Water Heater Questions, Answered
The 20 questions buyers ask most, answered short. Each one links the page that answers it properly.
Choosing a water heater
›What type of water heater should I buy?
If you have gas and a working flue, a gas storage tank for most households — it recovers fast and it is a like-for-like swap. If you are all-electric and have a garage, unfinished basement or utility space, a heat pump water heater, which uses roughly a quarter of the electricity. Tankless if you keep running out of hot water and your gas line can already feed a 199,900 BTU/h unit. Best water heaters for 2026 works through it.
›Is gas or electric better for a water heater?
Gas recovers two to three times faster, so a smaller gas tank serves the same household: a 50-gallon gas unit with a 50,000 BTU burner is rated at 91 gallons in the first hour against 63 for a 50-gallon electric resistance tank. Electric is cheaper to install and can go where a gas appliance cannot. If you are on electric, a heat pump beats both on running cost. Gas vs electric.
›Are tankless water heaters worth it?
They are worth it when your gas line already carries up to 199,900 BTU/h, you value the floor space, and you will stay long enough to recover the install cost. They are usually not worth it as an emergency same-day replacement, because upsizing the gas line and running new venting turns a half-day swap into a multi-day conversion. Tankless vs tank.
›Are heat pump water heaters worth it?
For an all-electric household with somewhere suitable to put one, yes — a 3.88 UEF against 0.93 is roughly a quarter of the electricity for the same hot water, with a better first-hour rating too. The answer is no in four specific cases: a sealed closet with no air volume, no route for condensate, noise that would carry into a bedroom, or a heated room in a cold climate. The full answer.
›Which water heater brand is best?
None across the board, and the spread between models within a brand is wider than the spread between brands. A. O. Smith leads on retail gas first-hour ratings and peak heat pump efficiency; Rheem on leak detection with automatic shutoff and published cold-climate data; Bradford White on direct venting. Brand comparisons.
Sizing
›What size water heater do I need?
Size by first-hour rating, not gallons, and match it to your peak-hour demand: roughly 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 for the same household. Full sizing method.
›What is a first-hour rating?
The gallons of hot water a tank can deliver in one hour starting from full. It combines the stored volume with how fast the unit reheats, which is why it is the only fair way to compare two tanks — and why a 50-gallon gas tank can be rated at 91 gallons while a 50-gallon electric one is rated at 63. It is printed on the yellow EnergyGuide label. Explained in full.
›Is a 50 gallon water heater enough for a family of 5?
On gas, yes — 91 gallons in the first hour from a 50,000 BTU unit covers five sequential showers. On electric resistance, no: 63 gallons in the first hour is well short of a five-person peak hour, and that specific mismatch is the most common undersizing error we see. Sizing for a family of 5.
›How many GPM do I need for a tankless water heater?
Add up the fixtures that will genuinely run at once — about 1.8 GPM per modern shower, 1.0 at a sink — then check the unit's output at your temperature rise, not its headline figure. Two showers plus a sink is about 4.6 GPM, which in most of the country means a 199,000 BTU gas unit. Tankless sizing chart.
Cost and incentives
›How much does a water heater cost?
We do not publish a single figure, because published install ranges for overlapping scopes of work differ by thousands of dollars and averaging them would invent a number nobody published. What we can tell you is what drives yours: whether it is a swap or a conversion, gas line capacity, venting, electrical work, access, and code-required extras. Cost guide.
›Is there still a federal tax credit for water heaters in 2026?
No. The Section 25C Energy Efficient Home Improvement Credit expired on December 31, 2025, terminated by the One Big Beautiful Bill Act (P.L. 119-21) for equipment placed in service after that date. Its cap had been $2,000 a year for a heat pump water heater. A great deal of published content still advertises it as available. State HEAR programs and utility rebates do still exist. Rebates in 2026.
›Why are there no prices on this site?
Because we have no live price feed for Heat & Tap, and a stale price is worse than no price — it is a number you might budget against. Every product link goes to the live Amazon listing where today's figure is the real one. How we pick explains the decision.
Installation and code
›Do I need an expansion tank?
If a pressure-reducing valve, check valve or backflow preventer sits where water enters your house, then yes. That makes it a closed system, and IPC Section 607.3 requires a thermal expansion tank on the cold supply downstream of those devices — and explicitly does not allow the relief valve to be used for the purpose. Most modern houses have a pressure-reducing valve. Code requirements.
›What size drain pan do I need?
Match it to the tank's diameter, not its capacity: 20 inches for a 30 to 40 gallon tank, 22 inches for a 50, 26 inches for a 75 to 80 gallon or a heat pump unit. Pan sizes are quoted as inside diameter, and the pan needs clearance for its drain fitting. Drain pan sizing.
›What size breaker does an electric water heater need?
It depends entirely on the unit. A 120 V mini tank uses a standard 15 A outlet; a 240 V resistance tank typically a 30 A circuit; a whole-house electric tankless unit draws 100 A or more — the Stiebel Eltron Tempra 24 Plus needs two 50 A breakers and a 150 A minimum service. Breaker and wire size.
Maintenance and lifespan
›How long do water heaters last?
About 10 to 15 years for a storage tank and up to 20 for a tankless unit, consistently across the manufacturer and retailer sources we checked. What decides where you land is the anode rod and your water chemistry rather than the brand. How long they last.
›How often should I flush my water heater?
A storage tank: annually, or every six months in hard water. A tankless unit: annually as the manufacturer baseline and more often in hard water — and on tankless it is a requirement with warranty implications rather than good practice. Flush a tank or flush a tankless.
›Why does my water heater run out of hot water so fast?
Five causes, and only one is the tank being too small: a failed lower heating element (the most common sudden cause on electric), a broken dip tube, a stuck thermostat, heavy sediment, or genuinely insufficient capacity. Check them in that order — the first four are cheap repairs. Troubleshooting.
›Should I repair or replace my water heater?
Replace if the tank is leaking, the hot water is rusty, it is past 12 years, or the quoted repair approaches the price of a new unit. Repair a heating element, thermocouple, thermostat or dip tube on a unit under about 10 years old — those are cheap parts and the tank itself is fine. Replace or repair.
›How often does an anode rod need replacing?
Inspect it every one to three years and replace it when it is substantially consumed. In hard water, reported replacement intervals for a sacrificial rod run from as little as 3 months to 18. It is the single highest-value hour of maintenance on a storage tank, because the anode is what stands between the water and the steel. Anode rods.
Not answered here?
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