🏠 Residential HVAC

Residential HVAC Calculators

25 free calculators for sizing, selecting, and diagnosing home heating and cooling systems — from whole-home load estimates to furnace, AC, and heat pump selection tools. Built for Canadian homeowners and contractors.

25
Free Tools
Load-Based
Sizing Approach
All Climates
Zones 4-8
PDF
Export Results
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Home HVAC Sizing Calculator

Get a whole-home starting point for heating and cooling equipment size based on square footage, insulation level, and Canadian climate zone.

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Heat Pump Selection Calculator

Compare cold-climate, standard, and geothermal heat pump types for your home and climate zone to find the right fit.

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Furnace Selection Calculator

Compare gas, propane, and electric furnace options by fuel availability, efficiency rating, and local operating costs.

AC Selection Calculator

Compare central AC, ductless, and packaged systems to find the right cooling option for your home layout and budget.

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Mini-Split Selection Calculator

Choose between single-zone and multi-zone ductless mini-split configurations based on rooms served and layout.

Dual Fuel System Calculator

Find the outdoor temperature switchover point between a heat pump and gas furnace for a hybrid dual-fuel setup.

HRV vs ERV Selection Calculator

Decide between a heat recovery ventilator and energy recovery ventilator based on your climate and indoor humidity needs.

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Dehumidifier Sizing Calculator

Size a whole-home or portable dehumidifier by square footage, basement conditions, and moisture load.

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Humidifier Sizing Calculator

Size a furnace-mounted or standalone humidifier for dry Canadian winters based on home volume and air changes.

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Air Purifier Selection Tool

Choose an air purifier or in-duct filtration upgrade based on room size, allergies, and wildfire smoke season needs.

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Thermostat Compatibility Checker

Check if a smart thermostat will work with your furnace, heat pump, or dual-fuel system wiring.

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Zoning System Calculator

Plan a multi-zone damper system by mapping rooms to zones and estimating the number of dampers needed.

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Home Energy Score Calculator

Get a quick home energy performance score based on insulation, age, windows, and HVAC equipment.

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Retrofit Priority Calculator

Rank insulation, air sealing, window, and HVAC upgrades by expected comfort and energy savings payback.

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Home Comfort Calculator

Diagnose comfort complaints like hot/cold rooms, drafts, and humidity swings and match them to likely causes.

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Bedroom Comfort Calculator

Size supplemental heating or cooling for an under-served bedroom based on size, orientation, and occupancy.

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Basement HVAC Calculator

Size heating, cooling, and dehumidification for a finished or unfinished basement below grade.

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Attic Ventilation Calculator

Calculate required intake and exhaust vent area for a balanced attic ventilation system.

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Garage HVAC Calculator

Size a heater or mini-split for an attached or detached garage workshop based on insulation and use.

Sunroom HVAC Calculator

Size heating and cooling for a three or four-season sunroom accounting for glazing area and solar gain.

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Home Addition HVAC Calculator

Check whether existing equipment has spare capacity for an addition or if a supplemental system is needed.

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Older Home HVAC Calculator

Account for higher infiltration and lower insulation in pre-1980 Canadian homes when sizing new equipment.

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New Home HVAC Calculator

Size HVAC equipment for new-construction homes built to current energy code insulation and airtightness levels.

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Net-Zero Home Calculator

Estimate HVAC electrical load for a net-zero or all-electric home paired with solar generation.

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Smart Home HVAC Calculator

Plan smart thermostat zoning, sensor placement, and automation rules for an existing HVAC system.

Sizing Residential HVAC Correctly

Oversized HVAC is the most common installation problem in Canadian homes. A furnace that's 50% too big short-cycles, creates uneven temperatures, and can't control humidity. An AC that's 40% too large cools the air fast, shuts off before removing enough moisture, and leaves the house feeling clammy even at the right temperature.

Start With a Load Calculation

Every equipment decision should start with a room-by-room or whole-home load calculation. This accounts for insulation levels, window area and orientation, air leakage, internal heat gains, and your local winter and summer design temperatures. Use the home HVAC sizing calculator to get a starting estimate, then move to the equipment-specific selection tools below.

Cold-Climate Heat Pumps in Canada

Modern cold-climate heat pumps can hold a large share of rated capacity down to -15°C and continue producing useful heat well below -25°C. A properly sized cold-climate heat pump can cover most of the annual heating load in cities like Toronto or Vancouver, with a small backup source for the coldest days. The heat pump selection calculator helps you compare options for your climate and home.

Matching Equipment to Your Calculated Load

Once you have a load number, equipment should be selected within a reasonable range of that figure rather than rounded up for a safety margin. Oversizing on cooling equipment is especially costly since it hurts humidity control, and oversizing on heating equipment leads to short-cycling and uneven comfort. The dual fuel calculator and other tools in this category help you fine-tune equipment choices once your load is known.

Related Tools You May Need

Frequently Asked Questions

Start with a whole-home load estimate based on square footage, insulation level, and climate zone using the home HVAC sizing calculator, then move to equipment-specific selection tools like the furnace selection calculator or AC selection calculator to compare options for your situation.

Modern cold-climate heat pumps can cover most of the annual heating load in many Canadian cities, often with a small backup source for the coldest days. A dual fuel setup pairing a heat pump with an existing furnace is also common. Compare types with the heat pump selection calculator and find your switchover point with the dual fuel calculator.

Oversized heating equipment short-cycles and wears out faster, while oversized cooling equipment cools the air quickly without running long enough to remove humidity effectively, leaving a home feeling clammy even at the right temperature. Accurate sizing from the start avoids both problems.

A single problem room usually points to a duct issue, insufficient insulation, or unusual heat gain or loss for that room. The home comfort calculator and bedroom comfort calculator help diagnose likely causes and suggest next steps, including supplemental heating or cooling options.

Yes, all AskHVAC.ca tools are fully responsive and work on any smartphone or tablet without an app install. Results can be exported to PDF or CSV directly from your phone, and the interface switches between Imperial and Metric with a single tap.