With three years elapsing since the 2019 standard, the anticipated release of ASHRAE 90.1-2022 is here.
Though it will take some time for jurisdictions to codify these changes, it’s helpful for building owners and facility managers to anticipate what’s coming by way of this latest energy efficiency standard, which is focused more on whole systems and system interactions rather than prescriptive-based component design.
New Mechanical System Compliance Path
The ASHRAE 90.1-2022 update marks the first time an optional compliance path for the total system performance requirement (TSPR) for mechanical systems is included in a U.S. model energy standard or code at the national level. To achieve the required TSPR, engineers can combine multiple HVAC efficiency measures including:
- Improved heating or cooling equipment efficiency with systems like packaged units, heat rejection and large boilers
- Reduced fan energy from fan selection or fan drive and motor efficiency, and improved fan controls
- Reduced pumping energy via better piping design, hydronic configuration, pump selection or pump motor and drive efficiency, and improved pump controls
- Separate ventilation management with low dedicated outdoor air system (DOAS) fan power, demand-controlled ventilation, energy recovery bypass or improved delivery effectiveness
- Expansion of heat pumps with large commercial chiller heat pumps
New Unitary Rooftop Product Requirements
The standard also includes significant increases in efficiency for unitary rooftop products that went into effect in January 2023. Here are a few of the new requirements:
- Higher IEERs (integrated energy efficiency ratios), i.e. better energy efficiencies
- A change for SEER (seasonal energy efficiency ratio) to SEER2, which is the cooling output of an air conditioner or heat pump divided by the energy it uses in a typical season
- A change from HSPF (heated seasonal performance factor) to HSPF2, which is how efficiently a heat pump heats up a space in a typical season
Other changes were made to variable refrigerant flow, DOAS equipment, heat pump chiller requirements, furnace efficiencies and expanded airside economizer requirements.
New Lighting Requirements
Revisions in lighting include a reduced lighting power density (LPD) threshold for daylight controls, horticulture lighting and multifamily units. This threshold is defined as the minimum wattage for zones which require daylight responsive lighting controls.
For this latest update, ASHRAE re-evaluated the wattage threshold against current “state of the shelf” LED technology, dimming and the cost of sensors. The lighting committee found that reducing this threshold from 150W to 75W per daylight zone is cost-effective and would result in greater energy savings.
Lighting solutions such as wireless control systems and light fixtures with integrated daylight sensors are two technologies that can be used to create more daylight zones in a space, as required by ASHRAE 90.1-2022.
On-site Renewable Energy
Also, for the first time, ASHRAE 90.1 has a new requirement for an on-site renewable energy system to be installed on new buildings.
This is a prescriptive requirement and may be traded off under the performance path. There are also exceptions for smaller buildings, alterations or where there is excessive shading.
Regarding renewable energy, it’s a challenging topic. “On the one hand, ASHRAE 90.1 is generally used for single building sites; however, the best economies of scale occur with large-scale off-site renewables. That explains the committee’s current bend towards on-site renewable energy credits,” said Don Brundage, chair of ASHRAE, SSPC 90.1 committee and principal engineer, codes and standards, for Southern Company Services.
“We don’t want a building to get a large credit from renewable energy purchases from off-site, then a few years later, the operator does not renew the renewable purchase agreement and uses more non-renewable energy at that time than one with a renewable energy source located at the building site,” he added.
While buildings most commonly install photovoltaics, solar water-heating panels, wind and geothermal sources can be used to meet this requirement as well.
With the ink barely drying on the 2022 release, ASHRAE is already working on the next update for 2025, as well as a longer plan for 2028 and 2031 carbon reduction.
In the meantime, buildings in states like New York and California could see ASHRAE 90.1-2022 adoption as early as a year from now, while other states will take longer. In either case, as owners and facility managers plan their upcoming facility improvements, upgrading to meet these newer standards is highly recommended.