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

Author: Dr. Alba Schaden IV  |  Last update: Saturday, June 21, 2025

Limited hot water supply. 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.

How big of a tankless water heater do I need for a shower?

To find the correct capacity, add up all of the fixtures that you expect to use at the same time. For example, if you know that two people will be showering while another person runs a sink, you would need a 5.75 gpm unit, based on two 2.5 gallon-per-minute showers and one 0.75 gallon-per-minute faucet.

Can a tankless water heater be used for a shower?

With a tankless water heater, you can take a shower, use the dishwasher, and do laundry all at the same time without losing hot water. On top of saving, you from the dreaded cold shower, it can also save you money and energy.

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.

Will a 20 gallon water heater work for a shower?

That said, the average shower would use 20 gallons. Add them up during your peak hours, and you'll have a basic idea of how much hot water your family requires.

Why does it take so long for my tankless water heater to deliver hot water?

Do long showers damage water heater?

Aside from risking mould growth without solid ventilation, excessive hot showers force your hot water tank into maximum output and drive more hot water through the piping system from the basement. In addition, the water heater must keep up with the demand and could wear out sooner.

How long of a shower can you take with a 30 gallon hot water heater?

A 30 gallon water heater can provide up to 20 minutes of hot water for activities such as showering, bathing, or washing dishes by hand.

Why do people not like tankless water heaters?

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.

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.

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.

Why does my shower get cold with a tankless water heater?

Low water pressure can affect the performance of a tankless water heater. A plumbing crossover can cause low water pressure by connecting the cold and hot water lines incorrectly. Installing a pressure regulator can help regulate water pressure and ensure a consistent flow of hot water to the tankless water heater.

Can you run out of 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.

How many gpm for a shower?

Standard shower heads use 2.5 gpm, but to earn the WaterSense label, a product must use no more than 2 gpm and still meet strict performance requirements. The EPA estimates that the average family could save 2,900 gallons of water per year by installing a WaterSense-labeled shower head.

Can you run 2 showers with a tankless water heater?

The right tankless water heater can definitely take care of all your family's hot water needs, including taking multiple showers at once. If you're considering upgrading to a tankless water heater, it's essential to work with experienced professionals.

Can you replace a 50 gallon water heater with a tankless water heater?

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.

Can I write off a water heater on my taxes?

Water Heater Tax Credit Details.

You can claim 30% of the project cost, up to a $2,000 maximum credit. Heat pump water heaters that have earned the ENERGY STAR are eligible for this credit. You can find a list of ENERGY STAR certified models here.

What is the best tankless water heater?

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.

What is the downfall to 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.

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.

When not to get a tankless water heater?

Electric Tankless Water Heaters

They're less expensive than gas-powered ones but aren't efficient if you run multiple hot water devices. They may struggle to keep up with multiple appliances at the same time.

What is a normal shower time?

The average shower lasts about eight minutes. If you're spending more than 15 minutes in the shower, you may need to make an adjustment. Dermatologists recommend keeping your showers between 5 and 10 minutes. This time period gives you enough time to properly clean your body without overdoing it.

How big of an on demand water heater do I need?

Proper sizing is important prior to select and installing a tankless, but in general the average rules for sizing the correct water heater for a household are roughly: 3.5 GPM for 1-2 fixtures simultaneously. 5 GPM for 2-3 fixtures simultaneously. 7 GPM for 3-4 fixtures simultaneously.

How long should a hot shower last with a 40 gallon water heater?

For instance, a typical shower uses about 10 gallons of hot water. So, if you have a 40-gallon hot water tank, you should be able to get four average-length showers out of your hot water tank. This also depends on how much hot water you use for other things.

Previous article
Can I just remove my thermostat?
Next article
Which perennial flowers bloom all summer?