The comfort of patrons is a top priority for managers and owners of retail facilities like restaurants and shops. Cost savings and energy efficiency go hand-in-hand. A simple solution HVAC professionals can recommend to their customers that checks all three boxes for light commercial applications is replacing aging or outdated rooftop HVAC systems with the latest innovation: inverter heat pump technology. While heat pumps have existed for years in residential applications, huge strides have been made in the technology, making today’s most cutting-edge models attractive for commercial contractors to offer to facility managers as an alternative to what they have been using for years.

The Department of Energy (DOE) is aware of the efficiencies that inverter heat pumps offer. In February 2022 it launched the Residential Cold-Climate Heat Pump Technology Challenge, which many HVAC manufacturers have joined. This initiative is encouraging the industry to develop the next generation of cold climate heat pump technology which can effectively generate the needed heat during colder weather without the need for auxiliary heat strips. Under guidance of the DOE, states including Washington, California, Oregon and Massachusetts, plus New York City, are beginning to phase out natural gas connections in the construction of new buildings, and many local utilities and municipalities offer homeowners tax credits or rebates for switching to more energy efficient systems like the most efficient inverter technology heat pumps. Rebates for commercial applications may be coming next.

Inverter technology heat pumps function as both air conditioners in the summertime and heaters in cooler months. They are far more efficient, comfortable and long-term cost effective than traditional rooftop commercial HVAC units. This next generation of heat pump compressor technology runs on variable speeds to use the minimum amount of energy required to maintain consistent comfort for temperature and humidity, while featuring ultra-quiet operation.

Consider a restaurant built 10-20 years ago with one 20-ton unit on its roof. On hot days, the compressor will run periodically to condition inside air to a set temperature. The unit shuts off at the desired temperature, then turns back on once the inside temperature rises. The system is loud, the "off" periods yield spikes in temperature without being able to consistently manage humidity and the constant on/off cycling is energy inefficient. Plus, in a traditional HVAC system only one thermostat and zone cover the entire space, resulting in uneven temperatures–customers by the east-side windows shiver as those by the sunny windows on the west side sweat while the system combats beaming afternoon sunlight with a one-size-fits-all approach. By leveraging multiple five-ton inverter technology heat pumps–which have higher Seasonal Energy Efficiency Ratio (SEER) ratings to begin with–along with an indoor air handling unit (AHU) working in tandem with custom selected multi-splits indoor heads, the same space could feature multiple thermostats and zones to offer tailored control and consistent comfort and humidity within a building.

Making this investment yields a final benefit: longevity. In traditional commercial rooftop HVAC units, all of the heating and cooling components sit outside, and that exposure to the elements reduces both efficiency and longevity. Installing these systems also requires multiple large roof penetrations and installation that is complicated, requiring coordination with a skilled roofer to prevent leaks or the heavy structure from damaging the roof over time.

Further, gas fired units that are exposed to outdoor elements must work harder to regulate inside climates, and 20% of the energy used to generate heat is wasted and vented into the atmosphere. Electric rooftop units, which cannot hold temperature on cold days, require the use of auxiliary heat strips–one of the most inefficient ways to generate heat. Inverter heat pump technology solves this issue as the evaporator coils within the air handling units are installed indoors, usually in a closet, utility room or hung horizontally, where temperature and humidity fluctuate minimally. By working more efficiently, inverter heat pumps can last about 20 years, or approximately twice as long as traditional commercial HVAC systems.

Switching to a residential-style inverter compressor heat pump also reduces the size and number of roof penetrations, which further promotes energy efficiency by minimizing unconditioned outside air infiltration as well as the safety and longevity of the roof.