A lot of people ask us this specific question “How long does a propane tank last?”.
Now, there are 3 types of interpretations of this question, and we’re going to answer all of them. Some people are interested in how long propane is good for, but most homeowners just want to know how long their 20 lbs propane tank or 500-gallon propane tank is going to last (consumption-dependant).
Here’s how we can pose these 3 questions:
- “How long does propane stay good for?” That’s something you’re probably interested in if you have a propane tank (be it a small 20 lbs or big 1000-gallon tank) will ‘old propane’. That propane has been in the tank for years now and what you’re really asking is “Does propane go bad?”. Here’s the short answer: Propane never goes bad. You can have it in a tank for 100 years, and it will still be good. Propane doesn’t have an expiry date; you can still use it no matter how old it is.
- “How long do small 1 lb to 100 lbs propane tanks last on a grill or patio heater?” (Consumption-dependant) This depends on the size of your grill, patio heater, and so on. Further on, we will calculate how many hours does a small propane tank last for different kinds of propane-powered appliances. We will need to take into account BTU content of propane and BTU generation of a grill, patio heater, you name it.
- “How long do big 100-gallon to 1,000-gallon propane tanks for a house last?” (House size-dependant) This primarily depends on how much heating your house needs in the winter. We will look into BTU heating output different house sizes (from 500 sq ft to 3,000 sq ft) require on average, and how quickly will delivering all that heat drain your residential propane tank.
Let’s clear one thing up:
Propane doesn’t go stale. It is a product of natural gas processing and petroleum refining. That means it has been in the ground for literally a million years. If you have a propane-filed tank for 1 year or 1,000 years, it will still be good and it will have the same BTU content.
On top of that, you can rest assured that the propane tank itself – the metal tank – can last for more than 12 years. It is basically a metal box that doesn’t corrode (anti-corrosion layer) and will last for more than a decade. Tanks in the US are recertified for 5, 7, and 12 years.
With this out of the way, let’s first look at how long does propane last for smaller appliances (grills, patio heaters, portable stoves, even propane generators). For this, we use 1 lb to 100 lbs propane tanks.
After that, we will look at how long does propane last in a big tank. In this case, we will look into 100-gallon to 1,000-gallon residential propane tanks used for heating. Based on the size of your home and the size of your propane tank, you will be able to tell how many times per winter you will need to refill the tank.
Note: If you need some help with the propane size calculations below, you can check all the 48 propane tank sizes, with dimensions, weight, and BTU content here.
How Long Do Small Propane Tanks Last? (1 lb to 100 lbs)
We use these small 1 lb, 10 lbs, 20 lbs, 30 lbs, 50 lbs, or even 100 lbs propane tanks for grilling, patio heating, propane stoves, and so on.
When figuring out how long do these propane tanks last, we only need to know two metrics:
- BTU content of propane in the tank. Example: 20 lbs propane tank contains 4.25 gallons of propane that contain a total of 430,588 BTU of energy.
- Consumption of a small appliance. Example: 30,000 BTU/h grill or 50,000 BTU/h propane patio heater.
Using these two metrics, we can calculate how long will propane last for any appliance. Let’s look at one example to illustrate how you can calculate that. After that, you will find a calculated table of how long does propane last for appliances with 10,000 to 80,000 BTU consumption.
How Long Does A 20 lbs Propane Tank Last On A Grill? (3-Step Calculation)
Alright, let’s say we have a standard 30,000 BTU/h grill powered by a 20 lbs propane tank. How long will it last?
We already know that the grill itself uses 30,000 BTU of heat every hour. Now we need to figure out how much energy does that 20 lbs heat tank contain. Here’s how we do that:
1 gallon of propane generates 91,500 BTU of energy. We also need to know that 1 gallon of propane is equal to 4.25 lbs of propane. How many gallons of propane are there in a 20 lbs tank?
20 lbs ÷ 4.25 lbs per gallon = 4.70588 gallons
20 lbs propane tanks contains 4.70588 gallons of propane. To calculate the BTU content of 20 lbs propane tank, we need to multiply the gallons by 91,500 BTU per gallon.
20 lbs BTU content = 4.70588 gallons × 91,500 BTU per gallon = 430,588 BTU
Here is the easy part. We know that a 20 lbs propane tank contains 430,588 BTU of energy. We also know that a standard grill uses 30,000 BTU of that energy every hour. To calculate how long will a 20 lbs last of this grill, we just divide BTU content by BTU consumption.
20 lbs tank lifespan = 430,588 BTU ÷ 30,000 BTU/h = 14.35 hours
That means that a 20 lbs tank will last for 14 hours and 21 minutes on an average 30,000 BTU/h grill.
Using this principle, we can figure out how long will any small propane tank last on any propane-powered appliance, be it a patio heater, grill, propane stove, anything.
To help you out, we have made the calculations of how long will 1-100 lbs propane tank last on 10,000-80,000 BTU/h propane-powered appliances, and summarized the results in this table:
How Many Hours Will A Propane Tank Last? (Calculated Table)
You might have to scroll a bit right and down to see the whole table:
|Propane Tank Size:||10,000 BTU/h||20,000 BTU/h||30,000 BTU/h||40,000 BTU/h||50,000 BTU/h||60,000 BTU/h||70,000 BTU/h||80,000 BTU/h|
|1 lb||2.15 h||1.07 h||43 min||32 min||26 min||21 min||18 min||16 min|
|5 lbs||10.76 h||5.38 h||3.59 h||2.69 h||2.15 h||1.79 h||1.54 h||1.35 h|
|10 lbs||21.53 h||10.76 h||7.18 h||5.38 h||4.31 h||3.59 h||3.08 h||2.69 h|
|20 lbs||43.06 h||21.53 h||14.35 h||10.76 h||8.61 h||7.18 h||6.15 h||5.38 h|
|30 lbs||64.59 h||32.29 h||21.53 h||16.15 h||12.92 h||10.76 h||9.23 h||8.07 h|
|50 lbs||107.65h||53.82 h||35.88 h||26.91 h||21.53 h||17.94 h||15.38 h||13.46 h|
|100 lbs||215.29h||107.65h||71.76 h||53.82 h||43.06 h||35.88 h||30.76 h||26.91 h|
Here is how to read this table:
For example, we want to figure out how long will a 20 lbs propane tank last on a 50,000 BTU patio heater. You just look at row with ’20 lbs’ and column with ‘50,000 BTU/h’ and you get ‘8.61 h’. That means that such a propane tank will last for 8.61 hours.
If you need to calculate any other combination, you can pose the question in the comments and we’ll try to help you out. You can also use this general equation for calculating how long will a propane tank last:
Propane Tank Lifespan = (Tank Size (in lbs) ÷ 4.25) × 91,500 BTU per gallon ÷ Consumption BTU =
Hours How Long Propane Tank Will Last
Quick example: Let’s say we have a big 50,000 BTU grill powered by a 33 lbs propane tank. How long will the propane tank last on a gas grill?
33 lbs Propane Tank Lifespan = (33 lbs ÷ 4.25) × 91,500 BTU per gallon ÷ 50,000 BTU/h = 14.21 Hours
Now, let’s have a look at the big 100+ gallon propane tanks, primarily used for heating:
How Long Do Big Propane Tanks Last? (100 to 1,000 gallons)
In much the same way, we could calculate how long will let’s say a 100-gallon tank for heating a house. However, as we have explained in the detailed article about how long does a 500-gallon tank last here, heating a house sometimes requires 10,000 BTU/h and other times up to 200,000 BTU/h.
The heating requirements depend on the size of your home (square footage), location, winter temperatures, insulations, and so on.
Given all these factors, we will get a much better estimate of how long will a propane tank for heating last if we base our estimate not on BTU consumption for heating, but on recorded heating needs statistics.
Here is this statistics:
Looking at the heating consumption data from 2009 to 2016, the average US household burned through about 750 gallons of propane per winter.
With an average size home being 2,200 square feet, we can pretty much estimate how many gallons of propane we burn in a winter per sq ft. Here is this calculation:
750 Gallons Of Propane ÷ 2,200 Sq Ft House = 0.34 Gallon Of Propane Per Sq Ft
Based on this estimate, here is how much propane different size homes will burn throughout the winter (6 months). We can also estimate how much propane do we use per day. All the estimates are summarized here:
|Home Size (Square Footage):||Propane Consumption (6 Months):||Propane Consumption (Per Average Day):|
|500 sq ft||170 Gallons||0.944 Gallons/Day|
|1,000 sq ft||340 Gallons||1.889 Gallons/Day|
|1,500 sq ft||510 Gallons||2.833 Gallons/Day|
|2,000 sq ft||680 Gallons||3.777 Gallons/Day|
|2,500 sq ft||850 Gallons||4.722 Gallons/Day|
|3,000 sq ft||1,020 Gallons||5.666 Gallons/Day|
|3,500 sq ft||1,190 Gallons||6.611 Gallons/Day|
|4,000 sq ft||1,360 Gallons||7.555 Gallons/Day|
If you check the table above, you can pretty much say that a small home (500 sq ft) uses about 1 gallon of propane per day. A big 4,000 sq ft house will burn through 7.555 gallons of propane every day.
Now we have all we need to calculate how long will big propane tanks last.
Note: We just need to be aware that even a full propane tank contains 80% capacity of the tank (that’s a security measure to avoid too high pressure inside the tank). That means that a 500-gallon tank contains 400 gallons of propane when completely full.
To illustrate how long do these big propane tanks last, let’s have a look at a 100-gallon tank heating up a 1,000 sq ft house. After that, we also added a table of all big propane tanks (100-gallon, 250-gallon, 500-gallon, 1,000-gallon, and 2,000-gallon) and the calculated time of how long will these propane tanks last, given the size of the house.
How Long Does A 100-Gallon Propane Tank Last? (Example)
From the winter heating consumption table above, we see that a 1,000 sq ft home burns through 1.889 gallons of propane per day (on average).
Now, we also know that a 100-gallon tank contains 80 gallons of propane when full (the 80% rule).
Using these two metrics, we can easily calculate how long will a 100-gallon propane tank last heating a 1,000 sq ft house:
100-Gallon Propane Tank Lifespan = 80 Gallons ÷ 1.889 Gallons/Day = 42.35 Days
Here you have it: A 100-gallon propane tank will last for 42.35 days (average estimate) when used for heating a 1,000 sq ft house.
Calculations were made for all big sizes of residential propane tanks (from 100-gallon to 2,000-gallon) for house sizes between 500 sq ft and 4,000 sq ft. The results are summaries in the following calculated table:
How Many Days Will A Big Propane Tank Last? (Calculated Table)
|Propane Tank Size:||500 sq ft house||1,000 sq ft house||1,500 sq ft house||2,000 sq ft house||2,500 sq ft house||3,000 sq ft house||3,500 sq ft house||4,000 sq ft house|
|100 Gallon||85 Days||42 Days||28 Days||21 Days||17 Days||14 Days||12 Days||11 Days|
|250 Gallon||212 Days||106 Days||71 Days||53 Days||42 Days||35 Days||30 Days||26 Days|
|500 Gallon||424 Days||212 Days||141 Days||106 Days||85 Days||71 Days||61 Days||53 Days|
|1,000 Gallon||847 Days||424 Days||282 Days||212 Days||170 Days||141 Days||121 Days||106 Days|
|2,000 Gallon||1695 Days||847 Days||564 Days||424 Days||370 Days||282 Days||141 Days||212 Days|
As we can see, the 100-gallon propane tank will heat a small 500 sq ft house for almost 3 months (85 days, to be exact). If we were to use it in a big 4,000 sq ft house, the 100-gallon propane tank would last for only 11 days.
On the other hand, the enormous 2,000-gallon propane tank will last for almost 5 years if it were used to heat a small 500 sq ft house (1695 days). These units are used only for big houses. In a 3,000 sq ft house, the 2,000-gallon propane tank will last for about 282 days, on average.
You can check in detail how long will different propane tanks last. Here are the connected articles you should look into:
- How long does a 100-gallon propane tank last for heating?
- How long does a 250-gallon propane tank last?
- How long does a 500-gallon propane tank last?
- How long does a 1,000-gallon propane tank last?
Hopefully, this helps answer the question of “How long do propane tanks last?” for everyone. If you haven’t found an adequate answer, you can use the comments below to pose your question and we’ll try to help you out.
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