What is one disadvantage of a whole house tankless water heater?

Author: Era Spinka  |  Last update: Tuesday, December 30, 2025

More expensive installation and maintenance. Tankless systems require special venting, rerouted gas lines, possibly multiple units for a larger household, and sometimes maintenance like installing a softener.

Why do people not like tankless water heaters?

The downside of tankless is that it uses a lot of energy in a short amount of time (which is a problem if you are using electricity instead of a combustible source), and generally has more maintenance required over its lifetime.

What is the downside of a tankless water heater?

Before you commit to buying a tankless water heater, the primary drawbacks to know include: Higher upfront costs. Tankless water heaters are, on average, quite a bit more expensive to buy and install than tank water heaters. Access to fuel.

Is a tankless water heater good for a whole house?

Yes, a whole-house tankless water heater is designed to meet the hot water needs of an entire household. These systems are capable of delivering a continuous supply of hot water, ensuring that multiple showers, appliances, and taps can run simultaneously without running out of hot water.

What do plumbers think of tankless water heaters?

St Paul Pipeworks plumbers advise against purchasing tankless water heaters from big box stores or online retailers, as homeowners often lack the expertise to determine the correct sizing for their specific needs. Many negative reviews about tankless systems stem from improper sizing or piping installations.

Pros And Cons Of Electric Tankless Water Heaters

Can I replace my 40 gallon water heater with a tankless water heater?

Absolutely! In fact, tankless water heaters are becoming the standard for new home construction because of the energy efficiency.

What is the lifespan of a tankless water heater?

Tankless water heaters usually last for around 15-20 years before they need to be replaced, but they may need replacing sooner if they start to break down or lose efficiency. Some common signs your tankless water heater needs to be replaced include: Low water pressure. Water doesn't get hot.

How much does your electric bill go up with a tankless water heater?

How Much Electricity Does a Tankless Water Heater Use? Many people wonder if tankless water heaters increase electric bills. The answer is no — tankless water heaters can save money on your monthly electric bill because they're 8%-34% more efficient than storage water heaters.

Do you ever run out of hot water with a tankless water heater?

You can't run out of hot water with tankless water heaters – unless, of course, the power supply is off or goes out. However, a tankless water heater can have trouble keeping up with demand if too many things require hot water all at once.

Is there an IRS tax credit for a tankless water heater?

The federal tax credit for tankless water heaters can lead to significant savings for homeowners. Eligible tankless gas water heaters must have an ENERGY STAR certification and a UEF of greater than 0.95. Homeowners can claim up to $3,200 in tax credits for eligible home improvements in a single year.

What is not a benefit of a tankless water heater?

A tankless water heater cannot provide hot water faster than its ability to heat the water. While a tank unit can provide hot water for multiple uses at once, a tankless unit might not be able to support simultaneous usage, such as washing dishes, taking a shower and running a washing machine all at once.

Can you take a long hot shower with a tankless water heater?

While a tankless water heater will deliver an unlimited stream of hot water, they struggle to deliver a lot of hot water at one time. So while you might be able to take 100 showers in a row if you have the dishwasher, washing machine, and shower going at the same time you might have problems.

What size tankless water heater to replace a 50 gallon?

A 50-gallon water heater should be replaced with a tankless system with a 10 GPM flow rate just to be safe. Selecting the right flow rate ensures you won't experience cold showers or excessive energy costs. Proper sizing optimizes performance, providing hot water on demand without unnecessary waste.

What is negative about a tankless water heater?

Unlike traditional storage water heaters, tankless units may not be able to meet your home's hot water needs if you have multiple outlets running simultaneously. This is because the flow rate of a tankless unit may not be high enough to support multiple uses of hot water at the same time.

Should I replace my water heater with a tankless?

Tankless water heaters can save you money on your energy bill in the long run, but they also require a greater initial financial investment upfront. Installation costs more, especially if you're installing your first tankless heater and require new gas lines and venting or a dedicated electrical circuit.

What is the upkeep on a tankless water heater?

Steps for Maintaining a Tankless Water Heater
  • Turn Off The Energy Source. ...
  • Close All Main Water Valves. ...
  • Remove Purge Port Valve Caps. ...
  • Attach Hoses To Each Valve. ...
  • Open the Port Valves. ...
  • Descale. ...
  • Flush and Drain the Unit.

Do you get endless hot water with a tankless water heater?

Because tankless water heaters provide an endless flow of hot water, they are becoming a “must-have” luxury for modern homeowners. However, there are a number of considerations for tankless water heaters, including options for gas, propane, and electric.

How long does it take to replace a water heater with a tankless water heater?

Installing a tankless water heater typically takes four to five hours, depending on the type of system and a household's needs.

Can a tankless water heater flood your house?

Tankless water heaters take up less space, and in the event of a leak, they won't flood your home like a tanked water heater.

How much should I expect to pay for a tankless water heater?

The initial investment for a tankless water heater is typically higher, with prices ranging from $1,000 to $3,000 or even more, depending on brand, size, and specific features.

Which tankless water heater is best?

7 Best Tankless Water Heaters for Large Homes in 2025
  • Best Overall: Rinnai RU199iN.
  • Best Premium: Navien NPE-240A.
  • Best Gas Option: Rheem RTGH-95DVLN.
  • Best Electric: Stiebel Eltron Tempra 36.
  • Best Value: EcoSmart ECO 36.
  • Best Compact: Takagi T-H3-DV-N.
  • Best Warranty: Noritz NR981-DVC-NG.

Why is tankless water heater installation so expensive?

Installing a tankless water heater can require gas line upgrades, electrical modifications, and specialized venting—all of which can increase costs. Professional labor also runs from $500–$1,500 due to complex installation requirements.

Why avoid a tankless water heater?

Additional Installation Costs

Tankless water heaters are much more complex than traditional hot water tanks. As a result, they require professional installation. If you're switching from a hot water tank to a tankless unit, you will likely need your gas lines rerouted, as well as a larger gas supply line.

Do tankless water heaters need to be flushed every year?

Over time, a tankless water heater may accumulate mineral build up which can erode the walls inside your tank's heating chamber. To properly maintain and clean your tankless water heater, it's important to flush those mineral deposits at least once a year.

Why does it take so long for hot water with a tankless water heater?

While tankless water heaters are designed for efficiency and on-demand hot water, they can sometimes take a bit longer to deliver the hot water we desire. The reasons can range from the size and capacity of the heater, the distance between the heater and tap, to mineral buildup and low gas pressure.

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