Life Cycle Analysis of SPF Insulation

All building products require energy for production, delivery and installation. It is becoming more and more common for manufacturers to conduct a Life Cycle Assessment (LCA) of the energy used and other environmental impacts of their products over the full life cycle of that product. Such an LCA typically includes the various stages of a product including:

• Raw Materials and manufacturing

• Transportation, distribution, and installation

• Use over time

• End of service life re-use, re-cycling, or disposal

In the case of SPF insulation, it is significant to note that it is a product that not only consumes energy during its lifecycle but it also reduces energy use in buildings. In fact the amount of energy saved in buildings usually dramatically exceeds the amount of energy used during its life cycle. By way of example, a typical residential installation using open cell low-density SPF insulation could be expected to contain on the order of 47 – 73 mega-joules (MJ) of embodied energy.

The ratio of energy avoided versus this embodied energy could result in an energy payback balance occurring in only a few months in cold climates but still about a year in warmer climates. If medium-density closed cell foam is used the embodied energy is a bit higher at 93-144 MJ so the energy payback takes a little while longer to balance out, but could still be expected to range from about 7 months to 2 years depending on the climate. Over the course of say a 60 year life expectancy for a residential installation, anywhere from 3,000 to 14,000 MJ of energy could be saved because of the insulation which helps to explain the quick energy payback balance. If medium-density closed cell insulation is used for commercial roofing, then the energy payback is also strong coming in between 1 – 2 years depending on climate.

When looking at the initial cost of installing spray foam insulation, it is appropriate to view it in the context of high performance building design. That means the performance and design of the building should be looked at based on a variety of interrelated factors. One of the important points to consider in creating a high performance building envelope is the potential to reduce the size of the mechanical equipment needed to heat and cool that building. This essentially becomes a “cost transfer” approach whereby any additional cost of increasing the performance of the insulation is offset by a reduced cost in mechanical systems. Over the life of the building that cost savings is compounded to the benefit of the owner in reduced energy costs, reduced maintenance costs, and replacement cost savings at the end of the service life of the equipment.

The Merrimack Valley High School in Penacook, New Hampshire, is an excellent example of this principle at work. The building was designed to be very energy-efficient addressing the multiple interrelated areas to achieve that goal. When the costs of the final built result was compared to the baseline comparable building costs, the savings were found to be dramatic as follows:

This fairly simple study shows that by utilizing SPF as an air impermeable insulation in a high performance, energy efficient building, the increased cost to the building shell was actually more than negated by the reduction in sizing and cost for the HVAC system. In fact the analysis in this case shows a net savings of initial construction costs of over 22% less than the standard construction cost. The end result is a higher performance building that will reduce the monthly and annual energy costs all at a lower initial construction cost.

Candlewood Suites Hotel, Rolla, Missouri The award-winning Candlewood Suites® hotel in Rolla, Missouri, provides guests with the highest level of quality and service for an extended stay or short-term visit. This 37,000 square foot facility is part of the Intercontinental Hotel Group (IHG) worldwide chain of hotels and is located near Fort Leonard Wood, Missouri, Interstate Highway 44, and some of the area’s leading companies. This location makes it easy for guests to visit the exciting museums on-Post, including Fort Leonard Wood Museum and the US Army Engineer Museum. Additionally, it is also about 35 miles from the popular Lake of the Ozarks State Park, where visitors enjoy fishing, hiking, camping and mountain biking. As part of IHG’s commitment to sustainability, they have implemented a program termed “Green Engage.” This innovative sustainability effort is based on an advanced online tool which measures the day-to-day environmental impact of participating IHG hotels. The online system monitors energy, water and waste usage of individual hotels while providing recommended actions to improve the property’s energy conservation and carbon footprint score. IHG created Green Engage to ensure that their hotels are designed, built and run for optimal sustainability. This commitment to sustainability was important in the design and construction of the Rolla, Missouri, hotel. The design team employed computerized energy modeling to compare design options using DOE 2.1 Energy Modeling Software. The areas of interest that were incorporated into the computer model included: • The Building Envelope • Insulation • Natural Air Changes • Lighting • HVAC • Hot water As with all computer modeling, a baseline or reference building is modeled based on meeting minimum baseline requirements. In this case that reference building design yielded an annual energy cost of approximately $95,100. An initial design using conventional insulation and air sealing tactics plus a conventional HVAC system reduced that annual energy cost by over 23% down to approximately $72,650 per year. Moving one step further, the design team looked at improving the performance by using spray foam insulation. This meant that the insulating values were increased while the air infiltration values were able to be decreased. It also meant that the HVAC system size could be reduced and operate more efficiently. The energy model for this design scenario showed a dramatic 55% decrease in annual energy cost compared to the baseline reference case coming in at only $42,350 per year. That is a $30,300 decrease or nearly 42% improvement over the initial conventional design approach. Given these energy modeling results, it was an easy decision for the architects to specify spray foam insulation. This choice not only met initial design goals and objectives, it also created a thermally high performing facility that allows this IHG property to meet its Green Engage goals year after year.