Buyers often ask how old the furnace is, and how long it will last. The first question has an answer. The second only has a range. The table below gives general ranges for common components in a Metro Vancouver house. They are typical figures for planning, not guarantees. A component can fail early, and many last well past the range.
How to use the table
Use it to build a replacement budget and to decide which items to ask a specialist about. If a component is at or past the top of its range, assume it will need replacing within your first years, and plan the cost. If it is in the middle, it may be fine for a long time. Age is only part of it: condition, maintenance and installation matter just as much.
The inspector can tell you the age when the item has a date label, the type, and the condition. We cannot tell you the day it will fail.
Reference table
| Component | Typical range (years) | What shortens it | What we note |
|---|---|---|---|
| Asphalt shingle roof | 15 to 30 | Moss, shade, poor ventilation, bad flashing | Granule loss, curling, lifted tabs |
| Cedar shake roof | 20 to 35 | Moss, rot, lack of maintenance | Splits, rot, moss depth |
| Metal roof | 40 to 60 | Loose fasteners, scratches, sealant failure | Fasteners, seams, coating |
| Flat roof membrane | 15 to 30 | Ponding, blocked drains, foot traffic | Blisters, seams, drainage |
| Gutters (aluminum) | 20 to 30 | Debris, ice, loose brackets | Sags, leaks, slope |
| Furnace (gas forced air) | 15 to 25 | Dirty filters, no servicing, short cycling | Age label, cracks, venting |
| Heat pump | 12 to 18 | Poor installation, dirty coils | Noise, refrigerant lines, clearances |
| Boiler (hydronic) | 20 to 30 | Water quality, leaks, no servicing | Corrosion, relief valve, pump |
| Water heater (tank) | 8 to 15 | Hard water, sediment, no anode check | Data label date, rust at base |
| Water heater (tankless) | 15 to 20 | Scale, no flushing | Age, venting, scale |
| Windows, vinyl double-glazed | 20 to 35 | Seal failure, poor installation | Fogging, sill rot, operation |
| Windows, wood | 30 years or more | Paint failure, moisture at the sill | Rot at sills and sashes |
| Exterior paint or stain | 5 to 10 | Sun exposure, damp | Peeling, bare wood |
| Wood deck | 15 to 25 | Moisture, poor flashing at the ledger | Rot, loose railings, ledger |
| Asphalt driveway | 15 to 25 | Water, tree roots, no sealing | Cracks, settlement |
| Electrical panel | 40 years or more | Heat, corrosion, brand issues | Brand, double taps, scorching |
| Copper supply pipe | 50 years or more | Aggressive water, pinholes | Green stains, pinhole leaks |
| Galvanized steel supply pipe | 40 to 60 | Internal corrosion | Low pressure, rust-coloured water |
| PEX supply pipe | 40 years or more | UV exposure, bad fittings | Sunlight, kinks, fittings |
| Poly-B supply pipe | Not predictable | Fitting failure over time | Presence and fittings; see Poly-B |
| Cast iron drain pipe | 50 to 80 | Corrosion inside the pipe | Rust at joints, slow drains |
| Clay drain pipe | 50 years or more | Root intrusion, cracking | A camera scan is the way to know |
| Sump pump | 7 to 10 | Sediment, float failure | Test, discharge, alarm |
| Bathroom exhaust fan | 10 to 20 | Dust, motor wear | Duct to outside, noise |
| Garage door opener | 10 to 15 | Use, sensors | Auto-reverse and sensors |
Notes on a few entries
Water heaters. A tank is the item most often at the end of its life when a house is sold. The date is on the data label, and it is not always easy to read. When it is near the top of its range, plan to replace it, and consider a leak sensor and a drain pan.
Furnaces and heat pumps. Age is one measure. The other is how it has been serviced. A 20-year-old furnace that was serviced every year may outlast a 12-year-old one that was not. If you plan to add cooling or switch to a heat pump, ask an HVAC contractor, and also ask whether your electrical service is big enough.
Roofs. On the south coast, moss, shade and poor attic ventilation shorten the range. The roof guide covers it.
Windows. A failed seal shows as fog between the panes. It is a comfort and energy issue, and does not usually mean a leak. Rot at the sill is the one to worry about.
Pipes. Age is a poor guide for pipes. Galvanized pipe may last decades and then clog. Copper may last for generations unless the water attacks it. Poly-B is not about age at all.
What the table cannot do
- It cannot give a date. A range is a range.
- It cannot account for installation. A poorly installed new item can fail sooner than a well-installed old one.
- It cannot replace a specialist. If an item is critical to your decision, ask a plumber, roofer, electrician or HVAC contractor to look at it.
Turning it into a budget
A simple method: list each major component, its age, and the top of its range. Subtract. Items with less than five years left go on the first-five-year plan. Get one or two rough quotes for the biggest ones, and add them up. That total is a more useful number for your negotiation, and for your first few years of ownership, than any general rule.
If you are reading this because of a report, the guide on reading your inspection report is the next step.