💰 Seasonal Cost Comparison by Fuel
| Heating Source | Annual Energy | Seasonal Cost (CAD) | Cost/GJ Delivered |
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Full Calculation Breakdown
| Parameter | Value | Notes |
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How to Use the Fuel Oil Boiler Calculator
Choose the efficiency category that matches your boiler. Oil boilers sold in Canada since the mid-1990s typically reach 83–87% AFUE. Older pre-1990 atmospheric units often sit at 65–72% AFUE. Modern high-efficiency oil boilers with flame-retention burners can reach 87–95% AFUE. The AFUE directly determines how much fuel you burn to deliver a given amount of heat - a 10-point AFUE improvement cuts fuel use by about 12%.
The boiler input rating is from the nameplate - needed for nozzle sizing. The building design heat loss drives seasonal consumption - use our heat load calculator if you don't have this figure. Heating degree days for your location set the seasonal duration; Canadian HDD values at base 18°C range from about 3,500 in southern Ontario to over 7,000 in Yellowknife.
Click a Canadian city preset to fill HDD, design temperature, and typical local oil price automatically. You can override any field afterward. Gas and electricity prices are used only for the fuel comparison table - if natural gas isn't available in your area, the gas comparison row is still shown for reference but labelled as not applicable.
The nozzle card shows the calculated required nozzle flow rate in US gallons per hour (USGPH) at standard 100 psi pump pressure, and the nearest standard nozzle sizes above and below. Always select the next standard size down from the maximum - never overfire a boiler. Confirm against the boiler manufacturer's specifications before ordering a replacement nozzle.
The fuel comparison table shows annual cost for oil heat at your AFUE, equivalent natural gas heat at a standard 90% AFUE, and an air-to-water heat pump at COP 2.5 using your local electricity rate. This lets you evaluate whether switching fuels makes financial sense given current pricing in your region.
Fuel Oil Heating in Canada - Consumption, Costs, and Alternatives
Heating oil remains the primary heating fuel for hundreds of thousands of Canadian homes, concentrated heavily in Atlantic Canada, rural Quebec, and parts of rural Ontario. Unlike natural gas, which is distributed through utility pipelines, fuel oil is delivered by truck and stored on site, making it the practical choice wherever gas infrastructure doesn't reach. Understanding oil consumption, nozzle sizing, and cost comparison is essential for anyone servicing, upgrading, or evaluating oil-heated buildings.
No. 2 Fuel Oil Properties
Residential heating oil in Canada is No. 2 distillate fuel oil, with a higher heating value of approximately 38.7 MJ/L (138,500 BTU/US gallon). At a typical burner efficiency of 83% AFUE, about 32.1 MJ of useful heat is delivered per litre consumed. The energy content is roughly 3.7 times higher per litre than natural gas (which provides about 10.4 MJ/m³ at typical distribution pressure), which is why you compare fuels on a cost-per-GJ-delivered basis rather than cost-per-unit. Use the boiler output calculator to find the effective heat delivered at any AFUE.
How Annual Consumption Is Calculated
Seasonal fuel consumption depends on three factors: design heat loss (the building's peak demand in kW), the ratio of actual heating hours to design hours (captured through heating degree days), and the boiler's AFUE. The basic formula: annual heat needed (GJ) = design heat loss (kW) × HDD (°C·days) × 86,400 s/day × (1/(design indoor temp − design outdoor temp)) / 1,000,000. Dividing the annual heat needed by AFUE gives annual fuel input in GJ, which converts to litres at 38.7 MJ/L. The boiler sizing calculator can help verify your design heat loss figure is correct before running a consumption estimate.
Oil Burner Nozzle Sizing
The oil burner nozzle atomises fuel oil into a fine mist for combustion. Nozzles are rated in US gallons per hour at 100 psi pump pressure, from about 0.50 USGPH to 3.00 USGPH in standard residential sizes. The correct nozzle size matches the boiler's rated input: nozzle flow (USGPH) = boiler input (BTU/h) ÷ 140,000. A boiler rated at 168,000 BTU/h input needs a 1.20 USGPH nozzle. Using too large a nozzle delivers too much fuel per firing cycle, overloading the heat exchanger, producing excess carbon, and potentially damaging the combustion chamber. Using too small a nozzle underperforms the boiler and starves the heat call. Check combustion quality after any nozzle change using the combustion efficiency calculator.
Fuel Oil vs. Natural Gas - An Honest Comparison
Where natural gas is available, it has historically been cheaper than fuel oil per GJ delivered in Canada. At typical 2025 prices - oil at $1.50/L and gas at $9.50/GJ - natural gas at 90% AFUE delivers heat at about $10.56/GJ while oil at 83% AFUE costs about $46.68/GJ. However, natural gas prices have risen substantially since 2021 and vary significantly by province. Nova Scotia, New Brunswick, and PEI have limited natural gas distribution and rely heavily on oil. In areas where pipeline conversion would require a capital investment of $5,000–$15,000 for the service connection alone, the payback calculation changes considerably. Explore your natural gas heating costs for a direct comparison using your local rates.
Oil-to-Heat-Pump Conversion
Air-to-water heat pumps are increasingly cost-competitive with oil heating in Atlantic Canada, especially since most provinces offer significant rebates - Nova Scotia's Efficiency Nova Scotia program, New Brunswick's Energy Efficiency Incentives, and federal Greener Homes grants all contribute to lowering the upfront cost. A heat pump with a seasonal average COP of 2.5 delivers 2.5 kWh of heat per kWh of electricity, which at $0.155/kWh (Nova Scotia 2025 residential rate) costs about $17.78/GJ delivered. At oil prices above $1.40/L and an aging 80% AFUE boiler, the crossover point where heat pump running costs equal oil running costs is well within reach in Atlantic Canada. The existing oil boiler can remain as backup for the coldest days when heat pump output drops. See the condensing boiler calculator to compare upgrading the boiler versus switching fuel.
Ultra-Low Sulphur Heating Oil and Blended Fuels
Canada has transitioned to ultra-low sulphur heating oil (ULSHO) in most provinces, with sulphur content reduced from 2,000 ppm to 15 ppm or lower. This reduces sulphur dioxide emissions and allows the use of advanced heat exchangers that would otherwise corrode quickly. Some distributors also offer biodiesel blends (B5, B10, B20) that reduce net carbon emissions. Check with your local oil supplier for blend availability, as higher biodiesel percentages can gel at cold temperatures in prairie provinces without cold-weather additives, but B10 and below perform reliably in Atlantic Canadian winters. Verify your boiler is approved for biodiesel use in the manufacturer's documentation before switching.
Frequently Asked Questions
Annual heating oil use varies widely by climate, house size, and insulation. A typical older detached home in Atlantic Canada uses 2,000–3,500 litres per heating season. Well-insulated newer homes can be under 1,500 litres. Colder locations consume more - a similar home in Quebec City (4,400 HDD) uses roughly 6% more oil than Halifax (4,100 HDD at base 18°C). This calculator estimates your specific consumption from design heat loss, AFUE, and local HDD, rather than relying on averages. Run your numbers through the heat load calculator first for the most accurate heat loss figure.
Divide the boiler's rated input in BTU/h by 140,000 (the approximate BTU per US gallon of No. 2 fuel oil) to get the required nozzle flow rate in USGPH. A 168,000 BTU/h boiler needs a 1.20 USGPH nozzle at standard 100 psi pump pressure. After replacing a nozzle, verify combustion quality with the combustion efficiency calculator - check O2, CO, and stack temperature to confirm the nozzle selection is correct for your specific burner setup. Always confirm against the boiler manufacturer's specifications before ordering, as spray angle and pattern also matter.