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Which Water Heater Do You Need?

Canada's cold inlet water changes everything. Use this guide to match your fixture and climate to the right tankless water heater — with wattage charts, a sizing formula, and links to every product we carry.

Browse All TapHeat Heaters →

Wattage Chart by Fixture Type

Find your use case, check the wattage range, then follow the product link. All prices are in CAD — 30–60% below retail.

Fixture / Use Case Required kW Voltage Circuit TapHeat Product
Bathroom sink
Ideal for hand-washing; low flow rate (0.5–1.5 LPM)
2.0–3.0 kW 120V 20A Budget point-of-use heaters
$39–$49 CAD
Kitchen sink
Handles dishwashing & food prep; 1.5–3 LPM flow
3.5–5.5 kW 120–240V 20–30A Mid-range point-of-use heaters
$49–$69 CAD
Laundry sink
Higher flow needed for utility washing; 2–3 LPM
4.5–5.5 kW 240V 30A Mid-range point-of-use heaters
$49–$69 CAD
Shower (single head)
Canadian cold inlets (4–8°C winter) demand higher kW
7.0–9.0 kW 240V 40A Shower heaters
$69–$149 CAD
Multiple fixtures
2+ simultaneous outlets; requires panel upgrade review
11–18 kW 240V 60A Whole-home units
$149–$349 CAD
RV / Portable
Off-grid camping, trailers, seasonal cabins
12V DC or propane 12V DC Battery/propane Portable units
$69–$129 CAD

🇨🇦 Canadian Climate Note: Why You Need More kW

Cold ground water is the hidden variable in Canadian sizing. Tap water entering your home drops to 4–10°C in winter depending on your province — far colder than the 12–16°C inlet temperatures used in US and European sizing guides.

The colder your inlet, the more energy needed to reach a comfortable temperature. A 3 kW unit that works fine in Texas will deliver barely-warm water at a Canadian kitchen sink in January.

Sizing Formula

Required kW = (desired temp °C − inlet temp °C) × flow rate (LPM) × 0.07

Example — Canadian bathroom sink (winter):
Target: 42°C  |  Inlet: 7°C  |  Flow: 1.5 LPM
= (42 − 7) × 1.5 × 0.07 = 3.675 kW → choose a 4 kW unit
Example — Canadian shower (winter):
Target: 42°C  |  Inlet: 5°C  |  Flow: 6 LPM
= (42 − 5) × 6 × 0.07 = 15.5 kW → choose a whole-home unit

Provincial inlet water temperatures (winter approximate):

When to Call a Plumber (or Electrician)

Many small point-of-use heaters are DIY-friendly. Here's when you need a professional:

⚡ Electrical Requirements

  • 120V units (2–3 kW): Standard outlet — DIY-friendly if you have a dedicated 15–20A circuit
  • 240V units (3.5+ kW): Need a dedicated 240V circuit; hire a licensed electrician if your panel lacks one
  • 11–18 kW whole-home: Often requires a 60–100A sub-panel or full panel upgrade; always use a licensed electrician
  • Canadian code: Electrical work typically requires permits for 240V circuit additions in all provinces

🔧 Plumbing Considerations

  • Under-sink POU units: Connect to existing shutoff valve — basic DIY plumbing skills are enough
  • Whole-home units: Require proper supply line sizing and pressure relief valves; hire a licensed plumber
  • PEX connections: Cannot run PEX directly to the heater outlet — 18" copper or CPVC transition required. Browse PEX fittings →
  • Older homes: If your water pressure exceeds 80 PSI, add a pressure reducing valve before the heater

Questions about your specific setup? Email us with your province, fixture type, and current panel size — we'll recommend the right unit.

Sizing FAQs

Use this formula: Required kW = (desired temp °C − inlet temp °C) × flow rate (LPM) × 0.07

Example: You want 45°C water, your Canadian inlet is 8°C in winter, and your shower head flows at 6 LPM. Required kW = (45 − 8) × 6 × 0.07 = 15.5 kW. That's a whole-home unit, not a point-of-use.

For a kitchen sink at 1.5 LPM wanting 40°C from a 10°C winter inlet: (40 − 10) × 1.5 × 0.07 = 3.15 kW. A 3.5 kW unit gives comfortable margin.

Cold ground water. In most Canadian provinces, incoming tap water drops to 4–10°C in winter — versus 10–16°C in the US Sun Belt. Every degree colder means more energy to reach the same hot water temperature.

Always size up one tier if you're in BC, Alberta, Ontario, or Quebec. US sizing guides assume ~12–15°C inlet temps that don't apply in a Canadian winter. When in doubt, pick the higher wattage model — an undersized unit just delivers lukewarm water at full flow.

Small bathroom-sink units (2–3 kW, 120V) often run on an existing 15–20A circuit if nothing else shares it. But most tankless heaters need a dedicated circuit.

Quick guide: 3.5 kW = 20A/240V dedicated; 5.5 kW = 30A/240V; 7–9 kW = 40A/240V; 11–18 kW = 60–80A/240V. If your panel doesn't have a free breaker slot of the right size, budget for an electrician to add a sub-breaker or upgrade your panel. In Canada this typically costs $150–$400 for a single new circuit.

Point-of-use (POU): Compact unit (think shoebox size) installed at a single fixture — under a sink, in a cabinet, near a shower. Heats only that fixture's water. Lower wattage (2–9 kW), lower cost ($39–$149), simple install. Eliminates the wait for hot water from a distant central heater.

Whole-home: Larger unit (often wall-mounted) that supplies hot water to every tap in the house. Requires high wattage (11–36 kW for electric) or gas/propane. More expensive to buy and install, but one unit handles everything. Best for new builds or full renovations. Browse all TapHeat tankless heaters →

Ready to Choose?

Browse our full selection of tankless water heaters — all priced 30–60% below retail with free shipping on orders over $200 CAD.