Water heater sizing Last reviewed June 2026

What Size Water Heater for a Family of 5?

By the WhatSize editorial team 4 min read Standards-reviewed

TL;DR

A family of 5 needs a 60-80 gallon storage tank water heater. If you choose tankless, you need a unit rated for 7.5+ GPM like the Rinnai RU160iN.

Looking for a different size? See What Size Water Heater for a 1-2 Person Household? or browse all water heater sizing guides.

Large Families Need Large Tanks

With 5+ people, hot water demand peaks in the morning when multiple showers, dishwashing, and laundry can happen simultaneously. A 60-gallon tank provides about 65 gallons of hot water in the first hour — enough for 3-4 showers plus kitchen use. For homes with 5+ people and a large soaking tub, an 80-gallon tank is the safer choice.

Large families should strongly consider a tankless water heater. The Rinnai RU160iN provides 7.5 GPM — enough for 2-3 simultaneous showers — and never runs out of hot water. The trade-off is higher upfront cost but lower operating costs.

Top picks for this size

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You can also consult a local contractor for product recommendations suited to your region and installation requirements. See our full Disclaimers.

Best Options for Large Families

Storage tank (60 gal): Rheem Performance 60 Gal (~$629) — 12-year warranty
Storage tank (80 gal): Rheem Performance 80 Gal (~$899) — maximum capacity for large families
Tankless gas: Rinnai RU160iN (~$1,299) — unlimited hot water, 20-year warranty

Frequently asked questions