Ventilation has defined the past two years as the world worked to mitigate the COVID-19 pandemic but it is insulation that will define the next decade. Increasingly stringent building energy efficiency standards will require insulation to work better and be more sustainably sourced. But rethinking the material is one of the most expensive tasks that can be undertaken. There are a few new promising technologies that could help us better insulate our buildings, but none has shown itself to be an obvious choice for what is already in our walls.
The most important thing to understand about insulation is that varying climates means the purpose and material of insulation are highly varied. Each different region requires different building materials and thermal insulation, making some materials better than others depending on the outside temperature. In Midwestern climates, buildings are wood framed with insulation to keep heat in but along the Gulf Coast buildings need to withstand wind and heat, so they’re designed with concrete frames and insulation that sheds heat instead of trapping it. We don’t need one new form of insulation, we need several, but as one of the most used building materials, cost is king.
Beat the heat
The good news is many different materials are suitable for insulation. The most common insulation materials are fiberglass, mineral wool, cellulose, natural fibers, polystyrene, polyurethane, perlite, and various types of foam. Understanding the pros and cons of each is an exhaustive process. They all differ in cost, efficacy, sustainability, fire resistance, sound insulation, weight, conductivity, and installation method. Figuring out the right type of insulation to use is key to lowering heating and cooling expenses that fuel buildings’ rampant demand for energy. It’s no stretch to say effective insulation combined with high-efficiency HVAC systems is the single best way to lower carbon emissions produced by building occupancy, but upgrading both must be done at scale.
Owners and asset managers understand how difficult it is to upgrade or retrofit a building. Even just replacing lighting is a challenge. Buildings aren’t like LEGOs that can simply be taken apart and pieced back together. The cost of the material is only part of the expense. Often installation and tenant disruption are the major hurdles. When thinking about retrofitting insulation upgrades, those issues are even more critical. To upgrade insulation you have to bust open walls, rip out what’s already there and replace it. You’re not just doing interior work, insulation is in the building envelope. If replacing the insulation in a single home can be a major challenge, doing so in entire commercial buildings seems nearly impossible.
Good insulation is centered around a high-performance roof, walls, fenestration, foundation, and facade. Leaks or poor insulation in any of those elements impacts them all. Uncertainty around envelope and insulation retrofits poses a serious obstacle to the prospect of serious energy use reduction.
Out with the old?
To measure a given material’s ability to block the flow of heat, engineers calculate each insulation’s R-Value. To figure out how to upgrade exterior walls to give them the best R-Value, the Wall Retrofit Solution project examined various materials and methods to identify retrofit recommendations and best practices. Researchers at the Oak Ridge National Laboratory and Bayer MaterialScience narrowed down their recommendation to two solutions, but each has major flaws.
The first is to retain existing interior insulation, steel studs, and drywall but install two inches rigid PIR foam board with taped seams over the existing wall. This gives the best R-Value per inch and provides superior performance at a minimized thickness with very construction. Saving the existing insulation results in the retrofit cannibalizing 3.5 inches of interior commercial floor space, however. Installation is highly dependent on the state of existing insulation. Special care must be taken to ensure proper installation, any gaps or seams permit convective gaps that disperse heat and moisture. New cables and wires are more difficult to run and electrical receptacles need to be pulled forward and reinstalled. Windowsills also needed to be extended. All told the researchers estimated the labor-intensive retrofit would have a payback period of 14 years, far from the three- to four-year amortization most landlords look for.
The other option is to remove existing interior insulation, steel studs, and drywall and install 3.5 inches of closed-cell spray foam offset 1.5 inches from the concrete block wall. The process requires a specially certified spray foam tradesman but the method allows one contractor to handle the whole process. Additional labor is needed to offset steel studs from concrete block walls. This method saves all previous commercial floor space but does disrupt tenants as work areas must be vacated and access restricted but most spaces can be reoccupied 24 hours after installation. The payback period is estimated at 16 years.
Both methods will give owners and asset managers sticker shock. The cost of the material, demolition, waste removal, installation, offsetting, and new drywall is significant compared to the savings. Research on the retrofits is still ongoing, tracking performance overtime but time is running out. More must be done to lower the cost of insulation retrofits. If that can’t be done through material science or reduced labor costs, regulators will likely need to step in to help cover the capital cost.
New York state is leading the nation in building energy performance standards. To help commercial owners improve their assets, Governor Kathy Hochul announced $20 million has been awarded to pioneer climate-friendly retrofit solutions for existing high-rise buildings. A significant portion of that will go towards insulation innovation. Other ‘green banks’ are helping owners make crucial investments in energy efficiency now to reap the rewards later. The earlier improvements can be made, the more savings can compound.
Easy improvements to efficiency and sustainability have already been made, owners and managers have picked what low-hanging fruit exists. Now is the time for the difficult work of replacing insulation to begin. Far more complicated than replacing an incandescent lightbulb with an LED one, replacing insulation can be a daunting and costly upgrade. There is little innovation that can get around the labor-intensive process, but that doesn’t make it any less necessary. Bringing our building stock into the 21st century will require major amounts of capital to overcome hurdles as large as the ones before the building sector.