Example of a Success Story
Building Owner Cuts Heating and Cooling Costs
by Jack McHale
When Don Reed of Genesee, Pennsylvania, decided to build a new 6800-square-foot (631.74-square-meter) Mini Mart/Service Station to replace his existing 2000-square-foot (185.8-square-meter) facility, he was advised by architects and engineers that a 10-ton (9.1 metric tons) air conditioner would be needed to achieve adequate summertime cooling. Fortunately for him, he met Frank Kennedy before he finalized his plan.
Kennedy is the inventor and developer of a specially designed insulated wall system. He suggested to Reed that the unique design of his product might offer more advantages than the building materials, which were originally being considered. After further discussion concerning the ability of the insulated wall system to reduce energy usage and construction costs, Reed asked his builder to use this innovative product in his new store, and he is glad he did.
The primary component of the system is an insulated concrete masonry unit (CMU), that can be produced on a block machine with patented molds. Each unit has three distinct parts: a concrete inner face, expanded polystyrene pieces as the insulator and a concrete outer face. The units arrive at the jobsite pre-insulated and ready to be installed, thereby eliminating the extra costs and inconsistencies of on-site insulating. Additionally, the builder is able to visually confirm that every unit is completely insulated.
However, the most striking feature of the product is that it has no webs or connections between the two faces, which is common in most blocks. Even though the unit is webless, it does have the cavities found in the conventional CMU that allows it to accept rebar, concrete, conduit and plumbing that might be run through any standard block wall.
Because there are no webs in the design, there are no “thermal bridges” that transfer heat between the inside and outside faces of the wall. This minimized the effect of outside weather conditions on inside temperatures.
Adding further to the stabilization of the inside ambient temperature is his use of what the inventor calls the “insulated thermal mass” principle. Thermal mass is the ability of a material to absorb and maintain the heat of its environment. Eventually the material releases this stored energy as the conditions of its surrounding change to become cooler.
According to Kennedy, many builders place their insulation between the thermal mass of the wall and the inside of the building. This placement, he says, “isolates the thermal mass and its benefit of temperature storage from the very areas we want it to effect.” He believes that his “insulated thermal mass” design allows his wall to maintain the desired inside temperature because it is a barrier only to outside conditions.
Owner Reed took Kennedy’s advice to delay the installation of an air-conditioner for at least a year to test the ability of the system to maintain inside temperatures. Despite the sometimes summer heat of 95 degrees and high humidity, Reed still has no air-conditioner after four years. He says that in the middle of a 90-degree day customers have walked into his store and said, “Wow, you must have the air-conditioning way up, it’s so cool in here.”
“We noticed the same advantage in the wintertime,” Reed continued. “I’ve got a heater that is no bigger than what was in my old store and even with thre times more square footage here we are paying less for energy than we did in the old building. We also installed radiant heating in a masonry floor, but to this day we haven’t had to hook it up…after four years!”
Thermal performance of wall systems continues to be an important factor considered by designers when choosing construction materials. A key requirement for architects and building owners is a source of reliable data for insulated concrete masonry systems to determine compliance with energy codes and evaluate overall efficiency.
The National Concrete Masonry Association (NCMA) has a new evaluation program to document and report the R-values of concrete masonry wall systems that are constructed with integral single-wythe insulation (inserts, loose-fill, etc.). The evaluation program provides the tool that designers and specifiers can use to obtain greater confidence in the performance capabilities of their purchased wall systems. NCMA uses either of two accepted methods of compliance – authentication of actual wall test results using ASTM procedures or ASHRAE series-parallel procedure for calculating the overall coefficient.
“Architects, specifiers and building owners that we have worked with have gained confidence in the value of an insulated masonry wall system,” says Lloyd West, president of West Materials Inc.
Details of the program are outlined in NCMA’s “Procedure for Evaluation of Thermal Performance of Integrally-Insulated Concrete Masonry Walls.”
One of the main resons that Reed chose concrete masonry for his building is that “after going through a fire we wanted something that just absolutely would not burn.” When Kennedy told him that the insulated wall system has a fire rating of four hours for its 10- and 12-inch (25.4- and 30.5-cm) units, Reed said, “We’ll feel much safer in this buiding than our old one.”
Another feature of the material that Reed appreciates is the versatility of its aesthetics. “It’s much more attractive than a steel or stick building, and we’re constantly getting compliments on how it looks.” The concrete unit can be produced in regular or split face in any color.
Reed is also pleased with the sound-blocking qualitites of the system. “We hardly hear the heavy truck traffic that goes by right out in front and which used to be very loud,” he said. Kennedy explained the units have a sound transmission class rating of 55, which compares favorably with acoustic block.
Jack McHale is an independent writer who works closely with the concrete masonry industry.