In this column, staff at the Center for EcoTechnology offer advice on easy ways for people — and businesses — to introduce green changes in their daily lives.
Q: I've been hearing about HERS ratings lately. What is a HERS rating?
A: HERS ratings are required for new construction projects and major renovations in any of the more than 175 Massachusetts cities and towns that have adopted the stretch energy code. The HERS Index is a number that tells homeowners and homebuyers how energy efficient a home is, and how much they should expect to spend on heating and cooling costs.
The HERS rating that you receive is on an index ranging from 0 to 150, with the standard new home falling at 100, and a lower score indicating a more energy-efficient home. So, for example, if your home has a rating of 70, your home is 30 percent more efficient than the average home built today. To give some perspective, a home built in the 1950s would most likely receive a rating of 120 or 130.
The HERS Index is not only used as a tool for new homebuyers and homeowners who are renovating, but is also used as a tool in meeting energy-reduction plans of many cities and towns in Massachusetts. Homes that are built today that are in one of the over 175 cities and towns in Massachusetts that follow the stretch energy code must have a HERS rating.
Currently in these stretch energy code towns, homes smaller than 3,000 square feet must have a 70 HERS index or lower, and homes larger than 3,000 square feet must have a HERS index of 65 or lower. Starting with new homes permitted in January 2017 in stretch energy code towns, the requirement will be a HERS index of 55 or lower. There are some exceptions to the HERS 55 index for homes with renewable energy systems, Passive Houses, and Energy Star-certified homes.
Q: How is the HERS rating of my home calculated?
A: Your HERS rating is calculated by a home energy rater, like the HERS-trained high-performance building experts at the Center for EcoTechnology. They perform an extensive examination of the home and use a computer model to generate your HERS rating. The model takes into account many different aspects of your home including (but not limited to) the insulation, the type of windows, how air tight the house is, the efficiency of your heating and cooling systems and the efficiency of your appliances.
Q: What are some other benefits of HERS ratings?
A: Getting a HERS rating can help you understand the energy performance of your new home, and where you can make the most efficient upgrades in order to reduce energy consumption, making your living space more comfortable and more affordable to heat and cool. Furthermore, when in the process of buying and selling a home, a HERS rating can be a useful tool in calculating the cost of homeownership and the resale value of a home.
Find more information on getting a HERS rating for a new home or a renovation on your existing home, and developing an energy efficiency plan for your home at cetonline.org/buildgreen.
Look for this column every two weeks. Send your Go Green questions to GoGreen@cetonline.org.