ASHRAE by definition is the American Society of Heating Refrigeration and Air-Conditioning and it is a US standard that provides minimum requirements for energy efficient designs for buildings except for low-rise residential buildings. Even though this in an American standard, it is adopted across Canada as a standard in the construction industry.
There are two means or paths for building designers to comply with ASHRAE 90.1;
Prescriptive Path - All components of the building meet the minimum standards specified by ASHRAE 90.1.
- Building Envelope (Section 5) : Minimum wall insulation, minimum roof insulation, roof reflectance, minimum glazing performance.
- HVAC (Section 6): Minimum equipment efficiency, minimum system features, limitation on reheat, limitation on fan power.
- Domestic Hot Water (Section 7): Minimum equipment efficiency, minimum system features.
- Power (Section 8): Transformer efficiency, automatic receptical controls, energy monitoring.
- Lighting (Section 9): Maximum indoor lighting power density (LPD, expressed in Watts/Sq. Ft.), minimum lighting controls, exterior lighting, parking garage lighting.
- Other Equipment (Section 10): Electric motors, potable water booster pumps, elevators and escalators.
Performance Path - A proposed building design is demonstrated (through building energy simulation) to use less energy than a baseline building built to ASHRAE 90.1 specifications.
- The building energy simulation is to model a building with the same size and program as the project building. It is built according to the prescriptive requirements of ASHRAE 90.1 (section 5-10). The ECB is expressed in units of dollars.
- A building energy simulation is then performed on the proposed building design. The proposed energy cost budget must be less than or equal to the baseline energy cost budget to achieve compliance.
- The performance approach is also used to demonstrate design energy efficiency, often expressed as percent better than ASHRAE Standard 90.1. Building designs will state their performance as "40% better than ASHRAE Standard 90.1-2007" or "20% better than ASHRAE 90.1-2010".
- Percent improvement over ASHRAE 90.1 is the basis for awarding energy points within the LEED Rating system.
ASHRAE 90.1 is an industry standard referenced by the USGBC in the LEED building certification program. It is frequently used as a baseline for comparison during energy retrofit projects or any project that employs building energy simulations.
Please visit www.ashrae.org for complete details on history, compliance, conferences and membership.
Advanced Insolutions products work to support building professionals when designing and building in compliance with ASHRAE 90.1.