Key Conversion Factors
1 lb = 0.453592 kg = 453.592 g = 16 oz
1 tonne = 1000 kg = 2204.62 lb
1 short ton = 2000 lb = 907.185 kg
Refrigerant Cylinder Mass Reference
| Cylinder Type | Rated Capacity (lb) | Rated Capacity (kg) | Notes |
|---|---|---|---|
| Small disposable (R-410A, R-32) | 10 lb | 4.54 kg | Small system top-up; being phased out in Canada |
| Standard disposable (R-410A) | 25 lb | 11.35 kg | Most common residential cylinder size |
| Large disposable (R-410A) | 50 lb | 22.7 kg | Commercial systems and stocking |
| Recovery cylinder (standard) | 30 lb rated | 13.6 kg rated | Max safe recovered refrigerant mass |
| Recovery cylinder (large) | 50 lb rated | 22.7 kg rated | Commercial recovery work |
| R-32 cylinder (new systems) | 25 lb | 11.35 kg | Common transition refrigerant for R-410A replacement |
| R-454B cylinder (new systems) | 25 lb | 11.35 kg | Low-GWP HFC blend, Canadian market expanding |
Typical Residential Refrigerant Charge Reference
| System Type / Size | Typical Charge (kg) | Typical Charge (lb) | Notes |
|---|---|---|---|
| Mini-split, single zone (1.5 ton) | 0.6 - 1.0 | 1.3 - 2.2 | Pre-charged; check nameplate for exact charge |
| Mini-split, single zone (2 ton) | 0.8 - 1.5 | 1.8 - 3.3 | Varies by line set length and refrigerant type |
| Central A/C, 2 ton (R-410A) | 1.5 - 2.5 | 3.3 - 5.5 | Factory charge plus line set addition |
| Central A/C, 3 ton (R-410A) | 2.5 - 4.0 | 5.5 - 8.8 | Most common Canadian home size |
| Central A/C, 5 ton (R-410A) | 4.0 - 7.0 | 8.8 - 15.4 | Large home or small commercial |
| Commercial rooftop, 10 ton | 10 - 20 | 22 - 44 | Depends on circuit count and refrigerant type |
Always verify refrigerant charge from the equipment nameplate and manufacturer commissioning data. Charge by weight using a calibrated scale and recovery cylinder for accurate work. Use the Refrigerant Unit Converter for P-T reference data during charging.
How to Use the Mass Converter
Type a value in kg, lb, g, oz, tonne, or short ton. All other units update instantly. Use the quick presets for common HVAC quantities: a standard 25 lb (11.35 kg) refrigerant cylinder, a 50 lb (22.7 kg) cylinder, or a 1-tonne round number for equipment shipping weights.
The refrigerant cylinder table shows rated capacities for common disposable and recovery cylinders in both lb and kg. Compare against your converted value to identify which cylinder size holds the charge quantity you're working with. Always stay within the rated capacity of recovery cylinders -- never overfill.
The residential refrigerant charge table gives typical charge ranges in both kg and lb by system size. Use this to confirm a converted nameplate charge weight is in a plausible range for the equipment type before charging, or to estimate how much refrigerant a recovery job will produce for cylinder capacity planning.
Equipment shipping weights on North American spec sheets are often in lb while Canadian rigging calculations and weight limits use kg. Enter the lb value and read the kg equivalent directly. For large equipment exceeding 1000 kg, the tonne and short ton fields provide convenient reference points for crane capacity planning.
Mass and Weight in Canadian HVAC
Mass conversion between kilograms and pounds is a routine task in Canadian HVAC work because equipment specifications, refrigerant cylinders, and shipping weights often mix metric and Imperial units. Canadian regulations and engineering use metric, including the Ozone-depleting Substances and Halocarbon Alternatives Regulations governing refrigerant handling, while much of the North American equipment market labels cylinder capacities and equipment weights in Imperial pounds.
The Core Conversion: kg to lb
1 kg = 2.20462 lb. For field use, the approximation of 2.2 lb per kg is accurate to within 0.2% and fine for most practical purposes. Going the other way: 1 lb = 0.4536 kg, a relationship set out precisely in the NIST Guide to the SI, Appendix B. A standard 25 lb refrigerant cylinder holds 11.35 kg of refrigerant. A 50 lb cylinder holds 22.7 kg. These round conversions are worth memorising since they come up constantly in refrigerant charging and recovery work.
Refrigerant Charge by Weight
Refrigerant charge is always specified and measured by mass -- never by volume -- because refrigerant density changes dramatically with temperature and pressure. Charging by weight using a calibrated scale is the industry-standard method for accurate refrigerant charge verification. The equipment nameplate specifies the correct charge in both metric (kg) and Imperial (lb or oz) in most cases. Deviation from nameplate charge -- high or low -- affects system capacity, efficiency, and compressor reliability. Use the Refrigerant Unit Converter for P-T saturation data during the charging process to verify conditions alongside the mass reading.
Recovery Cylinder Capacity and Safe Handling
Recovery cylinders are rated by the maximum safe working mass of refrigerant they can hold, not by their total internal volume. A standard 30 lb rated recovery cylinder can safely hold 13.6 kg (30 lb) of recovered refrigerant. Overfilling recovery cylinders is a serious safety and regulatory issue -- liquid expansion can cause catastrophic cylinder failure. Always weigh the cylinder during recovery, stop at the rated capacity, and switch to a fresh cylinder if more capacity is needed. The Refrigerant Recovery Calculator helps plan cylinder needs before starting a job. Canadian refrigerant regulations under the Ozone-depleting Substances and Halocarbon Alternatives Regulations prohibit venting and require proper recovery procedures.
Equipment Shipping and Rigging Weights
HVAC equipment shipping weights on North American spec sheets are typically shown in lb, while Canadian rigging plans, forklift capacity checks, and structural load calculations all use kg or kN. A rooftop unit listed at 880 lb weighs 399 kg -- close to the 400 kg round number that makes a useful mental reference. Chillers and large air handlers can range from 500 kg for small air-cooled units to several tonnes for large water-cooled centrifugal machines, making accurate mass conversion essential for safe rigging and structural planning. For rooftop units specifically, the RTU Sizing Calculator should be checked against the roof's structural capacity before selecting equipment.
Frequently Asked Questions
Multiply kg by 2.20462 to get lb. So 1 kg = 2.205 lb, 10 kg = 22.05 lb, and 100 kg = 220.5 lb. To go the other way, divide lb by 2.20462 (or multiply by 0.4536). For field work, 1 kg ≈ 2.2 lb is accurate enough for most purposes. A standard 25 lb refrigerant cylinder holds 11.35 kg -- worth knowing by memory for refrigerant charging and recovery work.
Refrigerant charge is always specified by mass (kg or lb), never by volume, because refrigerant density varies significantly with temperature and pressure. A residential split system typically requires 1.5 to 4 kg of refrigerant depending on size and line set length. Charging by weight using a calibrated scale is standard practice. Always verify the nameplate charge specification and compare against the Refrigerant Unit Converter P-T data to confirm conditions during charging.
Mass is the amount of matter (kg, lb-mass), constant regardless of location. Weight is the gravitational force on that mass (newtons), which varies slightly with location. In everyday HVAC practice the terms are used interchangeably since we work at essentially constant gravity near Earth's surface. In thermodynamic calculations, mass flow rate (kg/s) is the correct quantity for heat transfer equations -- the distinction matters there but not when reading a scale or checking a shipping weight.
A standard 25 lb (11.35 kg) disposable R-410A cylinder weighs approximately 14 to 16 kg (31 to 35 lb) full, including the cylinder tare weight of 3 to 5 kg. A 50 lb (22.7 kg) cylinder weighs roughly 28 to 32 kg (62 to 70 lb) full. Recovery cylinders are different -- a 30 lb rated recovery cylinder has a tare weight of about 7 to 9 kg and can safely hold up to 13.6 kg (30 lb) of recovered refrigerant. Never exceed rated recovery cylinder capacity.