Editor’s note: This is the second of a two-part series on natural ventilation and cooling tips.
With natural ventilation the trick is to open a building to the elements when the outside conditions are within the right temperature and humidity range to provide comfort, and then shut it down when they are not favorable. The Laguna climate cools off at night, so turn off the cooling system and open your windows while sleeping, and in the morning shut the windows and blinds to capture the cool air.
A building should respond to its place, maintaining a dialogue with its surroundings to enrich our experience at all levels. Laguna Beach has ideal conditions for natural ventilation and cooling. The prevailing breezes are consistently on-shore from the west and southwest throughout the year, and the relationship between the city grid and the onshore winds allows for use of natural ventilation for most parts of the city.
During the day, use fans to make indoor temperatures feel cool, and turn them off when you leave the room. For those with an attic, the installation of a fan draws cooler air into the home and forces hot air out through vents. Use it when the air is cool outside, such as in the early morning.
Buoyancy — also called “stack effect” — can induce natural cooling and ventilation within a building, as warm air rises and, if allowed, exits from the top of the building. Pressure differences due to buoyancy are directly proportional to both height and the temperature difference between incoming and outgoing air. Natural cooling should be examined on a whole-building basis to ensure airflow paths.
When considering its use, openings must be carefully sized, placing smaller openings at lower floors and larger one on upper floors to provide equal ventilation rates.
For those HVAC addicts, setting the air conditioner five degrees higher will save as much as 20% on cooling costs. Installing a programmable thermostat can save as much as $115 per year and perform functions such as repeat multiple daily settings or turning on the AC when outside temperatures change.
Checking AC settings to be sure that the “fresh air” vent on the air conditioner is closed so you are not cooling outside air; removing and cleaning filters regularly (dirty filters reduce HVAC efficiency), or having ducts professionally sealed can improve savings even further.
Weather stripping around openings to reduce drafts, and sealing the envelope, can provide an additional 10% savings on energy bills. Also, if your old air conditioner breaks down, an ENRGY STAR model can cut 20% to 40% off cooling costs.
It should be stressed that there is no such a thing as one perfect “green” solution or technology. Comfort needs to be evaluated on a building-by-building basis for a solution that is efficient. What is a fact is that a naturally ventilated building can be more comfortable and use significantly less energy than its mechanical counterpart. I am not looking to return to the old days, but to a responsible use of technology, and to understand that the unique characteristics of a place are to be celebrated and honored.
Summer is around the corner, and by spending a small amount on efficiencies you can save big.
GUSTAVO GRAD is a Laguna Beach resident and certified sustainable building advisor. He can be reached at firstname.lastname@example.org