Tankless vs. Tank Water Heater — A Fort Worth Plumber's Honest Take

The quick answer for most people

If your current water heater is under 8 years old and works fine — keep it. If it's over 8 years old and about to fail, you're facing a choice: replace it with another tank (cheaper, familiar, works) or upgrade to tankless (more expensive, longer-lasting, endless hot water).

For most Fort Worth families, the honest answer is replace the tank with another tank. Tankless makes sense for specific situations — I'll get into which — but the tankless-versus-tank pitch gets oversold. Let me walk through it plainly.

What each one actually costs — installed, over 10 years

Here's the number that matters. Not sticker price — total cost to own for a decade.

Tank water heater (40–50 gallon): $1,500–$2,800 installed. Lasts 8–12 years in DFW (the hard water shortens their life). Energy: about $300/year in gas for a typical family of four. 10-year total: ~$2,000–$3,300 installed + $3,000 energy = $5,000–$6,300.

Tankless water heater: $3,500–$6,000 installed (higher end if you need a gas line upgrade — which most older Fort Worth homes do). Lasts 15–20 years. Energy: about $200/year for a comparable family (saves ~30% on gas). 10-year total: $4,500–$6,500 + $2,000 energy = $6,500–$8,500.

Tankless is more expensive up front and more expensive over 10 years — but it lasts longer and gives you endless hot water. The math starts to favor tankless around year 12+.

The gas line requirement most people don't know about

Here's the thing your salesperson may not lead with: tankless water heaters need a bigger gas supply than tanks. A traditional tank needs 40,000–50,000 BTU. A whole-house tankless needs 150,000–199,000 BTU. That's 3–4× the gas demand.

Most Fort Worth homes built before 2000 have a ½-inch gas line running to the water heater. That's fine for a tank. It cannot support a tankless. Upgrading the supply line to ¾-inch or 1-inch, from the meter to the water heater location, adds $800–$2,500 to the install depending on the run length.

Any tankless quote that doesn't mention checking your gas line is a red flag. Ask.

When tank is the right answer

• You're replacing a failed tank and want the fastest, simplest, cheapest fix
• You're planning to sell the home in the next 5 years — the buyer doesn't care about a tankless
• Your gas line is ½-inch and the upgrade would cost more than $1,000
• Your hot water demand is normal (1–4 people, standard use)

When tankless is the right answer

• You've run out of hot water more than a few times and it drives you crazy
• You have a large family or teenagers taking back-to-back showers
• You're doing a major remodel or new construction and the gas line can be run properly from the start
• You plan to be in the home 10+ more years — the longevity pays off
• You want to free up the space where the tank sits (they mount on the wall)

Fort Worth-specific gotchas

Hard water eats tankless heat exchangers. DFW water is famously hard. A tankless heat exchanger will scale up in 3–5 years without treatment. If you install tankless, budget for a whole-home water softener OR plan for annual descaling ($150–$250 per service).

Permits are required in most DFW cities for either type of install. We pull them. Skipping the permit creates a paper problem at sale — the buyer's inspector finds it, and it has to be corrected before closing.

Location matters. Tanks can go almost anywhere with a drain and vent. Tankless needs a specific vent path (especially condensing units) — sometimes the existing tank location won't work for a tankless without additional venting work.

How we'd advise a friend

If a friend called us with a dead tank and asked what to do, honestly? Most of the time we'd say: put in another tank, buy yourself another decade, deal with tankless when the tank fails again if the technology has moved along.

The exceptions where we'd push tankless: large family with hot-water frustration, a remodel that's already opening walls (so the gas line upgrade is easy), or a homeowner staying 15+ years who values the longevity and space savings.

The pitch that a tankless "pays for itself" is oversold in DFW. It might, over 15+ years, if you factor in the energy savings and don't need a big gas line upgrade. Often it doesn't. Go into it with clear eyes.