How do I choose the right size tankless water heater?

The best sizing factor for a tankless water heater is its flow per minute rate. A 3.2 gpm, tankless heater can heat 3.2 gallons of water per minute, which is roughly enough to provide hot water to a shower and a sink. To find the correct capacity, add up all of the fixtures that you expect to use at the same time.

What size of tankless hot water heater do I need?

To replace a 50-gallon water heater, you would, roughly speaking, need: 10 GPM gas tankless heater or at least a 27 kW electric tankless water heater if you live in the northern part of the USA. 7 GPM gas tankless heater or at least an 18 kW electric tankless water heater if you live in the southern part of the USA.

What size tankless water heater do I need for a family of 4?

A family of 4 should look for a tankless water heater that can produce 7 gallons of hot water per minute. Most families use about 6.5 GPM during peak times. To determine the tankless water heater size, you'll need to know how many appliances your family will use simultaneously.

Can my tankless water heater be too big?

However, tankless water heaters are limited by how much water they can heat at any given time. Choose too small of a system and it won't have the capacity to provide enough hot water to meet your household needs. Go too big and you will overpay. This is why proper sizing is key – before making a purchase.

What happens if tankless water heater is undersized?

Undersized Water Heater

When a tankless water heater is sized too small, you don't run out of hot water as you do with a tank unit. Instead, water flow rate through taps is negatively impacted. The temperature of water remains consistently warm, but its flow from fixtures diminishes.

Tankless Sizing Guide Part 3 - Sizing Your Water Heater

What is the most common problems with tankless water heaters?

What are some of the problems with tankless water heaters?

Should I oversize tankless water heater?

As suggested when selecting a tank-type heater, you don't want to buy an oversized or undersized tankless water heater, as it will result in unnecessary issues such as the rising upfront price, operating costs, and wasted water, and energy - affecting your budget and time.

Can I install a tankless water heater myself?

While it is possible to install your own tankless water heater, it's not a job for inexperienced do-it-yourselfers. There are a number of different sizes and styles of tankless water heaters, including propane, natural gas and electric, along with single-room or whole-house sized models.

How many BTU do I need for tankless water heater?

If you currently have a gas tank water heater (natural gas or propane), you can install a gas tankless water heater. However, you will probably have to upsize the gas line coming from your meter to your heater, as tankless units typically require a dedicated line to service their high demands of up to 200,000 BTU.

How long can you shower with a 20 gallon water heater?

I generally take a 5-10 minute shower on a 20 gallon HWH which is fine for me. I don't think changing the temperature will make a difference, yes it'll increase temperature for those 30 gallons but after that it'll drop temp until the temp can build up again. The low flow showerhead I think is your best bet.

How long do tankless water heaters last?

Some people hesitate to decide on a tankless water heater because they can be a slightly higher cost; however, you get significantly more life out of one. A standard water heater tank lasts about 8-12 years. A tankless water heater can last as long as 25 years!

Are tankless water heaters worth it?

According to the U.S. Dept. of Energy, a tankless water heater is more efficient and uses less energy than a conventional water heater, providing a $25 to $107 in annual savings. If your hot water use is low (less than 41 gallons per day), a tankless water heater will be 24% to 34% more efficient.

How many GPM is 2 showers?

It is recommended that you use 1.0 GPM for bathroom water needs. If you are running two different showers at the same time, you will need at least 5 gallons of water from your tankless water heater. If you need to run both your washing machine and shower at the same time, you will use around 4.5 gallons per minute.

Can a tankless water heater fill a tub?

With tankless, you can fill a large tub and enjoy a nice bath. You're not ever going to run out of hot water.” He says usually the tankless water heaters are used to supply the entire home, including the bathrooms.

How many gallons of water heater do I need?

A small (50- to 60-gallon) storage tank is usually sufficient for one to two three people. A medium (80-gallon) storage tank works well for three to four people. A large tank is appropriate for four to six people.

Do tankless water heaters need a vent?

Tankless hot water heaters require special venting to blow hot exhaust gas outside, where it dissipates. Unlike traditional tank-style water heaters, gas tankless hot water heaters offer far more versatile venting options.

Can I use existing vent for tankless water heater?

Tankless units require 1/2" or 3/4" water lines and 3/4" gas lines. Keep in mind that the new tankless heater cannot be connected to the existing exhaust pipe from your old heater. All tankless direct vent heaters require a stand-alone intake/exhaust system.

What is the downside of a gas tankless water heater?

Power Outage

Because tankless water heaters, even gas models, need electricity in order to run and regulate, if the power goes out, then so does your hot water. If you live in an area prone to outages, a tankless water heater may not be the best choice.

Why does it take so long to get hot water from my tankless water heater?

The length of the delay can be determined by a few factors, including the distance between the water heater and the outlet. In other words, the longer the water has to travel, the more cold water will need to be discharged before the hot water appears.

Do tankless water heaters get clogged?

Deposits inside the heat exchanger can cause the outlets from the tankless system to become clogged. If you notice low water pressure coming from your hot water faucets, these clogs might be the reason. The most common cause of these deposits is hard water.

Will a tankless water heater run a dishwasher?

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.

Should you turn off tankless water heater when water is off?

Tankless and point-of-use water heaters do not need to be shut off in any case to a water shutoff, as they do not run heating elements continuously or hold water in a storage tank.

Can tankless water heaters leak?

It may seem impossible, but tankless water heaters can leak after some years of use.