Water Heater Sizing and Type

Direct Energy can assist the homeowner in the selection of the most appropriate size of water heater to meet their family's hot water needs.

A number of factors influence water usage in a home including the number and age of family members and quantity and types of water fixtures. In a home with many points of use (multiple baths, dishwasher, washer, separate apartment, etc.) a larger capacity water heater may be necessary.

Selecting an appropriate water heater is a function of:

Selecting the Size

Use this chart as a guide in selecting the most appropriate size of water heater to meet your homeowners' hot water needs.

Note: This sizing chart is NOT applicable in all situations. Larger homes that have unique water fixtures may require detailed analysis or an engineered solution. The number and type of water fixtures and peak load is paramount in appropriately sizing water heaters.

Usage Classification

Typical Home Attributes

Regular Demand

Minimum of:
Power Vent 50 U.S. Gallons¹
Direct Vent 50 U.S. Gallons¹
Power Vent 60 U.S. Gallons¹
Rinnai Tankless - R75LSi 

  • Standard water fixtures
  • Approximately 2-3 baths/showers, standard tub
  • Home < 2500 sq. ft. (approx.)
  • 2-4 occupants

Above Average Demand

Minimum of:
High Input Power Vent 50 U.S. Gallons¹
Power Vent 60 U.S. Gallons¹
High Input Power Vent 65 U.S. Gallons¹

  • Some upgraded water fixtures, 1 soaker tub/whirlpool
  • Approximately 3-4 baths/showers
  • Home 2500 - 3500 sq. ft. (approx.)
  • 4-5 occupants

High Demand

Minimum of:
High Input Power Vent 75 U. S. Gallons¹ 

  • Several upgraded water fixtures, 1-2 larger soaker tubs/whirlpools
  • 4-5 baths/showers, personal demand/high volume of hot water required
  • Home > 3000 sq. ft. (approx.)
  • Number of occupants may vary

Typical Hot Water Consumption

Use this chart only as a guideline to help determine your water usage by activity type. These consumption rates are approximate and do NOT apply to all situations.

Typical Hot Water Consumption2

Showers / Baths

  • Energy Efficient Shower Head
  • Standard Bath (1/2 full)
  • Whirlpool Bath
2.5 - 3 U.S. Gallons/minute3
20 -25 U.S. Gallons3
50 - 70 U.S. Gallons3

Dishwasher

9 - 13 U.S. Gallons3

Hand Dishwashing

1.5 - 3.5 U.S. Gallons3

Personal use/person/day

5 U.S. Gallons3

Laundry Usage

  • Hot wash/ Warm rinse
  • Hot wash/ Cold rinse
  • Warm wash/ Cold rinse
30 U.S. Gallons3
19 U.S. Gallons3
9 - 12 U.S. Gallons3

Questions to Consider

11 U.S. Gallon = 0.8327 Imperial Gallons = 3.7854 Liters
2 Amounts are hot water use only-not mixed or blended consumption
3 1 U.S. Gallon = 0.8327 Imperial Gallons = 3.7854 Liters

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