Is your furnace telling you it is time?
Most furnaces give some warning before they quit for good. The repair calls get closer together, rooms at the far end of the house never quite warm up, the blower gets louder, or the same part fails twice in one winter. The normal January daily average at the Hamilton RBG climate station near Waterdown is -4.7 °C, so an older furnace here runs hard for months, and that is when worn parts show it.
Some signs mean stop and act now. If a carbon monoxide alarm sounds, or people in the house feel headachy, dizzy or sick when the heat is running, get everyone outside and call 911 from there. A furnace with a cracked heat exchanger should not be left running. The Ontario Fire Code requires a working carbon monoxide alarm next to each sleeping area in a home with a fuel-burning appliance, so test yours before the cold sets in.
If the furnace still runs but you are unsure, a repair visit will tell you whether a fix makes sense. When it does not, we say so and give you both numbers.
What happens to the water heater in the old chimney?
In the post-war surveys, such as Glenlea, Buchan Court and Renwood Park, the furnace and the gas water heater often shared a masonry chimney. A high-efficiency furnace vents through plastic pipe in the side wall instead, so after the swap the water heater is left venting alone into a chimney sized for two appliances. The flue gases cool, the draft weakens, and the water heater can backdraft into the basement.
Older houses in the Griffin Survey and the McMonnies and Stock Survey have their own version of this. Many started on coal or wood, moved to oil and then to gas, and the chimney is often unlined brick. Condensation from a newer appliance can damage it from the inside.
Part of planning a replacement is looking at what will be left in that chimney. Depending on the house, the answer may be a liner sized for the water heater or a different way of venting it. We tell you which and put it in the written price, so it is not a surprise later.
How is a new furnace matched to your house and ducts?
The label on the old furnace is a starting point, not the answer. Plenty of furnaces were oversized when they went in, and a furnace bigger than the house needs short cycles, swings the temperature and wears out early. We look at the size of the house, the windows, the insulation and the attic, and work out how much heat it actually loses on a cold night.
Then we look at the ducts. In houses from the 1950s to the early 1980s the original ductwork is often on the small side, especially the returns. A modern variable-speed furnace pushed through undersized ducts runs noisy and never quite delivers. Sometimes adding a return in a cold back bedroom does more for comfort than a bigger furnace, and we will tell you when that is the case.
In the newer homes of Waterdown South and Waterdown Bay the ducts are usually fine, but the furnace works alongside a heat-recovery ventilator and central air, so the new unit has to suit both. If you are thinking about a heat pump with the gas furnace kept as backup for the coldest weeks, this is the time to plan for it.
Where will the new furnace vent, and will snow block it?
A high-efficiency furnace takes in air and sends out exhaust through two plastic pipes, usually in a side wall. The Hamilton RBG station records a normal 118.1 cm of snow a year, and it has seen 38.4 cm fall in a single January day. Pipes set too low, or under a roofline that sheds snow, get buried, and the furnace shuts itself off to stay safe.
So the vent location is chosen with winter in mind: high enough above the ground and the usual drift, clear of windows and doors, and placed as the CSA B149.1 gas code requires. The condensate drain gets a proper route to a floor drain or pump so it does not freeze or back up.
If your home is a designated heritage property, check with the City of Hamilton before adding new vent terminations to the outside of the house. It is far easier to sort out before the installation date than after.
What happens between the written price and the first heat?
After the visit you get a written price that lists the furnace, the venting, any chimney liner, duct changes and removal of the old unit. You read it, ask questions and approve it before any work begins. Work is performed by TSSA-certified gas technicians, and gas installations in Ontario follow the CSA B149.1 code under Ontario Regulation 212/01.
On installation day the old furnace comes out, the new one goes in, and the gas line, venting, condensate drain and thermostat are connected. We start it up, check combustion and temperature rise, test the water heater's draft if it stays on the chimney, and show you where the filter is and how to change it.
Register the furnace with the manufacturer soon after installation and keep the paperwork, since many manufacturer warranties depend on registration and regular maintenance. If you would like to understand the numbers first, our guide to what goes into the price of a new furnace walks through it.