Would it surprise you to know that energy ratings for homes aren’t a 21st century invention but actually have their history all the way back to the early 1980s? At the time, energy ratings were constrained due to a lack of knowledge among consumers and no national strategy for uniformity. Over time this was corrected with the creation of a non-profit, membership-driven corporation to oversee an energy standard for homes called RESNET.
HERS stands for Home Energy Rating System and is administered by the Residential Energy Services Network or RESNET which provides its Mortgage Industry National Home Energy Rating Standards for both new and existing homes. RESNET was founded in 1995 to develop home energy rating systems and energy efficient mortgages on a national and consistent level which had previously been lacking.
What is the HERS Index and why does it matter to your home?
Let’s take a closer look at 8 important facts about the HERS Index to help you improve the energy efficiency of your house.
Home energy ratings date back to 1981
The HERS Index came into existence in 2006 but home energy ratings were first created in 1981 to give credit to the energy efficiency of home residential mortgages.
Around the same time, energy mortgage programs also first became available in the US when several major lenders and government agencies introduced them but they were not widely taken advantage of largely due to lack of awareness by consumers, lack of uniform standards and a complicated application process.
Perhaps another reason is that in the early 1980s, we didn’t have the current environment of reducing, reusing and recycling as we do today and many of the energy saving programs and benefits we have today were only a thought back then. Whereas in the past many consumers didn’t bother with energy-saving benefits, today’s consumer is much more likely to ask for or even demand it especially if they can save money in the process.
The HERS Index score measure a home’s energy efficiency
Homes get rated on a 0 to 150 HERS scale with a net-zero home having the highest energy efficiency possible. Here are the expected yearly energy savings for each level of HERS-rated homes from 0 (best rated) to 150 (worst rated) in terms of energy efficiency and savings.
Existing homes are expected to achieve higher savings as they are presumed to be less efficient currently than new homes that are built to higher energy efficiency standards and therefore have more to gain.
| HERS Index rating | Existing home – Yearly savings | New home – Yearly savings |
| 0 | $2,355 | $1,796 |
| 10 | $2,155 | $1,616 |
| 20 | $1,976 | $1,437 |
| 30 | $1,796 | $1,257 |
| 40 | $1,616 | $1,078 |
| 50 | $1,437 | $898 |
| 60 | $1,257 | $718 |
| 70 | $1,078 | $539 |
| 80 | $898 | $359 |
| 90 | $718 | $180 |
| 100 | $539 | No energy savings |
| 110-150 | No energy savings | No energy savings |
A HERS score is relative to other houses
A baseline house that meets 2006 International Energy Conservation Code standards would score 100 on the HERS index and is thus considered the base standard. A typical resale home is assigned a score of 130. The lower the HERS rating, the more energy efficient your home with 0 being the best available rating possible.
A home with a HERS rating of 60 is 40% more efficient than a standard new home. A home with a HERS rating of 110 is 10% less efficient than a standard new home.
An existing home rated at 100 on the HERS Index is considered the lowest rated home that could expect energy savings. A brand new home at 100 HERS Index level won’t achieve savings as it’s considered the industry standard.
Any home rated at HERS 110 or greater is rated as energy inefficient and will not achieve energy savings and therefore has the most to gain by becoming energy efficient.
A HERS score is determined by a certified Home Energy Rater
A certified RESNET Home Energy Rater is the only person qualified to perform an evaluation of your home for the purpose of providing you with a HERS score.
You can access the current RESNET Home Energy Rater database to find someone in your state, zip code, by company or by name to get your home rated.
To date, over 3,038,000 homes have been HERS-rated. There are close to 2,000 active RESNET HERS Raters across the country.
A HERS test can cost up to $3,000 and take up to 2 hours
When I inquired directly with RESNET, they mentioned that $400 – $800 is what they hear is typically charged for the testing your home to receive a HERS certification rating. I also read online anecdotally that testing can be as high as $1,500 – $3,000.
Local HERS Home Energy Raters can set their own pricing and it will depend on the size of your home, too. The length of the test may take 1 – 2 hours in length to complete.
The test itself is very detailed and covers a number of aspects including:
- Ceilings and roof areas
- Attics, foundation and crawl spaces in the basement
- Windows and doors
- Heating, Ventilation, and Air Conditioning (HVAC) system, water heating system and thermostat
- Air leakage inside the home
- Vents and duct work
- All exterior walls above and below grade including insulated areas
- Floors over unconditioned spaces such as a garage or carport
The Home Energy Rater who tests your home can look for a number of problem areas in your home including building envelope air leaks, HVAC and duct work leaks, combustion risk and air infiltration rate which is the flow rate of outside air into the house.
Energy bills can be reduced from 5% – 30%
Stats from the Department of Energy suggest that energy efficient homes can help you reduce your energy bills by 5% – 30% with HERS testing to show you where you can make improvements. A wide range to be sure but it suggests that a large amount of savings can be achieved if you’re willing to put some work in and improve the energy efficiency of your home through testing.
One of the biggest problems in many homes is energy loss through duct work leaks and gaps. While there are methods to seal duct work and fix it, you would need to address these concerns before getting a HERS test done.
If you have an older home or a resale home in general, you might consider getting an energy audit professionally completed in your home first. This would enable to you identify your energy inefficiencies, address them and then perform the HERS Index test once the fixes have been taken care of.
Energy efficient homes can sell quicker and for more money
RESNET suggests that energy efficient homes can sell up to 89 days quicker than traditional homes and sell for 3.5% – 9% (and more) than their standard home counterparts. Zillow keeps track of the top 10 features that home buyers look for and buying a home that is energy efficient is on that list.
Increasingly, you see homes for sale with specific references to HERS Index Score, ENERGY STAR® Certified Appliances, energy-efficient lighting, Flow-Smart shower heads, Indoor airPLUS Certification, Low-E windows, SEER rating and more.
Consumers are becoming more aware of various aspects of energy efficiency within the home and the HERS rating is increasingly mentioned on that list.
You can hire an Energy Smart Builder
You can hire an Energy Smart Builder to build your home and can access the database nationally or by region.
You can even search the database to see which homes already built have a HERS rating if you’re looking to purchase it or want to see who in your home area has had their home rated.
MLS added HERS ratings to their home selling database back in 2013 and you will increasingly see real estate listings including references to HERS Index scores and other energy efficiency ratings on Zillow and other websites.
Bonus Fact: HERS Index testing is required in California
While HERS testing is optional throughout the US, in California it’s mandatory for homeowners and contractors.
All California homeowners and contractors must comply with the requirements of the California Code of Regulations Title 24, Part 6, Energy Efficiency Standards for Residential and Nonresidential Buildings. Title 24 was designed to meet California’s energy goals and requirements.
You may also come across references to three forms that come into play in California when discussing HERS:
- CF1R which is the Certificate of Compliance in the Building Permit phase.
- CF2R which is the Construction Phase Documentation in the Construction phase.
- CF3R which is the Field Verification and/or Diagnostic Testing Documentation phase.
All California homeowners must also perform a HERS test if they install a new mechanical system that requires verification or testing.
To complete all required HERS verifications on a new home as well as non-HERS verified CF2Rs that fall under the Title 24 umbrella, you can expect to pay from $600 – $1200 depending on what is required and who is performing the work.
Summary
With potential and current home owners becoming more interested in energy efficiency, owning a well-rated HERS Index home can help you not only save money on energy costs but perhaps positively affect the resale value and desirability if you sell it.
Check out the short video below for an audio and video explanation of how HERS works.