Filling Propane vs Exchange

Discussion in 'Propane Smokers' started by celloyd, Aug 4, 2014.

  1. celloyd

    celloyd Newbie

    Can anyone definitively tell me if you are better off cost-wise filling your tank at the local CO-OP vs exchanging it at Menards?  The guy at the CO-OP this morning just hooked it up and let it run until it was topped off I assume.  He did not weigh it or anything like that.  Then it was a flat rate $21.40.  I've heard that the exchange tanks are not filled all the way etc.  Just wonder what you all think or do in this case.  I just bought a nearly new tank this morning from a fella on craigslist for $10.  So I've got $31.40 into a new tank so I have a backup for smoking/grilling.
  2. ps0303

    ps0303 Meat Mopper

    Propane tanks are only filled to 80% of their capacity.  This allows for the gas to expand properly.  They should always be weighed because if you over fill things will not be right. 
    celloyd likes this.
  3. exchange places often put as little as 15 LBs in a 20 LB tank. The new type valve in the smaller tanks keeps you from going over 20 LB. Refilling is almost always a cheaper way to go.

    Happy smoken.

    celloyd likes this.
  4. garyinmd

    garyinmd Meat Mopper SMF Premier Member

    Is there another place that will fill them for you.  The place here in town I have mine filled at goes by the meter they have and I only have to pay for what they use.  With spare tanks I used to make sure they were empty or very close before I would exchange them.

    celloyd likes this.
  5. celloyd

    celloyd Newbie

    I will check around.  He may have just done it so quickly that I did not notice and I should have asked the questions.  Never hurts to comparison shop but I'm thinking refills may be the best option from the feedback so far.  Thank you.
  6. bmudd14474

    bmudd14474 Smoking Guru Staff Member Administrator Group Lead OTBS Member SMF Premier Member

    filled is always better for me
  7. foamheart

    foamheart Smoking Guru OTBS Member SMF Premier Member

    Another factor to think about, there is an up side to swaping tanks. I boiled crawfish a few weeks back and luckily I have 3 20's and a much bigger one that went on the old camping trailer and they are all out of date. Now I can't refill them nor swap them out.

    So watch your cert dates if you refill, and make sure and swap those puppies out before you lose certification. That way you'll get a newer more up to date cert. But I bet you knew that already.

    Mine had set out so long the quick hose connects I had installed, had rusted and the springs broke. Use 'em, trade 'em, or lose 'em like I did.
    Last edited: Aug 4, 2014
    celloyd likes this.
  8. noboundaries

    noboundaries Smoking Guru OTBS Member SMF Premier Member

    Yep.  Two or more tanks and fill.   
  9. welshrarebit

    welshrarebit Master of the Pit

    I went down to refill a tank and the dude told me that my tank only had a couple of months left before it expired and told me to go and exchange the tank for a newer one. I had no idea that they had an expiration date!
    celloyd likes this.
  10. ps0303

    ps0303 Meat Mopper

    I believe it's every 5 years that a tank needs to be re-certified.
  11. garyinmd

    garyinmd Meat Mopper SMF Premier Member

    Found this on the web

    Cylinders are subject to recertification (also known as requalification) twelve years from their date of manufacture and every five years after that. For example, a cylinder manufactured in January of 2000 will have to be recertified in January of 2012 meaning if you take your bottle to the propane company in April of 2012 to be refilled, it will have to be requalified by authorized personnel before it can be filled. The recertification process is simple and does not take too long to complete. Think of cylinder recertification as an inspection similar to that of your car. A vehicle has to be inspected annually so that it may continue to operate safely on the road. Similarly, a propane cylinder must be inspected so that it may continue to operate safely in LP Gas service.

  12. celloyd

    celloyd Newbie

    So its not like they are obsolete, just need safety checked. Makes more sense. Still can anyone speak with any firsthand knowledge as to how full the exchange tanks may or may not be compared to the refills?
    Last edited: Aug 5, 2014
  13. The store down the road from me has in small print 15 pounds. Most places that exchange cylinders have it in small print on the cage they keep them in.

    The highest I have seen since 2008 is 17 pounds. That has been a while.

    Refills will be 20 pounds or by the pound. Some places will refill by the pound.

    Happy smoken.

    Last edited: Aug 5, 2014
  14. ps0303

    ps0303 Meat Mopper

    Propane tanks can only be filled to 80% of capacity.  So a 20Lb tank can only be filled up to 16Lbs.

    Typo in original posting. Should have read 80% not 20%
    Last edited: Aug 6, 2014
  15. A 20# tank is filled to 20# which is 80%

    Happy smoken.

    Last edited: Aug 6, 2014

    These "20 lb" tanks are designed to take 20 pounds of propane. They can actually fit another 20% in the tank, but that extra space is designed for expansion as the temperature changes.


    All propane tanks have a "tare weight" or "T.W." stamped on the collar of the tank. For a grill sized tank you simply calculate the tare weight + 20 lbs, and that's how much the tank should weigh when it's full. Most 20 lb tanks have a tare weight of +/- 17 pounds when completely empty. This means a "full" propane tank should weigh about 37 pounds.

    There is also a month and year on the collar indicating the date the tank was made. For 20 lb propane tanks, you have 12 years from the manufacture date before the tank must be re-certified with a new date stamped on it. The re-certification only adds 5 years before having to re-certify again. The cost and inconvenience of re-certifying almost always outweighs the price of a new tank.

    Brand new propane tanks come with air inside and it needs to be "purged" before the first fill. Purging requires a special adapter to allow a small amount of propane in. The pressure then pushes air out of a one-way bleeder valve. Purging may add another $3-4 dollars to a new tank, though some places don't charge, especially if you buy the tank from them.


    Internet searches suggest the following:
    • 1 gallon of propane weighs 4.2 pounds
    • A "full" 20 lb cylinder should have 4.7 gallons or propane in it
    I called around and the local U-Haul place wanted $16 for a refill. I remember Costco has a sign for $9.99 refills. I thought I was getting a great deal, but it turns out I pretty much got no deal.


    Costco in Greenville, SC is a bit deceiving because they first hand you a slip that says "20 lb cylinder". When you pay inside the receipt says "20lb PROPANE", and the filling print out says "Cylinder: 20S lbs." The only defense is that the filling print out is honest and says "3.6 gallons". However, nobody knows off the top of their head that a propane tank is supposed to have 4.7 gallons to be considered "full". By saying 3.6 gallons, they are masking the fact that they put in 75%. If they wanted to be upfront they'd say "we will put 15 lbs of propane into this 20 lb cylinder".

    This means Costco puts in 15 lb of propane.

    3.6 gallons / 4.7 gallons = 75% of the normal fill.
    or, said another way

    (4.2 pounds/gallons) * (3.6 gallons) = 15 pounds
    The word on the web forums is that the Blue Rhino and AmeriGas similar exchange services put in 75%, or 15 lbs.

    If you do the math on Costco, it's actually not a bad price. It's in line, if not cheaper, than paying $16 for a full 20 lbs. Though, Costco's use of the "20 lb" phrase is unfortunate. I think their motivation is to have a cheaper price, so members think they are getting a great deal. Plus, by only filling 75% they make members come back more often, and go inside to shop while they wait.


    • If you're looking for the best price, owning a propane tank and re-filling it is going to be cheaper than using an exchange service. As always, you pay a premium for convenience.
    • Ask how much propane is going into the cylinder. There should be 20 pounds going in for full capacity.
    • Weigh the tank when you get home and it should be about 37 pounds. If it weighs 31-32 pounds then you know they only put in 15 lbs of propane.
    • Costco's propane price is still fair when you do the math.
    •  You are welcome to Google it
    Happy smoken.

    celloyd likes this.
  17. celloyd

    celloyd Newbie

    Knocked it out of the park!  Thanks for your time and the research you did.  Very clear to me now.
  18. shoneyboy

    shoneyboy Master of the Pit OTBS Member

    Foamheart, if you swap them out at Wally World, they usually do not look at the date....or at least they have not checked any of my so far.......If you need, I have many extra tanks that are empty, but are indate. If you want a couple of them you are welcome to them. Just PM me.......SB
  19. foamheart

    foamheart Smoking Guru OTBS Member SMF Premier Member

    Thanks man, I was just bitchin about the re-cert. But I really appreciate the offer. I have known about it since I bought that trailer to go to college. Its amazing how much you don't use gas in a trailer in south Lousisana...LOL
  20. sqwib

    sqwib Smoking Guru OTBS Member

    Sorry if this has been covered. I'm on my phone in OC MD.
    Uhaul fills by a meter and baz price breaks in my area.
    Exchanges are a rip off at 70-75% as opposed to 80% fills (need headspace)
    The only time an exchange is worth it is when your tanks DATE is up

    2,000 BTU pound
    Propane Weighs 4.24 pounds
    30 pounder is 7.075 gallons
    20 pounder is 4.716 gallons

    20# 4.7 gal 18 lbs (Tare) 38 lbs (Fill Wt.) 430,270 (BTU) 18 inches x 12.5 inches (Dimensions)
    30# 7.1 gal 24 lbs (Tare) 54 lbs (Fill Wt.) 649,980 (BTU) 24 inches x 12.5 inches (Dimensions)
    40# 9.4 gal 29 lbs (Tare) 70 lbs (Fill Wt.) 860,542 (BTU) 29 inches x 12.5 inches (Dimensions)
    100# 23.6 gal 68 lbs (Tare) 170 lbs (Fill Wt.) 2,160,509 (BTU) 48 inches x 14.5 inches (Dimensions)

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