How Much Propane Does A Tankless Water Heater Use? 2021 Complete Guide

Do you want to know how much propane does a tankless water heater use? Well, it is a logical query if your unit is powered by propane fuel.

We all have heard that tankless devices are packed with energy-efficiency capabilities. They operate 1.5X better than traditional tank storage machines. Yes, these claims are valid.

But still, it is compulsory to calculate how much amount of propane our powerful appliance needs.

Lately, the weather has been cold, so taking a shower or washing dishes during such gloomy days is difficult for many folks. However, some people decline to utilize water heating systems to help them take a bath or do laundry comfortably.

They are fearful of spending a lot of money on the heater to obtain warm water. Are you one of those individuals? If so, don’t panic. You can use a propane heater because it can help you save a lot of money and gas in the long run.

They are designed to save more gas and power, making them an ideal choice for residential and commercial properties. This post will notify you about how to save money and propane using tankless devices.

Also, you will gain insight into how much natural gas does a tankless water heater use. But, first, let’s talk a bit about what tankless propane heaters are and why you should invest in them.

What Is A Tankless Propane Water Heater?

They are a fantastic option for energy and money savings. It heats water only when you turn on the hot water faucet instead of boiling water stored in the container.

Besides, they are environment-friendly and permit you to reduce standby heat loss. You can acquire an unlimited amount of hot water without paying to keep it deposited.

Best of all, they provide you instant and constant supply, so there are minimal possibilities of running out of water. The propane heater relies on a flame to heat the water without storing it in the tank. It does not eat up energy and dollars when you are not using it.

All you have to do is activate the fixture, and the flow sensor will sense the water flow and turn on the burner to heat the water. It heats the water until you shut off the fixture. Once you turn it off, the propane gas burner will also stop operating.   

How Does A Propane Water Heater Work?

  1. When you open the tap, the heater starts working.
  2. Drift sensor detects the cold water that enters the unit. After that, it sends a signal to the control panel to generate heated water.
  3. In the propane-powered device, the control panel turns on the fan to draw external air. It is also liable for opening the fuel valve that permits the propane to come inside and igniting the burner.
  4. Then, the heat exchanger captures the warmth from the flames and transmits it through the tubing system.
  5. The integration valve is responsible for setting the heated water that leaves the heat exchanger. If the sensor detects that the heater water exceeds or drops fast of the preferred temperature, the control panel will regulate the gasoline valve, floating-regulating valve, and combination valve.  
  6. A venting system eliminates exhaust gas and transfers combustion air to the tankless machine.

What Are The Types Of Propane Tankless Water Heater?

Condensing Tankless Systems

They flaunt two heat exchangers. The secondary one is liable for capturing additional heat before it releases into the venting system.

It shifts the extra warmth to heat incoming water that travels through the primary heat exchanger. They are 90% energy-efficient. This rating is 10 to 15% higher than noncondensing ones.

Noncondensing Tankless Systems

They rely on a single heat exchanger to heat the water whenever required. It is 80% energy-efficient compared to the standard heater that is only 60% energy-efficient.

How Much Propane Does A Tankless Water Heater Use? Factors To Consider

If you want to estimate tankless water heater propane usage, you should consider the following factors:

The Installation Location Of The Device

Tankless machines have a compact design, and they also don’t require indoor air for ignition. So, you can mount it in non-traditional places. However, it is better to hang it in an area that can reduce installation expenses and enhance performance.

Therefore, your plumber should evaluate the venting, gas, and water lines before deployment. The right location will also help calculate how much natural gas does a tankless water heater use.

Numbers Of Individuals Live In The House

If you want to estimate Navien tankless water heater propane usage, it is crucial to consider how many people live in the house where the heater works. If there are seven to eight users, a higher propane amount will be required to produce heated water.

If there is one bathroom that is used by one or two people in residence, then 140,000 Btus or 15 gallons of propane will be required. If you have a family of three or four folks and have two bathrooms, then you will have to spend 190,000 Btus or 25 gallons of propane.

However, for a larger family of five with three bathrooms, 380,000 Btus or 35 to 40 gallons of propane will be needed.   

The Temperature Of The Locality Where You Want To Utilize The Unit

Your neighborhood’s temperature plays a significant role in knowing how much propane does a water heater use. If you live in a colder place, you will use the tankless appliance more frequently, which means your device will use more power created by the fuel.

Thus, if a place’s temperature is less, propane consumption will be higher to make the cold water perfectly hot. On the other hand, if you live in a country with a higher average temperature, your heater will use a lesser amount of propane to heat the water.

However, keep in mind, the location’s weather cannot help you faultlessly estimate the amount of propane your unit needs. By using the temperature, you can only predict that users will increase or reduce heater usage.

It is tough to determine how many times a day or months you will rely on the heater to get warm water.  

Type Of Water In The Neighborhood

Do you live in an area with hard water that contains undissolved salts? You will have to heat the water to soften it using a sufficient amount of power coming from propane gas.

If your area has soft water, propane consumption will be much lesser because it won’t need hefty energy to warm up the water. However, if we look at the other side, you can take advantage of alum to soften the water instead of warming it up.

Therefore, it is not mandatory to consider this factor to evaluate how much propane does a tankless water heater use, but you can add it in a few situations.

How Much Natural Gas Does A Tankless Water Heater Use?

They typically use about 40,000 BTU or 1.5 gallons of propane every day. If you don’t want to surpass the following amount, you need to deploy your device accurately. Don’t know how to do that? Follow these tips to install it correctly.

If you want your device’s burner to operate appropriately, you must place it in a gas supply line. The gas lines will offer an adequate amount of propane pressure. You will have to stretch the gas pipe’s diameter to about three-fourths of an inch in some conditions.

If you have a noncondensing tankless unit, you will have to install a stainless steel venting system that can endure excessive exhaust hotness.

Besides, the condensing device comes with more cooling exhaust and use affordable pipes. On the other hand, concentric venting systems feature an exhaust pipe inside a bigger air-combustion pipe.

It makes the installation process more straightforward because you only have to cut the most upfront hole in the wall. Scale deposits that buildup in the heat exchanger slow down warmth transmission and block water flow simultaneously.

Therefore, make sure to install a water softener to get rid of the scale. However, the water softener won’t help you if the hardness has surpassed 120 milligrams per liter. In this case, investing in a treatment machine would be the wisest idea.

How Many Dollars Do I Have To Spend On Monthly Propane Usage?

The price of one gallon of propane is about $2.20. Based on the following price, you will have to invest $33 every month if you have one bathroom and two people in the house.

However, if you are a family of three to four folks, you will have to spend $55. Besides, if more than five individuals live in your residence, you will have to invest $77 to $90 every month.

Myths About Tankless Propane Units

They Are Costly

The tank storage machines are inefficient, and the homeowners have to run out of hot water frequently. Also, they are designed to last for up to 10 years only. That’s why; it is a brilliant idea to upgrade to a tankless heater.

It has a higher initial cost, but it can help you to save more than $200 every year. In three to four years, you can get your money back that you spent on the upgrade.

They Don’t Work With Well Water

It does not matter what your residence’s water source is; the propane appliance will heat the water correctly. If you have hard water or need more hot water, you will have to deal with scale buildup.

Up-to-the-minute units inform the users when they need to be cleaned. You can also take advantage of a water softener to eliminate scale, increasing intervals between cleaning.  

They Need Natural Gas

The propane machines are packed with the same features as those powered by natural gas. They work on-demand and provide hot water only when you turn on the fixture. They don’t waste energy and water that happens with tank devices.

Standby heat loss occurs because the tank storage heater continuously warms the water, which means it uses energy always even when the water fixture is turned off.

They Need Complicated And Expensive Venting

Upgrading from a tank to a tankless water heater demands proper planning, but you can vent the higher energy-efficient appliance through the wall with cost-effective PVC pipes.

There is no need to vent them through the roof, unlike the tank storage heaters. Its combustion fan removes exhaust from the heater horizontally.

You can also rely on other venting options such as pipe covers and termination points. You won’t have to overthink how the venting system will appear on your property with a propane heater.

What Are The Reasons To Use A Propane Tankless Heater?

  • It supplies an endless amount of perfectly heated water whenever you need it.
  • It features a compact size that enables you to save approximately 12 square feet of storage space.
  • They qualify for rebates, so they are an affordable option.
  • They release 50 to 60% less CO2 emissions compared to electric tank-style devices.
  • They are called instant or on-demand machines, which means they are intended to work only when you activate the tap. This trait eliminates standby losses that occur in tank storage heaters.
  • You can save more than $150 in power expenditures compared to traditional units.


Evaluating how much propane does a tankless water heater use is a challenging task. This procedure involves a lot of consideration and estimation. However, in the end, you still cannot be sure of if the calculation is right or wrong.
In-depth information about this topic is scattered around the internet. That’s why; we designed this thorough article to help you calculate propane usage tankless water heater.
We hope that our guide will ease your confusion. Now, estimating propane gallons or BTUs and budgeting for it should be hassle-free for you. 

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