Know Your EPS

A clear view of home energy performance

EPSTM, brought to you by Energy Trust of Oregon, is an energy performance score that rates the efficiency of a home and measures it against similar-sized homes in Oregon. With EPS, the lower the score the more efficient the home. The score can range from zero to over 200, with zero being the most efficient rating.

To see how EPS works, take a look at our sample EPS sheet.

Our Smart Homebuyer Checklist can help prepare you to talk with builders and real estate professionals about the various aspects of a home that affect its level of energy efficiency and its score. The checklist provides questions and information so you’ll know what to look for and the questions to ask.

How does a home receive an EPS?

To determine a newly built home’s EPS, a third-party verifier analyzes the home's features and construction techniques and tests performance factors such as air leakage and duct tightness. EPS is a voluntary rating that builders request before construction.

If you recently bought a newly built home that did not receive an EPS, click here to learn more about how you can get an EPS for your home.

EPS works with home certifications

Many homes that have earned an EPS also have certifications such as Earth Advantage®, ENERGY STAR® or LEED for Homes®. Learn about the different certifications to make shopping easier.

EPS works with accessory dwelling units

Interest in accessory dwelling units, ADUs, is rising fast as more and more homeowners see the value of having an extra living or rental space on their property. Because of their small size, ADUs can be built to use very little energy if you plan ahead. Talk to your builder about including energy-efficient features and getting an EPS for your detached ADU. You can also call 1.877.283.0698 or email us for more information. Here are some additional resources:

Look for these features in homes with low scores

Improved insulation

Explanation: Insulation is given an “R-Value” rating that reflects its resistance to heat flow. The greater the number, the better the insulating quality.

Benefit: Properly installed floor, ceiling and wall insulation can help keep heat inside during winter and outside during summer.

Recommendation: EPS homes have an R-value of at least R-49 for ceilings, R-23 for walls and R-30 for floors.

Check the EPS sheet: Look for the R-Value on the backside of the EPS sheet sheet to find the home’s level of insulation.

Efficient windows

Explanation: The rate of heat loss in windows is indicated by the U-Value. The lower the U-Value, the greater a window's resistance to heat flow.

Benefit: Lower U-Value windows result in a more comfortable home and greater energy efficiency.

Recommendation: EPS homes have windows with a value of at least U-0.30.

Check the EPS sheet: Look for the U-Value on the backside of the EPS sheet to find the home’s window U-Value.

Advanced framing

Explanation: Advanced Framing is a technique where builders reduce the amount of lumber needed to build walls, floors and ceiling while maintaining structural integrity.

Benefit: Advanced framing improves the overall thermal performance of the wall. In addition, advanced framing can reduce the amount of lumber needed by up to 22 percent.

Recommendation: Energy Trust recommends builders of EPS homes use advanced framing techniques where possible.

Ask an expert: Be sure to ask the builder or realtor if advanced framing techniques were used in the home during construction.

Tighter construction

Explanation: 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.

Benefit: When a home is built tightly to control air leakage, and features properly installed insulation, its energy use can be reduced by as much as 20 percent. This tighter construction also enables the home to maintain consistent temperatures throughout, and works to lessen humidity, indoor air pollutants and noise.

Requirement: Newly built homes that receive an EPS are required to receive a blower door test to assess the tightness of the home. Typically, a newly built EPS home averages 4.0 ACH.

Check the EPS sheet: Look for the ACH on the backside of the EPS sheet to find the home’s air tightness result.

Properly sealed ducts

Explanation: When ducts are sealed with mastic paste, it ensures that heated/cooled air is transferred to the proper locations in the home.

Benefit: 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.

Requirement: Each EPS home is reviewed by a third-party verifier who performs a duct blaster test to measure the tightness of the duct system.

Ask an expert: Be sure to ask the builder or realtor if a duct blaster test was completed on the home, and if it passed.

Efficient appliances and lighting

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.

Benefit: ENERGY STAR® certified appliances use up to 50 percent less energy and water than standard models. Compact fluorescent lighting uses up to 75 percent less energy than standard incandescent lighting, while LEDs use up to 85 percent less energy.

Requirement: The dishwasher and 80 percent of all lighting must be ENERGY STAR certified for a home to earn an EPS.

Ask an expert: Be sure to ask the builder or realtor about ENERGY STAR lighting and appliances that may be included in the home.

Efficient water heating

Explanation: Water heater efficiency is measured by Energy Factors, EF. Higher EF ratings indicate greater energy efficiency.

Benefit: 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.

Requirement: EPS requirements for water heaters vary based on house size, fuel and the type of water heater.

Ask an expert: Be sure to ask the builder or realtor about the water heater and its efficiency when looking for a house.

Efficient heating, cooling and 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.

Benefit: Heating and cooling equipment is the largest energy user in the home. Energy-efficient furnaces, heat pumps, air conditioners and other equipment can lower energy bills, enhance comfort and improve indoor air quality.

Requirement: EPS requirements for heating, ventilation and air conditioning, HVAC, systems vary based on house size, fuel and the type of system.

Ask an expert: Be sure to ask the builder or realtor about the HVAC system and its efficiency when looking for a house.

Solar electric

Explanation: Solar panels use the sun to generate electricity to help power the home. The amount of energy generated in kilowatt-hours, kWh, depends on system size (referred to in kilowatts or kW) and geographic location plus shading, tilt and orientation at the site.

Benefit: 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.

Recommendation: EPS homes do not require a solar electric system. However solar electric systems are recommended for the best possible energy performance and lowest EPS.

For the best EPS: Look for a home that has a solar electric system or is built solar ready.

Solar water heating

Explanation: Solar water heating systems use energy from the sun to pre-heat water for use in the home. Solar water heating performance is determined by system size, system type and geographic location.

Considerations: In an average home, water heating may account for up to 30 percent of a home’s energy consumption depending on user behavior. Solar water heating could reduce this energy consumption by over 50 percent for homes that use larger amounts of hot water. Since these systems require minimal roof space, they can be ideal for new construction.

Energy Trust does not offer incentives for installing solar water heating systems however tax credits may be available to help make a solar water heating system more affordable.