Here are a few examples from historical data and experience:
Air conditioning compressor – air cooled, hermetically sealed | 12 to 15 years |
Air conditioning compressor – water-cooled, hermetically sealed | 20 years |
| Air conditioning compressor – reciprocating | 20 years |
| Rooftop heating and air conditioning unit | 20 years |
| Copper core boiler – heat exchanger | 15 to 20 years |
| Steel core boiler – heat exchanger | 10 to 15 years |
| New cast iron core boiler – heat exchanger | 20 to 25 years |
| Old cast iron core boiler – heat exchanger | 30 to 50 years |
| Steel tube boiler – heat exchanger | 20 to 40 years |
| Heat exchanger – standard rooftop unit | 15 to 20 years |
| Heat exchanger downstream of a cooling coil (package unit) | 10 to 20 years |
| Heat exchanger – standard combustion indoor system | 20 to 25 years |
| Cooling tower | 20 to 25 years |
| Central chiller | 20+ years |
| Air handler | 30+ years |
| Gas-fired ceiling-mount unit heater | 15 to 25 years |
| Gas-fired ceiling-mount radiant heater | 20 to 25 years |
| Built-up asphalt and gravel roof system | 20 to 25 years |
| Modified bitumen roof system | 15 to 20 years |
| Inverted EPDM rubber or PVC roof system | 25+ years |
| Asphalt paving for car parking | 20 years |
| Asphalt paving for trucks | 15 years |
| Sealed, double glazed windows | 20 to 30 years |
| Plywood overhead doors | 15 to 25 years |
| Pre-finished steel overhead doors | 20+ years |
| Electrical transformer | 30 years |
| Electrical switchgear | 30 years |