Tankless Water Heater Installation
A tankless water heater (also called 'on-demand' or 'instantaneous') heats water as you use it, rather than maintaining a 40–80 gallon tank at temperature 24/7. The result: endless hot water (you can't run out), 20–30% lower operating costs versus tank water heaters, and a substantially smaller footprint that frees up basement floor space. Modern tankless units last 20+ years versus 10–14 for tank water heaters.
The tradeoffs: higher upfront cost, sometimes need for gas line upsizing (tankless units use gas in concentrated bursts rather than steady draws), and venting requirements that may not match your existing setup. We assess these during the in-home consultation rather than promising a like-for-like swap that turns into a complicated install.
When tankless makes sense
Common scenarios where we recommend tankless over tank:
- Replacing a tank water heater that's at end of life — typically 10–14 years for tank units. Replacement is the natural moment to evaluate tankless.
- Households that regularly run out of hot water — homes with multiple bathrooms running simultaneously, large family showers, or whirlpool tubs benefit from tankless.
- Limited mechanical room space — tankless units mount on the wall and free up the floor footprint of a 40–80 gallon tank. Significant in tight basements or crowded mechanical rooms.
- Long-term ownership scenarios — the higher upfront cost recoups through lower operating cost over 8–12 years. Better fit for homes you'll own 7+ years than short-term ownership.
- Vacation homes / second properties — tankless eliminates standby losses (energy spent keeping tank water hot when no one's there). Significant savings on cottage and rental properties.
- New builds and major renovations — easier to install during construction than retrofit. Cost difference vs tank is smaller during new builds.
How a tankless installation goes
- 01
Assessment
We measure your gas line capacity (tankless units typically need a 3/4" line; many older homes have 1/2" supply that needs upsizing), check venting paths, evaluate electrical service for the unit's controls, and confirm water supply pressure. About a third of the assessments find an issue that affects pricing — better to know upfront than discover during install.
- 02
Equipment selection
Tankless capacity is rated in GPM (gallons per minute). Sizing depends on the simultaneous fixture demand at your home: a master shower, kitchen sink, and dishwasher running together is roughly 6 GPM. We size for peak realistic demand without overshooting (oversized tankless cycles less efficiently).
- 03
Installation
Tankless installs typically run 6–10 hours, completed in a day. The unit mounts on a wall (interior or exterior depending on venting plan), gas and water lines are run, venting is installed (typically 3" sidewall venting for high-efficiency models), electrical is connected, and the system is commissioned and pressure-tested.
- 04
Commissioning and walkthrough
We test for proper gas pressure, verify no leaks, set the temperature appropriately (120°F is the standard), and walk you through the controls and any maintenance the unit will need (most tankless units recommend annual descaling in hard-water areas).
Tankless brands we install
We're authorized installers for the major tankless water heater brands:
What tankless installation costs in Halton Hills
Standard residential tankless installation: $4,500–$7,500 installed.
Pricing factors:
- Equipment tier: entry-level models start around $1,800; high-end Navien NPE series and Rinnai Sensei models are $2,800–$3,500
- Gas line work: if your existing gas line needs upsizing to 3/4" or 1" supply, add $400–$1,200
- Venting: side-wall venting through standard PVC adds modest cost; chimney conversion or vertical roof venting on heritage homes can add $600–$1,500
- Electrical: most installs are simple 120V; some require a dedicated circuit ($200–$400)
- Old equipment removal: standard, included in install pricing
Greener Homes Loan financing applies to tankless water heater installations. HRS rebate eligibility applies for heat pump water heaters specifically (which are a different product — see our water heater installation page for the heat pump option).
Tankless Water Heater questions
Do tankless water heaters really provide endless hot water?
Yes — as long as the unit is properly sized for your simultaneous demand. A 7 GPM tankless unit can supply two showers and a kitchen sink running at the same time indefinitely. If you exceed the unit's rated capacity, water temperature will drop. Sizing matters — undersized tankless units do produce the 'cold sandwich' effect homeowners complain about.
What's the lifespan difference?
Tank water heaters typically last 10–14 years. Tankless units typically last 18–22 years with proper annual maintenance (mainly descaling in hard-water areas). Over a typical home ownership period, the tankless unit eliminates one full replacement cycle — meaningful in the long-run cost comparison.
Are tankless units worth the higher upfront cost?
Depends on ownership horizon. Tankless costs roughly $2,000–$4,000 more upfront than a comparable tank water heater. Operating cost savings (20–30% lower gas consumption due to no standby losses) typically run $80–$200/year. Combined with the longer lifespan, total cost of ownership math typically favors tankless for 8+ year ownership scenarios.
Will I need to upgrade my gas line?
Sometimes, yes. Tankless water heaters use gas in concentrated bursts (peak demand of 199,000 BTU is common for residential models, vs 40,000 BTU steady for a tank water heater). Many older Halton Hills homes have 1/2" gas line supply that's adequate for tank water heaters but undersized for tankless. The gas line work adds $400–$1,200 typically. We assess this during the in-home consultation.
Can my tankless heat water for radiant floors or hydronic baseboards?
Some tankless units are dual-purpose ('combi-boilers') — they handle both domestic hot water and space heating. Navien NCB and Rinnai Combi models are common in Ontario for this. Pure tankless water heaters can sometimes be adapted for low-load hydronic, but a proper combi-boiler is the right product for combined applications.
Does tankless make sense for vacation homes or rentals?
Yes, particularly. Standby losses on tank water heaters keep gas flowing 24/7 even when no one's home. Tankless eliminates that — the unit consumes gas only when hot water is actually being used. For cottage properties or homes with extended unoccupied periods, the operating savings are substantially larger than for full-time-occupied homes.
Ready to book tankless water heater?
Call us or submit a quick request. We'll get back to you within an hour during working hours.
Mon–Fri 7:00 AM – 7:00 PM · Saturday 8:00 AM – 5:00 PM · 24/7 emergency service available