In short
- Gas tankless installed, Canada-wide guide: $3,000–$5,000. Electric: $1,800–$3,000.
- A gas line too small for the burner adds $500–$1,500; an electric unit that needs a new panel adds $500–$2,000.
- A like-for-like gas swap with compatible venting takes three to five hours; new venting or gas work can take a full day.
- Ontario allows only a person holding the right certificate to install, alter or repair a gas appliance (O. Reg. 212/01, s. 6).
- The Home Renovation Savings list shows $500 for heat pump water heaters and names no tankless gas unit.
Typical prices in Ottawa
| Job | Typical range | Notes |
|---|---|---|
| Gas tankless, replacing a gas tank, compatible venting | $2,800–$4,500 | Canada-wide HomeStars guide |
| Gas tankless, condensing model with new PVC venting | $4,000–$6,500 | Same guide |
| Gas tankless, gas line upgrade needed | $5,000–$10,000 | Same guide |
| Electric tankless, no panel upgrade | $800–$2,500 | Same guide |
| Electric tankless, panel upgrade needed | $2,500–$4,500 | Same guide |
Sources. HomeStars, Tankless Water Heater Cost in Canada: 2026 Guide, Canada-wide, updated 21.08.2026, seen 29.10.2026. Rebates: Save on Energy, Home Renovation Savings, seen 29.10.2026. Rentals: Enbridge Gas, Heating water with gas, seen 29.10.2026. Gas rule: O. Reg. 212/01, s. 6, seen 29.10.2026. Contracts: Ontario, Door-to-door sales and home service contracts, seen 29.10.2026.
When a tankless unit makes sense
A tank keeps water hot all day. A tankless unit heats it as the tap opens. HomeStars gives service lives, in years, of 15 to 20 for a tankless unit and 8 to 12 for a storage tank, and says gas condensing models cut water heating bills by 20 to 30 percent a year. That adds up with heavy use and a long stay. A tank costs less to put in.
Tell us the age of the current tank, the fuel, and how many people use hot water at the same hour. For tank prices to compare against, see water heater cost in Ottawa.
Gas or electric
Gas units move more water per minute and hold output when the incoming water is cold. HomeStars adds that Canadian groundwater runs colder in winter, so the unit works harder than the flow rating on the box suggests. Electric units suit a condo or a house with no gas line, and cost less to buy. They draw far more current than an electric tank, which HomeStars says often calls for a panel upgrade of $500 to $2,000.
On a gas job the price swings on the gas line, the vent and the burner type. Lines sized for a storage tank can be too small for a tankless burner. A condensing unit exhausts through PVC, so an old metal flue gets replaced. Those two items explain most of the spread in the table above.
Who may connect the gas
Connecting a tankless burner to the gas line is certificate work under section 6 of O. Reg. 212/01. Enbridge Gas stays out of the heater business itself: it neither sells, rents nor repairs water heaters, and it sends customers to the TSSA and HRAI to check a contractor’s credentials.
An electric unit adds an electrician’s work on the circuit. HomeStars says gas and electrical work trigger permits in most municipalities and budgets $100 to $500 for them. Ask the company who pulls the permit and whether it sits inside the quote.
What drives the price
- Fuel and unit size. Gas costs more to install than electric when the panel can carry the electric load.
- Venting. Reusing a compatible vent keeps the job near $2,800 to $4,500. New PVC runs through a wall add cost.
- Gas line. A larger line means new pipe from the meter and can push the job past $5,000.
- Labour. HomeStars puts plumber labour at $80 to $150 an hour, the largest line on most tankless quotes.
- Access. Finished walls and long vent runs add hours.
Rebates and rental offers
Save on Energy and Enbridge run Home Renovation Savings. Its list shows $500 back on qualified heat pump water heaters and names no tankless gas unit. HomeStars adds that most rebate programs want pre-approval before work starts. Ask the company in writing which program covers your unit.
Tankless units are often offered on rental. Enbridge advises contacting your current provider before you buy or rent a new heater, because an existing contract may carry cancellation fees. Ontario’s rules for contracts signed at home are in water heater rentals in Ontario.
What the written quote should list
The unit by make, model and fuel. The vent type and length. Any gas line or electrical work, priced on its own line. Permit, isolation valves, a scale filter if advised, and removal of the old tank. Labour and parts warranty, apart from the maker’s warranty. Ontario requires a written agreement for work over $50. If you are still weighing a tank, start from water heater repair and replacement.
Who you are dealing with
The unit, the gas line, the vent and the permit are all priced by one independent Ottawa plumbing company. Ottawa Plumbing Desk passes along your morning shower count and photos; the company calls, sizes the heater and quotes every line, and no rental offer comes from us.
Questions to ask the company
- Is my gas line big enough for the burner, and what does an upgrade cost on top of the unit?
- Can the existing vent be reused, or does the unit need new PVC venting through the wall?
- What is the TSSA certificate number of the person who will connect the gas?
- Does the quote include the permit, a scale filter, isolation valves and removal of the old tank?
- Is the unit bought or rented, and what are the cancellation terms?
Have this ready for the call
- A photo of the label on your current tank: brand, model, capacity, gas or electric
- Photos of the gas meter, the pipe run to the heater and the vent pipe or flue
- How many people shower in the morning and which fixtures run together
- A photo of the electrical panel door, if the unit you are pricing is electric
- Your rental contract, if the current tank is rented
Questions people ask
Will a tankless unit fit where my tank sits now?
A tankless unit hangs on a wall, which frees the floor. Fit depends on the wall, the vent route and the gas or electrical supply. Photos of the corner, the vent and the meter let the company judge the job before its visit and name the extras.
Why does a condensing gas unit cost more to install?
A condensing unit needs PVC venting, and older metal flues often cannot be reused. HomeStars puts a condensing model with new PVC venting at $4,000–$6,500, against $2,800–$4,500 for a swap that keeps compatible venting. Ask which one your quote assumes.
Do I get endless hot water?
Enbridge says on-demand heaters heat water on demand, so you will never run out of hot water. The limit is flow: a unit sized for one shower can struggle when two fixtures run together. HomeStars suggests 6–8 gallons per minute for one or two people and 9–12 for four or more.
What maintenance does a tankless unit need?
HomeStars names descaling as the main recurring job, since mineral buildup collects in the heat exchanger. A yearly descale by a technician runs $150–$300 on its guide. A scale filter fitted at installation, listed at $200–$700, reduces how often it is needed.
Does the Ontario door-to-door ban cover tankless heaters?
Water heaters are on Ontario’s restricted list, and so is any good that performs a water heater’s function. A business may sell one at your home only if you started the contact. If you invite it in and sign, you have 10 days to cancel, starting when the written copy is in your hands.
