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To get the most out high-efficiency cooling equipment, builders and HVAC professionals need to be sure they are following efficient building design and installation practices. The following are a few best practices builders and their contractors can follow to pass the most energy savings on to their homeowners:

  • Start with a tight building envelope. Because a home operates as a system, the first step in optimizing the cooling system is to insulate and air seal as much as possible. Advanced framing techniques, continuous air barriers, and high efficiency windows are a few ways to reduce leakage and ensure that cold air stays inside where it belongs.
  • Properly size equipment and ductwork based on Air Conditioning Contractors of America (ACCA) standards. Accurate calculation of the home’s cooling load is critical to system efficiency and room comfort. A unit that is too large will not adequately remove humidity, and a unit that is too small not unable to attain a comfortable temperature on the hottest days. Most professionals use ACCA’s Manual J load calculation, which determines system size on a wide range of factors such as the local climate, window orientation, and insulation levels. Gone are the days of sizing a unit based on square footage or other “rules of thumb.”
  • Focus on ductwork design. Some experts believe that ductwork design can be just as important as equipment choice when it comes to cooling system efficiency. Minimize the length of the duct runs and place ductwork in conditioned space as much as possible (i.e., avoid attics). In unconditioned spaces like basements, be sure to insulate ductwork.
  • Duct sealing is also critical. According to Energy Star, in a typical house, about 20 percent of the air moving through the duct system is lost due to leaks, holes, and poor connections. Be sure that contractors properly seal ductwork, especially at connections to air inlets and registers where air can seep into walls and create moisture problems.
  • Design adequate returns. Working with contractors to ensure there are enough supply registers to deliver cool air and enough return air registers to carry warm house air back to the air conditioner.
  • Properly locate condenser and air handler. Place the condensing unit outdoors where no nearby objects will block airflow. Install the indoor air-handler in a centralized location to minimize duct runs and to allow for easier access for preventative maintenance.
  • Once installed, verify that the equipment has the proper refrigerant charge and airflow rate as specified by the manufacturer. Air-conditioning systems and heat pumps suffering from improper refrigerant charge can cause problems that range from reduced operating efficiency to system freeze-up. Measure the airflow of each room to make sure everything is running properly and that all rooms are comfortable.