Best Gas Water Heaters
Gas recovery is why a 50-gallon tank can deliver 91 gallons in an hour. That is the whole argument.
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The A. O. Smith Signature 100 in its 50-gallon, 50,000 BTU form is the gas tank most houses should buy: 91 gallons in the first hour, 22-inch diameter so it fits the existing alcove, and widely stocked for same-day replacement. For a sealed closet, the Bradford White Defender direct vent at 83 gallons first hour from only 40,000 BTU/h.
Gas storage is the quiet workhorse of American water heating. A gas burner adds hot water while you are still drawing it, which is why a gas tank serves a household an electric tank of the same size cannot. The published numbers make the case better than any argument:
Quick picks
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| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  A. O. Smith Signature 100, 50 gal gasThe straightforward 50-gallon gas replacement, and the reason to pay attention to the burner size: the 50,000 BTU version is rated at a 91-gallon first-hour rating against 77 gallons for the 40,000 BTU one. | Most gas tank replacements | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 2 | Bradford White RG2PDV50S6NThe direct-vent tank to specify when combustion air is the problem: 83-gallon first-hour rating from 40,000 BTU/h, and it draws its air from outside instead of from the room. | Sealed closets and tight mechanical rooms | Check price on Amazon No live price feed on this site, so we show none. #ad |
| 3 |  Rheem Performance 40 gal gasThe honest small-house gas tank: 36,000 BTU/h, around a 65-gallon first-hour delivery, and a recovery rate of about 36 gallons per hour — which is why a 40-gallon gas tank serves a family that would need a 50-gallon electric. | Smaller gas households | Check price on Amazon No live price feed on this site, so we show none. #ad |
The picks in full
Pick 1 — Most gas tank replacements
A. O. Smith Signature 100, 50 gal gas
The straightforward 50-gallon gas replacement, and the reason to pay attention to the burner size: the 50,000 BTU version is rated at a 91-gallon first-hour rating against 77 gallons for the 40,000 BTU one.
| Capacity | 50 gallons |
|---|---|
| First-hour rating | 91 gallons (50,000 BTU model); 77 gallons (40,000 BTU model) |
| Burner | 50,000 BTU/h ultra-low NOx, or 40,000 BTU/h |
| Dimensions | 61 in H x 22 in dia (50,000 BTU); 60-3/4 in H x 22 in dia (40,000 BTU) |
| Warranty | 6-year tank and parts with 1-year labor (50,000 BTU); 9-year tank and parts with 2-year labor (40,000 BTU) |
What is good
- A 91-gallon first-hour rating from a 50-gallon tank covers back-to-back showers that empty an electric tank of the same size
- Widely stocked at Lowe's, so same-day replacement is realistic when the old one fails
- Ultra-low NOx burner meets the stricter air-district rules in California and Texas
- 22-inch diameter fits most existing alcoves without re-plumbing
What is not
- The longer 9-year warranty is on the smaller burner, so warranty and recovery pull in opposite directions
- Atmospheric venting needs a working chimney or B-vent
- Standing pilot and flue losses mean it idles energy away all day
Skip it if: Skip it if your water heater sits in a sealed closet or a space with combustion air problems. An atmospheric gas tank needs real combustion air and a real flue — the power-vent or direct-vent models exist for exactly that case.
No live price feed on this site, so we show none. #ad
Specifications above from Lowe's listing, Signature 100 50-gal 50,000 BTU; Lowe's listing, Signature 100 50-gal 40,000 BTU 9-year. We have not tested this unit ourselves.
Pick 2 — Sealed closets and tight mechanical rooms
Bradford White RG2PDV50S6N
The direct-vent tank to specify when combustion air is the problem: 83-gallon first-hour rating from 40,000 BTU/h, and it draws its air from outside instead of from the room.
| Capacity | 50 gallons nominal, 48 gallons rated storage |
|---|---|
| First-hour rating | 83 gallons |
| Input | 40,000 BTU/h |
| Efficiency | 0.71 UEF, 78% recovery efficiency |
| Venting | Direct vent — combustion air from outdoors |
| Tank lining | Vitraglas enamel |
| Safety system | Defender FVIR with ScreenLok flame arrestor |
| Warranty | 6-year limited |
What is good
- 83 gallons in the first hour from a 40,000 BTU burner is the best ratio on this page
- Direct venting solves the sealed-closet and tight-house combustion air problem outright
- Hydrojet sediment reduction genuinely helps first-hour delivery on hard water
- Defender FVIR is standard, not an upcharge
What is not
- Sold through plumbing wholesalers rather than big-box retail, so weekend DIY sourcing is harder
- 6-year warranty where some competitors sell 9- and 12-year tanks
- 0.71 UEF is ordinary — this is a reliability and venting pick, not an efficiency one
Skip it if: Skip it if your old heater vents into a shared chimney with a furnace and you were not planning to touch the venting. Direct vent means cutting a new sidewall penetration, and that changes the job from a swap into an install.
No live price feed on this site, so we show none. #ad
Specifications above from PEX Universe listing, RG2PDV50S6N; Supply House listing, Bradford White RG2PV50T6N power vent. We have not tested this unit ourselves.
Pick 3 — Smaller gas households
Rheem Performance 40 gal gas
The honest small-house gas tank: 36,000 BTU/h, around a 65-gallon first-hour delivery, and a recovery rate of about 36 gallons per hour — which is why a 40-gallon gas tank serves a family that would need a 50-gallon electric.
| Capacity | 40 gallons |
|---|---|
| Input | 36,000 BTU/h |
| First-hour delivery | 65 gallons (Rheem PROG40-36N data); 68 gallons on the Performance retail model |
| Recovery | 36.4 gallons per hour |
| Energy factor | 0.62 (0.58 UEF on the retail Performance model) |
What is good
- Gas recovery means a 40-gallon tank behaves like a much larger electric one
- Cheapest route to a working hot water supply for one or two bathrooms
- Short and tall variants both exist, so it fits awkward spaces
- Parts on the shelf at every supply house in the country
What is not
- Published figures vary between the professional and retail versions of the same nominal unit — read the EnergyGuide label on the box you are buying
- 0.58 to 0.62 energy factor is the low end of current gas tanks
- 40 gallons is genuinely tight above three people
Skip it if: Skip it for a household of four or more with two bathrooms. The first-hour rating is adequate for one bathroom running at a time, and the complaint that follows a too-small tank is always the same: the last shower is cold.
No live price feed on this site, so we show none. #ad
Specifications above from Young Supply listing, Rheem PROG40-36N; Rheem Performance 40 gal retail listing. We have not tested this unit ourselves.
The burner-size trade nobody explains
Look at the A. O. Smith Signature 100 range and you find two 50-gallon models with the same name and very different specifications:
| Burner | First-hour rating | Warranty | Dimensions |
|---|---|---|---|
| 50,000 BTU ultra-low NOx | 91 gal | 6-year tank and parts, 1-year labor | 61 in H x 22 in dia |
| 40,000 BTU | 77 gal | 9-year tank and parts, 2-year labor | 60-3/4 in H x 22 in dia |
Venting decides which model, not which brand
Before comparing units, work out what your install can vent:
- Working chimney or B-vent, room with real combustion air → an atmospheric unit, which is the cheapest. The A. O. Smith Signature 100 in its standard form.
- No usable chimney, but an exterior wall and an outlet nearby → power vent. Exhausts horizontally through PVC with a blower.
- Sealed closet, or a very tight house where combustion air is the problem → direct vent, which takes its combustion air from outdoors. The Bradford White Defender is on this page for exactly this case.
Getting this wrong is not a comfort issue. An atmospheric gas appliance in a space without adequate combustion air can backdraft combustion products into the house. If your heater lives in a closet, take the direct-vent route seriously. Water heater venting.
Why the Bradford White earns its place
It gets an 83-gallon first-hour rating out of a 40,000 BTU burner, which is the best input-to-delivery ratio on this page. Part of that is the Hydrojet sediment-reducing dip tube, which keeps the tank bottom cleaner and preserves first-hour delivery over time — and matters particularly in hard water.
The trade is distribution: Bradford White sells through plumbing wholesalers rather than big-box retail, so a Saturday DIY purchase is harder. Its 6-year warranty is also shorter than some retail competitors. This is a unit you specify in advance, not one you grab in an emergency. Bradford White water heaters.
Sizing a gas tank
| Household | Capacity | First-hour rating to look for |
|---|---|---|
| 1 to 2 people | 30 to 40 gal | 55+ gal |
| 3 people | 40 gal | 65+ gal |
| 4 people | 40 to 50 gal | 75+ gal |
| 5 people | 50 gal | 85+ gal |
| 6 or more | 50 to 75 gal | 90+ gal, or stagger the draws |
What goes in with it
A water heater is a system, not a box. These are the parts that go in with it, and the ones people discover they need halfway through the job.
- Expansion tank
Required by code on a closed system, which is most homes with a pressure-reducing valve.
- Drain pan
Cheap insurance anywhere the tank sits above something you care about.
- Anode rod
The part that decides when the tank leaks. Replacing it is the highest-value hour of maintenance there is.
How we chose
Published first-hour rating against burner size first, then venting options, then warranty terms as published rather than as advertised, then availability — because a heater you cannot get today is not a replacement. We have not tested these units. How we pick.