Energy Benchmarking Can Spot Money Pitfalls

The practice can save owner–operators money by identifying their properties' energy-losing areas.

When it comes to day-to-day issues in apartment buildings, energy efficiency is often overlooked. Yet, its neglect can become an operator's most costly problem: Inefficient buildings typically incur four times the utility costs of efficient buildings.

Peer-to-peer energy benchmarking using energy efficiency software can help, by showing multifamily execs how their buildings' performance compares with that of other buildings.

Getting Started
The first step in energy benchmarking entails building a property profile by determining the property's climate zone, using authoritative references such as the Department of Energy's “Guide to Determining Climate Regions by County.” By grouping buildings according to weather similarities, operators can see how their buildings rate against others in their climate zone, for a more accurate, “apples to apples” comparison.

High-Rise Energy Savings

Elevators are an excellent example of why "like" buildings must be compared with other like buildings when using energy benchmarking.

High-rises typically contain elevators, which can account for 3 percent to 7 percent of a building's energy use. Thus, benchmarking high-rise buildings against low-rises, which lack elevators, will lead to inaccurate comparisons.

Fortunately, high-rise owners can take various steps to improve elevator efficiency, such as replacing their drive systems or updating the units' hydraulics.

Revolving doors are another feature that are more common in high-rise buildings than shorter structures. A recent MIT study indicates that high-rise owners can achieve an annual savings of 1.5 percent of their total energy use by investing in revolving doors, which typically save on heating and cooling versus a traditional swinging door. To maximize these savings, once the revolving units are installed, it is essential to keep all seals maintained, to avoid airflow leakage.

In this way, drafty apartment buildings in Philadelphia, Minneapolis, or Denver won’t be benchmarked against buildings in more-temperate zones such as Miami, Phoenix, or Houston.

Next, energy benchmarking software groups buildings by heating source. Electrically heated buildings perform much differently from gas-heated buildings, so it’s far more accurate to benchmark gas against gas and electric against electric.

Lastly, energy software can bucket buildings by size and—more specifically—height. Why? Taller buildings are typically less efficient than low- or mid-rise buildings. High-rise facilities have different systems and unique equipment, such as elevators and even revolving doors, which have a sizable effect on a building's energy usage.

Multifamily buildings should also be benchmarked by height because of the “stack effect”— a fancy way of describing the old science-class axiom that heat rises. In taller buildings, this fact can dramatically affect energy use.

In winter, a building’s heat escapes through the roof, and cold air is pulled in through basement and first-floor doors and windows. First-floor tenants may try to stay warm by cranking the thermostat while those on the middle and top floors open their windows for fresh-air relief. With hot air at the top and cold air at the bottom, this can create an inefficiency merry-go-round.

Help With Retrofitting Decisions
By benchmarking buildings using energy efficiency software, mid- and high-rise owners can see how their individual buildings are performing, prioritize energy retrofits for the least-efficient of them, and achieve a meaningful reduction in their energy use.

Finally, peer-to-peer energy benchmarking can identify spikes in energy use, which can aid owners in prioritizing retrofits while saving on energy and water costs. Benchmarking can also help operators gauge the size of their building’s carbon footprint and indicate steps to take to boost sustainability, which has been shown to play a key role in attracting better tenants and enhancing cash flow and building value.