Saving Big Bucks on Summer Utility Bills

Rice Terraces in Nepal

Scott Sturman
fliesinyoureyes.com

I live in Fresno, California, which is known for its hot summers, but never use the air conditioner to cool the house. Nothing is a bigger waste of money than utility bills or as shocking as when the bill arrives in the mail. For those living in hot, dry climates the simple clothes line and the whole house fan save hundreds of dollars per month.

Compressors used in air conditioning units and heating elements are the two largest energy consumers in residential property. Limiting their use results in substantial savings. Lower energy bills when using a clothes line rather a drying machine is obvious. However, the efficient use of a whole house fan bears some discussion.

For the system to work efficiently, the house must be well insulated, particularly the ceiling where the sun transmits most of its energy. Our house was constructed with R-30 insulation in the ceiling, but my wife and I installed additional R-38 batts on top of the old insulation. Being an older house, the walls are insulated with R-13. It is difficult to supplement this, so we planted either vines or bushes near the walls which receive direct sunlight. Large trees surround the house, but they are a sufficient distance away that they do not shade the R-70 insulated roof when the sun is high in the sky. The advantage of this placement is less leaf drop on the roof and shade for the walls before 10 AM and after 4 PM when the sun is low enough in the sky to shine directly on the them.

All rooms in the house have ceiling fans. Thermal glass is preferred but not necessary provided the sun does not strike windows or glass doors directly. Curtains, shutters, or trees are a less expensive option.

In the summer when daytime temperatures typically rise to 100 degrees and night time lows fall to 65-70 degrees, inside house temperatures rarely exceed 80 degrees. In the evening as soon as the outside temperature reaches the low 80’s, open several screened windows and doors, and activate the whole house fan. The fan replaces warm air inside the house with cooler air from outside. The fan vents through attic and forces this torrid air into the atmosphere through vents in the roof. The house becomes progressively cooler as the fan continues to run throughout the night until the next morning when the outside temperature exceeds the indoor temperature. At this point the fan is turned off and the house is shut tightly until the next evening. It is important to run the fan all night long, so solid structures in the house which have high heat capacity will have time to cool. This latter point cannot be stressed enough. The point of the house fan is not only to exchange air but to cool indoor structures which serve an heat sources.

A couple of suggestions are in order: Whole house fans tend to be noisy, so if one is a light sleeper it is best to place them away from bedrooms. However, the lower summer utility bills soon will make for a restful sleep even with the fan roaring in the background. Secondly, in order to maintain security in the house at night it is best to leave only windows open which have a robust screen or grating which will deter criminals but allow for the free passage of air.

The temperature of the air within the house will rise slowly throughout the day, but as long as doors and windows are shut, the temperature will remain tolerable. Think of this oasis of cool air as a pot of gold. It’s worth protecting and admonishing anyone leaving a door or window open during the heat of the day.