Tankless vs. Tank Water Heater: Cost Comparison
A tank water heater is cheaper to install and simpler to replace. A tankless unit costs more up front, lasts longer and never runs out of hot water. The right choice depends on your household, your fuel and what your home's gas line and venting can handle.
Short answer: Tank for lowest cost now; tankless for longevity and endless hot water.
Installed cost
A like-for-like 50-gallon gas tank replacement runs about $1,700 to $3,100. A gas condensing tankless unit runs about $3,600 to $6,400, and converting from a tank often adds gas line upsizing, new venting or electrical work on top.
Electric tankless units are cheaper to buy but draw a lot of power; whole-house models often need a panel upgrade.
| Option | Installed cost | Typical life |
|---|---|---|
| 50-gallon gas tank | $1,700 to $3,100 | 8 to 12 years |
| 50-gallon electric tank | $1,300 to $2,500 | 10 to 15 years |
| Heat pump (hybrid) tank | $2,500 to $4,800 | 10 to 15 years |
| Gas non-condensing tankless | $2,600 to $4,900 | 20 years or more |
| Gas condensing tankless | $3,600 to $6,400 | 20 years or more |
Operating cost
Tanks keep 40 to 50 gallons hot around the clock, so they lose energy even when nobody is using water. Tankless units heat only on demand and typically use noticeably less energy, with the biggest savings in smaller households.
A heat pump water heater is the most efficient tank option and a strong middle ground if you have the space and a warm enough location for it.
Lifespan and maintenance
Tanks commonly last 8 to 12 years. Tankless units often last 20 years or more, but they need annual descaling in hard-water areas or their efficiency and life drop.
Which should you choose?
Stay with a tank if you want the lowest cost now, your current setup is simple, or you plan to move soon. Go tankless if you want endless hot water, plan to stay 10 years or more, and your gas line or electrical service can support it without major upgrades.
Common questions
Does a tankless water heater save money?
It uses less energy, but the payback depends on your usage and fuel prices. Small households see the biggest percentage savings.
Can one tankless unit serve a whole house?
Yes, if sized for your peak demand. Large homes sometimes use two units.
Why do tankless quotes vary so much?
Because the unit is only part of the bill. Gas line, venting and electrical upgrades can double the total.