In short
- HomeStars' Ottawa guide puts a central air system at $3,000–$7,500 installed.
- Single-phase split central air conditioners made since 1 January 2023 must reach at least 13.4 SEER2 under Canada's Energy Efficiency Regulations.
- AHRI, the makers' institute, says the outdoor unit and indoor coil are designed as a pair; ask for the AHRI reference number of the combination quoted.
- The City of Ottawa lists air conditioning units among projects that need no building permit, outside heritage properties.
Typical prices in Ottawa
| Job | Typical range | Notes |
|---|---|---|
| Central air system, installed, Ottawa | $3,000–$7,500 | HomeStars Ottawa guide |
| Central AC on existing ductwork | $3,500–$7,000 | Canada-wide guide; unit, line set, electrical connections and labour |
| Central AC, 3- to 4-ton unit, 2,000–3,000 sq ft | $5,500–$8,500 | Canada-wide guide |
| Central AC where new ductwork is needed | $6,000–$14,000 | Canada-wide guide; ductwork alone adds $3,000–$7,000 |
| Existing ducts repaired or rebalanced first | $500–$2,000 | Canada-wide guide |
| Electrical work for the new circuit | $500–$2,000 | Canada-wide guide; a 100 A to 200 A panel upgrade runs $2,500–$4,500 |
Sources. HomeStars, How Much Does HVAC Cost in Ottawa?, seen 29.10.2026. HomeStars, Cost of Fitting an Air Conditioning Unit in 2026, Canada-wide, seen 29.10.2026. HomeStars, How much does a central air conditioner cost?, Canada-wide, seen 29.10.2026. Efficiency floor: NRCan, Split-system central air conditioners, seen 29.10.2026. Matching: AHRI, A Perfect Match, seen 29.10.2026. Rules: City of Ottawa, Projects not requiring building permits, seen 29.10.2026; Ontario, O. Reg. 463/10, seen 29.10.2026; ESA, Finding the Right Contractor, seen 29.10.2026; Ontario, Guide for home renovation businesses, seen 29.10.2026; Ontario, Contracts at a consumer’s home, seen 29.10.2026. Rebates: Home Renovation Savings and its heat pump page, seen 29.10.2026.
First install, replacement, or a house without ducts
A house with a forced-air furnace and no air conditioning needs an outdoor unit, a coil on the furnace, a refrigerant line set and a new circuit. Replacing an old unit adds removal of the equipment and its refrigerant. A house heated by baseboards or a boiler has no ducts; there, HomeStars puts central air with new ductwork at $6,000–$14,000 and a ductless mini-split often costs less overall.
Sizing: ask to see the cooling load
HomeStars gives 20 BTUs per square foot as a rough start; ceiling height, insulation, windows and sun change the real figure. A load calculation, known in the trade as Manual J, sets the size before anyone picks a model.
HomeStars says an oversized unit short-cycles and fails to pull humidity out, leaving the house clammy and wearing the compressor, and it names Ottawa among humid markets. For scale, it gives 18,000–24,000 BTUs for a 1,500 sq ft home and 3 to 4 tons for 2,000–3,000 sq ft. If a quote names a size with no calculation behind it, ask how it was reached.
SEER2: the legal floor and what more efficiency buys
Canada’s Energy Efficiency Regulations set 13.4 SEER2 as the minimum for single-phase split central air conditioners made since 1 January 2023.
Going higher is a trade-off. HomeStars says a 20 SEER2 unit uses roughly 20% less electricity than a 16 SEER2 unit, worth $100–$300 a year, and that the extra cost takes eight to twelve years to pay back in most Canadian markets. For the unit alone in a 1,500 sq ft home it lists $2,000–$4,500 single-stage and $4,000–$6,500 variable-speed. Variable-speed units run quieter and drier but have more parts. HomeStars points most homeowners replacing an older unit to 16–18 SEER2.
The indoor coil and the matched pair
Central air has two halves joined by copper tubing: the outdoor unit and the evaporator coil on the furnace. AHRI says the two are designed to work as a team; a new outdoor unit on a mismatched coil falls short of its promised efficiency and is under extra stress. A move to a different refrigerant means replacing both.
The proof is an AHRI reference number for the exact pair, which many rebate programs ask for. HomeStars notes that high-efficiency units often need a compatible furnace blower and thermostat. If the furnace is near the end of its life, see furnace replacement and price both together.
Power, refrigerant and where the unit sits
Central air needs its own 240-volt circuit. HomeStars puts that electrical work at $500–$2,000, and a 100 A to 200 A panel upgrade at $2,500–$4,500. ESA says only a Licensed Electrical Contractor may be hired for electrical work in a home, and that contractor notifies ESA before starting.
Ontario’s O. Reg. 463/10 lets only a certified person service the refrigerant side of a home air conditioner; ask how the old charge is recovered. The City of Ottawa requires no building permit for the unit outside heritage properties, yet the install must meet the Ontario Building Code and the Zoning By-law, so ask where the outdoor unit can sit on your lot. Condo boards often need approval first, says HomeStars.
Central air or a heat pump in the same spot
A ducted air-source heat pump uses the same layout outside and on the furnace, and it also heats. HomeStars puts one at $5,000–$10,000 installed, more for cold-climate models in larger homes. Home Renovation Savings offers heat pump rebates up to $12,000 depending on your heating fuel, with pre-approval required before the install. See the heat pump page, and hybrid heating for keeping the furnace as backup.
What the written quote should list
The quote should name the outdoor unit and coil by model, the AHRI number, size, SEER2 and refrigerant, with line set, pad, electrical work, old unit removal, labour and HST on separate lines. Ontario requires a written agreement for home renovation work over $50, and an estimate in it can be exceeded by 10% at most without your signed change. Air conditioners may be sold at your door only if you started the contact; a contract made after unsolicited door-to-door marketing is void.
Who handles your request
Ottawa Heating Desk takes requests and installs nothing itself. Yours goes to one independent Ottawa heating and cooling company, which calls you back, sizes and prices the system and carries out the installation.
Questions to ask the company
- What cooling load did you work out for this house, and can I see the calculation?
- What is the AHRI reference number for the outdoor unit and indoor coil you are quoting?
- Are the coil, line set and pad new, or are you reusing the old ones?
- Who does the electrical work, and is the ESA notification in the price?
- Can you price a ducted heat pump on the same quote, side by side?
Have this ready for the call
- House size in square feet, number of storeys and the year it was built
- A photo of the furnace rating plate, and of the old outdoor unit's plate if one is being replaced
- A photo of the open electrical panel showing the main breaker and any free spaces
- Where the outdoor unit could sit: side yard width, a deck, a fence, a neighbour's window
- Rooms that run hottest in July, and whether the house is a designated heritage property
Questions people ask
Do I need a building permit to add central air in Ottawa?
The City lists the installation of air conditioning units or heat pumps among projects that need no building permit. Designated heritage buildings and properties in a Heritage District Overlay are excluded, and every install must still meet the Ontario Building Code and the Zoning By-law.
How long does the install take?
HomeStars puts a standard central AC replacement on existing ductwork at four to eight hours. New ducts or panel work add time, and the company should give you the schedule before starting.
When should I book?
HomeStars names April to early June, before the summer rush, and autumn as slower periods. A unit that dies in a July heat wave leaves less room to compare quotes.
Is there a rebate for a new central air conditioner?
Home Renovation Savings, run by Enbridge Gas and Save on Energy, lists heat pumps, insulation, solar, smart thermostats and appliances. A cooling-only air conditioner is absent from that list.
