Types of Air Conditioners

Air conditioners cool your home by removing the heat and humidity inside, and venting it outdoors. They use a chemical called refrigerant, which quickly converts from a liquid to a gas and back again.

The system consists of an outdoor compressor/condenser and one or more indoor air handling units that are connected through copper tubing. A blower fan pulls warm indoor air across the evaporator coil, cooling it.


A window air conditioner is a good option for cooling just one room in your home or adding to your central AC system when you have additional space to cool. They’re fairly easy to install (although you may want to hire a professional if you need help with electrical work or window modifications). They come in a wide variety of BTU capacities and can be purchased for under $500, though they don’t have as much power as larger models.

Window ACs pull heat from the room through an evaporator and discharge it outside through the condenser. They typically have a fan that helps circulate the air. They also have a control panel that lets you adjust the settings manually and some type of remote control. Some models have digital controls and advanced features. Others are more basic, such as this Toshiba model that has seven temperature settings and can cool a small room up to 150 square feet.

Before you purchase a window unit, make sure it’s the right size for your window and check its installation requirements. Some are designed for casement windows and won’t fit double-hung windows, while others require a sill kit that includes Plexiglas or wood to cover the gap. They’re also heavy, so you may need a helping hand to lift and install them. You may also need a support bracket, which is installed on the bottom of the unit’s chassis and secured to the window frame or sill.


The portable air conditioner works much like a window air conditioning unit except it is designed to be moved from room to room and is typically smaller and less expensive. It is a good option for a single-room home, apartment or office and for homes where neighborhood restrictions prevent the installation of a window air conditioner.

It has several internal components to cool the air, including a fan that pulls in hot, humid air and blows it over a cooling coil to cool it. The refrigerant, which is used as a heat exchange medium, is compressed and then expanded rapidly, absorbing heat from the air. This cooled air is then vented through an exhaust hose out a window. Some units also use self-evaporation or a gravity drain to remove moisture from the air.

Some models have remote controls and/or interface with smart-home systems to control them from Air conditioner a smartphone or tablet. You can also set a timer to automatically start and stop the air conditioner at certain times of day.

When comparing different portable air conditioners, pay attention to their BTU rating as well as the EER (energy-efficiency rating). The higher the energy efficiency number, the more it will save on electricity over time. To calculate the cost to operate a specific model, find the wattage it uses and multiply it by your electric company’s price per kilowatt-hour.


The through-the-wall air conditioner is a permanent solution that allows cooling in spaces where windows are not available. It works by installing a metal sleeve into the wall and venting through it. Sleeves can either come with the AC unit or be purchased separately. They are designed for commercial-grade applications with components that withstand more demanding environments and are often used to cool offices, retail stores, multifamily buildings, barracks and dorms. These units are also available with remote capability to allow centralized control of settings for multiple AC units in the building.

The size of the space you want to cool is one of the biggest factors in determining what size through-the-wall AC unit you need. You will also need to look at the BTUs a given model has to ensure it is powerful enough for the job. Newer models from companies like MIDEA are redefining the thru-wall AC market with surprisingly low costs.

If you’re replacing an existing thru-wall AC, make sure the sleeve is compatible with the unit. Most owners manuals list the sleeve size you will need for the specific unit you are considering buying. It is also a good idea to look at the energy efficiency ratings of each model. The more efficient the unit, the less it will cost to run year-round.

Energy Star

Energy Star is a nationally recognized mark on products that meet specific energy efficiency requirements set by the Environmental Protection Agency. Air conditioning equipment that earns the ENERGY STAR label has higher Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Rating (EER) ratings than standard models, saving you money on monthly utility bills.

The ENERGY STAR label is on appliances, lighting, insulation and building products, windows, doors, air conditioners, dishwashers, dehumidifiers, clothes washers and dryers, and more. This program, established in 1992, promotes more efficient products and practices throughout the country. This leads to better utilization of energy, fewer greenhouse gasses and a decrease in air pollution.

To earn the ENERGY STAR label, an air conditioner must be third-party certified as meeting the EPA’s energy-saving performance standards. ENERGY STAR-certified heating and cooling systems have SEER ratings of at Air conditioner least 13. For central air conditioners, the EER is at least 12. ENERGY STAR-certified portable AC units have an EER of 12.5 or higher.

The initial cost of a high-efficiency air conditioner is more than that of an ordinary model, but it will pay for itself in lower electricity bills over the years. Plus, many utility companies offer incentives for installing ENERGY STAR-certified equipment. Check the ENERGY STAR website to find out which, if any, HVAC systems qualify for tax credits and rebates in your area.