Home / Services / Oil to Gas Furnace Conversion
Heating · Fuel ConversionOil to Gas Furnace Conversion
An oil to gas furnace conversion happens in a fixed order: Enbridge Gas confirms and installs service to the lot, a licensed gas technician runs the line from the meter, the high-efficiency gas furnace goes in, and the oil system is decommissioned. The furnace installation itself is $4,500–$7,500. The gas service connection is priced by Enbridge, and the oil tank is removed by a separate TSSA-registered fuel-oil contractor.
Step one is not ours, and it decides everything: is there a gas main on your road, and what will Enbridge charge to bring a service line to the house? The answer is address-specific, particularly on rural roads in Flamborough, north Burlington, Milton and Caledon, where the main can stop a few lots short. Ask Enbridge for the connection quote and the meter location in writing before booking anything else. If there is no main, the page you need is oil to heat pump conversion.
Once the meter is set, the inside work is ours. We size and run the gas line from the meter to the furnace under CSA B149.1, pressure-test it, and install a condensing furnace of at least 95% AFUE, the federal minimum for a new residential gas furnace. Oil-era ductwork is usually generous, but we measure static pressure and run a heat-loss calculation instead of matching the old nameplate, because oil furnaces were often oversized. The old furnace leaves the same day, so the house is without heat only for the working hours of the swap.
Venting changes completely. An oil furnace sends hot flue gas up a chimney; a condensing gas furnace sends cool, wet exhaust through plastic pipe out a sidewall and drains its condensate to a floor drain or pump. That leaves the old oil chimney with nothing on it, or with only a water heater: an oil-fired water heater has to be replaced as well, and a new atmospheric gas one venting into that large, cold flue needs a chimney liner sized for it. A power-vent, direct-vent or electric water heater avoids the chimney altogether, and then it can be capped.
The oil tank is not our trade, and the quote says so. Fuel oil is regulated by TSSA separately from gas, and decommissioning is done by a TSSA-registered fuel-oil contractor: the remaining oil is pumped out, the tank is cleaned and removed, and the fill and vent pipes come off the outside wall so a delivery can never be pumped into a basement with no tank. Book it for the days right after the gas furnace is running, unless the tank blocks the new furnace's location, and let the oil level run down beforehand. Keep the removal paperwork for your insurer and a future buyer; every route out of oil is compared in oil furnace replacement options in Ontario.
What the conversion includes, and who does each part
- Gas service line and meter to the house: Enbridge Gas, quoted to you directly
- Gas piping from the meter, furnace installation, venting and condensate drain: ZK Mechanical
- Any municipal permit the change of fuel needs: confirmed with the building department, then pulled and booked by us
- Oil tank pump-out, removal and fill-pipe removal: a TSSA-registered fuel-oil contractor
- Chimney liner or a new water heater, where the old chimney loses the furnace: itemized on our quote
How it works
You get Enbridge's written answer on service to the lot. We do the heat-loss calculation, check the ducts, chimney and water heater, and write one quote for everything in our scope.
After the meter is set: gas line run and pressure-tested, oil furnace out, condensing furnace in, sidewall venting and condensate drain installed, a full-fire test, and the inspection booked where a permit applies.
The fuel-oil contractor pumps and removes the tank and the exterior fill and vent pipes, and we cap or line the chimney as quoted. Request an oil to gas conversion quote.
Brands: Conversion furnaces we install include Lennox, Carrier, Goodman, Rheem and Daikin models at 95% AFUE and above.
Common questions
How long does an oil to gas conversion take?
The furnace swap is one working day. The calendar time is set by Enbridge: the service connection has to be applied for, scheduled and installed before any gas appliance can run, and that lead time varies by season and by address. Start the Enbridge application first, and plan the conversion for spring to fall so nothing depends on a January install date.
Can ZK remove my oil tank?
No. Gas and fuel oil are separate TSSA-regulated trades, and tank removal belongs to a registered fuel-oil contractor. We coordinate the timing so the tank comes out in the days after the gas furnace is running, and our quote states that tank work is outside it. An underground tank, or any staining around the tank, should be raised before scheduling.
Can the oil tank stay in the basement if it is empty?
It should not. An abandoned tank with a fill pipe still on the wall invites a mistaken delivery, insurers ask about oil tanks at renewal, and a buyer's inspector will flag it. Proper decommissioning removes the tank and the exterior piping and leaves you with documentation. Treat it as part of the conversion budget, not a later project.
Will my existing ductwork work with a gas furnace?
Usually, yes. Oil-era duct systems were typically built with generous trunks, so capacity is rarely the issue. What changes is the plenum connection and sometimes the return, and adding central air later needs room for a coil. We measure static pressure on the first visit and price any sheet-metal changes into the furnace installation quote.
Is gas still the right choice, or should I go to a heat pump?
Where a gas main is at the road and the connection cost is reasonable, a condensing gas furnace is the lower up-front route and can take a heat pump later as a hybrid. Where the connection is expensive, or you qualify for the oil-specific heat pump funding, the numbers can favour electrification. We price both for the same house on request.