DIY Network

The Basics of Air Conditioning

Blueprint for Home Building host Jeff Wilson concentrates on "cooling" the air in a home and explains how to choose an air-conditioning unit based on efficiency, climate and noise.

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choose correct air conditioning unit for home

The home heating, ventilation and cooling system (HVAC) consumes about 40 percent to 50 percent of all the electrical power in a house, so the efficiency of the HVAC system is extremely important to the overall power draw of the home.

What Is HVAC?
HVAC is an acronym for indoor air. So remember that when a builder or subcontractor uses the term "HVAC," he or she is talking about the entire air system of the home.

Air Conditioning Units
AC units can be compared on a multitude of dimensions. Certainly efficiency is one of the main drivers, and given what's happened lately with the cost of gas and electricity, efficiency has become extremely important.

In general, there are three factors to be aware of when selecting an air conditioning system:

1. Efficiency -- Buy the most efficient air conditioning unit available, especially in the desert Southwest. Efficiency refers to how much energy the system will require to do its job. HVAC specialists use what are called "S.E.E.R" numbers to rate and compare different cooling systems. SEER stands for Seasonal Energy Efficiency Rating. This is a standardized test, and the higher the SEER number, the more efficient the air conditioning unit is. Now the minimum efficiency, the builder's model, is rated a 10 and they go all the way up to 18. So make sure the air conditioning unit has a rating of 10 or higher.

2. Regional Climate -- When designing a home, it's important to know the external factors that will need to be solved. In the desert southwest, it's one of high summer heat. In the northwest, it may be one of damp, cold winter weather. In the northeast, it's most likely frost in the winter and high humidity in the summer.

3. Noise -- Internal sound is just as important as the sound coming externally from an air conditioning unit that's installed outside the kitchen or living room window. Be sure to purchase a unit that's as quiet as possible.
With all three of these areas, the builder and air conditioning distributor can help point you in the right direction.

Addition to the Home Building Team
The next person to join the home building team is an HVAC contractor, and the builder will hire him. Not only will he oversee the installation process, he or she will also make sure that one of the important elements of a good AC system -- its ability to create sufficient air movement throughout the house -- is included.

Note: Having proper return air and supply air is 100-percent dependent upon the installing contractor. So having a good, qualified HVAC contractor is the first and primary concern when installing an HVAC system.

"The first thing about being on the job site and being in charge is to make sure that everything goes in safely," Gary Ostler, president of Four Season Heating & A.C., Inc., said. "After that is to make sure that everything gets done properly and, upon completion, that it works properly."

Although your builder or architect will be able to recommend an HVAC contractor who they've worked with before, there are a few other ways to find one:

  • A referral from a friend or neighbor is the best way.

  • Phone book.

  • Websites and other research options.

The HVAC contractor should come in as soon as the plans are drawn so that they can site the equipment, leave room for ducting and let the contractor know the requirements for plumbing and electrical.

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