Size Guide
Water Heater Sizes: Cost by Gallon Capacity (30 - 80 Gal)
The right size water heater balances adequate hot water supply with energy efficiency. Here is what each tank size costs and which household it serves best.Last verified April 2026
Cost by Tank Size
Installation Cost by Gallon Capacity
| Size | Household | Unit Cost | Labor | Total Installed |
|---|---|---|---|---|
| 30 Gallon | 1 - 2 people | $400 - $900 | $300 - $700 | $700 - $1,600 |
| 40 Gallon | 2 - 3 people | $500 - $1,100 | $300 - $800 | $800 - $1,900 |
| 50 Gallon | 3 - 4 people | $600 - $1,400 | $350 - $900 | $950 - $2,300 |
| 65 Gallon | 4 - 5 people | $800 - $1,800 | $400 - $1,000 | $1,200 - $2,800 |
| 75 Gallon | 5 - 6 people | $1,000 - $2,200 | $450 - $1,200 | $1,450 - $3,400 |
| 80 Gallon | 6+ people | $1,200 - $2,500 | $500 - $1,500 | $1,700 - $4,000 |
Cost Comparison by Size
Sizing Guide
How to Choose the Right Size
| Bathrooms | People | Recommended Size | First-Hour Rating |
|---|---|---|---|
| 1 bathroom | 1 - 2 | 30 - 40 gallon | 40 - 50 gallons |
| 1 - 2 bathrooms | 2 - 3 | 40 - 50 gallon | 50 - 60 gallons |
| 2 - 3 bathrooms | 3 - 4 | 50 gallon | 60 - 80 gallons |
| 3 - 4 bathrooms | 4 - 5 | 50 - 65 gallon | 70 - 90 gallons |
| 4+ bathrooms | 5 - 6+ | 65 - 80 gallon | 85 - 100+ gallons |
Tip: The First-Hour Rating (FHR) on the EnergyGuide label is the most accurate sizing metric. It measures how many gallons of hot water the unit can deliver in the first hour of use starting with a full tank. Match this to your household's peak-hour demand.
FAQ
Water Heater Sizing Questions
What size water heater do I need for a family of 4?
A family of 4 typically needs a 50-gallon tank water heater, which costs $950 - $2,300 installed. If your household uses above-average hot water (multiple showers, dishwasher, and laundry running simultaneously), consider a 65-gallon tank at $1,200 - $2,800 installed.
Is a bigger water heater always better?
No. Oversized water heaters waste energy by keeping excess water hot that you do not use. They also cost more upfront ($200 - $800 more per size step). The ideal size matches your household's peak-hour demand — the gallons needed during the busiest hour of hot water use.
How much more does a 75-gallon water heater cost vs a 50-gallon?
A 75-gallon water heater costs approximately $500 - $1,100 more than a 50-gallon model when you include the higher unit price and slightly more expensive installation. Total installed: $1,450 - $3,400 for 75-gal vs $950 - $2,300 for 50-gal.