Masonry Magazine April 1979 Page. 3
How to put your building on a strict Btu diet.
Energy, as we all know, is money. It disappears faster than we can put our fingers on it. Soon, every one of us is going to have to start budgeting energy. The high costs of energy, as well as government regulations, are going to demand a strict accounting of the way our buildings consume energy.
But there are ways to make a Btu stretch farther. We believe there are four important things that every business manager should know about cutting down energy expenditures:
1.
To do a good job of saving energy, you have to be concerned with the energy performance of the entire building, not just a component like the walls, or a single system like heating and cooling.
Every facet has to be taken into account. The mass, or weight, of the walls, proper insulation, heating and cooling systems, air infiltration through doors and windows, water and lighting systems-all are critical.
Building performance standards that take this overall "thermal performance" (measured in Btus-British thermal units) into account are the best kind of standards. They give designers and builders freedom to use their skills and ingenuity. They encourage such things as proper solar orientation of buildings, reduced air infiltration and efficiently-sized mechanical equipment. A true "performance standard" simply sets an energy conservation goal, expressed as an energy budget for an entire building, and then permits that goal to be achieved by the designer, builder, and owner in whatever ways they can devise.
2.
We can use the sun's energy to cut energy costs. There are both "active" and "passive" solar collectors. "Active" solar collectors collect energy from the sun and then use mechanical equipment such as pumps or fans to distribute that energy. "Passive" collectors simply collect the sun's heat and hold it until it is released by radiation or conduction.
No materials serve as "passive" collectors better than masonry - brick, concrete block, stone.
Passive solar collectors have many advantages over active solar collectors. They have no working parts-nothing to go haywire. They are simple to design and build-and they are more economical.
3.
Massive walls of masonry, even when they're not designed as passive solar collectors, keep buildings warmer in winter, cooler in summer. Because of their weight, or mass, masonry walls act like thermal blankets. In many cases, masonry walls will mean that heating/cooling systems can be reduced in size.
4.
Insulation is important when properly used, and when its limitations are understood. We are still learning about the limitations. It's already clear that insulation is cost-effective only when used with restraint. After a certain point of thickness has been reached, the cost of additional insulation will no longer be recovered in energy savings.
And it's becoming clear that some assumptions made in the past about insulation are not justified. For example, there are indications from preliminary studies that in regions where more energy is expended in cooling than in heating, insulation used in the standard fashion in all walls may actually increase, instead of reduce, energy consumption.
One of insulation's limitations is that it affects only conduction-it doesn't affect air leakage, which is estimated to account for 25-30 percent of the thermal loss in buildings. A significant amount of air leakage occurs through windows and doors, so it's important to reduce the size of, and shield, these openings.
Masonry walls will further reduce air leakage because they are hand-fitted on the site (like custom-made suits) and thus are more airtight.
Furthermore, the effectiveness of insulation depends on the wall to which it is attached. Promoters who compare wall materials with insulation are making a meaningless comparison-the two have different functions, and one is not a substitute for the other.
Keeping to a strict Btu budget for your buildings is important today and will be even more so tomorrow. If you would like to know more about saving energy, write to International Masonry Institute, 823 15th Street, Northwest, Washington, D.C. 20005.
International
IMI Masonry Institute
The Bricklayers International Unice and the
Mason Contractors of the US and Canada)
823 15th Street, N.W., Suite 1001
Washington, D.C. 20005
(202) 783-3908