Enhabit assessors have completed 50 City of Portland Home Energy Score assessments to date. For the most part the results confirm what we expected, given our past energy efficiency field knowledge of the Portland housing stock. The average score so far is 4.
The Home Energy Score is a number that ranges from 1, for the least efficient homes, to a 10 for the most efficient.
So far we’ve scored homes built between 1895 and 2007, with an average age of 80 years. The average size has been just under 2,000 square feet of heated living space. We’ve seen a full range of scores, from a low of 1 to a high of 10.
You might expect that newer homes would always get higher scores. But that’s not always true. Modern building codes require a certain degree of efficiency, but unless the home is built to higher standards like LEED, it may not score as high as a well-retrofitted older home. There’s quite a lot of variation between older homes, reflecting the extent and quality of energy efficiency upgrades over the years.
The average score for homes built between 1895 and 1930 is a 4. Homes built between 1931 to 1996 produced an average score of 6, while a small sample of homes built 1997 or later average just a 4.
Because the majority of the houses were built before modern efficiency codes (80% built before 1960), insulation levels tend to be mixed. Many homes have partial insulation, or no insulation at all, which strongly influences scores. In some cases insulation has been added to walls, or the attic or floors and basements, but few of these old homes been fully sealed and insulated.
Upper half story rooms make things a little tricky for our assessors. These rooms are prevalent in older Portland craftsman and bungalow houses built in the early 1900s. It’s typical for these home’s upper floor bedrooms to have dormers and sloped ceilings, low knee walls and irregular shapes. These rooms take longer to measure than simple rectangular rooms with flat ceilings.
Look for an updated report after our first 100 scores.