Conversion Formulas
°F = (°C × 9/5) + 32
K = °C + 273.15
°R = °F + 459.67
Canadian HVAC Design Temperatures
| City | Winter Design (°C) | Winter Design (°F) | Summer Design (°C) | Summer Design (°F) |
|---|---|---|---|---|
| Calgary, AB | -29 | -20 | 29 | 84 |
| Edmonton, AB | -27 | -17 | 29 | 84 |
| Vancouver, BC | -4 | 25 | 28 | 82 |
| Victoria, BC | -2 | 28 | 26 | 79 |
| Toronto, ON | -16 | 3 | 33 | 91 |
| Ottawa, ON | -23 | -9 | 32 | 90 |
| Montreal, QC | -23 | -9 | 31 | 88 |
| Quebec City, QC | -25 | -13 | 30 | 86 |
| Winnipeg, MB | -31 | -24 | 32 | 90 |
| Regina, SK | -34 | -29 | 32 | 90 |
| Saskatoon, SK | -34 | -29 | 31 | 88 |
| Halifax, NS | -16 | 3 | 29 | 84 |
| St. John's, NL | -16 | 3 | 25 | 77 |
| Yellowknife, NT | -43 | -45 | 27 | 81 |
Values based on ASHRAE 2.5% heating / 1% cooling design conditions. Use the Design Temperature Lookup for full ASHRAE data.
Common HVAC Temperature Reference Points
| Reference Point | °C | °F | K |
|---|---|---|---|
| Absolute zero | -273.15 | -459.67 | 0 |
| CO₂ refrigerant triple point | -56.6 | -69.9 | 216.6 |
| R-410A boiling point (1 atm) | -48.5 | -55.3 | 224.7 |
| R-32 boiling point (1 atm) | -51.7 | -61.1 | 221.5 |
| Freezing point of water | 0 | 32 | 273.15 |
| Cold storage — fresh produce | 2 | 35.6 | 275.15 |
| Refrigerator setpoint (Health Canada) | 4 | 39.2 | 277.15 |
| ASHRAE comfort zone winter | 20–22 | 68–72 | 293–295 |
| ASHRAE comfort zone summer | 23–26 | 73–79 | 296–299 |
| Typical heating setpoint | 21 | 69.8 | 294.15 |
| Typical cooling setpoint | 24 | 75.2 | 297.15 |
| Supply air — heating (VAV) | 40–55 | 104–131 | 313–328 |
| Supply air — cooling (AHU) | 12–14 | 54–57 | 285–287 |
| Chilled water supply (typical) | 6–8 | 43–46 | 279–281 |
| Hot water heating supply (high-temp) | 80 | 176 | 353 |
| Hot water heating supply (low-temp) | 45–55 | 113–131 | 318–328 |
| Boiling point of water (sea level) | 100 | 212 | 373.15 |
How to Use the Temperature Converter
Enter a temperature in any of the four unit fields — Fahrenheit, Celsius, Kelvin, or Rankine. All other values update automatically as you type. No button press needed.
Click any of the quick-reference chips to load common Canadian HVAC design temperatures instantly. These cover winter and summer design conditions for Calgary, Edmonton, Toronto, and Vancouver — the cities most frequently used in Canadian load calculations.
The result panel shows what HVAC context that temperature falls in — whether it's a comfort zone, a design condition, a refrigerant operating range, or an extreme cold warning. This helps you quickly verify a converted value makes sense for your application.
Scroll down for the full Canadian HVAC design temperature table covering 14 cities, and the HVAC reference point table covering refrigerants, comfort zones, system setpoints, and process temperatures. For load calculations, feed your design temperature into the Heat Load Calculator or Cooling Load Calculator.
Temperature Conversion in HVAC — Complete Guide
Temperature is the most fundamental measurement in HVAC. It drives every heat transfer calculation, every equipment sizing decision, and every comfort evaluation. Canadian HVAC work spans two temperature scales — Celsius in engineering and codes, Fahrenheit on US equipment datasheets — so fluid conversion between the two is a daily requirement.
Fahrenheit to Celsius — The Most Common Conversion
The exact formula is °C = (°F - 32) × 5/9. For field work, the mental shortcut "subtract 30, divide by 2" gives a close-enough approximation for most checks. The key reference points to memorize: 32°F = 0°C (freezing), 68°F = 20°C (typical room temp), 212°F = 100°C (boiling). For HVAC specifically, 70°F is 21.1°C (standard heating setpoint) and 75°F is 23.9°C (standard cooling setpoint).
Celsius to Kelvin — For Thermodynamic Work
Kelvin and Celsius differ by a constant offset: K = °C + 273.15. A change of 1°C is identical to a change of 1 K, so temperature differences (ΔT) are the same in both scales. Kelvin matters in HVAC when working with heat transfer coefficients (W/m²·K), thermodynamic efficiency formulas such as Carnot COP = T_cold / (T_hot - T_cold), and psychrometric equations. Use the COP / EER Converter for efficiency calculations.
Canadian Design Temperatures and the NBC
The National Building Code of Canada requires HVAC systems to be sized for outdoor design conditions. These aren't the coldest or hottest temperature ever recorded — they're the temperature exceeded only 2.5% of winter hours (heating) or 1% of summer hours (cooling). This means a Calgary heating system designed for -29°C will be adequate for 97.5% of winter hours. The remaining 2.5% may see lower temperatures, but the building's thermal mass typically buffers the difference. For the full ASHRAE design condition dataset, use the Design Temperature Lookup.
Temperature in Refrigeration Systems
Refrigerant work requires understanding saturation temperatures at various pressures. R-410A boils at -48.5°C (-55.3°F) at atmospheric pressure, which is why it must be stored in sealed cylinders under pressure. Under Canada's SOR/2016-137 regulations and the Kigali Amendment HFC phase-down, R-410A is being replaced by lower-GWP refrigerants like R-32 (boiling point -51.7°C) and R-454B. The saturation temperature at system operating pressures determines the evaporating and condensing temperatures — the two most important temperatures in refrigeration cycle analysis. Use the Refrigerant Unit Converter and Pressure Converter together for refrigerant work.
Temperature and Human Comfort
ASHRAE 55 defines the thermal comfort zone as roughly 20–26°C (68–79°F) depending on clothing level and activity, with relative humidity between 30% and 60%. Canadian heating systems typically target 21°C (69.8°F) in winter; cooling systems target 24°C (75.2°F) in summer. The spread between indoor setpoint and outdoor design temperature defines the temperature differential (ΔT) that drives the entire heat load calculation. A Toronto home with a 21°C indoor setpoint and a -16°C design temperature has a heating ΔT of 37°C — compared to Vancouver's modest 25°C. That difference directly scales the heating equipment size.
Related Conversions
Temperature is rarely converted in isolation. Equipment performance data ties together temperature, pressure, and energy. Use the Pressure Converter for refrigerant pressures and duct static pressures, the Enthalpy Converter for psychrometric values, and the BTU to kWh Converter for energy units. For full load calculations using your converted design temperatures, see the Heat Load Calculator and Cooling Load Calculator.
Frequently Asked Questions
Subtract 32 from the Fahrenheit value, then multiply by 5/9. The formula is: °C = (°F - 32) × 5/9. For example, 72°F is (72 - 32) × 5/9 = 22.2°C. A handy field shortcut: subtract 30 and divide by 2, which gives a close enough result for most HVAC checks. To go the other way, multiply °C by 9/5 and add 32.
Calgary's ASHRAE 2.5% heating design temperature is -29°C (-20°F). This is the value used for sizing furnaces, heat pumps, and boilers serving Calgary buildings. Some engineers use a more conservative -33°C for critical applications. The summer 1% cooling design temperature is 29°C (84°F) dry bulb. For full ASHRAE design data, use the Design Temperature Lookup.
Celsius and Kelvin use the same degree size — a 1°C change equals a 1 K change. The difference is the zero point: 0°C = 273.15 K (the freezing point of water), while 0 K is absolute zero (-273.15°C). In HVAC, Kelvin appears in thermodynamic efficiency formulas and heat transfer coefficients like W/m²·K. Temperature differences (ΔT) are numerically identical in both scales, so you can use either for delta-T calculations.
Rankine is the Imperial absolute temperature scale. Like Kelvin is to Celsius, Rankine is to Fahrenheit — same degree size, different zero point. 0°F = 459.67°R, and 0°R is absolute zero. Rankine appears in Imperial thermodynamic formulas and some US refrigeration engineering references. Canadian HVAC practice uses Kelvin for absolute temperature work. The COP / EER Converter handles efficiency calculations in both unit systems.