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HVAC Ductwork Cost in Ontario (2026): New Build, Finished-House Retrofit, Ducts for a Heat Pump, Sealing, Returns and How to Read a Duct Quote
Heating, Cooling & Ventilation
What Ductwork Costs in Ontario: Cheap When the Joists Are Open, Expensive When They Are Not, and the Returns Nobody Prices Until the Bedrooms Are Too Hot
Ductwork is sheet metal and labour, and the sheet metal is the small part. The same 2,000 sq ft house can be ducted for $2,000 to $5,000 with the basement ceiling open or $9,000 to $12,000 and up once the drywall is on, and the difference is a crew working around finished rooms. This page puts the October 2026 Central Ontario ranges on one table, explains what a heat pump asks of the ducts that a furnace never did, and prices three real jobs. The numbers are before HST.
The numbers
$2,000 to $5,000new build or unfinished basement
$5,000 to $9,000partial retrofit, finished house
$9,000+full retrofit, finished house
$300 to $1,500duct changes at an equipment swap
| Job | Range | Notes |
|---|---|---|
| Ductwork, new build or unfinished basement | $2,000 to $5,000 | Joists open, straight runs, no patching |
| Partial retrofit, finished house | $5,000 to $9,000 | Added returns, a new branch to an addition or a cold room, upsized trunk |
| Full retrofit, finished house | $9,000 to $12,000 and up | A house that never had ducts, or ducts too small to keep |
| Duct modification at a furnace or heat pump swap | $300 to $1,500 | Plenum transitions, a bigger return drop, a new coil box |
| Municipal building permit, where needed | $90 to $350 | New ductwork usually needs one; a like-for-like swap often does not |
| Complete new-home system: ducted furnace, AC and ductwork | $10,000 to $20,000 | The whole package on a new house |
| Heat pump plus full new ductwork, finished existing house | $15,000 to $25,000 | Equipment and ducts together |
| Central AC where new ductwork is needed | $6,000 to $14,000 | Against $3,500 to $8,500 on existing ducts |
Duct sizes for any of these come from the room-by-room heat loss and gain, then the friction chart; the HVAC ductulator does the chart part on your screen. The equipment side of a heat pump job is priced on the heat pump cost page.
Why Ontario prices are all over the map: the contractors and price guides we checked for this page quoted the ducts very differently, partly because most of them do not price ducts on their own at all. One home-services marketplace had central air at $3,500 to $7,000 on existing ducts and $6,000 to $14,000 when ducts are needed, so the ducts moved the price by $2,500 at the bottom and $7,000 at the top. The same source put HRV ducts alone at $1,300 to $6,600. Finished ceilings, how many returns, and who patches the drywall are the reasons. Budget $7,000 for a partial retrofit, the middle of the range, and get two or three quotes on the same written scope.
A Heat Pump Wants More Air Than the Old Furnace Did
A gas furnace pushes a small amount of very hot air. A heat pump pushes a lot more air that is only warm, and it does the same in summer when it is cooling. Ducts sized in 1992 for a 100,000 BTU/h furnace and a 2 ton air conditioner often have enough supply for a 3 ton heat pump and not nearly enough return. The machine then runs against a choked return like a man breathing through a straw, gets noisy, moves less air than it is rated for, and the outdoor unit works harder in January than it should.
Rule of thumb: plan on about 400 cfm of airflow per ton of heat pump or air conditioning. A 3 ton unit wants about 1,200 cfm, and the return side has to bring all of it back. If the house has one return grille in the hall, that is the first thing to fix.
A good installer measures static pressure on the existing system before quoting, which takes ten minutes with a manometer. If the quote is for a heat pump on old ducts and nobody measured anything, the duct question was answered by hope. The ducted vs ductless page covers the house where the honest answer is no ducts at all.
Three Jobs Priced
Job one: cold-climate heat pump on the existing ducts of a 2,000 sq ft house, adding a second return. The heat pump at the default of $13,000 for 3 tons, plus a bigger return drop and a second return from the upstairs hall at $1,000, near the middle of the modification range. Subtotal $14,000, HST $1,820, total $15,820. A like-for-like equipment swap usually needs no permit; ask your municipality if the return work is more than a transition.
Job two: a 1990s two-storey with a finished basement and bedrooms that are too hot in July. Returns to the three upstairs bedrooms, the trunk upsized at the furnace and a new branch to a basement office: a partial retrofit, $7,000 as the middle of the range, plus a $200 permit. Subtotal $7,200, HST $936, total $8,136. This is the job that fixes the house more than any new equipment will, and it is the one that gets left off the quote because it is messy.
Job three: a 1960s bungalow on electric baseboards going to a ducted heat pump. No ducts at all, finished ceilings, plaster. Heat pump plus full new ductwork in a finished house is $15,000 to $25,000, with the ducts alone at $9,000 to $12,000 and up of that. Before you sign it, price the ductless version, because a bungalow with an open plan and three bedrooms is often a two- or three-head mini-split house and saves most of the duct money.
Sealing, Insulating and the Mistakes That Cost the Most
Leaky duct joints in a heated basement waste less than people think, because the heat stays in the house. Leaky ducts in an attic, a garage ceiling or a crawlspace waste a great deal, and in summer they suck in hot attic air. Any duct outside the heated envelope gets sealed with mastic or proper foil tape (not the cloth tape called duct tape, which is good for everything but ducts) and insulated, and the inspector will look. Ask for the sealing as its own line on the quote.
- Sizing ducts from the old furnace sticker. Duct sizes come from the room-by-room loads. The CSA F280 heat loss and the mechanical design are $395 and $695 from OntarioHeatLoss.ca, and they are what the permit asks for on new work.
- No return in the bedrooms. A closed door with no return is a room that cannot take its share of supply air. A return grille, a jumper duct over the door, or a transfer grille; an inch of door undercut is not a return.
- Ducts in exterior walls. A supply run squeezed into an outside wall loses its heat to the outdoors and takes the insulation’s place. In an ICF house there is no such thing, which is one more reason we run ducts in the floors and interior walls.
- Flex duct stretched across the attic like a garden hose. Kinked, sagging flex moves a fraction of its rated air. Short runs, pulled tight, supported.
- No balancing dampers. Without a damper on each branch, the room nearest the furnace gets the most air forever.
If the same job includes a new HRV, the HRV ducts are separate and priced on the HRV installation cost page. The rest of the section is on the ventilation and ductwork hub.
Questions people ask
How much does new ductwork cost in Ontario?
In October 2026, before HST: $2,000 to $5,000 in a new build or a house with an unfinished basement, $5,000 to $9,000 for a partial retrofit in a finished house, and $9,000 to $12,000 and up for a full retrofit. Finished ceilings and the number of returns are what move it.
Can I put a heat pump on my existing ducts?
Often, yes, but a heat pump moves more air than the furnace did, about 400 cfm per ton as a rule of thumb, and the return side is usually the weak spot. Have the installer measure static pressure before quoting; a second return or a bigger return drop is $300 to $1,500 at the swap and worth it.
Do I need a permit for ductwork?
New ductwork usually needs a building permit, $90 to $350 depending on the municipality, and a new house needs the heat loss and mechanical design as part of its permit. A like-for-like furnace swap often needs none. Call the building department before the crew arrives, not after.
Is it worth sealing my ducts?
In an attic, garage or crawlspace, yes, every time, with mastic or foil tape, and insulated. In a heated basement the lost heat mostly stays in the house, so sealing matters less for the bill and more for getting air to the rooms at the far end of the run.
Ducts or ductless for a house with no ducts?
Price both. Ducting a finished house is $9,000 to $12,000 and up before equipment. An open-plan bungalow is often better served by two or three ductless heads, and a house with many closed rooms often wants ducts.
See the Ducts Inside the Whole Budget
The cost comparison calculator runs the same house five ways, ducted and not, with the distribution priced in, so the duct line stops being a surprise at the end. If a quote in your hand says “ductwork as required” with no number beside it, the $99 review will tell you what it should say.
Sources and further reading
- Ontario’s Building Code: the official page with the current regulation; heating, ventilation and air conditioning in houses are Part 9, sections 9.32 (ventilation) and 9.33 (heating and air conditioning).
- HRAI consumer information: the Heating, Refrigeration and Air Conditioning Institute of Canada: what to ask an HVAC contractor and its member locator.
- OntarioHeatLoss.ca services: heat loss reports, full HVAC permit packages and radiant heating design, with prices.
