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Blue Rhino propane exchange vs refilling your own tank – All about propane tanks

I’ll have to admit, for years I have used Blue Rhino tank exchanges for my propane needs. It wasn’t until I begun homebrewing that I started to question what I was really paying for liquid propane. While brewing beer with my 55,000 BTU burner, I begun to use more gas that ever before.

Now, I have always heard that refilling your own tank is much less expensive than doing the exchange but never really investigated it until now…

Exchanging a propane tank vs using a filling station

The price of Propane (LP) per gallon and tank exchanges can vary greatly from one area to another. That being said, you should still get the general idea by reading this even if you live in a different part of the country. Lets begin by discussing exactly what you are getting with a Blue Rhino swap.

The Blue Rhino exchange tanks

Blue Rhino Propane tankThese days, it is rare to visit a Walmart, Lowes, Walgreen’s, or any major supermarket and not notice the steel cages containing BBQ propane tanks. But what are you really buying. The simple answer to this question is that you are purchasing convenience. Simply bring your old empty tank to the retailer, pay at the register, and an employee will come out to unlock the cage so that you can fetch a refurbished filled tank. So whats in the tank?


20 lb propane tankThe 20 lb tank

You may have heard your BBQ tank referred to as a 20 lb tank but are you really getting 20 lbs? Several years ago, gas exchange companies such as Blue Rhino started filling their tanks with 17 lbs instead of 20 lbs, as the price of propane rose. The companies cited the rising cost of fuel as the reason for getting less gas. In an effort to keep prices the same with rising costs, they decided to reduce the amount of fuel that goes into each tank, anticipating that the average consumer would not notice or simply did not care enough to do something about it. This same tactic has been used by many food and beverage makers. Look at the “20 oz Pepsi”, half gallon of Bryer’s ice cream, or that box of general mills cereal. In order to maintain strong profits in times where inflation is going crazy, they do these things and most consumers do not notice.

At first, Blue Rhino landed in some hot water as they failed to disclose this on their labeling. In the end, they ended up paying up $7.50 for every tank purchased between 2005 and 2011 as a result of a class action lawsuit. Consumers could file a claim and receive up to $150 in refunds (20 tanks) if they have a proof of purchase. Those without proof of purchase one can receive one refund for $7.50. Needless to say, the propane contents are clearly labeled on every tank today.

Fast forward a few years and the 20 lb propane tank is now being filled with 15 pounds, not 17 and defiantly not 20. Perhaps this was caused by BR paying millions of dollars out due to the lawsuit in addition to higher operation costs? I can only speculate.

Now, the once “20 lb tank”, as they are commonly referred to as, contains 15 lbs of actual propane. It is clearly labeled on the plastic wrapper surrounding the bottle so if you read the label you will not be deceived.

How much can the Blue Rhino tank hold?

Although the exchange tanks are now (January 2013) filled with 15 lbs of propane, this does not necessarly mean that this all they will hold.

While researching the topic of the maximum capacity of a 20lb tank, I ran across quite a bit of misinformation that actually led me to believe that these tanks are only capable of safely holding 16 lbs. Where did this number come from?

The statement on the label reads that the tank should only be filled to 80% capacity for safety reasons. The 20% void is left for gas expansion as the weather changes.  The general consensus by the masses was simple:

80% of a 20 lb tank is 16lbs. Blue Rhino fills their tanks to 15 lbs so what the big deal? Its just a pound short?

Upon further investigation, I learned that this is far from the truth. A 20 lb tank holds just a hair under 20 lbs or roughly 4.5 gallons of propane. Where did I come up with this number? Here is the math.

Water Capacity

Water Capacity of 20 lb propane tankTake a look at the handle of your propane tank. You will notice several numbers on here. One number that you will see is the water capacity or “WC”. My particular tank shows “WC 47.6 LBS”.

What this means is that you can figuratively speaking, fill the tank to the very top, leaving no void space and the weight of the water added will be 47.6 lbs.

Water weighs 8.35 lbs per gallon so 47.6 lbs is roughly 5.7 gallons. My particular tank will hold 5.7 gallons of liquid at maximum capacity. However, you can’t fill these tanks to the top. Remember, a maximum of 80% propane?

80% of 5.7 gallons is 4.56 gallons. In terms of weight (4.27 lbs per gallon), this is approx 19.5 lbs, a far cry from 16 lbs.

The water capacity will give you a good idea of how much LP your tank can safely hold.

Overfill Prevention Device

overflow prevention device OPDDon’t concern yourself with overfilling your tank and it exploding. New style tanks with the triangle valve handle have an Overfill Prevention Device or OPD. If overfilled, propane will spew out the release hole. Overfilling tanks is a thing of the past when this device is used. All tanks between 4 lbs and 40 lbs are required by law to have this device before they can be filled. In fact, many filling stations do not use a scale or meter. They just fill the tank until it spews and charge a flat rate. These stations rely on the built in OPD safety device to cut the flow of gas. Not the smartest move in my opinion.

Having your Blue Rhino tank filled locally vs exchanged – a cost comparison

Now that it has been established that the exchange tanks have 15 lbs in them although they are capable of holding 20 lbs, lets compare the price of these tanks compared to bringing your gas bottle to the filling station.

In all fairness, lets compare the 15lbs that you receive from Blue Rhino to 15 lbs filled at your local filling station. Here in North Carolina, the current going rate for a gallon of propane is $3.00. The going rate for a exchange tank is $17.82. Here’s what we get with a side-by-side comparison:

15 lbs of Blue Rhino gas : $17.82

15 lbs of filling station gas: $10.54

Difference of $7.28 or 69% more! 

Is Blue Rhino a rip off?

Those who have this knowledge may accuse Blue Rhino of being a rip off. Is this true?

On the surface, it is easy to say YES! They are charging 69% more than the local guys.

My personal opinion is that they are practicing business as usual. Think about it from a business standpoint. Blue Rhino has to pay additional expense that the local guy doesn’t. These prices include but are not limited to

  • Retailers discount so that they can profitably sell the exchanges
  • Supplying and maintaining the large steel cages that sit in front of the store
  • Vehicle fuel and maintenance for every gas delivery truck on the road
  • Costly insurance for these trucks. I can’t imagine how much it cost to insure a truck full of flammable propane.
  • Truck drivers salary
  • Cost to strip, paint, and relabel their exchanged tanks
  • Cost to replace bad tanks and have old tanks re-certified
  • re-certification of old tanks and replacing parts
  • Class action lawsuit payouts. Ferrell gas (Blue Rhino) has paid out $25,000,000 in lawsuit settlements.
  • Cost of several more staff members
  • Too many more to name

One can imagine the overall cost of operation. In the end, they are likely profiting, as they should.

As mentioned at the beginning, you are paying for the convenience. All of these additional expenses paid out by Blue Rhino are passed down to the consumer in the form of a convenience charge.

Advantages and disadvantages of both

 Blue Rhino


  • Convenience – can be found at several locations around town, more common than filling stations
  • No need to “re-certify” your own tank when it reaches 12 years of age
  • Always a clean, nice looking tank
  • You can get a tank any day, any time at many retailers such as Wal-Mart


  • Costly – nearly 70% more than filling your own
  • Potential to lose gas if you are not able to completely empty your tank prior to exchange
  • Hard to tell how much gas they are actually filled with at time of purchase
Propane filling stations


  • Cost effective – nearly 70% less than exchanging 
  • You can get a full 20 lbs, less trips to the store to fill up
  • You can see the tanks being filled so you know whats in them
  • In most cases, you can pay by the pound or gallon, no need to completely empty tank


  • Sometimes more difficult to locate in comparison to picking up an exchange at the supermarket 
  • Tank must be re-certified after 12 years in order to be legally filled. ( Use a service such as Blue Rhino to dump your old tanks to avoid this)
  • You have to clean and maintain your own tank
  • Most filling stations are going to have limited hours. If you run out of gas on a Sunday night you will likely be out of luck.

You are the only one that can determine which one will work best for you. For most people, refilling would be the most cost effective approach assuming there is a filling station near by and they are open when you need gas.

How to determine how much gas is left in my propane tank

Perhaps after reading this you decide that exchanging your tank is going to be the best option. The problem is, you only own one tank. This makes it very difficult to strike a balance between removing as much gas out of your tank while not running out while cooking that T-bone steak. What does one do to determine how much gas is left in a propane tank?

Unlike a gasoline can, you can not open the lid and take a look inside. This presents a challenge when you need to find out what’s left in your tank. There are actually three methods that you can use to determine what you have left.

Good – Pour hot water down side of tank

How to check propane levelsAn old time trick to determine the level of liquid in your tank is to take a glass of piping hot water and slowly pour it down the side of the tank. Use your sense of touch to feel along the side where the tank turns from warm to cold. The transition to the colder area marks where the propane level is. The difference if fairly obvious. This will give you general idea where you stand.

Better – Buy an inline propane gauge

Pick up an inline propane gauge. These are available online for $10 to $20 and can give you an idea of how much gas is left in your tank. Although they are not completely 100% dead on accurate, this may be sufficient and certainly better than taking a wild guess.

Best – Weigh it

Tare weight

Tare weight propane tankWeight of empty 20 lb propane tankThe first thing that you need to understand is the “tare weigh”. The tare weight or “TW” should be clearly marked on the tank handle. On my tank it is  stamped 16.6 LBS – yours will likely vary. This simply means that when completely empty, the tank should weigh 16.6 LBS.

Now that you have determined the tare weigh, put the tank on a scale and weight it. I use a postal scale but if that is not available a good bathroom scale will work.  Lets say this particular tank weighs 26.6 lbs. Simply subtract the actual weight from the tare weigh and you get 10lbs of gas remaining. A 15 lb (considered full by Blue Rhino) should weigh in around 31 – 32 lbs.

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