How Much Propane Does a Tankless Water Heater Use

Tankless water heaters running on propane are an exclusive example of energy efficiency. That is why most people prefer this highly economical method for instant hot water supply. However, we need to look out for a few factors to determine the total economic suitability of the propane-based tankless water heater. In this regard, the most obvious question is, “how much propane does a tankless water heater use?”. The correct estimation of the amount of propane in the long term will reflect the economic aspect.

If you are also curious about the amount of propane required to power a tankless water heater, sit back and relax because we have made this comprehensive guide covering the essential facts and details in this regard. We have written this guide based on our twenty years of experience with different propane-powered tankless water heaters and the analysis of the various researches done in this regard. Therefore, please keep reading to know more!

How Much Propane Does A Tankless Water Heater Use?

Brief Account

Tankless heaters are considered one of the most cost-effective and instant hot water sources. If you are using the propane-powered tankless water heater, then you will be enjoying the perks of energy and money-saving. A number of the people who use tankless water heaters for instant hot water supply ask, “how much propane does a tankless water heater use?”. Well, it is pretty essential to be mindful of the quantity of propane required by your tankless water heater in terms of weekly, monthly, and annual basis.

Generally, the amount of propane required to power your tankless water heater will be variable compared with other regular users. The difference in the propane quantity comes because every home has a difference in utilization pattern and the frequency of hot water. For example, if you have installed a tankless water heater in the office, only you or a few office mates might be using it.

However, if you install the same propane-powered tankless water heater inside your home’s kitchen, then all family members can use it for different chores in different parts of the day and night. Therefore, ultimately the amount of propane needed for the home-based tankless water heater will be greater. You need a simple calculation to estimate your propane consumption in this scenario. Let us help you understand this in the most simplified way.

Propane Consumption: Simplified Way of Calculation

If you are tired of reading blogs describing complicated mathematical calculations, don’t worry because we will help you calculate your quantity of propane most easily. We don’t want you to get confused with the numbers ending up with the wrong calculation, so we have a simplified trick for you as an alternative to this. In this regard, you need to be clear about hot water usage. By this, we mean that you should know the exact amount of gallons per month.

On a global scale, you will see different people measuring propane in both units of litres and gallons. However, considering my experience with propane-powered tankless water heaters, I strongly recommend you to use gallons. Also, I must not forget to mention that the production of propane gas is different in terms of the other models of tankless water heaters. The majority of tankless water heaters produce 2 to 5 gallons per minute (GPM).

Also, some larger units will be giving you 9 gallons per minute (GPM). The simple way to understand your propane consumption is to follow the US Energy Information Administration (EIA), which clearly states that your propane-powered tankless water heater will use one gallon of the propane for giving 91,452 BTUs per hour. With this simple BTU value, you can determine the propane requirement by relating it to the number of gallons you use.

This information is helpful if you are calculating the amount of propane. All you have to do is find out the BTU rating of your tankless water heater and simply divide it by 91,452. With this simple formula, the amount that you get will be the propane needed for heating the water. The final amount that you calculate for your weekly, monthly, or annual propane consumption will show the frequency of your utilization.

Propane Calculation and Influencing Factors

The simplified formula that we have shared with you is the best way to determine the amount of propane your tankless water heater needs to give you an instant and uninterrupted supply of hot water. However, we must educate you that the propane quantity estimation is devoid of other factors influencing it. Many factors play an active role in propane quantity estimation. Therefore, it is pretty vital to highlight these factors. They include:

  • Hours of the tankless water heater utilization: This factor highly influences propane consumption. If your utilization pattern is frequent and your hours of usage are more extended, then the propane consumption will be higher. Especially if you are using a tankless water heater for household chores, then propane consumption will be maximum.
  • The temperature of the groundwater: Another critical factor that influences propane consumption is groundwater temperature. However, propane is a very cost-effective source of power that causes a considerable reduction in expenses. However, if you are a resident of significantly colder areas, your propane consumption will be much higher when compared with the inhabitants living in the warmer regions.
  • Water hardness: You cannot neglect water hardness because it is the greater consumption of propane. Suppose you are a resident of an area with soft water, then good for you because you can save a great deal on the propane. However, if you are a resident of the hard water area, we strongly recommend you purchase a water softener so that you don’t have to use much propane in removing water hardness.
  • The number of individuals using tankless water heaters: This is a factor that highly impacts the amount of propane consumption. If you have a smaller family, then perhaps your propane consumption will be lesser. Roughly, a family comprising two members will consume 15 gallons of hot water. While a family comprising of 5 to 6 members consumes 40 to gallons of hot water every month.
  • The capacity of the tankless water heater: Different models have different propane consumption patterns, which is why this factor cannot be neglected. However, some models come with innovative and environmentally friendly technologies, e.g., water-saving technology. Such models will be using a lesser quantity of propane for a greater amount of hot water production. You may have to invest more initial money in such models, but they will give you long-term benefits.

These factors play an integral role in the amount of propane that you will require and consume for your hot water supply. Therefore, you cannot ignore them. Otherwise, you may do the wrong calculations and end up being astonished when you have to purchase more quantities of propane.

Financial Cost Spent on a Propane Powered Tankless Water Heater

Having a propane-powered tankless water heater means an uninterrupted and instant hot water supply. After reading about the calculation details and essential factors influencing propane consumption, you must be curious about the actual financial cost incurred on a propane-powered tankless water heater. That is why we have devised this section to throw light on this critical topic.

Based on the results of scientific research, it was indicated that American families have been paying almost $2.304 for each gallon of propane gas. This financial cost calculation was done in February 2021. To be more precise, if your family members are using almost 20 gallons of propane monthly, you will need to incur nearly $45 to $47 for enjoying the hot water.

On the other hand, if you have an extra-large family with greater demand for hot water, you will have to invest $115 to $120 for one month. You can enjoy almost 50 gallons of the hot water supply in this amount. From all these costs, you will be glad to see that the total cost associated with the propane-powered tankless water heaters is quite economical compared with the electric-powered tankless water heaters.


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Selection of the Correct Propane Tank Size

After reading about the essential details of the amount of propane needed for powering your tankless water heater, you will be curious about which propane tank to purchase. You will be glad to know that the marketplace has a varied range of tank sizes available. The manufacturers make such tanks to best suit the type of application you are using propane tanks for.

To be more specific, you will get propane tanks with the capacity of 100 pounds, 120 gallons, 250 gallons, 325 gallons, 500 gallons, and 1,000 gallons. In addition, if you need a propane tank for commercial applications, you can find tanks with more than 1,000 gallons capacity. In the case of the propane-powered tankless water heater, we strongly recommend you to go for the propane tank with the 120 gallons capacity.


What are the significant benefits of the propane-powered tankless water heater?

There are many benefits due to which people worldwide prefer purchasing propane-powered tankless water heaters. Some of these essential benefits include a constant and endless supply of hot water, energy efficiency because heat losses are minimum, a highly compact size occupying only 12 square feet of the total space on your floor, and economic viability. In addition to these benefits, propane-powered tankless water heaters are also an environmentally friendly option because they have minimal carbon dioxide emissions.

Which factors influence the calculation for the quantitative determination of the propane for the tankless water heater?

You can use a simplified formula to calculate the amount of propane you need for heating water via your tankless water heater. However, in real-life, many factors can influence the propane quantity. These factors include the time of the utilization, i.e., per hour usage, environmental conditions like the temperature of the groundwater and hardness, the capacity of the tankless water heater, and the number of family members using the tankless water heater.

Why propane-powered tankless water heaters are the most energy-efficient option to go for?

No other conventional tankless or tank-based water heater can beat the propane-powered tankless water heater for energy efficiency. The primary reason for this energy efficiency is that they are purely on-demand water heaters that will consume propane only if you open the tap. According to scientific research, the energy efficiency (EF) of propane gas burning starts at 80%. At the same time, the energy efficiency of a propane-powered tankless water heater is 99%.

Does propane burning incur the exact cost worldwide for the tankless water heater?

Not at all. The cost incurred on propane burning is variable around the globe, and several factors highly influence it. The time of year and your geographical locations are the most influencing factors. Based on my experience with propane-based tankless waters, I can confirm that you will have to spend less on propane in the warm season and when the water is soft. In the opposite case, the cost of propane will multiply.

Final Thoughts

After reading this detailed guide on the amount of propane used for running a tankless water heater, we hope you will now be in a better position to calculate it for your daily, weekly, monthly, and annual requirements. However, keep an eye on the influencing factors we shared with you. Also, we hope we answered your question, “how much propane does a tankless water heater use?”. Based on the discussion and details above, we found propane-powered tankless water heaters to be the most energy-efficient and economically viable.

We will be glad to see your worthy response in the form of suggestions, opinions, and experiences regarding your propane-powered tankless water heaters. Therefore, don’t forget to share it in the comments section. Thank you and take care!

With years of experience under his belt, Adam decided to put his water heater knowledge to work. By providing high-quality content and expert guides, Adam hopes to help anyone looking for expert water heater advice.