Deep Energy Retrofit Studies for Occupied Senior Housing - Suburban Chicago

FGA with Sustained Ability Construction and Evolve Buildings, 2022

Located in suburban Chicago and constructed in 1987, this building is a sprawling 2-story wood frame slab-on-grade structure with 32 apartment units - mostly 1 Bedrooms with a few 2 & 3 Bedrooms. As part of energy efficiency upgrades provided by the local municipality, we were tasked with studying various energy upgrades to the existing thermal envelope. Essentially, identifying “low hanging fruit” - knowing we likely would not be able to renovate the entire envelope with the grant money provided, our study helped to determine the best places to allocate funding.

In a climate like Chicago’s, that meant focusing on the building’s heating demand as summer cooling is so minimal as to make up a mere fraction of the building’s total energy use. Being a code-built building from the 80s, it has a moderate amount of wall and attic insulation but is extremely leaky (as preliminary blower door testing confirmed). Since heat rises, we rightly assumed the attic space would be the best place to make improvements. In Case 2, we double the amount of attic insulation and airsealed to create an air barrier between ceiling and ventilated attic space. We used blown cellulose, but also considered closed cell spray foam due to its inherent air sealing advantages. In Case 3, we added additional insulation outboard of the existing sheathing and sealed the sheathing to continue our air barrier down from the attic. In Case 4, we insulated the outside of the existing foundation. 

The results were fascinating, showing how relatively minor interventions to the building envelope can drastically reduce energy use. When renovating homes or apartments, it’s rare that renovating everything at once is on the table. This building, for instance, had pretty good 5-year old windows that did not need replacing. This specific / a la carte approach makes sense for a lot of homeowners looking to make the most simple and effective upgrades. In a winter where gas prices per therm have doubled and sometimes tripled in the Chicago area, this increased efficiency would save our residents a good amount of money on their monthly bills.