As the major Texas metros grow, the demand for high-rise apartment buildings continues to climb. In Dallas, Houston, and Austin columns of high rises are becoming a more prominent feature of the cityscape. The mammoth housing complexes help define the character and lifestyle of downtown neighborhoods, but they also make their mark on the electric grid.
According to the U.S. Department of Energy, residential and commercial buildings are responsible for 40% of the total energy consumption each year. The main factors in residential energy consumption relate to heating and cooling of the space:
High rise apartment buildings have unique challenges and needs when it comes to energy. Keep reading to explore how high-rise apartment building owners can make their property as efficient as possible and ultimately more comfortable and affordable for residents.
Windows Materials and Frames
Windows are a defining feature of high rise buildings. While single family homes have windows in most rooms, they are much more prevalent in many high rises, sometimes stretching from floor to ceiling. Windows help to reduce lighting needs, but they can also allow heat to enter or escape the apartments.
Low-Emissivity Film – Also known as Low-E film, the product can be applied to windows to block 97% of UV rays and keep heat out during summer. In the winter months, the film actually helps to retain heat in homes.
Window & Framing Materials – The materials used for the framing and windows themselves will impact the efficiency of your high rise. Look for windows that have low-e or double glazing and insulated frames that are made of vinyl, wood or fiberglass.
The construction of a building is just as important as the systems installed in it. Air leaks can add up to 30% to the heating and cooling costs of apartments and a substantial amount of wasted energy. Tight construction is focused on eliminating leaks, gaps and holes that are found throughout a building. It begins with the framing of a building and continues all the way through to the finishes.
The fewer holes, seams and joints a structure has the tighter the construction will naturally be. The use of sheet materials helps to minimize these occurrences. Proper sealing is also a key component of tight construction. But this expands beyond sealing around windows and doors. During construction, many holes are created by electricians, plumbers, builders, etc. Some are easily accessible while others are hidden within walls. It is virtually impossible to seal every hole, but making a conscious effort to reduce large gaps (known as effective leakage area) throughout the building will have the biggest return in improved energy efficiency.
Areas to focus on include:
- The tops and bottoms of the building
- Rooftop access points
High rise buildings that use tight construction techniques have far superior insulation, which dramatically increases energy efficiency. Another benefit of tight construction in a high rise is the noise reduction, which tenants will appreciate.
Tight construction needs to be paired with adequate mechanical ventilation systems to ensure good air quality. This alone makes investments in ventilation worthwhile, but from an energy efficiency standpoint, it is just as important. Ventilation systems are able to draw air out of apartments. Using vents when cooking or showering in the summer can help keep living spaces cooler.
Leaks within the ductwork cause a 20% air loss on average. Instead of cool and hot air moving into the living spaces it is lost in the cavities of the building. A thorough inspection of the duct system will undercover the poor connections, holes, blockages, duct tape failures, insulation loss and kinks that negatively impact airflow and efficiency. Special attention should be given to:
- All duct connections
- Refrigerant lines
- Air filter slots
Opt for Energy Efficient Equipment
The equipment and appliances in high-rise buildings can either save you thousands of dollars each year or significantly add to the utility bills. An integrated combined heat and power (CHP) system located at the basement or roof of a building can control many functions and reduce energy use. A CHP system also acts like a generator and can produce energy for the building.
ENERGY STAR labels are an easy way to identify appliances that are energy efficient. The yellow EnergyGuide labels also detail yearly operating cost and electricity use for appliances.
Even a highly efficient HVAC system or water heater can waste energy if it is not set up properly. The tips below can push energy efficiency to the max:
- Equip apartments with programmable thermostats.
- Set the water heating system to 15-120°F.
- Do not position dishwashers next to refrigerators.
- Properly maintain system components with annual inspections.
- Make repairs quickly.
- Replace outdated components.
- Use variable frequency drives to control and reduce motor waste in HVAC systems.
- Opt for a modular boiling system instead of using one or two large boilers.
- Use boiler controls like stack economizers to regulate the system.
The Energy Star Multifamily High Rise Program
ENERGY STAR has created a program for developers that are building brand new high rise buildings and/or rehabbing existing structures. The goal of the Multifamily High Rise Program is to provide developers with guidance on how to build their high rise so that energy efficiency is maximized. Developers that join the program will receive the ENERGY STAR designation after successfully building a multifamily mid or high rise that is 15+% more energy efficient than structures that are built to code.
Verifying that your building meets all of the requirements can be done using either performance-based process that estimates energy use or by the prescriptive path. Using the prescriptive path a builder must follow the set requirements that are defined by the program. The latter is an excellent option for high-rise developers and rehabbers that want more direction on what needs to be done to construct an energy efficient building. Utilities are also partnering with ENERGY STAR to provide additional incentives for participating buildings.
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