The right way to think about it
Every mechanical system in a house is consumable. A twenty-year-old furnace is not a defect — it is a known future cost with a reasonably predictable timeline. The question is never "is this bad" but "when will this need replacing, roughly what does that cost, and is the price of the house reflecting it".
An older system in a home priced as though everything were new is a negotiation. The same system in a home already priced for its age is simply the deal.
Rough service lives
- Furnace — typically well over a decade and often approaching two, with maintenance. Past that, function becomes unpredictable and efficiency is well behind current equipment. In this climate a furnace failing in January is not a minor inconvenience.
- Hot water tank — the shortest life of the three, usually around a decade. Cheap to replace relative to the others, but they tend to fail by leaking, and a leaking tank in a finished basement causes damage well beyond the tank.
- Roof — asphalt shingles have a wide range depending on product and exposure, and in Calgary they see hail. That shortens the working life relative to milder climates, sometimes considerably. Why hail matters here →
These are general ranges rather than guarantees. A well-maintained furnace can outlast a neglected newer one, and manufacturer and installation quality vary considerably.
What to ask about each
- How old is it, and is there documentation? A dated sticker or service record beats a seller's recollection.
- Has it been serviced? A furnace with annual service history is a different proposition from one nobody has touched.
- For the roof: has it been through a hail claim, was the claim paid, and was the work actually done? This is the question that catches people. A payout does not guarantee a repair.
- Is anything under warranty, and does the warranty transfer?
The most useful thing you can do with an inspection report is turn it into a schedule: what needs replacing in year one, year three, year five. That turns a list of worries into a budget, and a budget is negotiable.
How much should it affect your offer?
The honest answer is that it depends on whether the market has already priced it. If comparable homes that sold recently had newer systems and this one does not, that gap is real and defensible. If every comparable home of that age has the same profile, asking for a full replacement credit will not land, because you are asking to be compensated for the age of a house you knew the age of.
Get quotes rather than estimates when it matters. A number from a contractor is a negotiating position; "roofs are expensive" is not.
Hot water tanks: the one that fails first
The tank is the cheapest of the three to replace and the most likely to cause damage when it goes, because the usual failure mode is a slow leak rather than a clean stop. In a finished basement the tank is rarely the expensive part of that day.
- Find the age yourself. Most tanks carry a rating plate with a serial number encoding the manufacture date. An inspector will read it; so can you, on a showing.
- Ask whether it is owned or rented. Rented tanks are common here, and a rental contract generally has to be assumed by the buyer or bought out. Ask to see the agreement before conditions come off — the monthly cost and the buyout are contract terms, not fixed amounts.
- Look at what is around it. A floor drain nearby, a pan underneath, and a shut-off you can actually reach all change the size of the eventual mess.
- Tankless is a separate decision. Longer life, different servicing, and a venting and gas-supply question in an older house. Price it on the actual property rather than in general.
Whether a past leak was claimed matters too. Claim history attaches to the address, and a home with previous water claims is something an insurer will ask about — another reason to have your insurance answer before you waive conditions.
Windows: age, failed seals and what replacement involves
Windows are the item buyers most often misread. A failed thermal seal — fogging or a permanent haze between the panes — is a cosmetic and efficiency problem rather than a leak, and one failed unit is not evidence that the house needs windows.
What decides the cost is scope, not age:
- Glass or sash replacement keeps the existing frame and opening.
- Full-frame replacement removes the frame and disturbs the interior and exterior finish around it. A different job entirely.
- Changing the size of an opening is construction. It needs a permit, and in an older home it regularly uncovers the reason nobody did it sooner.
The one place window size is not optional is a bedroom. Under the code Calgary applies, a bedroom needs an openable window or exterior door providing an unobstructed opening of at least 0.35 m² — the City publishes egress window guidelines setting this out. It is why a basement room with a small original window is a den on a listing and a problem in a suite application. Adding a suite to a Calgary home.
Get a quote on the actual house. Window pricing varies too much with size, count, material and access for a general figure to be worth anything to you.