Heating a Hamilton century home works best when you build around what the house already is instead of forcing a suburban system into it. In Durand, Kirkendall, Corktown, Strathcona, Crown Point and the North End, most of these houses went up between the 1880s and the 1920s with solid multi-wythe brick walls that have no cavity to insulate, a stone or brick foundation, and either cast-iron radiators or ducts left over from a gravity furnace. The options below respect those facts; the quotes that go wrong tend to ignore them.
What a Century House Actually Does With Heat
Four physical facts drive every decision, and none of them apply to a house built after the war.
- Solid masonry walls: two or three courses of brick laid tight, with no air space. There is nothing to blow insulation into, so the wall gets improved only during a gut renovation with a new insulated assembly on the interior face. Everywhere else, the attic, the basement and the rim joist are where the money goes.
- Balloon framing: in many of these houses the stud bays run uninterrupted from the sill plate to the attic, so warm air rises inside the walls and leaves through the attic floor. Air sealing at the top of those cavities changes the comfort of a room more than a larger burner ever will.
- Thermal mass: brick and plaster are slow. The house takes hours to come up to temperature and hours to give it back, which is exactly why deep programmable setbacks disappoint people who move here from a newer build.
- Low, irregular basements: rubble foundations, stone ledges, beam pockets and headroom that runs out before the ductwork does. Any duct plan has to be drawn under the joists you actually have.
Fix the Envelope Before You Choose the Equipment
The single highest-return order of work in a century home is air sealing first, insulation second, equipment third. Sealing the attic hatch, the top plates, the old chimney chase and the rim joist, then bringing the attic up to a current insulation level, can shrink the heat loss enough that a smaller and better-modulating system fits the house — and a smaller system runs longer and steadier, which is what a masonry house wants.
Do it in the other order and you pay twice: once for capacity you did not need, and again in short cycling and uneven rooms. A measured assessment is the cheap way to find out where the heat is going — see home energy audits in Burlington, Oakville and Hamilton for what one actually involves.
If the House Has Radiators and a Boiler
Keep them. Cast-iron radiators are a genuinely good match for a heavy masonry house: they deliver steady, quiet, largely radiant heat, they have enormous surface area, and they are happy running at lower water temperatures than most people assume. The right move is almost never ripping them out for forced air — that means opening walls and ceilings across three floors of plaster to gain very little.
- Replace an end-of-life boiler with a modern condensing unit and set up outdoor reset, so the water temperature falls on milder days instead of the boiler cycling hard against the thermostat.
- Add thermostatic radiator valves to the rooms that overheat. In a Durand or Kirkendall house that usually means the front parlour roasting while a rear bedroom never catches up, and TRVs fix it for a fraction of a rebuild.
- Air-to-water heat pumps can feed radiators at lower temperatures and are worth asking about, but they need generous emitter surface and remain a specialist install in Ontario rather than a default choice — can a heat pump replace a boiler covers the trade-offs honestly.
- A handful of these houses are still on one-pipe steam. Steam is not a boiler swap; it needs a contractor who understands venting and pitch, and the wrong replacement will hammer and starve rooms.
- Cooling is the real gap in a radiator house, and that is a ductless conversation rather than a boiler one.
If the Ducts Came From a Converted Gravity Furnace
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The trunks are usually worth keeping and the distribution almost never is. A gravity furnace moved air by buoyancy alone, so its ducts are enormous, short and nearly straight; when a fan-driven furnace was dropped in decades later, the same octopus was simply reused. The result is a system with one giant central return, no return anywhere above the main floor, registers that whistle at the nearest rooms and a top storey that never gets its share.
- Add return paths before you add capacity: a dedicated return in each bedroom where the walls allow, or transfer grilles and jump ducts where they do not. A closed door with no return path is what starves those rooms.
- Seal and, where they are wildly oversized, reduce the old trunks so air actually reaches the far branches at a useful velocity.
- Fit balancing dampers on the branches, then balance the system with the doors closed the way the family really lives.
- Only then choose the furnace. A two-stage or modulating unit with an ECM blower suits a slow masonry house far better than a single-stage burner, which delivers heat faster than brick and plaster can absorb it.
Adding Cooling Without Wrecking the Plaster
For a radiator house, a multi-zone ductless system is the least destructive route to real cooling. Heads go in the main living space and the bedrooms, and the line sets run through a closet chase, the old chimney chase, or along a rear elevation where they are out of sight from the street. Installed costs run $4,000–$7,000 for a single zone, $7,500–$11,000 for two, and $10,000–$16,000 or more for three to four zones, with cold-climate models adding roughly $500–$1,500 per zone but earning it back by heating the same rooms in shoulder season.
Small-duct high-velocity systems are the other route: two-inch flexible tubing threaded through stud bays and closet corners, feeding small outlets. They cost more than a conventional install and they need a contractor who has done them before, but in a house with no ducts and no tolerance for wall damage they are a legitimate answer. The trade-off against ductless is straightforward: small-duct high-velocity conditions the whole house from one indoor unit and leaves only small round outlets in the plaster, while ductless costs less, zones room by room, and puts a visible head on the wall of every room it serves.
The Third Floor Problem Every 2.5-Storey Has
Hamilton's century stock is full of 2.5-storey houses with a finished attic bedroom, and that room is at the end of every duct run, directly under a roof, above an open stairwell that pulls warm air up all winter and hot air up all summer. It is the single most complained-about room in these houses.
Work it in order: seal and insulate the roofline and knee walls first, since a finished attic usually has almost nothing behind the plaster. Then give the room a dedicated return so air can leave it rather than just pressurising it. If it is still failing after both, one ductless head serves that floor better than any duct you could run to it, and it answers the summer version of the same complaint at no extra cost.
Three Common Hamilton Cases, and What We Would Do
- Durand semi, radiators, no cooling: keep the radiators, replace the boiler with a condensing unit on outdoor reset when it reaches end of life, add TRVs, and put in a two- or three-zone ductless system for summer.
- Crown Point 1.5-storey with converted gravity ducts and an ageing mid-efficiency furnace: rework the returns first, then install a right-sized two-stage condensing furnace at $4,500–$7,500, and deal with the water heater left alone on the masonry flue at the same time — chimney liners during a furnace replacement explains why that is not optional.
- Westdale two-storey from the 1920s already on forced air with sound ducts: this is the strongest candidate for dual fuel in the lower city. Keep the furnace, add a cold-climate heat pump, and set a switchover temperature so the two trade off instead of fighting.
Every one of these jobs is permitted work, and older lower-city addresses can carry heritage considerations on anything visible from the street — the process is set out in our guide to HVAC permits in Hamilton. If you own one of these houses and want a plan rather than a sales pitch, look at heating service in Hamilton or book a visit — we will walk the basement and the attic with you before anyone quotes equipment.
Frequently asked questions
Should I replace my radiators with forced air?
Usually not. Converting a radiator house to ducted forced air means opening plaster walls and ceilings across every floor, and cast-iron radiators heat a masonry house well. Modernising the boiler and adding ductless for cooling costs less and damages less.
Can I insulate the brick walls of a Hamilton century home?
Not by blowing insulation in — solid multi-wythe brick has no cavity. The practical improvements are the attic, the rim joist, the basement and air sealing. Insulating the wall itself means building a new insulated assembly on the inside face during a renovation, which needs careful moisture detailing.
Why is my top floor freezing when the rest of the house is fine?
In a converted gravity system the top floor is at the end of the longest run with no return path, and in a finished attic there is often very little insulation behind the plaster. Seal and insulate first, then add a return, then consider a dedicated ductless head.
Is a heat pump realistic in a century home?
Yes, in two situations: added to an existing forced-air furnace as a dual-fuel system where the ducts are sound, or as a ductless multi-zone system in a house with radiators. Sizing follows the improved envelope, so air sealing first changes the equipment you need.
Do I need a permit for heating work in a heritage district?
The mechanical building permit from the City of Hamilton applies as it does anywhere. If the property is designated or inside a heritage conservation district, anything visible from the street may need a separate heritage review, so raise placement of vents and outdoor units early.