40 vs 50 gallon: is the bigger tank worth it?
The price gap is small — often $100–$300 installed. Getting the size wrong costs more than the upgrade either way.
The 2026 numbers
| 40 gallon | 50 gallon | |
|---|---|---|
| Unit price | $400 – $2,000 | $500 – $2,100 |
| Installed | $600 – $3,000 | $700 – $3,100 |
| Right for | 2–4 people, regular use | 3–5 people, or 2–3 heavy users |
| First-hour rating (typical gas) | ~60–70 gallons | ~75–90 gallons |
Labor is identical — same connections, same footprint in most closets. You're paying only the unit delta, which is why plumbers often quote the two together.
How to actually size it
Count your busiest hour, not your family size. Two back-to-back showers (about 20 gallons each), a dishwasher cycle, and a laundry load in the same morning window will drain a 40-gallon gas unit's first-hour output. If that's a normal Tuesday, buy the 50.
Flip side: two people in the house, showers staggered? The 40 keeps a slightly lower gas bill and a slightly smaller footprint, and you'll never notice the difference.
One warning on upsizing
Jumping past 50 — to a 75 or 80 — is not the same casual decision. Those can need upgraded venting or gas supply, which is where installed cost jumps to $1,100–$4,000. If a 50 isn't cutting it, price a high-recovery 50 or a tankless before defaulting to a 75.
If you're supplying the unit yourself
Some homeowners split the job: buy the tank, pay labor only. Electric models are the practical case — they ship freight direct, so you can compare 40-gallon electric units against 50-gallon electric units and put the difference toward the install. Ask first whether your plumber warranties labor on an owner-supplied unit; some won't touch them.
Prices and availability are accurate as of the date and time shown and can change. The price shown on Amazon at the time of purchase is the one that applies.
Questions people ask
How much more does a 50 gallon water heater cost than a 40 gallon?
About $100–$300 more installed in 2026. Labor is the same; you're only paying the unit price difference.
Should I get a 40 or 50 gallon water heater for a family of 4?
A family of four with overlapping morning showers should take the 50. If usage is staggered and you've never run out with a 40, a like-for-like 40 swap is fine.