1. dishwasher
   refrigerator
2. oven

Air conditioners are basically just refrigerators, but they make the space outside them cool, while fridges keep the space inside them cool.

1. dehumidify
   humidify
2. sterilize

Air conditioners also work as dehumidifiers. Less humid air feels cooler.

1. size
   age
2. exterior material

The size of your home determines what type of air-conditioning system is best for cooling your home.

1. price
   energy efficiency
2. size

Most consumers are very price-conscious when purchasing an air conditioner. A split unit, used in most homes, costs thousands of dollars.

1. split unit
   cooling tower
2. window unit

A window unit is an easy and affordable way to cool a small space. Choose a window to install it in and you're well on your way to chilling out!

1. Parts of the unit are installed inside and outside the home.
   Parts of the units are installed on different floors of the home.
2. Parts of the unit are interchangeable with other home appliances.

In a split air-conditioning unit, the noisy compressor is located outside, and the air handler is inside the home.

1. They use different coolants.
   They use different types of thermometers.
2. There is no difference.

There is no significant mechanical difference between a window unit and a larger split unit; they both operate the same way.

1. filter
   air handler
2. air compressor

The filter is a very important part of the air conditioner because it cleans dust, pollen, mold and other allergens from the air. Be sure to change your filter frequently.

1. basement
   attic
2. roof

Some buildings have their air compressor on the roof. Have a look the next time you are taking off in a plane.

1. It will help you calculate energy costs.
   If you know the Btu, you can convert it to the American thermal unit rating.
2. It will help you determine how long the air conditioner will last.

A British thermal unit (Btu) is the amount of heat needed to raise one pound of water one degree Fahrenheit. It's a standard unit of efficiency measurement in heating and cooling systems.

1. higher
   lower
2. Energy efficiency doesn't affect price.

The higher the efficiency rating, generally the higher the price. A system with a high rating might pay for itself over time.

1. chilled water units
   window units
2. split units

Chilled water air-conditioning systems are the least costly of these very expensive systems.

1. ground source heat pump
   split unit
2. cooling tower

The most energy-efficient cooling system, and also the most environmentally friendly, is the ground source heat pump.

1. manufacturer rebate
   federal tax credit
2. lowered electricity bill

You can recoup the cost by saving money on your electric bill, but it may take several years to do so.

1. electricity
   an air-conditioning unit
2. a temperature that's actually lowered

Passive cooling is a method of cooling your house without an air-conditioning unit. Some passive cooling methods include heat shielding, landscaping, ceiling fans and good insulation.

1. Give everyone in your home paper fans.
   Open the windows on nice days to create airflow.
2. Put reflective tape over all windows.

A popular passive cooling method is to open windows and create airflow. Let some fresh air in!

1. Compressors cannot be on the roofs of multifamily buildings.
   Each living unit has its own compressor.
2. Building codes require all compressors to be installed together.

Apartment buildings and other multifamily homes have a compressor for each living unit.

1. There is a campuswide central air-conditioning system.
   Each building has its own air-conditioning unit.
2. Each building has window units on every floor.

Large campuses such as a university have a central cooling unit and run pipes with chilled water to different air handlers.

1. Ice is needed to keep the compressor cool.
   Ice is needed to keep the refrigerant cool.
2. It's a new "green" method of air-conditioning.

Ice cooling is a new "green" type of air-conditioning. It involves freezing water into ice overnight when electricity rates are lowest and then blowing fans over the blocks of ice.

1. 30
   300
2. 3,000

As of 2007, there were more than 3,000 ice coolers worldwide, according to New York state officials. They're expensive to install but help reduce air pollution and are easier on the power grid than traditional air conditioners.