Mississauga Tankless Water Heater Installation & Repair
Short answer: a gas condensing tankless water heater costs about $3,000 to $5,200 installed in Mississauga, uses roughly 27 to 35 per cent less gas than a storage tank and is rated to last about 20 years, against 8 to 12 for a tank. It suits homes that run out of hot water or want the floor space back. It needs the right gas line, the right venting and a yearly descaling, all of which we check and quote before you commit.
Aire One Peel installs, services and repairs Navien tankless water heaters from our head office at 1625 Courtneypark Dr E in Mississauga. Estimates are free, and financing is available.
Last reviewed: September 18, 2026 · Figures from our 2026 Ontario cost comparison
What We Offer
Every installation starts with a visit to size the unit to your household and to check the three things that decide the price: the gas line, the venting route and the water hardness. You get a written quote, the installation is normally finished in a day, and we show you how to use the controls before we leave.
- Compact wall-mounted units that free up the floor space a tank takes
- Models with built-in recirculation and Wi-Fi control
- Sizing to your household’s peak hot water use, not a guess
- Gas line, venting and condensate drain installed to code by licensed gas technicians
- Yearly descaling and service to protect the heat exchanger
- Financing options
Tankless Water Heater Cost in Mississauga (2026)
These are typical installed prices in the Greater Toronto Area, taken from our tankless versus tank cost comparison, which shows the method behind every figure. Your own quote depends on the model, the gas line and the venting route.
| Job | Typical installed price, CAD | Time on site |
|---|---|---|
| Gas condensing tankless, mid-tier (Navien NPE-180 class) | $3,000 to $3,800 | 4 to 7 hours |
| Gas condensing tankless, high output (Navien NPE-210 class) | $3,900 to $5,000 | 4 to 7 hours |
| Gas condensing tankless, 199,000 BTU class (Navien NPE-240 class) | $3,800 to $5,200 | 5 to 8 hours |
| Tank to tankless conversion, whole job | $3,400 to $4,400 simple; $4,200 to $5,500 with a gas line upgrade | Total, not an adder |
| For comparison: gas storage tank, 40 or 50 gallon | $1,600 to $2,800 | 2 to 3 hours |
| Yearly descaling service | $150 to $300 per visit | Booked yearly |
What can add to the price
- Gas line capacity: long runs, shared lines or an undersized meter can mean a larger gas line.
- Venting: the cost rises with the distance to an outside wall.
- Condensate drain and neutralizer: needed on every condensing unit.
- Electrical outlet: a 120 volt receptacle at the unit, if one is not already there.
- Scale protection: a softener or a scale filter on hard well water.
- Recirculation: worth pricing when the far bathroom waits a long time for hot water.
Is Tankless Right for Your Home?
At the Ontario gas rates in effect on July 1, 2026, a tankless unit saves a household of four about $59 to $76 a year in gas. That alone does not pay for the upgrade. The real case for tankless is hot water that does not run out, the floor space you get back and a rated life of about 20 years. Water in Mississauga and Brampton is moderately hard (the Region of Peel reports 120 to 130 mg/L), so plan on a yearly descaling; our water heater maintenance checklist covers it, and the Navien warranty guide explains why the service records matter. If a tank suits you better, see our hot water tank page, or compare buying or financing a water heater. For a unit that has stopped working, go to water heater repair.
Get A free Estimate on Installation, maintenance and Repair.
Why Tankless?
- Hot water that does not run out, within the flow rate of the unit
- Wall-mounted, so it frees the floor space a tank takes
- About 27 to 35 per cent less gas than a storage tank
- A rated life of about 20 years, against 8 to 12 for a tank
Tankless Water Heater Maintenance and Descaling in Mississauga
A tankless water heater has no storage tank to drain, but it still needs a yearly service. Navien, the brand we install, recommends annual maintenance to remove the mineral deposits (scale) that collect on the heat exchangers, and says homes with hard water may need it more often. Peel’s hardness figure is in the FAQ below.
What the manufacturer’s maintenance includes
Navien’s maintenance list for its tankless gas water heaters is short:
- Descaling (flushing) the heat exchangers. A pump circulates a cleaning solution that removes lime and mineral deposits, followed by a rinse.
- Cleaning the cold water inlet filter. The filter is removed, rinsed under cold running water and brushed clean if needed.
- Cleaning the air intake filter. Dust and lint are brushed off under cold water, and the filter is left to dry completely.
- Cleaning the condensate trap at the bottom of the unit.
- A working check afterwards, including gas pressure, before the heater goes back into use.
What you can do yourself, and what to leave to a technician
| Job | Who should do it, and why |
|---|---|
| Air intake filter and cold water inlet filter | Homeowner or technician. Navien describes its routine maintenance as relatively simple. The unit has to be drained first, and the steps are in the user manual. |
| Descaling the heat exchangers | Technician recommended. Navien says a certified technician saves time and helps protect the warranty, and that damage done during do-it-yourself maintenance may void it. |
| Gas pressure and any gas work | Registered fuels contractor only. In Ontario, TSSA-registered fuels contractors are the only businesses legally authorized to do fuels-related work. |
Aire One Peel is a TSSA-registered heating and cooling contractor. To book tankless water heater maintenance in Mississauga, call 905-564-8545. If the unit shows an error code or the water runs lukewarm, that is a repair call: see water heater repair. For tank and tankless routines side by side, see our water heater maintenance checklist.
Sources: Navien, Tankless Water Heater Maintenance Tips (November 26, 2024) and TSSA, Authorized Heating Fuel Contractors, read October 2026.
Tankless Water Heater FAQ
How much does a tankless water heater cost installed in Mississauga?
A gas condensing tankless water heater typically costs $3,000 to $5,200 installed in the Greater Toronto Area in 2026, depending on the model class. A full tank to tankless conversion runs about $3,400 to $4,400 for a simple job and $4,200 to $5,500 when the gas line has to be upgraded.
How much gas does a tankless water heater save?
A gas tankless water heater uses about 27 to 35 per cent less gas than a storage tank. At the Ontario gas rates in effect on July 1, 2026, that is roughly $59 to $76 a year for a household of four, so the saving alone does not pay for the upgrade.
How long does a tankless installation take?
Most installations take 4 to 8 hours on site, including the gas line, the venting and the condensate drain, so the job is normally finished in a day.
Do tankless water heaters need maintenance?
Yes. Scale builds up inside the heat exchanger, so the unit should be descaled about once a year, which typically costs $150 to $300 per visit, and the cold water inlet filter should be cleaned every 6 to 12 months.
Is the water in Mississauga hard enough to damage a tankless water heater?
The Region of Peel reports 120 to 130 mg/L for Mississauga, Brampton and south Caledon, which is moderately hard. A yearly descaling is enough for most homes. On harder well water, a softener or a scale filter ahead of the unit is worth pricing.
Is there a rebate for a tankless water heater in Ontario?
As of September 2026 there is no rebate for a gas tankless water heater in Ontario. The only water heater rebate is $500 for a heat pump water heater.
Can I descale a tankless water heater myself?
Navien says its routine maintenance is relatively simple and does not require a professional plumber, but it also warns that damage done during do-it-yourself maintenance may void the warranty. Descaling means draining the unit and using a pump to circulate a cleaning solution through the heat exchangers, then rinsing. Navien notes that a certified technician saves time and helps protect the warranty, and in Ontario any gas work belongs to a TSSA-registered fuels contractor.
What happens if a tankless water heater is not descaled?
Scale keeps building. Navien lists four results of neglected maintenance: mineral deposits on the heat exchanger that reduce efficiency, mineral buildup in the pipes and filter that reduces water flow, a shorter service life, and warranty issues, because failing to do the maintenance set out in the user manual may void the manufacturer's limited warranty.