ASHRAE 90.1-2022: Energy Standard Updates and Compliance Guide
ASHRAE 90.1-2022 Overview
ASHRAE Standard 90.1-2022 represents a significant advancement in building energy efficiency requirements, introducing new compliance pathways and updated efficiency metrics. The standard achieves approximately 15% energy cost reduction compared to the 2019 edition.
Major Changes from 2019
New Mechanical System Performance Path (MSPR)
The 2022 edition introduces Section 6.6, the Mechanical System Performance Path, as an alternative to prescriptive compliance. This path uses the Total System Performance Ratio (TSPR) to evaluate complete HVAC system efficiency.
TSPR Calculation:
TSPR = Annual Cooling Output + Annual Heating Output
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Annual Energy Input (electricity + fuel)
Minimum TSPR Requirements by Climate Zone:
| Climate Zone | Minimum TSPR | Baseline System |
|---|---|---|
| 1A, 2A | 3.8 | Packaged rooftop, VAV |
| 3A, 4A | 3.5 | Packaged rooftop, VAV |
| 5A, 6A | 3.2 | Boiler + chiller, VAV |
| 7, 8 | 2.8 | Boiler + chiller, VAV |
Heat Recovery Chiller Credit (COPHR)
New metric for evaluating heat recovery during chiller operation:
COPHR = Useful Heating Output / Compressor Energy Input
Systems with COPHR ≥3.0 receive prescriptive trade-off credits.
Updated Equipment Efficiency Requirements
Air-Cooled Chillers (≥150 tons):
| Metric | 2019 Requirement | 2022 Requirement | Improvement |
|---|---|---|---|
| Full Load EER | 9.7 | 10.1 | +4.1% |
| IPLV | 12.5 | 13.2 | +5.6% |
Water-Cooled Chillers (300-600 tons, positive displacement):
| Metric | 2019 Requirement | 2022 Requirement | Improvement |
|---|---|---|---|
| Full Load kW/ton | 0.56 | 0.52 | +7.1% |
| IPLV | 0.38 | 0.35 | +7.9% |
Boilers (≥1,000,000 Btu/h):
| Type | 2019 Efficiency | 2022 Efficiency |
|---|---|---|
| Gas-fired, hot water | 82% Et | 90% Et (condensing) |
| Gas-fired, steam | 80% Et | 82% Et |
Energy Recovery Ventilation
Minimum Enthalpy Recovery Ratio (ERR):
| Exhaust Airflow | Climate Zones 3B, 3C, 4B, 4C, 5B | All Other Zones |
|---|---|---|
| ≥1,500 cfm | 50% | 55% |
| ≥5,000 cfm | 55% | 60% |
| ≥10,000 cfm | 60% | 65% |
VRF and DOAS Requirements
Variable Refrigerant Flow (VRF) Systems:
| Cooling Capacity | Minimum IEER |
|---|---|
| <65,000 Btu/h | 16.0 |
| 65,000-135,000 Btu/h | 15.5 |
| >135,000 Btu/h | 14.5 |
Dedicated Outdoor Air Systems (DOAS):
- Mandatory energy recovery for systems >1,000 cfm outdoor air
- Demand control ventilation required for spaces >500 sq ft with design occupancy >25 people
Compliance Pathways
Path Comparison
| Pathway | Description | Best For |
|---|---|---|
| Prescriptive (6.5) | Meet all individual equipment requirements | Simple systems, standard buildings |
| MSPR (6.6) | Meet TSPR for complete mechanical system | Complex systems, integrated design |
| Performance (11) | Whole-building energy modeling | High-performance, innovative designs |
MSPR Advantages
- System Integration Credit: Accounts for heat recovery, economizers, and controls synergies
- Equipment Trade-offs: Higher efficiency equipment can offset lower efficiency elsewhere
- Innovation Allowance: Enables emerging technologies not covered by prescriptive requirements
Prescriptive Changes Summary
Fan System Power
Maximum Fan System Power (W/cfm):
| System Type | 2019 Limit | 2022 Limit |
|---|---|---|
| CV systems, no heating/cooling | 0.30 | 0.28 |
| CV systems with heating/cooling | 0.60 | 0.55 |
| VAV systems | Variable | Variable (-5%) |
Piping Insulation
Increased Pipe Insulation Requirements:
| Fluid Temp Range | Pipe Size | 2022 Insulation (inches) |
|---|---|---|
| 40-60°F | <1" | 1.0 |
| 40-60°F | 1"-4" | 1.5 |
| 40-60°F | >4" | 2.0 |
Economizer Requirements
Integrated Economizer Requirements:
| Climate Zone | Cooling Capacity Threshold |
|---|---|
| 1A, 1B | Not required |
| 2A, 2B, 3A | ≥54,000 Btu/h |
| All others | ≥33,000 Btu/h |
Controls Requirements
Demand Control Ventilation (DCV)
Required for spaces meeting ALL criteria:
- Design occupancy ≥25 people
- Floor area ≥500 sq ft
- Design outdoor airflow >0.3 cfm/sq ft
Setpoint Reset
Supply Air Temperature Reset:
- Required for all VAV systems >10,000 cfm
- Minimum reset range: 5°F from design
- Based on zone demand or outdoor air temperature
Chilled Water Reset:
- Required for chilled water systems >300,000 Btu/h
- Reset based on valve position or outdoor air
Documentation Requirements
Compliance Documentation Package
- Mechanical schedules with efficiency ratings
- TSPR calculations (if using MSPR path)
- Controls sequences demonstrating required strategies
- Commissioning plan per Section 8
Testing and Balancing
- Air system balancing within ±10% of design
- Hydronic balancing within ±5% of design
- Economizer functional testing required
Adoption Status
US Adoption Timeline
| Jurisdiction | Adoption Date | Notes |
|---|---|---|
| California (Title 24) | 2026 | Based on 90.1-2022 |
| Washington | 2025 | State amendments |
| Massachusetts | 2025 | Stretch code option |
| Federal buildings | 2024 | GSA requirement |
International Adoption
- IECC 2024 references 90.1-2022
- ASHRAE 189.1-2023 builds upon 90.1-2022
References
- ASHRAE Standard 90.1-2022: Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings
- ASHRAE 90.1-2022 User’s Manual
- PNNL Technical Support Documents for ASHRAE 90.1-2022