Efficient Home Cooling
Conservation means sweating with the air conditioning off. Efficiency means installing a more efficient AC unit, and using an automatic thermostat to save energy when you are away from home. A national standard issued by the Department of Energy in January, 2001 mandated a 30 percent efficiency increase in air conditioners, which would prevent the need for 138 300-Megawatt power plants. A Bush Administration rollback of that standard to a 20 percent improvement would have forced us to build 43 of those plants (these are peak-coincident numbers). But a federal appeals court decision in January, 2004 upheld the 30 percent increase in efficiency. By 2020, the higher energy efficiency standard for central air conditioning systems is expected to cut consumer electricity bills by $1.1 billion a year.How We Can Reduce 1,300 Power Plants to 490: Conservation vs. Efficiency. 16 May 2001
Buildings consume two thirds of our electricity. Most of that energy is not used by lights or computers, but by motors for refrigeration and cooling. A graph of California's electricity demand shows that usage peaks in the mid afternoon when appliances and air conditioners kick in, not during the evening hours when lights are turned on. Notice that peak utility loads are during hot summer days (when solar thermal power plants would be most effective), not during evening hours when more lights, even Christmas lights, are turned on. Yes, you should still convert commonly used bulbs to compact fluorescents at save 75 % on your lighting bill. However, your refrigerator and air conditioner use the bulk of your electricity. You will save the most money by making these two items more efficient. Plus, you pay more for peak-load power compared to base-load electricity.
There are many steps you can take to reduce your energy bill and stay comfortable. The efficient use of energy can help maintain a lifestyle without wasting resources, and save 10 to 30 percent off air conditioning bills. Efficiency can also help to significantly reduce the peak electrical demand which may cause blackouts during hot, summer months. Too much of our generated electricity is wasted during those peak times since it is being used to cool overheated roofs and crawlspaces, and not people. The following suggestions will improve the amount of cooling provided to you.
- Light colors reflect heat. Paint flat roofs with white rubberized roof coating to reduce the temperature of the roof. The estimated energy savings is ten percent. These coatings will also extend the life of your roof and insulation. Cool roof strategies are the first priority in creating a cool, comfortable living space, regardless of that active cooling system is used for the building.
- Removing heat from the attic crawl space is a must. The temperature should not rise above 110° F in the attic. If your attic crawl temperature reaches 140 degrees (which is not uncommon for a poorly vented attic space), then your cooling system has to reduce the temperature in your living space by roughly 60 degrees. Install passive roof turbines or powered attic fans equipped with thermostats. Solar powered attic fans are available and often rebates are available from local utility companies. Many roofing material warranties require that steps be taken to reduce the attic temperature. This step alone can reduce the air conditioning load by ten percent. If your attic crawl temperature reaches 140 degrees, then your cooling system has to reduce the temperature in your living space by roughly 60 degrees. If you . To help prevent fires, install wire mesh that is no bigger then 1/8 inch on all roof vents. Blowing embers from nearby fires can enter the attic space through roof vents. Wire mesh will catch the embers before they enter the attic or crawl space.
- Shade the air conditioner itself so that the unit is not working to cool itself off. The estimated energy savings is 10%.
- When you replace your air conditioner, make sure it is at least efficiency rated at SEER (Seasonal Energy Efficiency Ratio) 14. Do the math to calculate the actual cost of ownership of more efficient air conditioners and you will find that they will often pay for themselves in 3-5 years, and continue to offer savings for the next 10-15 years.
- Check that the duct work is not leaking, especially around vents where poor connections can allow cooled air to enter crawl spaces, walls, and other unused living areas. You may need to professional to completely inspect your duct work delivery and return system.
- A whole-house fan is more efficient then an air conditioner for climates that are usually under 100 degrees F. By opening some windows and turning on the fan, cooler outside air is actively circulated into the house and hot, trapped air is forced out. re
- Install insulation in the attic, at least R19. Keep heat from entering the living space. Again, cool roof strategies are the first priority in creating an efficient, comfortable living space.
- Block heat and light from entering the house through windows. Shade windows with awnings.
- Install blinds, screens and/or window films that block light and heat from entering windows. Blocking ultraviolet light can also help prevent fabrics and furniture from fading.
- Plant trees that will shade the roof. The best locations are on the east and west side of the house. Native trees are preferred, especially species that do not require a lot of water. Shade trees can create microclimates which can reduce local temperatures by over 15 degrees. See the TreePeople for some suggestions. Many cities and utilities (see LADWP) offer free trees through tree planting programs. TreePeople worked on a retrofitting project at the Broadous Elementary school in Pacoima, California that through the shading and cooling of the buildings and their air conditioning units will reduce energy consumption by 18%.
- Take advantage of natural breezes. Keep windows closed in the morning when it is hotter outside then inside. Open the house after sunset when temperatures cool. Plant trees and shrubs to help direct breezes into the house.
- Installing fans does not reduce the temperature, but they can give the impression of cooler temperatures and help you feel more comfortable. Hunter Fan claims that ceiling fans can make you feel eight degrees cooler.
- Don't cool what you don't use. Close off air conditioning vents to rooms that are not used often. Use a programmable thermostat to turn off the A.C. during hours that you are not home, such as during work or school hours.
- The most important air conditioning maintenance tip is to replace the filters regularly. This alone can save 10% on air conditioning costs. Get the best filter that you can afford and you will probably also experience a more dust-free household. Good filters also help to maintain your air conditioner and duct work. In fact, Consumer Reports suggests trying good quality air filters before you invest in an indoor air cleaning system. You may find that better air filters provide the improved air quality that you are looking for. Check these 11 issues that should be serviced also.
Related Links
- Cool Roofs: Cool Roof Rating Council, California Cosumer Energy Center.
- Wikipedia air conditioning
- SEER air conditioning information: SEERS rating expalined, top-rated air conditioners, Buying vs. Replacing , SEER regulations backgound.