Updated April 2026
Water Heater Replacement Cost by Size: 30 to 80 Gallon (2026)
No competitor has a dedicated size-by-size guide. Here is the full breakdown: installed cost for every common tank size, by fuel type, with brand comparisons for the two most common sizes.
Quick Answer: Cost by Tank Size
30 gal
$600-$1,200
1-2 people
Small home or apt
40 gal
$700-$1,500
2-3 people
Most common starter size
50 gal
$800-$1,800
3-4 people
Family standard
75 gal
$1,200-$2,200
5-6 people
Large household
80 gal
$1,400-$2,500
6+ people
High-demand homes
Installed cost (electric). Gas adds $150-$400. Excludes permits and fuel conversion work.
Cost by Size and Fuel Type
Fully installed cost including unit, labor, connections, and haul-away.
| Tank Size | Electric (Installed) | Gas (Installed) | Best For |
|---|---|---|---|
| 30 gal | $600-$1,200 | $800-$1,600 | 1-2 people, apartments, vacation homes |
| 40 gal | $700-$1,500 | $900-$2,000 | 2-3 people, small homes |
| 50 gal | $800-$1,800 | $1,000-$2,500 | 3-4 people, family homes |
| 75 gal | $1,200-$2,200 | $1,500-$3,000 | 5-6 people, large homes |
| 80 gal | $1,400-$2,500 | $1,800-$3,200 | 6+ people, high-demand households |
How to Pick the Right Size
First Hour Rating (FHR) Method
The DOE recommends sizing by First Hour Rating -- how many gallons of hot water the tank delivers in the first hour of use. Calculate your peak hour demand:
- 1. Count the number of people who shower in the morning (12 gallons each)
- 2. Add dishwasher use (6 gallons)
- 3. Add clothes washer loads (7 gallons per load)
- 4. Total = your FHR requirement
1-2 people
30-50 gallons FHR
Recommended: 30-40 gal tank
Small household, staggered use
3-4 people
50-80 gallons FHR
Recommended: 40-50 gal tank
Family home, typical morning rush
5-6 people
70-100 gallons FHR
Recommended: 50-75 gal tank
Large family or consider tankless
6+ people
90-120+ gallons FHR
Recommended: 75-80 gal or tankless
High demand; tankless often better
Brand Comparison: 40 and 50 Gallon Units
These are the most commonly replaced sizes. Prices shown are retail (Home Depot/Lowes). Labor typically adds $300-$900.
| Brand / Model | Size | Fuel | Retail Price | Warranty | Notes |
|---|---|---|---|---|---|
| Rheem PROE40 T2 | 40 gal | Electric | $580-$640 | 6 yr tank | Most popular electric; widely stocked |
| A.O. Smith ENS-40 | 40 gal | Electric | $540-$600 | 6 yr tank | Similar spec to Rheem; slightly cheaper |
| Bradford White RE340S6 | 40 gal | Electric | $560-$620 | 6 yr tank | Professional-grade; plumbers prefer it |
| Rheem PROG50 | 50 gal | Gas | $850-$920 | 6 yr tank | Best seller in gas tank category |
| A.O. Smith GCN-50 | 50 gal | Gas | $800-$880 | 6 yr tank | Comparable to Rheem; competitive pricing |
| Bradford White RG250S6N | 50 gal | Gas | $820-$900 | 6 yr tank | Tall design; standard residential install |
75+ Gallon Tank vs Tankless: When to Switch
If you are replacing a 75 or 80-gallon tank, do the math before defaulting to like-for-like. A high-flow gas tankless unit at $2,500-$4,000 installed competes directly on price with a large tank replacement, and it lasts 15-20 years vs 8-12 for the tank.
80-Gal Tank Replacement
Install cost: $1,800-$3,200
Lifespan: 8-12 years
Energy cost/yr: $300-$500 (gas)
Hot water limit: Yes, can run out
Gas Tankless (9 GPM)
Install cost: $2,500-$4,500
Lifespan: 15-20 years
Energy cost/yr: $200-$300 (gas)
Hot water limit: None (on demand)
For large-home replacements, see the full comparison at tankvstanklesswaterheater.com.
Frequently Asked Questions
How much does a 75 gallon water heater replacement cost?
A 75-gallon water heater replacement costs $1,200 to $2,200 installed for electric, or $1,500 to $3,000 for gas. The larger tank requires more materials and more labor time, which is why costs are 30-40% higher than a 50-gallon unit. At this size, tankless is often competitive on total installed cost and offers significant advantages in lifespan and energy use.
How much does it cost to replace an 80 gallon water heater?
An 80-gallon water heater replacement costs $1,400 to $2,500 installed for electric, or $1,800 to $3,200 for gas. Very few homes actually need an 80-gallon tank. If your household is 5 people or fewer, a 50-gallon gas tank or a high-flow tankless unit is a more cost-effective choice.
Is a 40-gallon water heater enough for a family of 4?
A 40-gallon water heater is borderline for a family of 4. It will work if showers are staggered, but two people showering back-to-back plus running a dishwasher may exhaust the tank. A 50-gallon unit is the safer choice for a family of 4 and costs only $100-$300 more installed.
What size water heater do I need for a family of 5?
A family of 5 typically needs a 50-75 gallon tank or a whole-home tankless unit rated at 7+ GPM. The DOE recommends sizing based on First Hour Rating (FHR): calculate peak hour demand by counting all hot water activities in your busiest hour. Most families of 5 need 70-90 gallons FHR, which a 75-gallon tank covers comfortably.
Should I get a 75 or 80 gallon water heater instead of tankless?
If you are replacing a 75 or 80-gallon tank, seriously consider upgrading to a high-flow gas tankless unit instead. The installed cost is similar ($2,500-$4,500) but tankless lasts 15-20 years vs 8-12 for a tank, you never run out of hot water, and annual energy costs are $100-$200 lower. The extra upfront cost typically pays back in 5-8 years.