Air Conditioners

Low price and high efficiency make room air conditioners an inexpensive alternative to central air for cooling one or two rooms. By choosing an energy star qualified air conditioner, it would prevent 1.2 billion pounds of greenhouse gas emissions, the equivalent emissions from 100,000 cars. Energy star qualified room air conditioners often include timers for better temperature control, allowing you to use the minimum amount of energy you need to cool the room.

Many people buy an air conditioner that is too large thinking it will provide better cooling. However, an oversized air conditioner is actually less effective and wastes energy. A properly sized unit will remove humidity effectively as it cools.

Using the square footage and the chart below, determine the correct cooling capacity. Cooling capacity is measured in British thermal units (BTUs) per hour.

Area To Be Cooled (square feet)	Capacity Needed (BTUs per hour)
100 to 150	5,000
150 to 250	6,000
250 to 300	7,000
300 to 350	8,000
350 to 400	9,000
400 to 450	10,000
450 to 550	12,000
550 to 700	14,000
700 to 1,000	18,000
1,000 to 1,200	21,000
1,200 to 1,400	23,000
1,400 to 1,500	24,000
1,500 to 2,000	30,000
2,000 to 2,500	34,000

Make any adjustments for the following circumstances:

• If the room is heavily shaded, reduce capacity by 10 percent.
• If the room is very sunny, increase capacity by 10 percent.
• If more than two people regularly occupy the room, add 600 BTUs for each additional person.
• If the unit is used in a kitchen, increase capacity by 4,000 BTUs.

Dehumidifiers

Condition without Dehumidification	Area (Sq. Feet)
	500	1,000	1,500	2,000	2,500
Moderately Damp (space feels damp and has musty odor only in humid weather)	10	14	18	22	26
Very Damp (space always feels damp and has musty odor. Damp spots show on walls and floor.)	12	17	22	27	32
Wet (space feels and smells wet. Walls or floor sweat, or seepage is present.)	14	20	26	32	38
Extremely Wet (laundry drying, wet floor, high load conditions.)	16	23	30	37	44

Dehumidifier capacity is usually measured in pints per 24 hours and is determined by two factors- the size of the space that needs to be dehumidified and the conditions that exist in the space before dehumidification. Use the chart below to estimate the capacity you are looking for. The energy efficiency of dehumidifiers is measured by its energy factor. A higher energy factor means a more efficient dehumidifier.

Source: Association of Home Appliance Manufacturers (AHA)