Energy Performance Score

Today, more than ever, homebuyers and builders are placing high value on energy efficiency and carbon footprint. Efficient homes offer superior performance, lower operating costs and a reduced environmental impact. But how do you compare newly built homes based on their energy consumption?

The Energy Trust of Oregon assigns an Energy Performance Score (EPS) to rate the efficiency of a home and measure it against similar-sized homes in Oregon. The lower the score the more efficient the home. The score can range from zero to over 200, with zero being the best possible rating.

EPS Score Contributors:

• Improved InsulationExplanation: Insulation is given an “R-Value” rating that reflects its resistance to heat flow. The greater the number, the better the insulating quality. Properly installed floor, ceiling and wall insulation help keep heat inside during winter and outside during summer. EPS homes have an R-value of at least R-49 for ceilings, R-23 for walls and R-30 for floors.

• Envelope Tightness: Tight construction focuses on preventing air from entering and leaving the home in an uncontrolled manner from unplanned locations like garages and crawlspace. Building tighter homes helps ensure that unwanted pollutants don’t enter the home and heated/cooled air doesn’t leak out. Tightness is tested using a blower door test which indicates the home’s air changes per hour, ACH. This represents the number of times the complete air volume of a home is exchanged for outside air each hour. A low number denotes a well-sealed home with fewer air leaks, resulting in increased energy efficiency overall. Typically, a newly built EPS home averages 5.0 ACH.

• Properly Sealed Ducts: Properly sealed ductwork reduces the potential for heat loss from ducts leaking into unconditioned areas such as attics and crawlspaces. It also keeps the air in the home cleaner, helping to reduce allergens and potential moisture problems.

• Efficient Windows: U-Value indicates the rate of heat loss in windows; a lower U-Value demonstrates the effectiveness of a window, resulting in a more comfortable home. Lower U-Value windows result in a more comfortable home and greater energy efficiency. EPS homes have windows with a value of at least U-0.30.

• Water Heating Efficiency: Measured by “Energy Factor;” the higher EF, the more energy efficient the model. In an average home, water heating may account for up to 30 percent of a home’s energy consumption depending on user behavior. Higher EF water heaters can significantly reduce the home’s overall energy consumption.

• Advanced Framing: Advanced Framing is a technique where builders reduce the amount of lumber needed to build walls, floors and ceiling while maintaining structural integrity and improving the overall thermal performance of the wall.

• Lighting & Appliances Explanation: Many appliances and energy-efficient lighting choices are made after the home is purchased. EPS homes require that the dishwasher and lighting must meet certain energy efficient requirements at the time of construction. Energy Trust offers cash incentives to homeowners that purchase qualifying energy-efficient appliances.

• Efficient Heating, Cooling, & Ventilation  Explanation: The energy efficiency of appliances and mechanical equipment is measured in different terms. Reference the list below to find brief descriptions of these terms and the information they provide:
  • Gas furnace efficiency is measured using Annual Fuel Utilization Efficiency, AFUE, a laboratory-derived efficiency rating for heating appliances. A higher AFUE indicates a more energy-efficient model.
  • Heat pumps are fueled by electricity and provide heating and cooling to a home. Heat pump efficiency is rated using a Heating Seasonal Performance Factor, HSPF. A higher HSPF indicates a more energy-efficient model.
  • Air conditioner efficiency is rated using Seasonal Energy Efficiency Ratio, SEER. The higher the SEER rating, the more energy efficient the cooling.

• Solar Explanation: Solar panels use the sun to generate electricity to help power the home. A solar electric system reduces the amount of electricity that your home requires from the utility. In a typical home, the average solar electric system can offset 50 percent of the home’s electric usage on an annual basis with clean energy.

Winsome-Built Homes Are Comfortable, the Highest Quality, and Highly Efficient.  Call us today to discuss the green building technologies that are right for your next custom home.

503-472-7402