Welcome to Part IV of our ongoing series demystifying American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards.
ASHRAE Standard 90.1 establishes guidelines for reducing energy consumption in commercial buildings. This article provides an overview of ASHRAE Standard 90.1 and demonstrates how energy recovery ventilators (ERVs) can play a key role in meeting the standard’s requirements.
In this installment of our ASHRAE Standards series, we dig into Standard 90.1 is and how ERVs can help meet its energy efficiency requirements.
What is ASHRAE Standard 90.1 and Why Was It Created
Formally titled Energy Standard for Sites and Buildings Except Low-Rise Residential Buildings, ASHRAE Standard 90.1 is the widely adopted standard for commercial buildings. The standard is frequently referenced by state and local jurisdictions and serves as the basis for many energy codes, including the International Energy Conservation Code (IECC).
To understand the origin of ASHRAE Standard 90.1, it helps to look back at mid-20th-century commercial building design. The 1973 Organization of the Petroleum Exporting Countries (OPEC) oil embargo triggered fuel shortages and soaring energy costs. The energy crisis demonstrated the need for a more energy-efficient approach to commercial building design. In response, ASHRAE published Standard 90 to improve energy efficiency in commercial buildings. It was later updated as ASHRAE Standard 90.1, which remains in use today.
Who Standard 90.1 Impacts and Where It Applies
Mechanical engineers, architects, building owners, and code officials rely on Standard 90.1 to guide energy-conscious design and ensure local code compliance. The standard applies to both new construction and major renovation projects across a wide range of commercial verticals:
- Commercial & Office Spaces: Multi-story office buildings, financial centers, and retail spaces.
- Institutional & Healthcare: Schools, healthcare facilities, and higher education campuses.
- Specialized Facilities: Animal care centers, senior living communities, salons, and high-rise residential structures over three stories above grade.
Meeting ASHRAE Standard 90.1 Section 6 Requirements with ERVs
Standard 90.1 covers five sections: building envelope, HVAC systems, service water heating, power, and lighting. Each section plays a vital role in overall performance. However, since HVAC systems typically account for 40% to 50% of a commercial building’s total energy consumption—with a significant portion dedicated to conditioning raw outdoor air—engineers often focus heavily on reducing energy use in this area to meet the standard.
To address this primary energy load, Section 6 (HVAC Systems) outlines mandatory and prescriptive performance requirements designed to optimize system efficiency.
Navigating the Ventilation Dilemma in Section 6.5
Within Section 6, the Prescriptive Path (Section 6.5) directly addresses a core challenge in commercial building design: balancing indoor air quality (IAQ) with energy efficiency. While higher ventilation rates are essential for occupant health, conditioning raw outdoor air—heating, cooling, and dehumidifying every cubic foot—drastically increases HVAC energy loads. To offset this penalty, Section 6.5 mandates exhaust-air energy recovery for systems meeting specific thresholds:
- Supply Fan Airflow Rates (CFM): System size and total volume of air being moved.
- Percent Outdoor Air (%OA): The proportion of fresh ventilation air versus recirculated air.
- Climate Zone & Operating Hours: Local design conditions and facility usage schedules.
By reclaiming thermal energy from outgoing exhaust air before it exits the facility, energy recovery systems reduce the energy required to condition incoming outdoor air, enabling project teams to maintain high ventilation rates without overloading primary HVAC equipment.
Meeting Section 6 Requirements with RenewAire ERVs
RenewAire ERVs provide a reliable, high-performance solution for achieving Section 6.5 compliance. Utilizing static-plate enthalpy core technology, these units capture both sensible heat and latent moisture from the outgoing exhaust airstream and transfer it to the incoming outdoor air. This process preconditions fresh outdoor air before it reaches primary cooling and heating equipment, helping facilities satisfy code objectives effortlessly. By capturing up to 70% of energy from the exhaust airstream, RenewAire ERVs convert code compliance into measurable building performance gains:
| Value Delivered | Performance Benefit |
|---|---|
| Capital Expenditure (CapEx) Savings | RenewAire ERVs precondition incoming outdoor air to reduce HVAC energy loads associated with increased ventilation. This lowers total tonnage demand on chillers, boilers, and rooftop units (RTUs). As a result, engineers can size primary equipment down to meet strict code baselines, helping offset the initial ERV investment. |
| Operational Expenditure (OpEx) Savings | Continuous year-round energy recovery lowers the utility load needed to condition incoming ventilation air across various climate conditions. |
Driving Commercial Building Efficiency with ASHRAE Standard 90.1
Standard 90.1 provides a clear roadmap for reducing energy consumption across commercial facilities. Focusing on Section 6 HVAC optimizations allows project teams to meet mandatory efficiency baselines effectively—lowering peak equipment loads and securing long-term utility savings through energy recovery ventilation.
Frequently Asked Questions (FAQs) About ASHRAE Standard 90.1
What is ASHRAE Standard 90.1?
ASHRAE Standard 90.1 is a widely recognized energy efficiency benchmark for commercial facilities. It offers baseline requirements for building envelopes, HVAC equipment, water heating, lighting, and power systems.
How do ERVs help support ASHRAE Standard 90.1 compliance?
Energy recovery ventilators (ERVs) help commercial buildings meet ASHRAE Standard 90.1 energy recovery requirements by capturing heat and moisture from the exhaust airstream and transferring that energy to incoming outdoor air. This process preconditions the outdoor air before it reaches the heating and cooling equipment, reducing HVAC energy loads and supporting Section 6.5 compliance.
How can ERVs lower equipment capital costs?
Energy recovery ventilators (ERVs) can lower equipment capital costs by reducing peak heating and cooling loads required to condition incoming outdoor air. This transfer sensible heat and latent moisture between airstreams, allowing engineers to specify smaller primary HVAC equipment—such as chillers, boilers, and rooftop units—which can offset the initial investment of the ventilation system.
What is the largest energy consumption in commercial buildings?
Heating, ventilation, and air conditioning (HVAC) systems typically account for 40% to 50% of energy consumption in commercial buildings. Much of this energy is used to condition incoming outdoor air, making thermal load reduction and energy recovery ventilation important strategies to improve overall energy efficiency.