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Best Condensing Tankless Water Heater Of 2022

Brandon Forder
  Nov 28, 2022 3:54 AM

In search of the top tankless water heater condensing model?

Exhaust gases from condensing tankless water heaters can reach temperatures as low as 100°F, which means that PVC piping can be used for venting rather than stainless steel.

OK, let's go into this manual.

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Last update on 2022-11-28 / Affiliate links / Images, Product Titles, and Product Highlights from Amazon Product Advertising API

Buying Guide

Propane vs. Natural Gas

For most homeowners, a natural gas tankless water heater is a great option because natural Because natural gas is typically piped directly into homes from a utility provider, tankless water heaters powered by this fuel source are a fantastic alternative for most homeowners. While propane prices can vary by region, in general, natural gas is less expensive.

However, many people who live off the grid or in rural areas can only access propane for their gas needs. You should opt for a tankless water heater that can run on propane if this is the case. Manufacturers of both natural gas and propane water heaters typically sell conversion kits that allow for easy switching between the two fuel types.

Indoor vs. Outdoor Application

Cold weather will lower the efficiency of an outdoor tankless water heater and could possibly cause it to freeze and break in most parts of the country where winter lows regularly fall below freezing. Because of this, a tankless water heater is the most popular choice for residential use. Yet there are times when an outdoor model makes the most sense, such as when you need hot water for a pool house or when you're in a particularly remote area, as when you're camping.

Also, if there is already a gas water heater in the house, then there is no need to create venting or bring in a gas line to accommodate the installation of a tankless gas heater to replace an existing electric water heater in the home. If an outdoor gas tankless water heater is wanted in this specific case, proper insulation and protection from the elements, such as a detached garage or shed, should be provided.

Flow Rate (GPM)

Selecting the appropriate size of tankless water heater is crucial, since it will influence whether or not your household will have enough hot water. Hot water production rates in gallons per minute are used to categorize tankless water heaters (GPM). Take into account the average hot water consumption of the following appliances and fixtures to establish the GPM requirement for your household.

  • Bathroom or kitchen faucet: 0.5 GPM

  • Shower: 2.5 GPM

  • Dishwasher: 1.0 GPM

  • Clothes washer: 1.5 GPM

Applying the preceding examples as a rule of thumb, think about when in the day your household consumes the most hot water. Your tankless water heater should supply at least 6.0 GPM if, for instance, two people in your household will be taking showers at once while the dishwasher is operating. If you aren't sure how much hot water you'll need during peak hours, it's probably safest to go with a water heater that provides 0.5 to 1.0 GPM more than you anticipate needing.


Tankless water heaters can be purchased in a number of different sizes. How many people live in your household and how frequently they will use hot water will determine which model is best for your home. The quantity of hot water available to the whole family will decrease if the unit is too small. Having one that is too big will result in higher maintenance costs.

The number of fixtures you plan to run at once, along with their individual hot water needs, will help you establish the ideal size for your home. As a result of adding these numbers, you will get the required capacity for your hot water heater.

You can install one large tankless water heater for the whole house, or you can install a number of smaller point-of-use water heaters, each of which is dedicated to a single appliance or faucet. To avoid any unnecessary waiting for hot water, point-of-use heaters are typically put as close as possible to the appliance they supply with hot water.

Fuel Type

Both gas and electric tankless water heaters are highly effective, yet they each have their own advantages and disadvantages.

Tankless water heaters powered by natural gas can heat more water at once, but they are more expensive and need more maintenance than electric water heaters.

Because they don't produce exhaust, electric heaters can be installed almost anyplace. However, if you have a high demand for hot water, you may need to improve your electrical system to keep up with the additional power requirements of your water heater.

Your specific requirements should determine the model of tankless water heater you invest in. If you need help deciding between fuel types, it's advisable to consult an expert.


We advise having a professional inspect and service your tankless water heater annually. If you live in a particularly cold climate or your water is constantly hard, you may want to increase that frequency to twice a year.

Heating systems that run on electricity don't require as much upkeep as gas ones, but it's still a good idea to have a professional inspect it every so often to make sure it's in good working order.

Keeping this in mind while you hunt for a tankless water heater is a good idea. The average cost of a professional service ranges from $45 to $130.

Power input

Tankless water heaters require energy to heat the water to the required temperature. Power input is the amount of energy needed to achieve this temperature, and it is expressed in BTUs (BTUs). As a unit of energy, one BTU is equal to the amount of heat needed to increase the temperature of one pound of water by one degree Fahrenheit.

Most products will list the power input, but this quantity is meaningless if you have no idea how much power you'll actually require. First, determine the typical temperature of the water that is delivered to your house. To do this, just let the cold water flow for a few minutes before taking a temperature reading.

The temperature of the water that you use will depend on your preference. For the shower to produce water at 120 degrees Fahrenheit, for example, the incoming water temperature must be raised by 70 degrees from, say, 50 degrees. Since a gallon of water weighs 8.33 pounds and the temperature difference is 70 degrees Fahrenheit, we need 583 BTUs to do this at a constant flow rate. However, given that you'll be using the water in a shower, you can safely assume a flow rate of around 3 gallons per minute (GPM).

To find the required power input, use the equation: GPM x Temperature Change x 500.

An hour of water weights 8.33 pounds, thus a gallon of water multiplied by that gives you 500. This example calculates 105,000 BTUs per hour, assuming a perfect efficiency rating of 100%. Using this easy math, you can figure out how much power your tankless water heater needs.


What Is A Condensing Tankless Water Heater?

It's true that conventional tankless water heaters save energy, but condensing tankless water heaters save even more.

An efficiency of 93% or greater is possible with these water heaters.

In other words, the majority of the energy from the gas or propane is transmitted to the water.

Why condensing water heaters?

The most energy-efficient gas water heaters now on the market are condensing and tankless models. These appliances have two heat exchangers: a primary one that gets its heat straight from the gas burner, and a secondary one made of stainless steel that makes use of the heat that would have been lost in the flue gases.

Condensation improves performance and efficiency while decreasing wasteful energy use and greenhouse gas emissions. Over 90% efficiency is achieved by the condensing versions, with the energy factor reaching 0.98 or higher on some models.

Because the flue gases are cooled and the condensate is acidic, it is suggested that every condensing water heater use the PVC vent pipe, which is a more cost-effective alternative than the steel vent typically used in non-condensing units. Read about the top tankless water heaters that do not use condensing technology.

The initial investment in a condensing water heater is more, but the long-term savings more than make up for the difference. They are bulkier due to an extra heat exchanger, but they are more cost-effective due to their improved energy efficiency. The heaters are sleek and contemporary in style, with a big LCD screen on the front.

How do you install an electric tankless water heater?

Do-it-yourselfers should not set up a tankless water heater powered by electricity or gas. Hire an expert instead. Some household systems, including those associated with installing a tankless water heater, must be serviced or upgraded by a trained and certified professional, regardless of whether the heater is powered by electricity or natural gas. Gas tankless water heaters require a gas line and adequate ventilation for the exhaust system, while electric tankless water heaters only require an electrical system with the required rating. Local building codes will also need to be adhered to during installation. As a result of these rules, it is wise to employ a professional, for both your protection and your peace of mind.

How do you know what size electric water heater you need?

An appropriate electric water heater size can be determined by taking into account the number of people living in the household, the average temperature of the incoming water, the size of the house, and the desired water temperature. Generally, a water heater with a flow rate of 3 to 5 GPM is enough for a home with one to three people, while a water heater with a flow rate of 8 or 9 GPM is recommended for a home with four or more people.


Increased interest in condensing tankless water heaters can be attributed to its various benefits, including their eco-friendliness, cost-effectiveness, and the fact that they help save money. Energy savings, reduced gas emissions, and more efficiency are just some of the benefits of the latest generation of tankless and cutting-edge technology. It's an excellent option for people with spacious houses who want even more space.

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