CSA F280 Sizing Guide for BC Builders
Understand CSA F280 block-load and room-by-room calculations, when each is useful, what to send, and how F280 differs from HOT2000 modelling.
Do not use HOT2000 output to size HVAC equipment. CSA F280 is the code-referenced calculation used to determine residential heating and cooling capacity; HOT2000 models annual energy use for Step Code and EnerGuide work.
The F280 block load gives the whole-house load for equipment selection. Room-by-room F280 gives the per-room loads used for duct, register, distribution, and zoning decisions. The F280 service page explains the quoted scope.
Both calculations depend on stable drawings, windows, assemblies, orientation, ventilation, and mechanical choices. Send the same coordinated drawing set used for the energy model. Your quote states whether block-load, room-by-room, or both are included.
CSA F280 and permit-document expectations can change. Confirm the current building-department checklist for the project.
Match the calculation to the decision.
- Use a block load for whole-house equipment selection
- Use room-by-room F280 when the mechanical design needs per-room duct, register, or zone detail
- Confirm what the building department or mechanical team expects
- Complete the calculation before final equipment selection
Use the same stable project information.
- Floor plans, elevations, sections, room names, and ceiling heights
- Window and exterior-door sizes and performance values
- Wall, roof, floor, slab, and foundation assemblies
- Project orientation, ventilation notes, and equipment preferences
Questions about this stage.
What is an F280 block load?
It is the whole-house heating and cooling load used for equipment selection.
What is room-by-room F280?
It provides per-room loads used for duct, register, distribution, or zoning decisions.
Can HOT2000 replace F280?
No. HOT2000 models annual energy use. F280 calculates design heating and cooling loads separately.
When should F280 work start?
Start before final equipment selection, once the drawings and envelope information are stable.
Send the drawings. Get a straight answer.
Send me the plans and whatever information you have. I'll take a look and get back to you with a quote.