Energy Raters
What is an Energy Rater
Programs such as ENERGY STAR, Built-Green, and LEED for Homes all require a third-party verification of energy systems and green building performance. This verification is done by an Energy Rater who is a licensed professional working under the auspices of the Residential Energy Services Network (RESNET).
For a new home being designed, an Energy Rater may perform what is called a “Projected Rating” from a home’s drawings and specifications. This gives the design team an accurate prediction of the home’s energy usage and a preliminary HERS Index score. Design changes can be proposed and their energy effects checked by re-running the Projected Rating with these changes and checking the change in score. In this process the Energy Rater can help the design team in determining energy design measures to incorporate into the home while evaluating their costs and energy usage benefits.
The HERS Index score, a value of 0 to over 100, is an indicator of a home’s energy usage versus a model “standard home” of the same size and subject to the same climate as the home being rated. A HERS Index score of 100 means that the home being rated should use the same energy as a home built to the minimum code requirements. A HERS Index score of 0 means that the home will projected to be a “net zero energy” home, the ultimate in energy efficiency. All new homes will be within the range of 0 to 100 with the lower the score the better. Existing homes, which likely don’t meet current code requirements, usually have a HERS Index score of over 100.
During construction an Energy Rater will visit the jobsite and do various inspections to verify that the home is constructed to specifications in regards to the planned energy savings measures. These inspections include checking quality of the insulation placement, and the correct alignment of insulation with air barrier systems which are necessary for the insulation system to be effective. Various other inspections are additionally required depending upon the green building program the home is being constructed under.
At completion of construction the Energy Rater will do performance testing of the home to verify the energy effectiveness of the construction work and to determine a “Confirmed Rating” and HERS Index score. One of these tests is a building envelope leakage test which is done by pressurizing the home with a special calibrated fan unit called a Blower Door. This envelope leakage test gives a calibrated reading of the amount of air that will leak into or out of a home at a specific air pressure, also known as the infiltration rate. This rate must meet the requirements of the program the home is being tested against. Another test done is a HVAC system duct leakage test using a Duct Blaster, which similarly gives an indication of how tight the ductwork system is. Other required tests may include measuring HVAC unit airflow rates to verify proper and efficient operation of furnace and air conditioning systems.
Finally the Energy Rater will complete the required documentation as needed for the certification the home is being tested under. If there are problems that keep a home from meeting the requirements, the rater will work with the builder to identify corrective actions and then retest if required. The end result should be complete confidence that the home is built to the necessary standards with a proven quality assurance procedure to prove it.
Energy Raters are usually hired by the builder, but in custom home construction may also be brought-in by the architect or even directly by the owner. In any case his job is to be part of the design and build team to make sure that in the end the home is energy efficient and certified.
For projects outside of new home design and construction, a Energy Rater’s HERS Index Score and associated inspections can be used in qualifying for Energy Efficiency loans, for the Federal Energy Tax Credit program, for home energy-retrofit decision making, and to help grade the energy efficiency of a home that is being considered for purchase or for a home being marketed for sale. An Energy Rater can provide many different services valuable to today’s home owner.
Programs such as ENERGY STAR, Built-Green, and LEED for Homes all require a third-party verification of energy systems and green building performance. This verification is done by an Energy Rater who is a licensed professional working under the auspices of the Residential Energy Services Network (RESNET).
For a new home being designed, an Energy Rater may perform what is called a “Projected Rating” from a home’s drawings and specifications. This gives the design team an accurate prediction of the home’s energy usage and a preliminary HERS Index score. Design changes can be proposed and their energy effects checked by re-running the Projected Rating with these changes and checking the change in score. In this process the Energy Rater can help the design team in determining energy design measures to incorporate into the home while evaluating their costs and energy usage benefits.
The HERS Index score, a value of 0 to over 100, is an indicator of a home’s energy usage versus a model “standard home” of the same size and subject to the same climate as the home being rated. A HERS Index score of 100 means that the home being rated should use the same energy as a home built to the minimum code requirements. A HERS Index score of 0 means that the home will projected to be a “net zero energy” home, the ultimate in energy efficiency. All new homes will be within the range of 0 to 100 with the lower the score the better. Existing homes, which likely don’t meet current code requirements, usually have a HERS Index score of over 100.
During construction an Energy Rater will visit the jobsite and do various inspections to verify that the home is constructed to specifications in regards to the planned energy savings measures. These inspections include checking quality of the insulation placement, and the correct alignment of insulation with air barrier systems which are necessary for the insulation system to be effective. Various other inspections are additionally required depending upon the green building program the home is being constructed under.
At completion of construction the Energy Rater will do performance testing of the home to verify the energy effectiveness of the construction work and to determine a “Confirmed Rating” and HERS Index score. One of these tests is a building envelope leakage test which is done by pressurizing the home with a special calibrated fan unit called a Blower Door. This envelope leakage test gives a calibrated reading of the amount of air that will leak into or out of a home at a specific air pressure, also known as the infiltration rate. This rate must meet the requirements of the program the home is being tested against. Another test done is a HVAC system duct leakage test using a Duct Blaster, which similarly gives an indication of how tight the ductwork system is. Other required tests may include measuring HVAC unit airflow rates to verify proper and efficient operation of furnace and air conditioning systems.
Finally the Energy Rater will complete the required documentation as needed for the certification the home is being tested under. If there are problems that keep a home from meeting the requirements, the rater will work with the builder to identify corrective actions and then retest if required. The end result should be complete confidence that the home is built to the necessary standards with a proven quality assurance procedure to prove it.
Energy Raters are usually hired by the builder, but in custom home construction may also be brought-in by the architect or even directly by the owner. In any case his job is to be part of the design and build team to make sure that in the end the home is energy efficient and certified.
For projects outside of new home design and construction, a Energy Rater’s HERS Index Score and associated inspections can be used in qualifying for Energy Efficiency loans, for the Federal Energy Tax Credit program, for home energy-retrofit decision making, and to help grade the energy efficiency of a home that is being considered for purchase or for a home being marketed for sale. An Energy Rater can provide many different services valuable to today’s home owner.
