window's width and height. Once you have that noted down, confirm its compatibility with the unit's dimensions.

Most window AC units are designed for standard double-hung windows, but there are models suitable for slider or casement windows as well. It's important to check the manufacturer's specifications for minimum and maximum window dimensions to ensure a proper fit.

Additionally, consider the unit's weight and ensure your window frame can support it securely. You might also want to hire professional help for installation. While many window ACs come with guides and simple installation, even if you’re off by a few millimeters, your AC unit won’t give you the performance it promises.

Highest Rated Window Air Conditioner in 2025

With so many models and brands around, even those who know all the jargon regarding window ACs are bound to get confused. We’ve curated a list of the highest-rated window air conditioners for you based on your room type and features.

Best Window Air Conditioner for Apartments

The Frigidaire GHWQ123WC1 12,000 BTU Window Air Conditioner is praised for its efficiency and quiet operation. So, if you’re living in an apartment, this quiet window AC will be a great fit.

Best Window Air Conditioner for Large Rooms

The Midea 12,000 BTU Smart Inverter Air Conditioner is perfect for rooms up to 550 square feet. Its smart features also allow the occupants to control the AC without hassle.

Best Window Air Conditioner for Mobile/Small Homes

The Windmill 8,300 BTU 115V Window Air Conditioner is the best for mobile homes. It can cool mobile homes up to 350 square feet. Plus, its compact design doesn’t take up much space.

Best Window AC Units for Garages

The GE 5,000 BTU Mechanical Window Air Conditioner is a budget-friendly option that effectively cools smaller spaces like garages. Its 5000-BTU capacity means it can cool even garages that are 250 square feet since garages don’t have a lot of sun exposure.

Best Budget Window Air Conditioner

If you’re looking for a window AC on a small budget, the GE 5,000 BTU Mechanical Window Air Conditioner is your pick. It is a simple and effective cooling unit, best for small spaces. Plus, it is priced at a level that wouldn’t break your bank.

Most Quiet Window AC Unit

The DELLA Miri Series 8000 BTU ultra quiet AC unit operates at a quiet 42 decibels. So, if you’re a light sleeper and AC noise can be a nuisance, this window AC is the best pick for you.

Best Small Window AC Unit

July Window Air Conditioners stand out for their compact size and customizable covers. July also boasts an extremely easy self-installation process. You can install the small window AC on slider windows too! Plus, its design blends seamlessly with home decor.

Best Window Air Conditioner with Heat Pump

The Midea 12,000 BTU Smart Inverter Air Conditioner provides both cooling and heating capabilities. So, if you want an all-in-one air conditioning unit, this is the best pick. Plus, its inverter technology ensures that using it isn’t heavy on your pocket.

Best Smart Window Air Conditioner

DELLA’s Fenestra Series smart 5000 BTU window AC is one of the best and smartest window ACs out there for rooms up to 150 square feet. It features Wi-Fi connectivity, voice control compatibility, and an innovative design for noise reduction. Plus, with a Combined Energy Efficiency Rate (CEER) of 11.0, you can be worry-free about your energy bills.

How to Save Window AC Electric Bills?

Window ACs are notorious for their high energy consumption. But with the latest technology in window ACs like timers and some maintenance activities, you can save money and enjoy cooling with your window AC. Here are some tips that you can follow:

• Choose an Energy-Efficient Unit: Opt for air conditioners with an Energy Star certification, as they consume less electricity without compromising performance.

• Regular Maintenance: Clean or replace filters monthly during peak usage to ensure efficient airflow and cooling.

• Optimal Thermostat Settings: Set your thermostat to a comfortable yet energy-efficient temperature. Raising the temperature by a few degrees can significantly reduce energy consumption.

• Utilize Programmable Timers: Use timers or smart controls to operate the AC only when needed, avoiding unnecessary cooling when rooms are unoccupied.

• Enhance Room Insulation: Seal any gaps or cracks in windows and doors to prevent cool air from escaping, reducing the workload on your AC unit.

Implementing these strategies can help maintain a comfortable environment while keeping energy costs in check.

Window Air Conditioner Maintenance Tips

Window air conditioners also need maintenance. If you’re choosing a window AC for your home or commercial property, here are some maintenance activities that you’ll need to carry out to keep your unit performing optimally:

Filter Care

Clean or replace the air filter every month during the cooling season to maintain efficient airflow and air quality. Clogged filters force the AC to work harder, increasing energy consumption.

Clean the Unit

Dust and debris can accumulate on the evaporator and condenser coils. This dust and debris reduces the unit’s efficiency. However, cleaning the condenser coils with abrasive cleaners is not recommended.

Also while you’re cleaning, wipe down the fan blades. Also, inspect if they move freely without obstruction. If they’re not moving freely, lubrication might be required.

Inspect and Clean the Drainage System

A clogged drain can cause water buildup, leading to leaks or mold growth. Ensure the drain holes are clear and unobstructed.

During your inspection, don’t forget to check the foam insulation around the AC unit to ensure a tight seal. Gaps can cause cool air to escape, making the unit work harder and pulling more electricity. If you suddenly have higher-than-expected electricity bills, it might also indicate an insulation issue.

Seasonal Storage

Many people remove their window ACs during colder months. While this is not a problem, you need to store it in a dry place and cover it to prevent dust accumulation.

Final Words

We hope that with this guide, you can pick a window AC unit that provides a comfortable environment for years to come. To make your decision even easier, check out Dellahome’s selection of top-rated window AC units. Don’t miss their current air conditioner sale, offering great deals on quality units designed to meet your needs!

Read More:

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