Skip to content
Heat & Tap
A storage water heater standing against a wall in a service space

Tank Water Heaters

The storage tank still wins most replacements, and the reasons are better than habit.

By Brijon M., Owner and writer, MadGrey LLC·Last updated October 6, 2026·How we pick →

A storage tank water heater is the right choice for most replacements: it is a like-for-like swap, it needs no new gas line or electrical service, and on gas the first-hour ratings are excellent — a 50-gallon unit with a 50,000 BTU burner delivers 91 gallons in the first hour. Size by first-hour rating, not gallons.

Tankless gets the marketing and heat pumps get the incentives, but the storage tank is still the correct answer in the majority of American replacements, and not out of inertia. It is cheap to buy, simple to service, and crucially it is a half-day job rather than a project: the same gas line, the same flue, the same circuit, the same footprint.

When your old unit is leaking on a Saturday, that matters more than a UEF comparison.

The two things that decide a tank

Fuel and first-hour rating. Everything else — brand, warranty length, control board features — is secondary to getting those two right.

What the same capacity delivers on different fuels
Fuel50 gal first-hour ratingRecoveryWho it suits
Natural gas, 50,000 BTU91 gal40 to 50 gal/hr4 to 5 people
Natural gas, 40,000 BTU77 galAbout 36 gal/hr4 people
Electric heat pump67 gal27 gal/hr (Rheem ProTerra)4 people, at a quarter of the running cost
Electric resistance63 gal21 gal/hr at a 90°F rise3 to 4 people

That table is the single most useful thing on this page. Same volume, four different appliances. Never compare tanks by gallons across fuels. First-hour rating explained.

By fuel

By capacity

Gas venting: the decision inside the gas decision

If you are buying a gas tank, the venting type is usually a bigger constraint than the brand.

  • Atmospheric (natural draft). The cheapest, and what most older houses have. Needs a working chimney or B-vent and real combustion air in the room. In a tight modern house or a sealed closet it can backdraft.
  • Power vent. A blower pushes exhaust out through PVC, so it can vent horizontally through a wall. Needs an electrical outlet beside the heater. Solves awkward flue geometry.
  • Direct vent. Draws combustion air from outdoors through a concentric or twin pipe. This is the answer for a sealed closet or a very tight house — the Bradford White Defender direct-vent model is in our gas roundup specifically for that case.

What actually kills a tank

Not the burner and not the control board. The tank itself rusts through, and what stands between the steel and the water is a glass lining plus a sacrificial anode rod. The anode is consumed; in hard water it can need replacing within a year or two.

That makes anode replacement the highest-value hour of maintenance available on a storage tank, and it is the reason tanks that get looked after reach 15 years while identical neglected ones leak at 8. Anode rods, and how long water heaters last for the full failure analysis.

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.

When not to buy a tank

  • You genuinely run out of hot water and cannot fit a bigger tank. That is a tankless or two-tank conversation.
  • The tank's floor space is valuable and you are already doing construction.
  • You are all-electric with somewhere unconditioned to put a unit. A heat pump water heater is a storage tank and costs a quarter as much to run.
  • You are away for long stretches. Standby loss runs whether you are home or not; tankless loses nothing while idle.

Questions people actually ask

›Are tank water heaters still worth buying?
For most replacements, yes. They are cheaper to buy, simpler to service, and a like-for-like swap rather than a conversion. On gas the first-hour ratings are better than anything else at the same capacity.
›How long does a tank water heater last?
About 10 to 15 years, consistent across the sources we checked. What decides where in that range you land is the anode rod and the water chemistry, not the brand. How long they last.
›What size tank water heater do I need?
Size by first-hour rating against your peak-hour demand: 70+ gallons for four people, 80+ for five, 90+ for six. On gas that is usually a 50-gallon tank; on electric resistance it can be 65 or 80. Sizing guide.
›Is gas or electric better for a tank water heater?
Gas recovers two to three times faster, so a smaller gas tank serves the same household. Electric is cheaper to install and has no venting. If you are on electric and have somewhere to put it, a heat pump water heater beats both on running cost. Gas vs electric.
›What is the difference between power vent and direct vent?
A power vent uses a blower to push exhaust out through PVC and draws combustion air from the room. A direct vent draws combustion air from outdoors, which is what you need in a sealed closet or a very tight house.
›Do I need an expansion tank with a storage water heater?
If a pressure-reducing valve, check valve or backflow preventer sits where water enters the house, yes — that makes it a closed system and IPC 607.3 requires thermal expansion control. Expansion tank code requirements.