Healthy Cooling System
If you are purchasing a house or condominium, air conditioning (A.C.) certainly is a feature, but just the presence of cooling does pose some issues for both the buyer and the homeowner. For example, in the winter, it is simply impossible for a home inspector or anyone to test or guaranty the operability of a system. If a seller is willing, either a condition can be left in the purchase and sale for testing the system when suitable weather occurs; or money can he held back from the closing if there is some question about the condition of a complex system. Maintenance of A.C. systems is far more important than heating systems; if a seller does have a service company, find out if the seller is willing to allow the company to supply you with relevant information.
Apart from inadequate capacity or distribution, the biggest problem with A.C. is the air quality. How often have you noticed the odor of sweat socks when an air conditioner was turned on? Probably more than once. The odor is a sign of a problem and the cause is worth looking at.
The big difference between heating and cooling is that in the summer, you can’t just lower the temperature of air the way you can raise it in winter. Summer air is humid and when it is cooled, the air reaches its dew point and moisture condenses on the cooling coils. This is the water you see dripping from window A.C. units. Central units also condense water from the air, but the water is collected in hidden drip pans. The water is then either allowed to flow by gravity into drains; or into pumps which discharge the water to the exterior.
Condensation water is one reason why A.C. maintenance is so important. If water accumulates in a drip pan that is clogged, the overflowing water can do all sorts of damaging work. It can rust out and destroy the heat exchanger (if above a furnace) or it can drip onto the blower unit and create damp conditions conducive to mold growth.
The worst situation created by condensation occurs when there has been inadequate filtration of air flow through the A.C. system; unfortunately, poor filtration is the rule rather than the exception, and both portable and central A.C. units suffer. The result of poor filtration is a build-up of biodegradable dust on the A.C.cooling coils. The dust blocks the flow of air but worse still, it provides a substrate for biological growth as soon as the it is wet by the condensation water.
I often find A.C. coils severely contaminated with mold and/or bacteria. A small portion of these biological materials become airborne every time the system operates, particularly during start-up. The odor associated with A.C. systems is the odor associated with the growth of these organisms.
Here are some suggestions to avoid problems:
1. Have the A.C. coils on both portable and central A.C. units cleaned annually.
2. In central A.C. systems, install the best and most efficient filter you can afford.
3. If possible, replace any fiberglass liner that has been wet and is stained.
4. In new construction or remodeling, keep the A.C./heat off during dusty work.
5. Protect return ducts from debris at all times.
6. On new installations, be sure that the evaporator coil is accessible for cleaning.
For now, keep in mind that if you have mold allergy or asthma, the debris in heating or cooling systems can be extremely irritating; you should not attempt to clean this equipment yourself. Next month, we’ll look at duct cleaning.