1. He now has a cool, clammy, uncomfortable store.

2. His utility bills do not drop.

3. In a very short time the black stuff returns on the air grills. Now it is also on the walls and he recalls that his insurance policy covers the presence of mold and mildew. Mr. “P” still suffers from his allergies and is most unhappy. He phones his insurance agent for help.

ENTER TECHNOLOGY MAN! He is called by the insurance agent to determine if the claim to remediate the mold and mildew damage is to be paid or denied. A thorough computerized comfort analysis is done to the store and the following is discovered:

1. Up-sizing the air conditioning system has caused short cycling. By the time the evaporator coil cools enough to begin to remove the moisture from the air passing over it, the thermostat is satisfied and the unit stops. The volume of air passing over the coil is not sufficient to remove the moisture from the conditioned air, resulting in a cold humid store.

2. The cold registers had condensed moisture and created a perfect environment for mold, mildew, and dust mites to grow.

3. The return air duct is not sealed and is drawing hot humid air from the attic. Some of the flex duct in the attic had deteriorated and is leaking conditioned air into the attic. His high efficiency system is operating at very low efficiency due to the air leakage.

The “fix” is as follows:

1. A heat load calculation according to “manual J”, or “manual N” should be done on the store to determine the ideal size for the system to not only cool the air, but also to run long enough to filter the air and to extract enough moisture to maintain a comfortable 40% to 45% relative humidity. A three and a half ton would have done the trick. This eliminates the moisture from collecting on the air grills and inside the ductwork. Therefore, the mold, mildew, and dust mites are deprived of one element they need to survive and grow – moisture.

2. The air ducts should be replaced as the mold and mildew can not be effectively removed from the existing duct system. The new duct system should be totally sealed and designed to distribute air to each room according to the CFM specified by the load calculation.

3. The store conditioned envelope should be sealed to allow .35 exchanges of air per hour. More than that makes the air conditioning system work longer and harder to maintain the temperature desired, increases cost, and allows hot humid unfiltered air to enter the envelope. Less than that makes for stale air and a “sick building”.

If Mr. “P” had called THE TECHNOLOGY MAN in the first place, he would have saved himself money and had the job done right in the first place. Proper air conditioning installation is as important in achieving comfort as the quality of the equipment itself.

Before purchasing air conditioning equipment, consider doing the following:

1. Ask your contractor for a copy of the heat load calculation and make sure the equipment is sized properly

2. Have your contractor do a thorough inspection of the air distribution (duct) system preferably done by measuring the static pressure of each duct run to make sure all the conditioned air is getting to the right places.

3. Have your contractor do a thorough building inspection to make sure the conditioned envelope is not infiltrating “bad” air either from a hot attic, or from a moist crawl space.