Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 9008:2019 Part 1 is the Indian Standard (BIS) for energy performance of buildings - part 1: general requirements for hvac systems. This standard specifies the minimum energy performance requirements for the design, installation, and commissioning of HVAC systems in buildings. It provides a comprehensive framework covering system design, equipment sizing, controls, and insulation to promote energy efficiency in building operations.
Specifies general requirements and methodologies for calculating and evaluating the energy performance of HVAC systems in buildings.
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! This standard is aligned with international norms (ISO/EN) and is intended for detailed energy simulation and performance analysis, not just basic equipment sizing.
! The total required ventilation rate is a sum of the rate for occupants (bio-effluents) and the rate for the building itself (diluting pollutants from materials). Both components must be calculated.
! Pay close attention to the 'System Ventilation Efficiency' (Table A.2), a critical factor that represents how effectively fresh air is distributed to occupants.
ASHRAE 90.1-2022American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), USA
HighCurrent
Energy Standard for Buildings Except Low-Rise Residential Buildings
Both standards provide minimum energy efficiency requirements for commercial building HVAC systems, including equipment, controls, and system design.
EN 16798-3:2017European Committee for Standardization (CEN), Europe
HighCurrent
Energy performance of buildings - Ventilation for buildings - Part 3: For non-residential buildings - Performance requirements for ventilation and room-conditioning systems (Modules M5-1, M5-4)
Focuses specifically on performance requirements for ventilation and air-conditioning systems in non-residential buildings, aligning with the HVAC scope of IS 9008.
ISO 52000-1:2017International Organization for Standardization (ISO), International
MediumCurrent
Energy performance of buildings — Overarching EPB assessment — Part 1: General framework and procedures
Provides a high-level framework for assessing building energy performance, under which specific HVAC requirements similar to IS 9008 would fall.
ASHRAE 189.1-2023American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), USA
MediumCurrent
Standard for the Design of High-Performance Green Buildings
Covers HVAC energy efficiency but as part of a broader, more stringent 'green building' standard, setting requirements that often exceed minimum code.
Key Differences
≠IS 9008:2019 is primarily prescriptive, while ASHRAE 90.1 offers well-defined alternative performance paths like the Energy Cost Budget (ECB) method, allowing more design flexibility.
≠Climate zone definitions differ significantly. IS 9008 uses the 5 Indian climatic zones (Hot-Dry, Warm-Humid, Composite, etc.), whereas ASHRAE 90.1 uses a more granular system of 8 primary zones based on heating and cooling degree days.
≠Equipment efficiency requirements in IS 9008 are referenced to Indian standards (IS) and the Bureau of Energy Efficiency (BEE) star labeling program, while international standards reference their regional schemes (e.g., AHRI in the US, Eurovent in Europe).
≠Air-side economizer requirements in IS 9008 are based on broader climate zones and system capacities, while ASHRAE 90.1 provides very specific, climate-zone-dependent trade-off tables and thresholds for when economizers are mandatory.
Key Similarities
≈Both standards contain a set of mandatory provisions covering fundamental aspects like equipment efficiency, system controls, and insulation that must be met regardless of the compliance approach.
≈A core principle in both IS 9008 and its international counterparts is setting minimum efficiency levels for HVAC equipment such as chillers, boilers, pumps, and fans.
≈Both mandate minimum levels of thermal insulation for HVAC ductwork and piping to reduce energy losses, with required thickness typically varying by pipe/duct size and fluid/air temperature.
≈Both standards require system controls such as thermostats for individual zones, automatic shutdown capabilities, and, in certain high-density applications, Demand Controlled Ventilation (DCV).
≈Both emphasize the need for proper system installation and performance, requiring air and hydronic systems to be balanced to ensure they operate according to the design intent.
Parameter Comparison
Parameter
IS Value
International
Source
Chiller Min. Efficiency (Water-cooled Centrifugal, >528 kW)
IPLV of 6.2 (as per BEE Schedule 1)
IPLV of 6.176 (for 1055-2110 kW range, Path A)
ASHRAE 90.1-2022
Fan Power Limitation (VAV Systems)
Max 2.2 W/(L/s) or 1.17 hp/1000 cfm
Max 0.9 hp/1000 cfm (plus allowances for certain filtration/treatment components)
ASHRAE 90.1-2022
Demand Controlled Ventilation (DCV) Trigger
Required for spaces with occupant density > 25 people/100 m²
Required for spaces > 46 m² with design occupant density > 27 people/100 m²
ASHRAE 90.1-2022
Duct Leakage Test Requirement
Mandatory for ducts with static pressure class > 750 Pa
Mandatory for ducts designed to operate at static pressure > 750 Pa (3 in. w.g.)
What is the minimum fresh air required in an office?+
For a standard low-pollutant office (Category II), the requirement is 7.5 l/s per person plus 0.6 l/s per m² of floor area. (Table 1)
How do I calculate total ventilation rate?+
It's the sum of the rate required for occupants and the rate required for the building fabric: q_v,tot = q_v,pers + q_v,build. (Clause 5.2)
What are the building categories mentioned in the code?+
Category I (low-polluting), Category II (medium-polluting, e.g., offices), Category III (high-polluting), and Category IV (very high-polluting). (Table 1, Note)
Is this code mandatory?+
Its adoption is voluntary unless cited by a regulatory authority, such as in building energy codes like ECBC (Energy Conservation Building Code).