Parsing the Region’s Home Energy Rating Data: The Basketball Edition

This is the 2017 installment of this series. Click here for the 2016 update.

If the 12 states in our region were NBA teams and they scored points with home energy ratings instead of layups and three-pointers, Massachusetts and Maryland would be the Cleveland Cavaliers and the Golden State Warriors. Maine would be our Boston Celtics. Vermont? They’d be the San Antonio Spurs. These might sound like nonsensical claims, but I do have data to back them up. Allow me to explain…

For those who don’t follow basketball, LeBron James and the Cavs are currently playing against Steph Curry and the Warriors in the teams’ third straight NBA Finals matchup – quite an uncommon happening in the sports world. After looking at the past three years of another data set, HERS ratings across NEEP’s twelve-state region (see the blue "PRIMER" box below), I discovered some parallels to this year’s top NBA teams:

  • Massachusetts and Maryland, clearly on another level above the rest of our region in the number of homes receiving HERS ratings, are like the Cavaliers and the Warriors.
  • Maine, which boasts the lowest average HERS Index in the country but has very few total home ratings, is like the Celtics, who had the best record in their conference this year but came up short in the postseason.
  • And Vermont, long a leader in high performance homes and consistently low HERS indices, is similar to the Spurs, who have enjoyed sustained success since the beginning of the Tim Duncan era.



The Home Energy Rating System (HERS) Index provides a way to boil down a home’s energy efficiency into a single number similar to a vehicle’s MPG. A house that uses no energy would have a HERS Index of zero. The higher a home’s HERS Index, the worse its energy performance. Modern code-built homes achieve indices of about 60-80 and older, less efficient homes have indices well over 100. The HERS Index is a useful metric for above-code programs (as most utility efficiency programs in our region use it) as well as for tracking our progress towards our region’s adoption of zero energy building practices.

A Closer Look at the Stats

Looking a little deeper into the HERS data, I identified three major findings:

1. Massachusetts and Maryland continue to foster the most HERS rating activity followed by the trifecta of New Jersey, New York, and Pennsylvania. I’ve employed the national median to contextualize these figures in the chart below since Texas’ 40,000+ ratings – by far the most in the country – skew the average considerably.

Number of HERS Ratings, 2014-2016

2. The region’s high performance home industry is very consistent across all of our states, with Maine and Vermont leading the pack. As you can see below, nearly all of our states are building homes with HERS indices averaging in mid- to high-50s despite the fact that new construction program performance criteria and the underlying state energy codes vary from state to state.

Average HERS Index, 2014-2016

3. Across the region, the trend is plain and simple: more homes are being rated, and the ratings demonstrate that these homes are increasingly efficient. In 2016, the average rated home in our region (56) was eight percent more efficient than the national average (61).

Total and Average HERS Ratings in NEEP Region, 2014-2016


Is Continued Progress a Slam Dunk?

The 2014, 2015, and 2016 HERS data presented in the charts above is evidence that as the housing industry continues to recover from the mortgage crisis of the late 2000s and as more builders implement energy-conscious designs and systems in response to rising energy code baselines and advancing efficiency program standards, the efficient home industry is improving its end product. It is not being “watered down” by new builder participation. This bodes well for the industry’s ability to deliver progressively more efficient homes as the efficiency of home designs continues to increase.   

Regarding energy codes, it will be interesting to track what impact the introduction of a HERS rating compliance option into 2015 (and 2018) International Energy Conservation Code (IECC) will have on both of the number of HERS ratings and the average HERS Index in each state. Thus far, Maryland, Massachusetts, New Jersey, New York, and Vermont have adopted the 2015 IECC in our region, as have several other jurisdictions across the country.

Also, while this analysis only considers HERS, use of the U.S. Department of Energy’s Home Energy Score is beginning to pick up in our region. This is especially true in Connecticut, where integration with statewide utility programs has led to the scoring of over 10,000 homes per year – a figure which dwarfs the totals presented here. The EMPRESS project led by Rhode Island seeks to find ways to harmonize these two energy rating metrics.

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