If you are installing a new water heater installation(new location, new fuel line, or a first-time system), it will generally be more costly than a water heater replacement, which will be more cost effective since it reuses your existing gas line, vent, and water connections. In the Canadian market, the standard tank swap costs $1,500 to $4,500, and the tankless type costs $3,500 to $8,500, depending on your city and home.
Water Installation vs. Replacement: What’s the Difference?
Replacement involves replacing the existing old water heater with a new water heater in the same location with the same gas, electrical, and water lines. Typically, installation involves installing a water heater when one was previously not installed, or converting from one fuel or water heater type to another (e.g., changing from a tank to a tankless), and often involves an electrical circuit or venting and/or upsizing gas lines.
This is important for your budget. The lowest-cost route is to do a same-location, same-fuel replacement. Changes to the amount of vents, gas capacity or electrical load increase labour and material costs above the unit price.
Key takeaway: If you don’t need a new type of unit, and your current one is still in code, request a quote from your plumber to change out the unit, don’t assume that you must do a full installation.
Average Costs Across Canada
| System Type | Typical Installed Cost (CAD) | Lifespan |
| Standard tank (gas or electric) | $1,500 – $4,500 | 8–12 years |
| Tankless water heater | $3,500 – $8,500 | 15–20+ years |
| Heat pump water heater | $3,000 – $6,000+ | 10–15 years |
These are statistics from the national markets based on up-to-date Ontario and BC market information. Tank-to-tank replacement typically ranges from $1,500 to $4,500 in the GTA, and if gas line upgrades or new PVC venting is required, tankless water heater installation cost is $3,500 to $8,500. Leasing is another popular option in Ontario, with costs of $20-$55/month for tank units and $40-$69/month for tankless.
What Drives the Price of Water Heater Tank Replacement Cost
Several factors push water heater tank replacement cost up or down:
- Tank size and fuel type larger tanks and gas units generally cost more than smaller electric ones
- Venting changes switching from a chimney vent to direct PVC venting adds $200–$600
- Gas line upgrades undersized gas lines for tankless demand can add $500–$1,500
- Electrical panel capacity/electric tankless units need a dedicated high-amp circuit, sometimes requiring a panel upgrade
- Permitsmost Canadian municipalities require a permit for gas or electrical water heater work, typically $75–$800
- Access and locationtight basements, condo mechanical closets, or upper-floor installs add labour time
- Emergency service after-hours or same-day replacement often costs 50–100% more than scheduled work
Tank vs. Tankless: Which Costs Less Long-Term?
A standard tank can be cheaper in the long run, as it will need to be replaced every 8-12 years. A tankless water heater cost is higher upfront but can last 15-20+ years and only heats water when needed, so there is less standby water loss.
Quick comparison:
| Factor | Tank | Tankless |
| Upfront cost | Lower | Higher |
| Hot water supply | Limited by tank size | Continuous |
| Space needed | More (floor space) | Less (wall-mounted) |
| Energy efficiency | Lower (standby loss) | Higher |
| Best for | Budget-conscious, smaller households | Larger households, long-term savings |
Two replacements of the tanks will cost nearly as much over 20 years as it does to install a tankless water heater initially, so the “cheaper” route may be dependent upon how long you’re in your home.
Heat Pump Water Heater Installation: A Middle Ground
Operating costs of the heat pump water heater installation(HPWH) are drastically reduced by withdrawing heat from the ambient air, rather than burning gas or consuming pure resistance electricity. Installed cost is typically between the tank and tankless cost, and could be eligible for provincial or utility rebates, which should be investigated before purchasing a tank.
Signs You Need Replacement, Not Repair
- Unit is over 8–10 years old and showing rust or corrosion
- Water heater is leaking from the tank itself (not a fitting)
- Rumbling or popping noises from sediment buildup
- Inconsistent water temperature despite repairs
- Rising energy bills with no change in usage
Expert tip: A leaking tank is not repairable, replace it immediately to avoid water damage.
Common Mistakes Homeowners Make
- Choosing tank size based on price alone, not household hot water demand
- Skipping permits on gas or electrical work, which can cause issues at resale
- Assuming tankless always saves money without checking gas line capacity first
- Delaying replacement until a full failure causes flooding
About BOS Plumbing and Drains
BOS Plumbing and Drains has been servicing the Toronto Mississauga area for over 20 years with teams of Residential Plumbers and Commercial Plumbers providing a variety of hot water tank installation, hot water tank replacement and full tankless water heater install projects in Mississauga, Oakville, Brampton, Hamilton, Milton, North York, Niagara, Cambridge, Toronto, and Etobicoke. BOS Plumbing is a licensed insured plumbing company and offers transparent, upfront pricing out of the door, no hidden expenses, a 24 hour plumber team and if applicable, same day service for a real plumbing emergency such as a failed or leaking water heater. A 25-year transferable warranty covers all sewer and water line work, and all estimates come with free expert advice to help you know what to expect when it comes to tank, tankless or heat pump choices.
Key Takeaways
- Water heater replacement (same location, same fuel) is cheaper than full water heater installation
- Standard tanks cost $1,500–$4,500 installed; tankless runs $3,500–$8,500
- Venting, gas line sizing, and electrical capacity are the biggest hidden cost drivers
- Tankless and heat pump units cost more upfront but last longer and use less energy
- Always get a written, itemized quote before work begins
Thinking about installing a new water heater or not sure if it’s time for repair or replacement? To schedule an assessment, simply give BOS Plumbing and Drains a call (905) 247-5747 for a free, no obligation quote and expert advice.
Disclaimer: The prices mentioned above are general estimates for informational purposes only and are not pricing from BOS Plumbing & Drains. Actual costs may vary based on the water heater type, installation requirements, materials, and job conditions.