Our home was evaluated to determine its Home Energy Rating System (HERS) score. This is a way to compare it to other homes, including old and new construction. The home received a score of 5 star plus and the HERS index was 32.
This means the house is estimated to be 68% more energy efficient than standard new construction and 100% more efficient than older existing homes. The HERS report includes an estimate of the annual energy cost which was $1,249, broken down to heating ($256), cooling ($80), water heating ($104), lights/appliances ($692) and service charges ($116). Knowing what our montly energy bills were for our last house, it's hard to believe those numbers are for the entire year! The annual savings is reported to be about $2,840 over a comparable size existing home rated at 130. Without adjusting for increasing cost of utilities over time, that's a savings of $85,200 over 30 years.
While it's fabulous to see that we'll save money on utilities from now on, that wasn't our main motivation to build this type of house. We were really impressed with the quality of construction and how comfortable the Passive homes were that we toured. Once we learned about the Passive house concept, it really made sense to us to build a home this way. Perhaps living in a century-old-home for 12 years put us in the right mindset to build for longevity, knowing this structure will be here long after we're gone. It feels good and really makes sense to build a home that minimizes its impact on our environment, and will do so for well over 100 years. In the meantime, we have the pleasure of living in it and enjoying its comforts as a family.