What Size Water Heater Do I Need for My House?

Vertical Plumbing
Nov 22
1 min read

Choosing the right water heater size is essential for maintaining comfort and energy efficiency in your home. A unit that’s too small will leave you without hot water, while one that’s too large will waste energy and increase utility costs. Here’s how to determine the best fit for your household.

Determine the Right Water Heater Size

Household size

More people mean higher hot water demand. A family of 4 typically requires a larger system than a single-person household.

Bathroom and appliance usage

Homes with multiple showers, dishwashers, and washing machines running simultaneously need higher capacity.

Peak hour demand

This is the busiest time for hot water use, usually mornings or evenings.

Type of water heater

Tank and tankless systems require different sizing approaches.

General Water Heater Size Guide

1–2 people: 30–40 gallon tank
3–4 people: 40–50 gallon tank
5+ people: 50–80 gallon tank
Tankless systems: Sized by gallons per minute (GPM), based on simultaneous usage

Signs Your Current Water Heater Is the Wrong Size

Hot water runs out quickly
Water temperature fluctuates
Long wait times for hot water
Increased energy bills

Why Proper Sizing Matters

Ensures a consistent hot water supply
Prevents unnecessary wear on the system
Reduces utility costs
Extends the lifespan of the water heater

If you're unsure which size is best for your home, a professional plumbing inspection can provide accurate recommendations and help you avoid costly mistakes.