How Much Propane Does An RV Water Heater Use?

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Propane is the VIP member in many RVs, and veteran RVers are intimately acquainted with how much propane the RV water heater is gobbling up daily. Even if you have a pop-up or a teardrop, you probably have a water heater. It’s always a good idea to stay up-to-date on your propane consumption.

A family of three will chew through about 2 gallons (8.5 lbs) of propane a week, showering daily. That’s almost half of a 20 lbs propane tank, but it doesn’t take much to heat 6 to 10 gallons of water, which is pretty standard in terms of size (holding capacity). 

If you want it broken down further, a 10,000 BTU, 6-gallon water heater will run for about 42 hours continuously before consuming 20 pounds of propane. Every pound equals 0.236 gallons. Keep in mind, that last is a hypothetical scenario, assuming you could run continuously and only use the water heater. 

Does an RV Water Heater Run on Propane?

The majority of RV water heaters run on propane, and most come equipped with “direct spark ignition (DSI),” which is electric. Veteran RVers know about the old school “standing pilot,” which meant trudging outside, rain or shine, and manually lighting the pilot flame. 

Unless you’re in an older rig, you probably have a DSI, and some RVers replace their water heaters with tankless versions. Tankless water heaters heat the water only when you actively use it and run on either propane or electricity.  

How Much Propane Does a 6-Gallon Water Heater Use? 

To determine how much propane your water heater uses, you need to know four things:

  1. The amount of water usage
  2. The hot water tank’s size
  3. The BTU rating for the propane tank
  4. The BTU rating of the water heater.

With those four things, you have the complete formula for calculating usage. 

# of propane gallons x 91,502= BTUs Of Your Propane Tank

Your propane tank probably has a label that references the BTUs, but, just in case it doesn’t, the above formula will give you the answer you need. Now, the next part:

BTUs of your propane tank ÷ Water Heater BTU Rating = Hours of Use

Of course, it’s important to remember that hours of use include more than just taking a shower or using hot water to wash dishes at the sink. With that being said, a 6-gallon water heater at 10,000 BTUs will consume 0.11 gallons of propane per hour of continuous use (from a hypothetical standpoint). 

How Much Propane Does a 10-Gallon RV Water Heater Use?

How Much Propane Does a 10-Gallon RV Water Heater Use

The same thing applies here. Since it’s a 10-gallon water heater, the BTUs are probably higher than what you’ll find on a 6-gallon tank. For instance, the 10-gallon Suburban Advantage Water Heater is a 12,000 BTU appliance. 

A 20 lb propane tank is equivalent to 4.6 lbs of propane,  which is 420,909 BTUs. With a BTU rating of 12,000 on a 10-gallon water heater, you end up with 35.1 hours of continuous use or about .131 gallons per hour. See? Math can be fun and useful, after all. 

How Much Propane Does a Tankless RV Water Heater Use?

There are advantages and disadvantages to using tankless water heaters, just like anything else. On average, they last twice as long as standard RV water heaters, produce instant and continuous hot water, and produce long-term energy savings (electric versions only). 

Some RVers stick with electric tankless water heaters because the gas variations lack efficiency when it comes to propane usage. Gas RV tankless water heaters have much higher BTU ratings and consume more propane than regular water heaters. 

How Long Can an RV Water Heater Run on Propane?

It depends on the water heater’s BTU rating and the size of the propane tank. With smaller propane tanks, you should be able to heat your water heater for an hour per day for 33 to 55 days. You don’t have to leave the water heater on either. 

A 6-gallon water heater takes about 30 minutes to heat up. There’s a fine line to draw if you’re trying to save propane because it does consume more propane to heat the water than it does to maintain the current water temperature. 

How Much Propane Does a Water Heater Use Daily?

How Much Propane Does a Water Heater Use Daily

Don’t you love math? It varies, depending on the size and BTU rating of your water heater and the size of your propane tank. The above-listed formula is the best way to determine how much you’re consuming daily. 

You should be using well under a gallon of propane per day. Propane tanks don’t have to expend much to maintain the temperature in a water tank. 

Can You Leave Your Water Heater On All The Time? 

Leaving it on brings up several points, including cost, safety, and overall wear and tear on the water heater. Turning your propane tanks off while traveling is always the smart move. That makes sense for a variety of reasons. 

For one, equipment moves around while you’re traveling. Now, these appliances are designed not to roll around and bounce down the road when you’re taking on the stop-and-go grind of inner city and suburban traffic. 

But, that doesn’t mean they can’t shift, even if the movement is ever so slight. Unfortunately, that’s all it takes to pop a line somewhere. The last thing you want is an LP gas leak filling up the cabin while you’re heading down the road. 

However, let’s say you’re camping in one spot for longer than just a day or two. Well, that’s perfectly fine, though it’s more efficient to turn it off when you’re not using it. Plus, there’s a bit of a safety factor there as well. 

There’s always the possibility of a slow leak, which is why you should always make general maintenance and inspection of your RV a part of your routine. Electric water heaters are a different story. 

It’s considered safe to leave them on, even during travel. The only drawback is power consumption. But if you accidentally leave it on before you hit the road, it’s not as big of a deal.

Does Leaving Your RV Water Heater On Waste Propane?

There is a trickle effect when you leave it on. A water heater doesn’t gobble propane in significant portions. If it did, no one would use them. It does draw on your propane tank to maintain temperature, but it’s a very slow draw. 

A lot of RVers simply turn theirs off when it’s not needed. In residential homes, people use timers or turn theirs off as well. They do it for the same reason. RV water heaters are smaller in scale, but the logic remains the same. 

How Many Gallons of Water Will a 100 lb Propane Tank Heat?

How Many Gallons of Water Will a 100 lb Propane Tank Heat

A 100 lb propane tank holds 23.6 gallons of propane. That’s 2,159,447.2 BTUs of output. The largest water heaters you will find in an RV are 16-gallon heaters. We know that a single gallon of propane has a BTU output of 91,502 per hour. A single BTU is required to raise one pound of water by 1°F

That means a single gallon of propane will raise one pound of water by over 1,500°F per minute. Now, you obviously don’t want to melt your shower, but it’s nice to know that propane is more than capable. For hybrid water heaters, propane is useful for quick heating since electric heating elements are notoriously slow. 

One gallon of water equals 8.33 lbs, so a single BTU can raise a gallon of water by 180°F in 60 seconds. From a mathematical perspective, assuming everything is in good working order, a 100-lb propane is capable of raising a 16-gallon water heater capacity by 180°F in 16 minutes. 

A 20 lb tank is capable of doing the same thing. The only difference is in how long they can do it. For obvious reasons, a 100-lb tank can maintain that 180° temperature for a lot longer than a 20-lb tank. 

Is Propane or Electric Cheaper for Your RV Water Heater?

Propane water heaters consume your propane, but electric water heaters often require shore power or a generator. Then there are the water heaters that utilize both gas and electricity. 

There’s no better option for boondocking, going off the grid, or getting out to explore remote areas than propane water heaters. An electric water heater has a cheaper upfront cost than a gas water heater, but the costs are often tied to the price of the RV unless you buy one separately.

In the long term, gas water heaters consume less LP and have a lower cost. However, since they are far more independent than electric water heaters, electricity may cost less in the long run. 

Think about it like this, you are likely to run an electric water heater when connected to shore power. But, if you spend a lot of time boondocking, your usage is exponentially higher with a propane water heater. In other words, costs are closely related to use. 

Motorhomes often utilize the main fuel line to quickly heat the water, offsetting the need for electricity to slowly heat it. 

How Many Gallons of Water Do You Need to Shower in an RV?

If you’re dry camping, anything between 1 and 5 gallons is fairly reasonable. Otherwise, anywhere between 3 and 10 gallons is typical. While some people prefer long, muscle-relaxing showers, that’s best for when you have shore power and the water is hooked up. 

How Long Can You Shower with a Propane-Powered Water Heater?

How Long Can You Shower with an RV Water Heater

Most RV water heaters are between 6 and 10 gallons, with 4 gallons and 16 gallons examples of rarer but existing options. If you are hooked up, you can shower as long as you like, but you’ll run out of hot water in about 10 to 15 minutes with a 6 or 10-gallon water heater respectively. 

If you’re dry camping, learn to make your showers quick. Greywater tanks fill up quicker than you think, and freshwater tanks don’t last forever. 

How Long Can You Shower with an Electric RV Water Heater?

Since an electric water heater will most likely draw shore power, you’ll have your water hooked up as well. So, it’s just a matter of how many heated gallons you have in your water heater. 

Your shower head matters as well, and a lot of RVs have “water-saver” features as well. If you prefer to do a lot of boondocking, you want to avoid those gigantic, rain shower heads and stick with something more economical. 

How Many Gallons Does The Average RVer Use When Showering?

On average, anywhere between 2 and 6 gallons of water per shower. Everybody’s different, but, when you average everything out, 2 to 6 gallons is a reasonably accurate number. Average RVers will use far less shower water than RVers who prefer shore hookups. 

How Big is My RV Propane Tank?

How Big is My RV Propane Tank

ASME tanks (tanks built into the framework of the RV and aren’t removable) are common in motorhomes, and tank size depends on the drivable class and available options. Another common tank is the DOT cylinder, mostly found on travel trailers. 

DOT cylinders, like ASME tanks, come in a variety of sizes depending on the RV and available options. The biggest difference between a DOT and an ASME is the DOT is removable. 

Outside of that, four propane tank sizes are commonly associated with RVs. 

  • 20-lb tanks
  • 30-lb tanks
  • 40-lb tanks
  • 60-lb tanks

The 20 and 30-lb varieties are the most common propane tank sizes. 

Is it Better to Use Generator Power or Propane for Your Water Heater When Boondocking?

Boondocking is all about the careful management of resources unless you enjoy spending a lot of time in town resupplying. Everything down to the time spent in the shower has the potential to be too much. 

When it comes to a generator or propane, what matters is what you have more of, what you prefer for simplicity’s sake, and what onboard power source your RV can be devoted to the water heater. There isn’t a wrong answer if you know your RV well.

How Can I Conserve Propane When Using My RV Water Heater?

How Can I Conserve Propane When Using My RV Water Heater

There are several things you can do to conserve your propane and still enjoy the amenities of a hot shower, among other uses. 

  • Depending on the Propane tank’s location, use an insulating skirt
  • Carefully track and adjust your energy use
  • Cut your water heater off when it’s not needed
  • Limit hot water usage outside of showering
  • Take advantage of alternate energy sources if you have a hybrid water heater

Final Thoughts on Propane-Powered Water Heaters

Keep in mind, although a water heater uses propane at a stable level, it’s not the only device pulling propane from the tank. It’s easy to get so tied up in how much the water heater uses that you lose track of what everything in your RV also uses. 

Propane is an efficient and prevalent source of energy, and it always has been. It makes sense that it would be a primary focus in RV manufacturing and the third-party market. Propane-powered water heaters don’t use that much propane and are very efficient. 

Related Reading:

1. Is it OK to Drive an RV with the Propane On

2. How Long Will an RV Fridge Run on Propane

3. How Long Does an RV Propane Tank Last

4. RV Propane Not Flowing? How To Troubleshoot and Solve

Thomas Godwin – Author and Part-Time RVer

Thomas Godwin is a full-time freelance writer with a BFA in Creative Writing, a U.S. Marine, and an avid outdoorsman.

Thomas’s love for RVing began at an early age spending time camping in the family vintage Airstream.

His background and education in writing, combined with his passion for the outdoors, can be seen in publications such as Camper Smarts and Vanlifers, as well as multiple animal and outdoor recreational publications.

When he’s not writing, he’s raising chickens and Appleyard ducks. Thomas also constructs teardrop campers (attempting to anyway) and kayaks the Blackwater River with his wife, two daughters, and his Dobermans.

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1 thought on “How Much Propane Does An RV Water Heater Use?”

  1. My wife had been complaining about the hot water heater firing up right behind where she sits.
    So now I turn it off after dinner and on when I get up.
    She likes the quiet and propane use has gone down by not heating water while we sleep.


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