Tankless Water
Heaters, Explained
A tankless water heater does one thing differently. Instead of keeping 40 or 50 gallons hot around the clock, it heats water only when you turn on a tap. Whether that is worth it depends on your home, your water, and how long you plan to stay.
Cold water runs through the unit, a burner fires, and hot water comes out. There is no tank to drain, so you do not run out mid-shower. There is no tank to keep warm, so you stop paying for heat you are not using.
How a tankless heater actually works
That on-demand design is the whole story. A standard tank is basically a giant thermos. It reheats itself all day and night to keep the water warm, even when you are asleep or at work. That constant reheating is called standby heat loss, and it is the single biggest reason tank heaters cost more to run. A tankless unit skips it entirely because it only fires when you need hot water.
For daily life that means a few things. You do not run out of hot water in the middle of a shower because there is no tank to drain. You stop paying to keep a big tank warm all day. And the unit hangs on a wall instead of taking up a corner of your basement or utility closet.
The real numbers on savings
The savings are real, but they depend on how much hot water your home uses. The U.S. Department of Energy estimates that for homes using 41 gallons a day or less, a tankless unit runs 24 to 34 percent more efficient than a standard tank. For heavy hot water users at around 86 gallons a day, the edge is smaller, closer to 8 to 14 percent. In dollar terms, DOE puts the average savings for a gas tankless unit at about $108 a year over a tank.
Pros and cons at a glance
- Hot water that does not run out. Back-to-back showers, a full tub, dishes running, no cold surprise.
- Lower energy bills. No standby heat loss. DOE-level savings run around $108 a year on gas, and a Minnesota study measured 37 percent less water heating energy.
- Long lifespan. DOE says a well-maintained tankless unit lasts more than 20 years. A standard tank usually gives you 8 to 12.
- Space back. No floor tank. The unit mounts on a wall and frees up the room around it.
- Less flood risk. No tank sitting full of water waiting to rupture and soak a finished basement.
- Higher upfront cost. The unit and the install cost more than a like-for-like tank swap. The payback comes over years, not months.
- Gas or venting upgrades. Many homes need a larger gas line or new venting. That is real work and real cost.
- Flow-rate limits. Size it too small and running several fixtures at once can stretch it thin. Sizing has to be right.
- Needs annual maintenance. A tankless unit has to be descaled once a year, more often on hard water. Skip it and you lose efficiency and life.
- No hot water in an outage. Gas tankless units use electronic ignition, so they will not run when the power is out.
Hard water is the Twin Cities catch
This is the one most homeowners here miss. Twin Cities water is hard, and hard water is tough on a tankless unit. As water heats, calcium and magnesium drop out and form scale inside the heat exchanger. Left alone, that scale insulates the metal, drives up your energy use, and eventually cracks the exchanger.
The fix is simple and it matters a lot. Descale the unit once a year, and run a water softener if you do not have one. Do that and you hit the 20-plus year lifespan. Skip it, and industry data shows hard water can cut a tankless unit’s life roughly in half, down to 7 to 10 years.
Who it fits, and who it doesn’t
You run out of hot water now, you want the space back, you plan to stay in the home long enough to earn back the upfront cost, and you either have soft water or are ready to add a softener. Bigger households that hammer hot water at peak times feel the upgrade the most.
Your current tank works fine, you are moving in a year or two, or a proper install would need heavy gas and venting work that outweighs the payoff. In some homes a good tank is the smarter money, and we will tell you that straight.
The honest answer depends on your home, your water, and how long you plan to stay. That is exactly the kind of thing worth having a plumber look at before you spend a dollar.
How Bedrock does tankless
We install tankless units regularly, and our master plumber-led team knows them inside and out. We size the unit to your home so you are not stuck with too little capacity or paying for too much. We handle the gas and venting work a proper install needs, and we stand behind it when we are done. We install Bradford White equipment.
Here is the part that matters most. Our plumbers are not commissioned, and we do not upsell. Nobody at Bedrock makes an extra dollar for talking you into a tankless unit you do not need. If a tank is the better call for your home, that is what we will tell you. Flat-rate pricing, honest advice, every time.
Tankless water heater FAQ
How long does a tankless water heater last?
The Department of Energy puts it at more than 20 years with proper maintenance, versus 8 to 12 for a standard tank. On hard water without descaling, that number can drop to 7 to 10 years, so annual maintenance is the key to reaching the full lifespan.
Do tankless water heaters really save money?
Yes, on energy. DOE estimates about $108 a year on a gas unit, and a Minnesota study measured 37 percent less water heating energy. The savings build over years, so the payback depends on how long you stay in the home and how much hot water you use.
Do I need a water softener for a tankless heater in Minnesota?
It is strongly recommended. Twin Cities water is hard, and a softener protects the heat exchanger from scale, keeps the unit efficient, and helps it reach its full lifespan.
Will a tankless unit give my whole house enough hot water?
It can, as long as it is sized right for your home and your peak demand. Undersizing is the most common mistake, which is why proper sizing is the most important part of the install.
The bottom line
- Endless hot water and no standby heat loss, on demand
- Roughly $108 a year on gas, and 37 percent less water heating energy in a Minnesota study
- 20-plus years of service, against 8 to 12 for a tank
- Hard water cuts that to 7 to 10 years without annual descaling and a softener
- Higher upfront cost, and many homes need gas or venting work
- Sizing is the make-or-break part of the install
Want a straight answer for your home?
Call for a no-pressure assessment. We will tell you if tankless makes sense, and if it doesn’t.
Sources: U.S. Department of Energy; Minnesota Center for Energy and Environment field study. Savings and lifespan figures are typical results, not a guarantee for any specific home. Actual performance depends on hot water use, water hardness, equipment sizing, and maintenance.