As winter temperatures drop, commercial building owners and operators face rising energy costs and performance challenges. Heating demands, occupant comfort, and indoor air quality all converge to create a delicate balancing act between efficiency and tenant satisfaction. Fortunately, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) provides a well-established framework for optimizing energy performance during the heating season. By applying ASHRAE-based strategies, real estate stakeholders can reduce costs, extend equipment life, and improve market competitiveness through high-performing, energy-conscious buildings.

Why Winter Efficiency Matters in Commercial Real Estate

Energy use typically spikes during winter months, with heating often representing the largest single end-use in commercial facilities. According to the U.S. Energy Information Administration (EIA), space heating accounts for nearly one-third of total commercial building energy consumption in colder climates. Rising utility rates and corporate sustainability commitments add further urgency for real estate owners to adopt efficiency measures that not only lower costs but also strengthen Environmental, Social, and Governance (ESG) performance.

ASHRAE’s Guiding Framework

ASHRAE standards—particularly Standard 62.1 (Ventilation for Acceptable Indoor Air Quality) and Standard 55 (Thermal Environmental Conditions for Human Occupancy)—provide the foundation for winter energy management. These standards guide building professionals in designing and operating systems that balance comfort, efficiency, and health.

Key Strategies for Winter Energy Efficiency

Based on differing building’s size, usage, and operational demands; there is not a one-size-fits-all solution for Winter Energy Efficiency,” said Chris Lelle, Senior Operations Manager at Lincoln Property Companies.” Our winter strategies revolve around creating a plan early, adding checklist of to-do items, and moving towards customized plans for each building, making sure their specific needs are met.”

The following provides some strategies to identify energy efficiency during the winter or perhaps assists in the development of an energy saving plan moving forward.

1. Identify Hidden Losses with Thermographic Scans
Even when a building appears well-sealed, unseen thermal weaknesses can drive up heating demand. Thermographic imaging during winter identifies air leakage, poorly insulated areas, and thermal bridges. This data allows owners to prioritize targeted upgrades with measurable return on investment. Any time the building envelope has leaks where infiltration occurs, the HVAC system is put in a position to chase thermal comfort rather than to control it by providing all heating, ventilation, and air conditioning to the building.

2. Control Stack Effect Through Building Pressurization
The stack effect—caused by warm air rising and escaping at the top of a building while cold air is drawn in at the base—intensifies in winter, leading to drafts, uneven heating, and higher energy use.

• Maintain slight positive building pressurization by carefully balancing supply and exhaust airflow.
• Use vestibules, revolving doors, and air curtains to limit uncontrolled infiltration at entry points.
• Monitor building differential pressure with sensors integrated into the BAS, adjusting outside air and exhaust fan operation in real time.
• Regularly check that stairwells, elevator shafts, and mechanical chases are sealed to minimize vertical air leakage pathways.

Controlling pressurization not only reduces heating loads but also improves occupant comfort and system stability.

Real-world example: A building in New York City that was undergoing Retro-Commissioning identified stack effect causing elevator doors not being able to close on the coldest days of the year. One of the engineering team members noted that he slowed down some of the return fans and was able to mitigate the elevator issue.

In order to back up his solution with data, the differential pressure was measured across the lobby doors and was found to be -0.2” (negative indicates a larger pressure outside causing air to rush inside when doors open) whereas many buildings target +0.05”. When walking into this building, you felt as if you were in a wind tunnel. All of the large return fans were incrementally slowed down to minimum speeds which led to a neutral pressurization condition during that cold day.

By implementing a heating season return fan strategy, the building was able to realize 70 kW in fan savings (equivalent to lighting an entire 6-story building). After a year of modified operation, the Engineer reported back that their number of cold calls was reduced dramatically because ventilation was now being entirely provided through the HVAC system instead of infiltration drafts around the perimeter of the building through leaks in the envelope.

3. Tune HVAC Controls – Night setback temperatures
During unoccupied periods, zone heating setpoints can be lowered by several degrees to reduce the heat loss from inside to outside the building. This prevents unnecessary heating when spaces are empty overnight, while ensuring the system warms back up before occupants arrive. The setback range should be calibrated to balance savings with reheat time. If the night setback temperature is set to 60 degrees, it will have a greater reduction in energy savings than if the setback is 65 degrees, which will take less time to heat back to 70 degrees. There is likely little difference in the heating demand between these two, just a function of how long that peak heating demand lasts in the morning.

4. Tune HVAC Controls – Heat Lockout Strategy
Heating and cooling systems can sometimes operate simultaneously, especially in shoulder seasons or transitional weather. A heat lockout prevents this energy waste by disabling heating when outdoor air temperatures are above a certain threshold (for example, 65°F). While this article is centered on strategies most productive during heating season, implementing this strategy when ambient temperatures are above 65°F can maximize savings during heating season. This strategy will identify VAV zones that may be overcooling a space because of a damper that is stuck open. If the fan and heat energize and are able to heat the air to a comfortable temperature, the operator may not notice there is an issue because it isn’t possible to track each piece of equipment in a building.

5. Tune HVAC Controls – Supply Air Temperature Reset
Instead of delivering a constant 55°F supply temperature, the system can automatically adjust based on outdoor air conditions or actual building load. For example, on a 40°F day, supplying warmer supply air (63°F) can drastically reduce the amount of reheat required to maintain the perimeter areas. This reset upper limit has diminishing returns if you get too warm as interior loads may drive increased fan speeds for those cooling-only zones.

6. Tune HVAC Controls – Static Pressure Reset
Variable air volume (VAV) systems often operate with fixed duct static pressure setpoints, leading to excessive fan energy use. By measuring the position of all VAV box dampers on a given air handler system, the BAS can reset duct static pressure lower whenever airflow demand is reduced. This “trim and respond” strategy reduces fan horsepower, lowers noise, and improves comfort while keeping enough pressure available for critical zones.

7. Tune HVAC Controls – Demand-Controlled Ventilation
By using CO₂ sensors or occupancy schedules, outdoor air ventilation rates can be adjusted dynamically. In winter, this prevents the system from over-ventilating and unnecessarily heating large volumes of cold outside air. For high-occupancy spaces like conference rooms, ventilation can ramp up when needed, then scale back once the space is empty. Lower ventilation rates can also help avoid bursting sprinkler heads in mechanical room plenums.

8. Tune HVAC Controls – Ensure Proper Economizer Operation
During the heating season, buildings with air or water-side economizers should ensure that these sequences are operating properly. If these systems are not providing economizer functionality at all, the mechanical cooling system (compressors) use more energy to maintain the cooling comfort levels required. If the economizer system is providing too much cooling, the system is at risk of freezing coils or requiring pre-heat or reheat systems to operate longer than necessary. For those systems with air-side economizer, checking outdoor air dampers for leaks and range of operation is a must on at least an annual basis.

9. Calibrate to Occupant Comfort Standards
A common mistake is overheating spaces, which wastes energy and decreases comfort.

• ASHRAE 55 defines acceptable temperature and humidity ranges for winter occupancy.
• Occupant surveys and feedback loops help fine-tune heating setpoints, ensuring both efficiency and tenant satisfaction.

10. Embrace Data-Driven Operations
Modern building automation systems (BAS) provide powerful tools for winter efficiency when used proactively.

• Trending space and system data (temperature, humidity, CO₂, occupancy) allows operators to identify performance drifts, hot/cold spots, and simultaneous heating/cooling.
• Smart sensors and BAS sequences aligned with ASHRAE Guideline 36 (High-Performance Sequences of Operation) enable continuous optimization of heating, ventilation, and air distribution.
• Data analytics can flag inefficiencies early, avoiding comfort complaints and unnecessary energy use.

The Real Estate Advantage

For commercial real estate investors and asset managers, adopting ASHRAE-based winter efficiency strategies goes beyond operational savings. Energy-efficient buildings demonstrate higher net operating income, stronger tenant retention, and increased property valuation. Additionally, they support compliance with emerging local building performance standards and carbon reduction mandates.

Winter energy efficiency is not just a technical exercise—it’s a strategic advantage in today’s commercial real estate market. By leveraging ASHRAE standards and best practices, building owners can maintain occupant comfort, reduce operating costs, and elevate their assets. As we enter another heating season, aligning building operations with ASHRAE guidance represents a clear path to performance, profitability, and resilience.

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