When a water heater dies, most Marietta homeowners ask the same question: should I replace it with another tank, or switch to a tankless water heater? Both can be the right answer. It depends on how your household uses hot water, what your gas line and venting can support, and how long you plan to stay in the home. Here’s how we walk customers in Cobb and Paulding County through the decision.
A tankless water heater heats water only when you need it, so it uses less energy, lasts longer and never runs out of hot water. The trade-offs are a higher upfront cost, a limited flow rate when several fixtures run at once, and possible gas line or venting upgrades. A tank heater costs less to install and handles several showers at once, but it loses heat while it sits and wears out sooner.
Reviewed by the Plumbers 4 Real team · Updated October 2026
Water heater out right now?
Call or text and a real person answers. We repair and replace tank and tankless water heaters 24/7.
★★★★★ 4.8 from 240+ Google reviews · Licensed & insured · You approve the price before work starts
Tankless water heater vs. tank: the numbers
Here’s how the U.S. Department of Energy compares them:
- Efficiency: tankless models are about 8% to 34% more efficient than storage tank heaters, because they don’t lose heat keeping a full tank warm around the clock.
- Lifespan: a tankless heater lasts about 20 years; a storage tank lasts about 10 to 15 years.
- Flow: a tankless unit delivers roughly 2 to 5 gallons of hot water per minute. Bigger households may need a larger unit or two units.
- Upfront cost: tankless costs more to buy and install; a tank heater costs less up front.
- Savings: an ENERGY STAR tankless model could save $100 or more a year in energy.
When a tankless water heater makes sense
- You plan to stay in the home long enough for the energy savings to add up.
- Your household runs out of hot water with your current tank.
- You want to free up the floor space a tank takes.
- Your water heater is in a spot where a tank leak would do real damage, such as an attic or finished space.
When another tank is the better choice
- Several people shower at the same time every morning and you don’t want to size up to a large tankless unit.
- Your budget for the replacement is tight right now.
- Upgrading the gas line or venting for tankless would add a lot to the job.
- You may sell the home in the next few years.
What the switch to tankless involves
Going from a tank to a gas tankless unit isn’t a straight swap. A tankless heater burns a lot of gas for short bursts, so the gas line often needs to be larger. It also needs its own venting, and it needs an electrical outlet nearby. Electric tankless units may need a much larger electrical circuit. We check all of this before quoting, so there are no surprises on install day.
Maintenance either way
A tank heater should be flushed about once a year to clear the sediment that causes rumbling and early failure. A tankless unit needs a periodic descaling flush to keep mineral scale off its heat exchanger. Regular maintenance is the best way to get the full lifespan out of either one. See our guide to when to inspect your water heater.
Frequently Asked Questions
Is a tankless water heater worth it?
It depends on your household. The U.S. Department of Energy says tankless models are about 8% to 34% more efficient and last about 20 years, compared with 10 to 15 for a tank. The higher upfront cost pays off best if you stay in the home for years.
Will a tankless water heater run out of hot water?
No, but it has a flow limit, roughly 2 to 5 gallons per minute. If several showers and appliances run at once, a larger unit or a second unit may be needed.
Can I replace my tank water heater with tankless?
Usually yes, but gas tankless units often need a larger gas line, new venting and an outlet nearby. A plumber should check these before quoting.
How long does a tank water heater last?
The U.S. Department of Energy estimates a storage tank water heater lasts about 10 to 15 years.
Do tankless water heaters need maintenance?
Yes. They need a periodic descaling flush to keep mineral scale off the heat exchanger, just as a tank needs a yearly flush to clear sediment.
Ready to compare tank and tankless?
Call (404) 819-2137 or text (404) 436-6116. We’ll price both options for your home before any work starts.