How Long Does a Propane Tank Last?

Not having enough propane on hand can be both a burden and a danger. From running out of fuel during the middle of a cookout to not having heating oil on a cold winter’s night, it’s important to know the specifics of propane tank maintenance, how quickly the fuel burns, and how to tell if you’re running low on fuel.

Residential propane tanks range in size from 100-1,000 gallons. Smaller tanks, like 20-pound tanks, are sold for modest needs like outdoor barbecuing or small appliances like fireplaces.

Homes 2,500 square feet or larger, that have multiple appliances running on propane, will most likely use a 500-gallon tank. Propane tanks any larger than 500-gallons are often reserved for commercial use.

How you put your propane to use will play a role in how long your fuel source will last. 

Grilling

Twenty-pound propane tanks are used for modest tasks like cooking individual meals. As a rule of thumb, one tank of propane will typically last between 18-20 hours if you’re grilling on a medium-sized grill. Whereas larger grills can burn through 20-pounds of propane in as little as 10 hours.

On average, you’ll use one or two pounds of fuel per meal if you use a medium-sized grill on high heat. That equals roughly 8 grilling sessions per tank

Furnaces

British Thermal Unit, or BTUs, is the industry standard used to measure the heating efficiency of household appliances. The average home furnace runs on roughly 100,000 BTUs, and one gallon of propane equals 92,000 BTUs. That means the average home furnace burns roughly one gallon of propane per hour.

In this example, a home furnace will burn anywhere from 500-1,200 gallons of propane per year, depending on how often you turn on your furnace

Hot Water Heaters

Your hot water heater usage will vary based on how many bathrooms you have in your home, and how many people are in and out of your home. As a rule of thumb, the average home uses about 1.5 gallons of propane a day for typical hot water heating use.

The average homeowner can expect to use somewhere between 200-300 gallons of propane per year for hot water.

Overall, the average homeowner will use roughly 2.5, 500-gallon tanks of propane each year for home heating and cooking.

How Else Can I Check My Propane Levels?

While these aren’t the most accurate ways to test your levels, these alternatives might come in handy at some point.

Pour Water on It:  pour a glass of water down the side of the tank. Use your hand to find the spot where the tank goes from feeling warm to feeling cool. The line where it begins to feel cool is about how much propane you have left.

Weigh It: You’ll need a scale for this one. The average empty propane tank for grilling weighs about 17 pounds and can hold about 20 pounds of gas. Current tank weight – base weight = how much propane is left. So, if you weigh a container that you know is 15 pounds when empty and it weighs 20 pounds currently, you know you have 5 pounds of gas left.

We always recommend you have an extra tank on hand because you don’t want to run out in the middle of a BBQ!

How long a propane tank will last depends on what you’re using the propane for. A large BBQ grill, for example, will demand more gas than a small propane camping stove.

Most people don’t cook at the maximum grill setting for an extended length of time. In fact, propane usage during typical cooking conditions is normally around 50-75% of the maximum heat output. If you cook with the all the burners set on medium, your output would be around 75% of the maximum. If you use fewer burners, your actual output will also change.  If you crank that same burner to its maximum setting, you will only be generating about 17% of the maximum heat that could be generated by the grill.

Most people don’t cook at the maximum grill setting for an extended length of time. In fact, propane usage during typical cooking conditions is normally around 50-75% of the maximum heat output. If you cook with the all the burners set on medium, your output would be around 75% of the maximum. If you use fewer burners, your actual output will also change. This is where I introduce an efficiency factor, ‘k,’ to adjust the time calculation for this variation.

How to Determine the ‘k’ Factor

The ‘k’ factor effectively reduces your grill’s total output in the computation. Use the chart below to determine the ‘k’ value for your typical grilling scheme. Once you select a ‘k’ factor based on your typical grill’s usage, you can compute the total estimated grilling time (T). Divide this time by the average time it takes to cook a meal to estimate the number of meals you can grill. Now keep track of how many times you use the grill to know how much fuel you have left.

For example, if you have a six-burner grill and only cook with one burner on the lowest setting, you are effectively generating only 10% (0.10) of the maximum heat output of that grill. However, if you crank that same burner to its maximum setting, you will only be generating about 17% of the maximum heat that could be generated by the grill.