SEER Ratings: SEER stands for Seasonal Energy Efficiency Ratio, and is a measurement of the energy efficiency of an A/C system. The higher the SEER rating, the more money you will save in electric bills.
BTU’s: British Thermal Units. The term “BTU” is used to describe the heat value (energy content) of fuels, and also to describe the power of heating and cooling systems such as furnaces, stoves, barbecue grills, and air conditioners.
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Ton: You may hear people referring to A/C units in terms of “tons”. In North America, a standard ton of refrigeration is 12,000 BTU /h = 200 BTU/min ˜ 3,517 W . This is approximately the power required to melt one short ton (2,000 lb. ) of ice at 0 °C in 24 hours, thus representing the delivery of 1 ton of ice per day.
Manual J Load Calculation: The industry standard for residential HVAC building load calculation, developed by ACCA.
Degrees of Comfort: The Capacity Question: How much power do you need? Maybe not as much as you think. Yes, you want something that can do the job of cooling you off fast. But an air conditioner that cools too fast is actually not a good thing. Here’s why: If the machine cools the space quickly, it will cycle off and back on again more frequently than a smaller unit that runs more consistently. Those short bursts of cooling aren’t adequate to dehumidify the air, so you can end up with a room that feels cool but damp, which is neither pleasant nor a good use of your power.
The cooling capacity of a AC unit is measured in British thermal units per hour (Btu/h). Gulf Coast will provide you with a chart to help you find the best size for the square footage of your home; you can also find one on the Energy Star web site. As an example, for a room that’s 280 square feet in size, you’ll want a 7,000 Btu/h model. If the room is heavily shaded (by thick draperies or by trees and other landscaping elements outside), you can go about 10 percent smaller; if the room is very sunny, you’ll probably want to go about 10 percent larger. You’ll also need to consider where you’ll use the air conditioner. A Manual J load calculation can be performed free of charge by one of our comfort consultants to help you determine the best fit for your home.
Here in the Tampa area, we live in a climate known for hot, wet summers. “You want to balance the actual cooling effectiveness with dehumidification effectiveness,” says Alex Wilson, co-author of Consumer Guide to Home Energy Savings, published by the American Council for an Energy Efficient Economy (ACEEE). “Removing moisture is an important part of the cooling process, as it deals with the latent heat in moist air.” This is especially true here in Florida. Fighting that moisture is part of the job of a good air conditioner, but some do it better than others. Choosing the correct capacity will help. Beyond that, you’ll want to look at the available features. Some very efficient machines with high fan speeds cool quickly, leaving dampness behind. It can be useful to choose an air conditioner with an optional low fan speed, as well; it will cool less quickly but will fight moisture better on those really humid days.
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