--- title: "ASHRAE 62.1 and How to Monitor It | Aethair" description: "ANSI/ASHRAE Standard 62.1, Ventilation and Acceptable Indoor Air Quality, is the ventilation design standard for commercial and institutional buildings in…" url: https://aethair.io/standards/ashrae_62_1/ --- Guidance · ASHRAE # ANSI/ASHRAE Standard 62.1: ventilation for acceptable indoor air quality Indoor: ventilation design (USA) **ANSI/ASHRAE Standard 62.1**, Ventilation and Acceptable Indoor Air Quality, is the ventilation design standard for commercial and institutional buildings in the United States: it sets **minimum outdoor air rates** by space type and occupancy, and procedures for designing ventilation systems to deliver them. It **does not set a limit for indoor CO₂**. ASHRAE's Position Document on Indoor Carbon Dioxide, reaffirmed in February 2025, says so explicitly and notes that misreadings of earlier editions still lead people to attribute a 1,000 ppm limit to ASHRAE. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure ASHRAE 62.1 Monitoring](https://aethair.io/build/?params=co2) At a glance **ASHRAE** Indoor: ventilation design (USA) 1 parameter [Carbon Dioxide (CO₂)](https://aethair.io/parameters/co2/) 1 device measures them all - **Aethair IAQ** [Official text from ASHRAE](https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2) Who it applies to ## Who Uses It Building designers and engineers, and the building codes that adopt it; classroom ventilation generally follows it. [WELL v2](https://aethair.io/resources/well-building-standard-air-quality/) accepts ventilation designed and balanced to ASHRAE 62.1 as one way to meet its ventilation precondition, and employers managing office space often align with it because OSHA has no indoor air quality standard for offices. Monitoring ## How Monitoring Relates to It Because 62.1 sets ventilation rates rather than concentrations, CO₂ is used as a proxy for how well a space is ventilated for its occupancy, and as the control input for demand-controlled ventilation. A CO₂ trend shows whether the outdoor air the design called for is actually reaching the room. The configurator assembles a monitor for CO₂ with temperature and humidity. [Customize this configuration](https://aethair.io/build/?params=co2) ### Who measures each parameter | Parameter | Aethair PRO | Aethair IAQ | External | | - | - | - | - | | [Carbon Dioxide (CO₂)](https://aethair.io/parameters/co2/) | CO₂ (dual NDIR), CO₂ (self-calibrating NDIR) cartridges | Built in | [2 instruments](https://aethair.io/parameters/co2/) via Thiamis | Devices ## Devices That Measure What ASHRAE 62.1 Relies On How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out. Aethair monitors [**Aethair PRO** Built in + Aethair CO₂ (dual NDIR) Covers it](https://aethair.io/products/pro/) [**Aethair IAQ** Built-in sensors Covers it](https://aethair.io/products/iaq/) Covers it on its own [**Particles Plus** Particulate & Dust Monitors](https://aethair.io/sensors/particles-plus-particulate-dust-monitors/) [**RAE** Gas Detectors](https://aethair.io/sensors/rae-gas-detectors/) Solutions ## Solutions That Rely on ASHRAE 62.1 ### [HVAC & Building Management](https://aethair.io/solutions/hvac-building/) Monitor ventilation and filtration, with data for your BMS ### [Indoor Air Quality](https://aethair.io/solutions/iaq-monitoring/) Offices, schools, homes, and public buildings ### [School Air Monitoring](https://aethair.io/solutions/education/) Classroom CO₂, particulates, and campus IAQ [All solutions](https://aethair.io/solutions/) Article Library ## Articles on ASHRAE 62.1 ### [Indoor Air Quality in Schools: Standards & Monitoring 2026](https://aethair.io/resources/indoor-air-quality-schools/) Indoor air quality in schools: which standards apply, what to monitor, and how CO2 and ventilation affect student attendance, health, and test scores. ### [Commercial Building IAQ Monitoring: ASHRAE 62.1 & WELL](https://aethair.io/resources/indoor-air-quality-monitoring-commercial-buildings/) Indoor air quality monitoring for commercial buildings: what to measure, which standards apply, and how property managers build a program tenants trust. ### [IAQ Monitoring Parameters: PM2.5, CO2, VOCs & Formaldehyde](https://aethair.io/resources/indoor-air-quality-monitoring-parameters/) Indoor air quality monitoring parameters explained: PM2.5, CO2, VOCs, and formaldehyde, plus the sensors, thresholds, and OSHA, ASHRAE 62.1, and WELL limits. ### [ASHRAE 170 Requirements and Which Edition Applies to You](https://aethair.io/resources/ashrae-170-requirements/) ASHRAE 170 requirements explained: what the standard sets, which edition your facility is held to, what changed in 2025, and how each value gets verified. ### [Workplace Air Quality Monitoring for Offices and Employers](https://aethair.io/resources/workplace-air-quality-monitoring/) How to monitor workplace air quality in offices, what to measure for employee health and focus, and how continuous connected monitoring documents the result. ### [Types of Air Quality Monitors: Indoor, Outdoor, and Combined](https://aethair.io/resources/types-of-air-quality-monitors/) Learn the three types of air quality monitors (indoor, outdoor, and combined), what each one measures, and when to use each one. [All articles](https://aethair.io/resources/) Questions ## ASHRAE 62.1 FAQ Does ASHRAE 62.1 set a CO₂ limit? No. ASHRAE's Position Document on Indoor Carbon Dioxide states that Standard 62.1 does not provide a limit value for indoor CO₂; it sets minimum ventilation rates. What does ASHRAE 62.1 set? Minimum outdoor air ventilation rates by space type and occupancy, and procedures for designing ventilation systems that deliver them. Why monitor CO₂ if ASHRAE 62.1 sets no limit? CO₂ is a proxy for ventilation per occupant: a rising trend shows a space is getting less outdoor air than its occupancy needs, and it drives demand-controlled ventilation.