How Much Propane Does A 40 Gallon Water Heater Use (Explained)

How Much Propane Does A 40 Gallon Water Heater Use

How much propane a hot water heater uses will depend on factors such as how old the water heater is and how much hot water in the house is being used.

A 40-gallon hot water heater is a popular tank size as it can meet the needs of your average household demands, with the average household housing up to two to three people.

So, how much propane does a 40-gallon hot water heater use? For a typical household of two to three people with a 40-gallon water heater, you can expect your water heater to use approximately 1.5 gallons of propane a day, or 200 to 300 hundred gallons of propane a year.

This is, however, a rough estimate. As mentioned above, how much propane a forty-gallon water heater actually uses will depend on factors that may either increase the amount of propane your heater uses or decreases it.

Factors That Affect How Much Propane Is Used

The amount of propane your forty-gallon water heater uses can vary from the above estimate, unfortunately. This is due to several reasons.

Below are two of the main factors that will affect your water heater’s propane use.   

How Old Is the Water Heater?

Water heaters have a rather long lifespan, lasting anywhere from 8 to 12 years. It is one of the reasons why selecting a water heater and its energy source is so important.

Between the use of showers, laundry machines, dishwashers, and other hot water using appliances, your water heater will be one of the busiest components of your household.  

As a result of water heaters playing such a vital role in the home, they are designed to be as efficient as possible.

However, as is normal for anything in your household, as your water heater ages it will become less and less efficient and require the use of more energy, and thus more propane.

Over time, your water heater will also build up sediment that can at times erode the tank.

For the most part, however, the sediment will build up and negatively impact the water heater’s ability to heat the water in an energy-efficient manner.

 Read also: RV Propane Refill Near Me – Stations & Locations [UPDATED]

How Much Is the Hot Water Being Used?

A forty-gallon water heater will use more propane than it should if it is trying to meet the needs of a large household.

A forty-gallon water heater should meet the needs of a three-person household just fine.

Still, if it happens to be a busy household and you happen to have a lot of people over very often, then your water heater will need to use more propane to keep up with the demand.

Even without frequent guests, there are other reasons why your water heater might use more than two to three hundred gallons of propane a year.

Variables such as the length of time in which everyone in the household takes a shower, how often you use hot water to cook and clean, and how efficient appliances like dishwashers and laundry washing machines are, and how often they are used will impact propane use.    

 Read also: How Much Water Do You Use In A Shower? [Shower Cost]

How To Reduce Energy Consumption/Propane Use

Finding out how much propane a water heater uses can be a valuable piece of information for homeowners to make informed decisions about their energy needs.

Whether you are attempting to be ecofriendly, looking to reduce your bills, keep to a budget, or you are looking to have hot water for longer, you’ll find that there are many ways to reduce energy consumption to get the most out of both your propane and your water heater.

Below are a few ways to help reduce the amount of propane your water heater uses.

 Read also: How Long Will an RV Refrigerator Run On Propane? RV Fridge Power Usage

Old Water Heater- Replace It

As previously mentioned, an old water heater does not use propane as efficiently as back when it was new.

If your water heater is up there in age and you want to reduce the amount of propane used to run your household’s hot water needs, then your best option would be to invest in a new unit before the current one fails to function.

Spending that chunk of money may seem disheartening when you are looking to reduce costs, not increase them. However, with a new one, you can reduce the amount of propane needed to heat up the water inside the tank and get your money back in what you’d be saving in propane use.

Getting a new water heater and choosing the right one has also been made much easier so that you are in better control of your propane consumption.

Prior to 2017, the energy efficiency of water heaters had a less uniform rating system amongst the different brands.

“To address this and give consumers the ability to choose more accurately between brands, the Department of Energy replaced the previous energy efficiency rating with what is now the Uniform Energy Factor or UFE.”

One of the important pieces of information that a UFE rating gives homeowners is a water heater’s first-hour rating.

This will let you know how well your forty-gallon water heater will be able to keep up with multiple uses at once and whether it can meet peak demand.          

Newer models also have the added bonus that they have better tank insulation quality.

This means that your water heater will be better able to retain its heat while waiting to be used instead of losing it through the walls of the tank.

 Read also: How long Does a 30 Pound Propane Tank Last In an RV?

Heater Still Has Some Years Left In It?

If you feel your water heater has some more good years of use left in it then investing in a new one may be a bit extreme.

Instead, there are a few things you can do to help improve your water heater’s efficiency and reduce the propane consumption of your water heater.

For instance, sediment build-up that occurs over time can be prevented.

1. Clear Out Sediment

As explained earlier, a buildup of sediment can affect your water heater’s performance. As such, it is recommended to flush your water heater one to two times a year depending on your water source.

This is because minerals like calcium and magnesium turn into small particles of sediment when the water is heated up.

Well water is especially high in these minerals, needing to be flushed out twice a year to keep the heater from failing.

2. Keep Up On Maintenance

Keeping up on maintenance is important. Not only can a water heater be costly to replace, but by making sure all its working parts are in order you are ensuring that things are running smoothly and efficiently.

The more efficiently the parts work the less propane needed to heat the water.  

If you are unsure of what maintenance entails, it is always recommended to follow the maintenance instructions in the owner’s manual.

You can also have a plumber come in to take a look at it, especially if you feel it is not performing as well as usual.

3. Insulate Your 40 Gallon Water Heater

You can also insulate your forty-gallon water heater to help retain its heat and thus, increase performance.

As previously mentioned, newer models of water heaters are designed to address standing heat loss (the heat it loses just from being idle in the water heater tank).

Whether you have a newer model or not, you can always increase its ability to retain heat by using an insulating water heater jacket.  

4. Limit the Amount of Hot Water Being Used

This one may seem like a no-brainer when it comes to reducing the amount of propane your water heater uses.

If you are not having to use the hot water as much, then you are not needing as much propane to replenish the hot water in the tank.

Simple changes like using the cold water setting on your washing machine, only washing full loads, and making sure the dishwasher is full before starting a load of dishes can make all the difference.

All these small changes will begin to add up and reduce how often and how much hot water is needed to run a household.

5. Update Appliances

If you happen to have outdated appliances that use hot water, a great way to reduce how much propane your water heater uses is to update those outdated appliances.

In today’s rather eco-friendly climate, with manufacturers competing to provide consumers with energy-saving products, you will be able to find products that will save you money in the long run because of their energy efficiency.

Just like with buying a new water heater, buying and updating appliances that consume a lot of energy will lower your propane cost and allow you to recoup the money down the line through savings.

Read also: Can I Store Propane Tanks In Shed (FACTS You Need To Know

Final Thoughts…

As you can see, there are a lot of factors that can impact how much propane a forty-gallon water heater uses.

If you find you use more than two to three hundred gallons of propane a year with a forty-gallon tank, then it may be time to give the unit a once-over with maintenance care.

With propane prices constantly fluctuating, conserving your propane and saving a few cents can truly make all the difference.   


Mike Gilmour

Hi, I'm Mike, co-founder, and editor of RV and Playa. My passion is traveling (with my RV) and enjoying the day at the beach (Playa)! Well, I originally created this blog as a way to share what I've learned by experimenting with the RV lifestyle, and I want to help others develop in life through new skills and opportunities.

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