Propane refill vs exchange: which one saves more money?
Walk into almost any gas station or big-box store and you will see a cage of pre-filled 20-lb propane tanks labeled "Exchange." It feels convenient — swap your empty for a full one and go. But there is a quiet catch most people never notice: exchange tanks are almost never actually full.
Here is the straight comparison, with math, and when exchange makes sense anyway.
The 15-lb "gotcha"
A standard propane tank is called a "20-pound" tank because it can hold 20 pounds (about 4.7 gallons) of propane when filled to the 80% safety limit. Exchange providers — Blue Rhino, AmeriGas, and the store-brand services — fill them to only 15 pounds. That is 25% less propane than a true full tank.
The label on the exchange cage will tell you this, but it is usually in small print near the bottom. Most shoppers assume they are getting 20 lbs because that is what the tank is sized for.
Price comparison
Let's use typical Bay Area prices. Exchange tanks run $25-30 for 15 lbs. A refill at Super Station Concord typically costs less per pound, and you get the full 20 lbs. That math works out to roughly 35-50% more propane for less money when you refill.
For a household that does a few BBQs a month, that difference is a few dollars per tank. For food trucks, caterers, or RV owners, it stacks up to real money across a season.
What about tank condition?
The other unspoken thing with exchanges: you give up your tank. If you bought a brand-new, clean, well-maintained tank and trade it for whatever is next in the cage, you could walk away with a 20-year-old rusty one. The exchange company does not differentiate.
Refilling keeps your tank. We do a quick safety check (valve, O-ring, visible rust, recertification date) every time, and we only fill tanks that meet safety standards. If a tank needs recertifying (tanks expire 12 years after manufacture, then every 5 years after), we can usually handle that too.
When does exchange actually make sense?
A few situations where exchange wins:
- Your tank is past its recert date and damaged. Exchange is a way to "reset" to a compliant tank without paying the recert fee.
- It's Sunday night and the propane shop is closed. Big-box stores have 24/7 exchange cages. Convenience has a price — and sometimes that is worth it.
- You are brand-new to propane. The first tank — the one you buy empty — often costs as much as an exchange that comes pre-filled.
Super Station Concord propane fills
We refill all kinds of tanks at 1650 Monument Boulevard, Concord — BBQ tanks (20 lb, 30 lb, 40 lb), RV cylinders, patio heater tanks, food truck tanks, and forklift cylinders. Pull up, pop the trunk, and we take it from there. Most visits take under 5 minutes.