What a load calculation report needs to include
Most Canadian building departments require a load calculation summary for a mechanical permit on new construction and major equipment replacements. The minimum typically includes: design temperatures, heating and cooling loads by component, total design loads, and proposed equipment with input and output capacities. The calculation method behind these numbers is set out in CSA F280, the Canadian standard for sizing residential heating and cooling equipment. Some jurisdictions require specific software output formats, so check with your local AHJ before using a simplified calculation for permit purposes.
How to use this generator
Run your loads through the individual calculators first: wall, window, roof, floor, basement, and infiltration. Enter those results here along with your equipment selection. If you need to confirm what your municipality requires before submitting, the building permit calculator is a useful starting point for typical documentation thresholds. Click Generate, then use your browser's Print to PDF function to save the formatted report.
Equipment sizing verification
Before finalizing equipment, verify sizing with furnace sizing or heat pump sizing calculators. Standard equipment sizing practice requires furnace output between 100-140% of design heat loss and AC between 95-115% of design cooling load. If your project includes an air sealing target for the permit file, the blower door calculator can help document the achieved ACH50 result alongside the load numbers.
Building code context
For background on how mechanical permit requirements fit into the broader building code framework, see Codes Canada, published by the National Research Council. Provincial and municipal codes typically adopt the National Building Code with local amendments, so always confirm the current edition in effect for your jurisdiction.
Frequently Asked Questions
Requirements vary by province and municipality. Ontario, BC, and Alberta increasingly require formal load calculations for new HVAC installations and major replacements. Some Ontario municipalities (Toronto, Ottawa) require it for all HVAC permits. Quebec requires heat loss calculations for new construction. Even where not legally required, a load calculation is best practice and protects against liability from oversized equipment. Check with your local AHJ (Authority Having Jurisdiction) before submitting a permit application.
A complete load calculation report for permit purposes should include: project address and date, design temperatures (indoor setpoint and outdoor design temp with source), floor area and building type, component-by-component heat loss and gain breakdown (walls, windows, roof, floor, infiltration), total design heating and cooling loads in BTU/hr and kW, proposed equipment with input capacity, output capacity, and efficiency rating, and the engineer or designer name and credentials where required. This generator produces all these elements in a printable format.