CSA Group has published an update to its sizing standard for residential heating and cooling equipment, reports the Heating, Refrigeration & Air Conditioning Institute of Canada (HRAI).
Changes to F280-12: Determining the Required Capacity of Residential Space Heating and Cooling Appliances, include:
- The ventilation sensible heat gain calculation formula has been revised. It now uses adjusted total recovery efficiency (ATRE) of an HRV/ERV instead of apparent sensible effectiveness (E), that was used previously.
- Default SHGC values are updated to 0.47 for all low-E double-glazed windows on Table 6F
- Default SHGC values are updated to 0.40 for all low-E triple-glazed windows on Table 6G
- Annex D of the standard is updated to require designers to configure a building to have largest glazed area to face southwest, if the facing direction of the building is unknown.
- Annex E of the standard is updated to prompt designers to report SHGC for windows and skylights on the heat loss and gain calculation summary sheet.
HRAI encourages its members to review the update and use it in their residential heat loss and heat gain calculation work going forward.
For more information, please contact HRAI technical adviser Chang Lee at clee@hrai.ca