Equipment Size

It is important that new or replacement equipment not be sized by “Rule of Thumb” or by the existing equipment. The only accurate way to determine the correct capacity of heating and air conditioning equipment for your home is to have a heat load calculation performed on your home. This will determine the design data for your home. These figures can then be used to select the appropriately sized cooling system for your home, based on equipment performance data.

Many factors determine the size (capacity) system your home requires. Some of these are:
• square feet to be cooled and heated
• climate
• humidity
• number of windows
• insulation factors
• which direction your home faces
• attic and outdoor air infiltration
• heat producing appliances, and
• the number of people who will be in the home

Oversized cooling systems will not remove adequate moisture from the indoor air due to short cycling. Oversized systems quickly cool the indoor air temperature, but they do not run long enough to remove the humidity. They leave you feeling stuffy and uncomfortable. Comfort is rarely achieved and electricity consumption is higher than with a properly sized system.
An undersized cooling system will not adequately cool your home on the hottest days and an undersized furnace will not adequately heat your house on the coldest days.

The capacity in tons of the outdoor unit can be determined by dividing the 7th and 8th digit of the model number by 12, such as 4A7A4036A1000A - 36 divided by 12 = 3 tons. Central air conditioners are more efficient than room air conditioners. In addition, they are out of the way, quiet, and convenient to operate.
To save energy and money, you should try to buy an energy-efficient air conditioner and reduce your central air conditioner's energy use.

If you have an older central air conditioning system, and you choose to replace your air conditioning system with a modern, high-efficiency system, consult with Art Plumbing & Air Conditioning, Inc. to assure that the new system is properly sized to your home.
Today's best air conditioners use 30%50% less energy to produce the same amount of cooling as air conditioners made in the mid 1980s and 90’s. Even if your air conditioner is only 10 years old, you may save 20%40% of your cooling energy costs by replacing it with a newer, more efficient model. Proper sizing and installation are key elements in determining air conditioner efficiency. Too large a unit will not adequately remove humidity. Too small a unit will not be able to attain a comfortable temperature on the hottest days. Improper unit location, lack of insulation, and improper duct installation can greatly diminish efficiency.
When buying an air conditioner, look for a model with a high efficiency. Central air conditioners are rated according to their seasonal energy efficiency ratio (SEER). SEER indicates the relative amount of energy needed to provide a specific cooling output. Many older systems have SEER ratings of 6 or less. The minimum SEER allowed today is 13. Look for the ENERGY STAR label for central air conditioners with SEER ratings of 13 or greater, but consider using air conditioning equipment with higher SEER ratings for greater savings.
New residential central air conditioner standards went into effect on January 23, 2006. Air conditioners manufactured after January 26, 2006 must achieve a Seasonal Energy Efficiency Ratio (SEER) of 13 or higher. SEER 13 is 30% more efficient than the previous minimum SEER of 10. The standard applies only to equipment manufactured after January 23, 2006. Equipment with a rating less than SEER 13 manufactured before this date may not be sold and installed.
The average homeowner will remain unaffected by this standard change for some time to come. The standards do not require you to change your existing central air conditioning units, and replacement parts and services should still be available for your home's systems. The lifespan of a central air conditioner is about 10 to 15 years. Manufacturers typically continue to support existing equipment by making replacement parts available and honoring maintenance contracts after the new standard goes into effect.

Effective January 2010 all air conditioning equipment manufactured, sold and installed in the United States must use R410A as the systems refrigerant. R410A is a chlorine free refrigerant that will not deplete the planets Ozone layer, like it’s predecessor R-22.
R410A is considered a green refrigerant. As time goes on the availability of R-22 refrigerant will become less and less, therefore the cost of R-22 will increase.
When choosing a new air conditioning system you should consider choosing a system that uses R410A.

• A programmable thermostat so that you can set your homes temperature to a higher setting while you are out of the home and to a lower setting when you are home., thereby saving you money on your homes energy costs.

• A variable speed air handler for your new system, which gives you better de-humidification.

• A unit that operates quietly.

• A high quality air filter to reduce dust in your, so that your lungs do not have to filter he air you breath, and to protect your new equipment.

• A filter check light to remind you to check the filter after a predetermined number of operating hours.

• An automatic-delay fan switch to turn off the fan a few minutes after the compressor turns off, this protects your systems compressor.