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WaterHeaterSizeCalculator

Calculate the right size water heater for your home based on number of occupants and water usage patterns.

Normal household use

Show detailed information

Recommended Size

Tank Capacity
100 gallons
First Hour Rating
90 gal
Daily Use
120 gal
Recommendation
Recommend 50+ gallon tank or tankless

Size by Number of Occupants

Recommended Tank Sizes

1 person40 gal
2 people40 gal
3 people50 gal
4 people66 gal
5 people80 gal

Water Heater Types

Traditional Tank

Stores 30-120 gallons, keeps water hot continuously

Pros: Lower upfront cost, reliable

Cons: Standby heat loss, larger footprint

Tankless (On-Demand)

Heats water as it flows through

Pros: Energy efficient, compact, endless hot water

Cons: Higher upfront cost, may need upgrade

Heat Pump

Uses electricity to move heat from air to water

Pros: Very efficient, lower operating cost

Cons: Higher upfront, needs air space

Quick Reference: Water Heater Terminology

First Hour Rating (FHR)

Hot water available in first hour of use

Recovery Rate

Speed at which heater reheats water

BTU

British Thermal Unit - heating capacity

UEF

Uniform Energy Factor - efficiency rating

Standby Loss

Heat loss from stored hot water

Thermostat Setting

Standard 120°F (prevents scalding)