How Much Propane Does An RV Water Heater Use?

If traveling and camping are in your blood, you will experience sites that no one else can imagine. Waking up in the middle of nature’s glory is what makes camping exhilarating. Traveling with an RV brings you the little comforts of home, of which heated water makes your trip that much more enjoyable.

An RVs water heater uses 0.109 gallons of propane per hour to heat a 6-gallon tank of about 10,0000 Btu. Tankless water heaters can reduce this amount as the water is heated on demand, eliminating the need to keep the tank’s water hot. The heater Btu capacity and hot water tank size can also affect this usage.

Recreational vehicles are little homes on wheels with the luxuries you would find in your house. So taking a shower and using hot water in the comfort of your RV is a norm, but how do you know if you have enough propane for your trip and how long your hot water will last? We simplify the calculations, so you know just how much propane you need.

How Much Propane Will You Need For An RV Water Heater?

How much propane you use depends on certain factors that may vary the amount slightly.

You need to consider some factors like

  • Tank capacity
  • Frequency of water usage
  • Environmental factors
  • BTU ratings

The type of water heater you use also affects how much propane you will use.

Most RVs water tanks are either a 6 or 10-gallon water capacity tank, with an average of 8,800 to 12,000 Btu. At the same time, some have tankless water heaters with a higher Btu of about 30,000 to 40,000.

Calculating the amount of propane, you will need a quick formula to work out your heater’s Btu (British thermal units). This is the amount of heat a system uses to increase a pound of water by one degree Fahrenheit per hour. The higher the Btu of a system, the faster it will heat the water.

Thanks to the U.S. Energy Information Administration (EIA), we know that propane gas has a Btu of 91,452 per gallon.

Find out the Btu of your water tank heater to calculate how much propane you will use.

Most RVs will have 6 to 10-gallon water tank heaters with an average of 10,000 Btu.


Tanks Btu ÷ propane Btu per gallon = X gallon of propane per hour

A 6-gallon water tank heater:

10,000 Btu ÷ 91,452 = 0.109 gallons of propane per hour

A tankless water heater:

40,000 Btu ÷ 91,452 = 0.437 gallons of propane per hour

Tankless water heaters are also becoming a popular addition to RVs. There is no tank that needs heating up, and the water is heated on demand. This can also reduce the consumption of propane gas to a certain degree.

For example, using a tankless heater will give you instant hot water for a 5 minutes shower, instead of heating a 6-gallon tank for 40 minutes to provide you a 5 minutes shower. Remember that the tank will fill up with cold water, which will lower the temp of the water and increase the need for the heater to warm the water again. This is where there you could have variables in your calculations.

Using tankless water heaters only heats the water you use and eliminates the need to keep the water in the tank hot.

A 6-gallon tank takes about 40 minutes to heat up, providing you with a hot shower for about 5 minutes, whereas a 10-gallon tank would take about 70 minutes.

How Long Can An RV Water Heater Run On Propane?

To calculate how long your propane bottle will run your water heater, we use some math again to figure this equation out.

There are different classes of RVs, and each has different tank ranges. These can range from a 20-pound tank for a class BRV or travel trailer to 100 pounds for a class A RV.

Propane tanks are measured in their total weight in pounds, so to find out how many gallons you will have, you can calculate 25% of the weight, which will be the gallon quantity.


20lb tank X 25% = 5 gallons of propane.

So now that you know how many gallons you have, you can work out how long an RV water heater will run on propane gas.


Quantity of propane gallon X propane Btu per gallon = Tank Btu capacity


5gal X 91,452 = 457,260 Btu capacity for the whole tank


Take the tank Btu capacity ÷ heater Btu usage = number of continuous hours your tank will last


457,260 ÷ 10,000 =45.72 continuous hours

Propane tanks are never filled 100% full, so real life numbers will be about 20% less.

How long your propane gas will last depends on how many people use hot water and how often.

Let’s say two people are showering once a day and washing dishes twice a day. Then your 5 gallons of propane gas should last about 7 to 9 days if you are only using it for hot water.

Most of the time we are running our propane fridge, RV heater, and sometimes bbq’s so count on it being less if you are running additional appliances.

Remember that environmental factors, such as water temperature from the connections or the external atmospheric temperatures, can vary the results slightly.


When heading out on your next camping trip, you want to ensure you have enough propane to last you for your trip. Making a few calculations can save you some unnecessary headaches of running out of gas. Still, in general, a 5 gallons tank of propane can last two people a week if it’s just used for the RVs water tank heater.

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