Energy Efficiency in Modern Buildings
As modern building materials advance, energy efficiency is inescapable. Near-zero energy buildings are becoming increasingly popular in Europe. However, this will not have a great effect on energy consumption as a whole until energy efficient building materials and practices are widespread.
Iowa State University Professor Yu Wang states that energy efficiency is relatively inexpensive when compared to other climate change choices. If all buildings implemented various energy efficiency measures, she predicts that electric bills would be 10 percent lower by 2035. She posits simple changes, like switching out your current lightbulbs with new LED lightbulbs to installing insulation panels, dynamic windows, and photovoltaic modules integrated into the building’s structure.
8 Steps Towards An Energy Efficient Building Envelope
1. Avoid Thermal Bridging
When designing your building envelope to be efficient, strive to avoid thermal bridging. Thermal bridging occurs when structural elements conduct heat through the insulation. Thermal bridging can lower your insulation’s R-value by 50 percent. Avoid this by making sure the insulation isn’t being significantly compressed, and that there’s an uninterrupted area of rigid insulation located in the cold side of the wall assembly.
2. Ensure Airtightness
Leaky windows, walls, ductwork, doors, louvers, and roofs are not only allow heat to escape and cold to come in, but they can allow condensation to form in the building envelope, which can lead to mold growth. A continuous air barrier will help maintain the interior temperature, thus ensuring that the occupant is comfortable. Additionally, installing heat recovery ventilation systems can safeguard building occupant health while simultaneously recapturing 50 percent or more of exhausted air energy. Ideally, the supply of fresh outside air should only be via the building’s ventilation system.
3. Understand Your HVAC System
HVAC equipment needs to be sized for the maximum load, or they can consume more energy than necessary 95 to 99 percent of the time. This can affect almost 30 percent of a building’s total electricity consumption. To minimize this, implement a variable frequency drive in your HVAC system. The results can be startling, reducing system pump and fan speed by half, and can result in lowering energy use by 90 percent.
4. Invest in Smart Control Lighting
Smart control lighting can affect 25 percent of the building’s total electric consumption. Daylight and occupancy lighting sensors are necessary for an energy-efficient building.
5. Thermostats and Occupancy Sensors
Linking thermostats with occupancy sensors can greatly reduce temperature control-related energy consumption. Automatically raising or lowering temperatures during preset hours is inefficient since occupants don’t always use every room in the building during the same hours each day. Linking occupancy sensors with room thermostats saves money by ensuring unoccupied rooms aren’t needlessly being heated or cooled. Additionally, it helps ensure that occupants experience comfortable temperatures wherever they are in the building at any time.
Ensure your energy-efficient building envelope allows for daylighting. According to the U.S. Department of Energy, 80 percent of lighting-related energy costs can be reduced by using daylighting. This can be achieved by designing high-efficiency skylights into your building envelope.
7. South Facing Windows
Design your building envelope with ample south-facing windows. These windows passively absorb heat from the facing sun during the winter. These windows also need to be fit with a system of shading to keep the building cool during the summer. Proper window design can reduce temperature control-related energy consumption by 85 percent.
8. Be Aware of New Energy Efficient Technologies
Finally, always keep current on new technologies. For example, large-area fluidic windows are being developed to, “reduce embodied energy and CO2 to 0 for window surfaces after four months of usage.” They work by using, “a fluid contained in micro-channels to harvest ambient heat and solar energy and manage heat exchange, thereby boosting energy efficiency.” They are projected to lower total energy consumption by 10 percent for the complete longevity of a building.