I had an question last week. ‘What types of homes can you put a HERS Rating on?” A second question came along with it, “What types of buildings can you certify as Energy Star?”
These are great questions! We usually think of homes as being a house in a subdivision or older neighborhood. It usually houses one family. These are referred to in the trade as ‘Single Family Homes’. Not everyone lives in one of these. There are duplexes, four-plexes and all sorts of high rise apartment houses. These are referred to as ‘Multi-Family Housing’. There are also buildings that have retail shops or other non-residential areas, with living units on the upper floors. These are referred to as ‘Mixed Occupancy’.
A HERS Rating is applied only to residential units. The ‘Home Energy Rating System’ was developed by the Residential Energy Network, commonly called RESNET. This non-profit organization provides guidelines for training, maintains the standards for the HERS Rating process, certifies the software used to IRS Standards, and finally enforces a Quality Assurance Program on all Ratings issued.
There is an organization that is developing a similar set up for commercial structures called COMNET.
The HERS Rating results in a score on the HERS Index. This score can be used by home buyers, realtors, appraisers, and many others in the property sale transaction. This rating is a private transaction usually between a HERS Rater and the property owner. Many HERS Index Scores are specifically used to market a property. A HERS Rating may be completed for a new or an existing home. Lenders in some cases are requiring HERS Rating.
The HERS standard does not specify any specific products, methods or other requirements. The resulting Index Score reflects different levels of energy efficiency between rated homes. A home with a higher score will use more energy than a home with a lower score. The index starts at Zero and goes up. The highest score I have personally completed was 384. Most existing homes score between 95 and 150.
A HERS Rating can be completed for single family or multi-family homes. The limitation applies to buildings that are 3 stores or less. In the trade these are referred to as ‘Low Rise Residential buildings.
Energy Star is a Brand that is promoted by the Federal Government since 1992. It is designed to designate the top 20% of a product line with the most energy efficient features built in. Every product line has standards for energy use. Specific tests are required on the different products.
Refrigerators are a great example. A 25 cubic foot refrigerator is only compared to similar size units. A 10 cubic foot unit designed for a smaller apartment is not compared to larger units. there are a large number of refrigerator classes available.
Some products do not have an Energy Star qualifying standard. Examples here would include clothes dryers and ranges, ovens and cook tops.
Energy Star Homes use a set of mandatory requirements that must be followed and a HERS Rating that must be earned. The requirements are detailed, covering 7 pages of checklists. They require specific energy related items, for example, continuous insulation. They also require things such as flashing of windows and doors for durability. It makes little sense to build an energy efficiency home that would allow water to enter the wall and destroy the insulation.
A maximum HERS Index score is set, based on the size and number of bedrooms of a home.
Commercial buildings also qualify for an Energy Star Rating. Existing building qualify by reducing energy usage. This process, like most Energy Star certifications, is voluntary and as a HERS Rater and Thermographer, I am qualified to assist with, or to complete.
New commercial buildings qualify for Energy Star, by design and verification of the actual design being present in the completed building. I can help with this also. Since most of these buildings have architects and other professional engineers involved in the planning, my role is more in the verification process. In the commercial area this process is called Building Commissioning. I would work primarily with the Thermal Enclosure and some of the HVAC issues.