The Better Way to Buy Propane

You've seen them everywhere: propane tank exchanges. They offer convenience and speed but for a price that's hidden to most folks.

Propane gas grills have become a fixture across the American landscape, and, consequently, so have propane tank exchanges. These can be seen almost anywhere, from gas stations to mega stores, and it makes sense from a retailer's perspective. They don't have to train their staff on how to fill propane tanks, store a big propane tank with filling equipment, or work with a local company to get the propane tank periodically filled. And there's no disputing that it's easy and fast for consumers to exchange their empty propane tank for a full one.

But how much does it cost to exchange a propane tank? You might think that to be the price of the exchange, but there's a key factor involved that the price doesn't tell you. In the picture above or on any of the propane tanks available for an exchange, look at the net weight of the propane in the tank. It's 15 pounds. But that tank is actually rated for 20 pounds of propane. The propane tanks at these exchanges are only filling the tanks to 75% of their rated capacity. (Note that propane tanks' rated capacity is only 80% of the volume of the tank, but the 20 pound rated capacity takes this into account.)

How much does it cost to get one of these propane tanks filled to its 20 pound limit? Like the price of propane tank exchanges, it varies depending mostly on location, but when I just had a propane tank filled at a local rental store, it cost $16.91, plus tax. By comparison, the propane tank exchanges near me usually cost $19.99 but are sometimes a dollar or two more.

This means that the propane tank exchanges costs about $1.33 per pound of propane, whereas getting the tank filled costs about $.85 per pound of propane. That means that the exchange costs 56% more than getting the tank filled!

But that's not all! Since the tanks available at propane exchanges only have 15 pounds of propane rather than 20 pounds, they will need to be exchanged or filled more often too! Four tank exchanges only get you as much propane as three fillings.

So, does that mean that you should never exchange a propane tank? Not at all! There are times when exchanging your propane tank makes great sense.

Around the 'collar', called a neck ring, at the top of a propane tank will be stamped some numbers. These are the month and year that the propane tank was last certified as being safe. In the U.S., new propane tanks are certified for 12 years, and after this period, a tank must be recertified to ensure that it is still safe. Tanks that are older than their certification period cannot be filled. You can figure out if your tank is still within its certification period yourself (see here for details), or the folks who fill your tank will tell you.

If your tank needs to be recertified, you have two choices: get the tank recertified by a specialist for a cost ranging from $35 to $60, or exchange the tank for another. Considering that, at least in my area, a propane tank can be exchanged for about $20, it's a no-brainer to just exchange your empty tank for another with 15 pounds of propane in it rather than pay multiples of that just to get an old tank recertified.

Also, if you come across an old, rusty propane tank, don't throw it away! You can very likely get it exchanged for a 'new' one. Retailers aren't required to accept an damaged, very rusty, or old propane tank for an exchanged, but I've never seen one that did.