New Residential Energy Code Explained
Enforcement of the latest Energy Code, as decreed by the federal government, began in April of 2012. This code specifies minimum insulation values for wall and ceiling assemblies, as well as windows and doors. The code also determines the minimum efficiency of heating and cooling equipment.
The assemblies and equipment installed on each project are then required to be inspected by a state certified independent company to verify that these minimums have been achieved. A blower door test is also performed by this company for each new building. This test is to determine the air leakage of the completed building, which must meet the criteria specified in the energy code.
The state of Indiana addressed the responsibility of enforcing this code by allowing builders to choose between two options to meet the requirements spelled out in this code. The local building officials are required to document the method the builder selects and to verify that the builder complied with the code per the option they selected. The building official requires documentation from the independent company verifying that the builder complied.
One option is called the Prescriptive method. If a builder chooses this method, they must build the wall / ceiling assemblies and install windows, doors and equipment with the minimum insulation and efficiency values. Each component must meet or exceed the requirements as individually specified in the code.
Another option is referred to as the Performance method. This method allows the builder to approach the project more holistically instead of a compilation of individual components. Using the Performance method allows the builder to build assemblies or install equipment that does not comply with the code, as individually specified, as long as there are offsets by using methods or equipment that exceed code requirements in other areas of the building. The independent company must verify that, as a whole, the new building is in compliance with the code.
I prefer to use the Performance method. This allows us the freedom to adjust how we construct the building to best accommodate our local weather and to factor in cost efficiencies and the ultimate return on the investment for the owner.
Since we historically have built our homes to achieve the Energy Star rating, complying with the energy code has been a minor adjustment. Using the Performance method allows us to use methods and equipment proven to provide the efficiency that our customers expect.