Are We Measuring the Same Thing? How HERS and Passive House Provide Different Answers to Different Questions. The “Home Energy Rating System (HERS) Index is a nationally recognized metric for residential energy efficiency that’s integral to numerous government programs and financial incentives. Yet the HERS results of Passive House buildings leave practitioners scratching their heads, as powerful Passive House Performance levers sometimes barely budge the HERS needle. To demystify their…