Tankless water heater sizing for a Calgary home
Start with simultaneous fixtures and temperature rise. Household size is useful context, but it is not a capacity calculation.
Compare the hot-water demand happening at the same time with the unit’s output at the required temperature rise. A qualified assessment also checks the actual supply and equipment limits.
One appliance. A complete connection plan.
Conceptual illustration · not an installation diagram or completed projectSimultaneous use comes first
Count the fixtures that actually run together. Two showers plus a kitchen tap can be a very different load from sequential showers. Fixture flow, mixed-water temperature and the hot-water share matter.
Our planner uses editable illustrative flow and temperature assumptions to organize an assessment request. It reports the total mixed fixture flow and estimated hot-side flow separately, making the assumptions visible instead of presenting a model recommendation.
Temperature rise changes output
Temperature rise is the difference between incoming water temperature and the required hot-water output. A greater rise generally reduces the flow available from a given heater.
Calgary’s climate is a reason to ask about the design inlet temperature, not a reason to insert an unmeasured temperature as fact. A professional should confirm the site assumptions and compare the exact model’s performance information.
Supply is part of sizing
The gas supply, other appliances, venting and model requirements need to support the selected unit. Electric tankless options need an electrical load and circuit assessment. A panel’s enclosure label alone is not evidence of spare service capacity.
The result should be a documented equipment and connection scope. Ask the provider how the recommendation handles your peak use and what happens if demand exceeds output.
Official references
Editorial references reviewed September 30, 2026. Requirements and equipment suitability depend on the address, model and actual work.
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Read the guide ↗Tankless water heater sizing for a Calgary home
Start with simultaneous fixtures and temperature rise. Household size is useful context, but it is not a capacity calculation.
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