Challenge
One of the drivers for updating the 1990 version of the F280 Standard was to address the short cycling of mechanical equipment in energy efficient homes. Conventional sizing practice can result in oversized and inefficient heating and cooling systems, which can lead to increased energy bills and uneven temperatures within homes. The updated Standard contains substantive changes to the way design heating and cooling loads are determined.
The primary objective for NRCan’s research was to enable the home building industry to consider the impact the new CSA F280-2012 can have on sizing equipment based on a sampling of high performance homes in their region.
The second objective was to compare the results with emerging software choices for sizing equipment, and provide LEEP builders with a field trial home with design heating and cooling loads that meet the new Standard.
A third objective was to trial the use of the draft duct design guide from NRCan and provide constructive feedback.
Client:
Natural Resources Canada
Approach
Using the current envelope and mechanical equipment specifications, Ecolighten worked with builders to gather plans, alternative building assemblies/window packages, air tightness expectations, and HVAC systems already under consideration.
With this information, Ecolighten conducted: heat loss and gain calculations using Wrightsoft version 17.0.23 (Build 4680) software (using the BC Building Code minimums as the baseline with adjustments for specific climate zone requirements); performance modeling comparisons between the old and new Standards; comparisons of load calculation software tools; HVAC design and commissioning services; and presentations to builders at LEEP sessions.
Results
Ecolighten summarized technical analysis and lessons learned through a group of leading BC builders to examine the impact the revised CSA F280-12 could have on sizing mechanical systems for the homes they build.
This contribution will help the building industry to:
- Understand how using CSA F280-12 Standard can reduce sizing of heating and cooling equipment and distribution systems
- Consider envelope and ventilation upgrade options that could further reduce system size and cost
- Consider right-sizing to improve efficiency, optimize ducting systems and improve home comfort
- Know where to focus on reducing loads on future builds
- Arm builders to ensure they are using CSA F280-12 Standard calculations
- Understand the impact of heating and cooling requirements from a baseline of BC Building Code minimums to ENERGY STAR® building standards and Builder Specified Custom Standards