Tankless water heaters (also called on-demand or continuous-flow) heat water as it flows through the unit rather than maintaining a tank of hot water 24/7. The benefits are well-documented: endless hot water (you can shower for 4 hours straight), 95%+ efficiency (versus 60-80% for a typical tank), 20-25 year service life (versus 10-12 for a tank), no standby losses, and significant floor-space recovery.
Kanata-area homes are excellent candidates for tankless conversion. Most homes have gas service, mechanical rooms with reasonable access, and household sizes that match available tankless capacities perfectly.
The most common reason homeowners convert is the combination of an aging tank reaching end-of-life and wanting to eliminate the 'someone took the last shower' problem in larger families.
Common signs you need this service
- Existing water heater is 10+ years old
- Family runs out of hot water during back-to-back showers
- Looking to reclaim the floor space the tank occupies
- Want lower monthly energy costs
- Renovating and want a future-proof system
- Vacation home where standby losses from a tank are wasteful
How tankless sizing works
Tankless water heaters are sized by their ability to raise water temperature at a given flow rate. The two numbers that matter are the BTU rating (how much heat the unit can produce) and the maximum flow rate at a temperature rise. In Kanata, incoming municipal water is cold — typically 4-7°C in winter, 12-15°C in summer. To get a 49°C output (comfortable shower), the unit needs to add 35-45°C in winter. A typical 150,000 BTU residential tankless can deliver about 4.5 GPM at that winter temperature rise — enough for two showers plus a kitchen sink running simultaneously. A 199,000 BTU unit handles closer to 6 GPM. We size based on simultaneous demand — count your bathrooms, your kitchen, your laundry, and the largest realistic simultaneous draw, then size accordingly.
Gas line sizing — the most common gotcha
Tankless water heaters demand significantly more gas than tank units. A typical tank water heater is 40,000 BTU; a typical tankless is 150,000-199,000 BTU. The existing 1/2 inch gas line that fed your tank may not be adequate for tankless — particularly if the run from the meter is long, or if the gas line shares with other appliances (range, dryer, furnace, BBQ). Part of every tankless install is gas line sizing. If upsizing is required (usually to 3/4 inch from the meter to the water heater location), we include it in the quote. Skipping this step causes nuisance shutdowns and incomplete combustion — both dangerous and warranty-voiding.
Venting and condensate
Modern condensing tankless units (the only kind worth installing in 2026) use 3-inch PVC venting and produce condensate as a byproduct of high-efficiency combustion. The vent runs through an exterior wall (concentric — intake and exhaust in one penetration) and the condensate drains to a floor drain or laundry standpipe. Both are simple in most Kanata mechanical rooms. Side-wall venting is much simpler than the old B-vent up through the roof.
Recirculation: the upgrade you'll thank us for
Built-in recirculation (Navien A2 series and similar) addresses the one legitimate complaint about tankless: cold-water sandwich and wait time at distant fixtures. With recirculation, the unit periodically pre-heats the supply line so hot water is available almost immediately at every tap. The energy cost is minimal and the convenience is significant — particularly in larger homes where the kitchen or master bath is far from the mechanical room.
Annual maintenance
Tankless units need an annual descaling — running a vinegar solution through the heat exchanger to remove mineral scale. It takes 60-90 minutes and protects the heat exchanger (the most expensive part of the unit). If you have a water softener, descaling can be every 18-24 months. We offer annual maintenance contracts that include descaling, combustion analysis, and filter cleaning.
When tankless is NOT the right answer
Tankless isn't always best. Small condos with minimal simultaneous demand often do fine with a small tank or a small tankless without all the conversion complexity. Homes with electric water heating where converting to gas isn't practical may be better served by a heat pump water heater. Vacation properties used a few weekends a year might be better with a small tank that's easily isolated when not in use. We assess and recommend honestly — tankless is great when it fits, less great when it's forced.
Our process
- 1
Sizing and gas line check
Tankless units are sized by flow rate (GPM at temperature rise) — we calculate based on your fixture count and simultaneous demand. We also verify the gas line size is adequate (often needs upsizing from 1/2 inch to 3/4 inch for tankless).
- 2
Venting plan
Most modern tankless units use 3-inch PVC concentric venting through an exterior wall — much simpler than B-vent from a tank.
- 3
Remove old tank
Drain, disconnect, and remove the old tank. Cap any obsolete venting.
- 4
Install and connect
Wall-mount the new unit, run new gas, water, and condensate connections, and run new vent.
- 5
Commission and instruct
Start-up sequence, check combustion analysis, set water temperature, instruct on use and annual descaling.
What's included
- Sizing and full assessment
- Old tank removal and disposal
- New tankless installation (Navien NPE-A2 series or Rinnai RUR series typical)
- Gas line upsizing if needed
- PVC concentric venting through exterior wall
- Condensate drain to nearest acceptable drain
- Permit and TSSA inspection
- Warranty registration
- Owner walkthrough
What affects the price
Gas line sizing
If the existing gas line to the water heater is undersized for tankless, we upsize from the meter — adds $300-$700 depending on length.
Venting path
If the unit can be wall-mounted near an exterior wall, venting is short and simple. Longer vent runs or multiple elbows add cost.
Choice of unit
Navien NPE-A2-150S, NPE-S, Rinnai RUR series — typical Kanata residential units range $2,200-$3,400 for the unit itself.
Recirculation
Built-in recirculation (Navien A2 series) eliminates wait time at distant fixtures — highly recommended in larger homes.
Why Kanata homeowners choose us
- We are Navien and Rinnai certified installers — warranty is intact
- We size correctly the first time — undersized tankless is the single most common installation mistake
- We pull TSSA permits and schedule inspection
- We service what we install — annual descaling and combustion analysis available
Kanata homes are typically gas-fired (Enbridge service) and tankless conversion is straightforward. Existing 40-50 gallon tank installations convert cleanly to a 150,000-180,000 BTU tankless. Larger homes or homes with high simultaneous demand (multiple bathrooms, large soaker tubs) may need a 199,000 BTU unit or twin units in cascade.
Materials & brands we trust
- Navien NPE-A2 series
Our most-installed unit — built-in recirculation pump, excellent reliability, 15-year heat exchanger warranty.
- Rinnai RUR Series
Excellent alternative with strong reliability.
- Bradford White (tank backup)
When a tank is still the right answer — see our Water Heaters page.
Tankless installation involves gas, venting, and condensate work, all under TSSA jurisdiction. Permit is pulled, work is inspected, combustion analysis is performed at startup. CO/CO2/O2 readings documented and within manufacturer spec.
Tankless installation is not a DIY project — gas work in Ontario requires a TSSA-certified contractor, venting must follow manufacturer-specific instructions, and improper installation voids the warranty and can be dangerous.