Beneficial Home Inspection Services, Inc.

August 2008

Question: What is a whole house fan? Are they better or more cost efficient than a central air conditioner?

Answer:

In some climates, whole house ventilation using a whole house fan can substitute for the use of an air conditioner most of the year. Whole house fans combined with ceiling fans and room fans can provide enough air flow to make the interior of a home very comfortable, even in hot weather. These fans work by pulling in air from open windows and exhausting it through the attic and roof. This provides good attic ventilation in addition to whole house ventilation. Whole house fans are sized in cubic feet per minute (cfm) of ventilating power. If you're considering the purchase of a whole house fan, you can compute the size you'll need at the U.S. Department of Energy website. One drawback of this approach to cooling is the noise generated by a whole house fan. In many cases, rubber or felt gaskets can dampen noise.

If you're considering the purchase of a new air conditioning unit, products with EPA's Energy Star® label can save homeowners 10% to 40% on their heating and cooling bills every year.

When it comes to the heating and cooling components in your heating, ventilation and air-conditioning (HVAC) system, performing semi-annual inspections makes good sense.

Indoor and outdoor coils need to be cleaned as the weather gets warmer. A dirty coil will reduce the system's ability to cool a home and causes the system to run longer, costing homeowners more energy dollars and decreasing the life of the equipment. A homeowner or an HVAC professional can clean and adjust blower components to provide proper system airflow. Proper airflow over the indoor coil is necessary for efficient equipment operation and reliability. Also on the check list should be routine monitoring of the refrigerant charge. The charge can be adjusted to meet manufacturer specifications. Too much or too little refirgerant charge can damage the compressor, reducing the life of the equipment and increasing costs. It's estimated that more than sixty percent of central air conditioners are incorrectly charged during installation.

A check of the condensate drain in the central air conditioner is important, because if the drain is plugged, the subsequent water damage can affect the interior of the home, as well as breed bacteria and mold.

Air filters also need to be cleaned or changed, and can usually be done by homeowners. Filters can be found in the duct system or the air conditioning unit itself. A dirty filter will cause energy costs to be greater than they should be.

Ceiling fans throughout the home can help reduct cooling and heating costs. In the summer, use the ceiling fan in the counter-clockwise direction. The airflow produced creates a wind-chill effect, making it "feel" cooler in the room. In the winter, reverse the direction of the motor to clockwise and decrease the speed of the ceiling fan to a low setting. This produces a gentle updraft, forcing the warmer air near the ceiling down into the room.

Ducts are an integral part of a central air conditioning system, and they work to circulate heated or cooled air evenly to every room in a house. Poorly performing ducts can leak conditioned air and reduce a system's efficiency by as much as twenty percent, by causing it to work harder to keep a home at a comforable temperature.

Finally, a programmable thermostat is recommended for individuals and families who are away from home during certain periods of time throughout the week. Temperatures are adjusted by the thermostat to allow for temperature fluctuations, yet keep the home at a comfortable termperature when occupants are home. To increase energy savings, it's important for homeowners to set the thermostat at energy-saving temperatures for long periods of time, such as during the day when no one is home. These thermostats come with four pre-programmed temperature settings for typical weekday and weekend patterns.