Net Zero Living | August 20, 2010 | Palo Alto Weekly | Palo Alto Online |

Palo Alto Weekly

Real Estate - August 20, 2010

Net Zero Living

Is your air conditioner affecting your family's health?

by Forrest Linebarger

Historically, most of the houses built on the Peninsula did not have air conditioners installed. Beginning in the 1980s we began to see an increase in installations.

"Today we see virtually every new home and a large portion of older homes have air conditioners installed," says Kacey Fitzpatrick of Avalon Enterprises, a Los Altos green designer and builder.

There are increasing reasons to question the benefit of this trend, particularly in moderate climates such as ours. Hardly anyone likes dry and odd-smelling air emanating from our air conditioners, but few know that these seemingly helpful appliances may have a deleterious impact on our health. Research strongly suggests that exposing our families to compressor air conditioning increases respiratory infections, including influenza viruses, colds, asthma attacks and other sinus and lung complications. Children are particularly susceptible to these types of upper respiratory diseases.

Air conditioners have been found to increase the respiratory disease by 250 percent.

"Upper-respiratory-tract infections such as the common cold are one of the main reasons for absence from work. Air conditioning circulates the air and can carry airborne bacteria and fungi." says Dr. D.B. Teculescu, who has extensively studied the effects of air conditioners on office workers. He found two-and-a-half times more respiratory illness in air-conditioned offices than in naturally ventilated ones.

An air conditioner's moist, confined environment provides a safe harbor for bacteria and molds. They also kick up dust and allergens within the house.

Contrary to popular belief, indoor air typically contains much greater levels of pollutants than outside air. By keeping our houses closed up, air conditioners trap these pollutants within the house, and increase our exposure levels.

Air conditioners are also the single biggest user of energy of all household appliances, representing 16 percent of all electricity consumed in the average home. To add insult to injury, PG&E's tiered billing system heavily penalizes AC use, often bringing one's home up to the next higher tier, resulting in energy use penalties that can more than double the cost of power.

Air conditioners also have a disproportionate impact on global warming. Power companies build our power infrastructure to accommodate energy use during peak power use. These peak loads occur during hot summer afternoons due entirely to the huge energy requirements of air conditioners. Electricity providers fire up their dirtiest, most polluting power plants during these peak times, resulting in a substantial increase in carbon emissions and air pollutants.

Some people point out that air conditioners can sometimes save lives, particularly among the elderly, who are more sensitive to heatstroke on hot days. This is true. However, air conditioners also impact our thermal regulation, making us less able to control our internal temperature when we leave air-conditioned spaces or encounter those frequent summer power blackouts.

Our reliance on air conditioners is unnecessary. We live in a Mediterranean climate, characterized by warm summer days with cooler nights. A well-built, energy-efficient house will protect against the summer sun and reflect heat away from the interior. Properly designed and insulated houses allow the cooler nighttime temperatures to be retained until early evening, when our cooling trend starts again.

Unfortunately, as a culture we have come to rely on air conditioners. Most housing built today is not designed "green," with careful solar orientation and attention to thermal performance. This is a shame.

An energy-efficient house does not need an air conditioner to maintain comfortable summer temperatures. Ironically, the overall cost of a green home is substantially the same as its poorly built brethren. Although some parts of a green home initially cost more, these costs are often offset by the elimination of the air conditioner and reduced heating requirements. Lower monthly utility bills and special tax treatment of energy-efficient building applications make green building even more attractive.

Alternatives to air-conditioner use

1. Open windows at night to let cool air in. Shut them in the morning and draw the blinds to reduce sun exposure.

2. Only use AC on the hottest days by setting the cooling temperature at 80° or more.

3. Install a whole-house fan with insulated doors to cool your house at night.

4. Insulate your home and install high-quality windows, and heat-reflecting membranes.

5. Design new homes and renovations "green" to eliminate need for AC.

Forrest Linebarger is the CEO and principal designer at VOX Design Group Inc., Mountain View. He can be reached at or at 650-694-6200 ext. 11.


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