Selecting the best air conditioning system for the spaces in your home requires you to consider several factors. These include the type of room, its total volume, the number of people who use the space on average and the amount of sunlight the room receives. The options and terms listed below along with the information provided with each system should allow you to find the solutions that are right for your home. 

Portable and window/wall air conditioners

These products are typically employed for cooling single rooms. They are popular thanks to their affordability, portability and versatility. They are a single, self-contained unit that fits on a windowsill or in a hole cut into a wall.

Central air conditioning systems

A great choice for whole-house cooling, central air conditioning systems usually consist of a large, external condenser unit connected to an indoor air handling unit and a system of ducts. Though efficient and effective, installing them in a home without existing work can be a major undertaking.

Ductless air conditioners

Also marketed as mini-split, multi-split or split-ductless systems, these devices are suited to cooling one or two rooms, though multi-room systems are available. Similar to central AC, these units consist of an outdoor condenser and an indoor air handling unit, but rather than ductwork, a single conduit line runs between the two units. As there is no need to tear apart walls and ceilings to install ductwork with these devices, they are great for older or architecturally sensitive homes.

Important terms

Before shopping for air conditioner units, you’ll want to familiarize yourself with a few terms.

Firstly, air conditioners are rated by a seasonal energy efficiency ratio (SEER). This is a measurement of an air conditioner’s efficiency – the ratio of cooling output to energy input – over a full cooling season. Higher numbers indicate better efficiency.

The British thermal unit (BTU) rating is another figure to consider. This measures the cooling capacity of the air conditioner. Units with higher BTUs will cool a given space more quickly and effectively.

The rating that has the biggest impact on your electric bill is the energy efficiency ratio (EER). This is the ratio of cooling capacity to electrical input. This rating shows how efficiently an air conditioner operates. Look for the EER rating on each unit’s yellow Energy Guide label. Ranges often run from 8 to 11.5, and 10 or higher are considered the most efficient.

If energy efficiency is a priority for you, consider a unit that is certified by the U.S. Energy Star program, which recognizes models with good SEER and EER ratings. An Energy Star-approved room air conditioner will likely be about 10 percent more efficiently than an older device, and an Energy Star-approved central unit may be 15 percent or more efficient than one without the rating. In addition to savings on your energy bills, state and local government programs may also offer rebates or other incentives for making energy-efficient choices.


Outfitting a whole house with air conditioning can be a major investment, but by choosing the right solution, you can enjoy convenient, effective, efficient and reliable climate control through the worst summer heat.