RV Propane Plan: Big vs Small Tanks

Tue Mar 08 2022

While RV camping off-grid on our property in Vermont we had a big decision to make - should we have a large propane tank delivered or refill our small tanks?

RV Propane Plan: Big vs Small Tanks
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Last year, while staying in our RV at the Green Mountain Family Campground in Vermont, we had a 100 gallon propane tank delivered and hooked up to our RV. It was great - we never had to worry about running out of propane, or hauling tanks to be refilled.

Green Mountain Family Campground Review

If you are looking for a quiet, rustic campground in Vermont that's open in winter, I highly recommend Green Mountain Family Campground!

Green Mountain Family Campground Review

But in our blog post last week I shared that we're not planning to do the same on our property this year, even though we're completely off-grid here and our propane usage will be even higher as we run dual-fuel appliances on propane rather than electricity.

Snowboarding... on our driveway!

Our 1,000ft driveway was covered with a foot of fresh snow so there was just one question - could we snowboard down it? Only one way to find out!

Snowboarding... on our driveway!

In this article, I want to share the advantages and disadvantages of having a large propane tank delivered vs using smaller tanks with your RV, especially in a cold weather climate like Vermont.

Capacity

Our travel trailer has two 30lb propane tanks. When filled to the maximum allowed 80% capacity, this equates to about 7 gallons. With two of them, that means we have a total capacity of about 14 gallons.

Compare that to a 100 gallon tank like the one we had delivered last year and, well, there's really no comparison! The big tank will last about 7 times longer than our two tanks combined.

Plus, particularly in cold weather, it's not really that simple. If you've ever tried moving a full or partially-filled, you'll no doubt have felt liquid sloshing around inside - that's liquid propane. But the propane when it comes out of the tank is gas, not liquid - how come?

Essentially the bottom of the tank is full of dense, propane liquid which then evaporates to fill the remainder of the tank volume with propane gas - that's why it's important to always keep tanks upright so that gas, not liquid, comes out of the valve and all the safety features work as designed.

In cold weather, the propane doesn't evaporate as readily, meaning as the propane level gets lower, the gas pressure will drop until it gets so low that the regulator decides the tank is essentially empty. The result of this is that in very cold conditions, there could be ~2 gallons of liquid propane left in a 7 gallon tank when the regulator thinks it's empty.

A larger surface area means the propane can evaporate more easily so not only does a big 100 gallon tank store more propane in the first place, but it's not as liable to cutting out early due to low pressure.

In the very cold conditions we have here in Vermont during the winter, we may burn 1-2 gallons of propane per day (especially because we don't have skirting this year). At that rate, a 7 gallon tank with only 5 gallons of usable capacity may only last a few days before it needs refilling.

As a point of reference, in the 12 months we were camping in Vermont last year we used a total of around 120 gallons of propane.

Bottom Line: A 100 gallon tank would give us plenty of capacity to use propane as much as we want without worrying about it running out, whereas our two 30lb tanks may last barely a week in the coldest times of year.

Refilling

The section above leads us neatly onto the next issue - the task of refilling itself. Tanks of all sizes, big and small, will need refilling at some point. But there's a big difference when it comes to how often they need refilling, and how to refill them.

The two propane tanks on our travel trailer are connected via a high-capacity regulator with an auto-switchover - a custom mod I installed a couple of years ago, and a big upgrade vs the lower capacity regulator we had previously.

Installing a High Capacity Propane Regulator

We upgraded our propane regulator to a high capacity model to ensure we can reliably run all the propane appliances in our RV.

Installing a High Capacity Propane Regulator

As long as both tank valves are open, when one tank runs out the regulator will seamless switch to the other tank, showing a red rather than green indicator so you know the first tank is empty. This works well, and means we're not going to run out of propane in the middle of the night, assuming we remember to regularly check to see if the tanks have switched over and one is empty!

But, you have to remember to check! We suddenly remembered to check at 6pm on Thursday last week and found we had one tank empty and the other partially full with temperatures forecast to drop to 2°F that night. Worse yet, I was going to be gone the entire following day, leaving Diana alone in the RV with no way to get to town to refill the propane. Fortunately we found somewhere still open to refill a tank for us!

Incidentally, for that very reason, we're considering getting the Mopeka Propane Tank Level Sensors which connect to your phone via Bluetooth to monitor your propane levels.

For us, refilling tanks means unscrewing it from the tongue of the trailer, putting it in the truck bed and taking it down to a propane refilling station. If you have a larger RV or motorhome, you may have a built-in propane tank, in which case removing the tank and having it refilled may not be an option.

By contrast, a tank provided by a propane company will be refilled on-site by the propane supplier, usually a truck that can either visit on demand or on a regular schedule, depending on your needs.

Bottom Line: Removing the tanks from the trailer and taking them to be refilled is an additional job that needs doing - and you have to remember to check the propane levels in the first place too! With a big tank, there's nothing to worry about, the supplier will take care of it for you.

Pressure

As I mentioned above, we upgraded our RV's propane regulator to a high capacity one, and it made a big difference to the propane pressure within the RV - our stove ran a little bit hotter, our outdoor grill had more power, etc.

Installing a Propane Quick Connect

This inexpensive and simple mod lets us easily run our Blackstone griddle directly from our onboard propane without clunky adapters or separate tanks.

Installing a Propane Quick Connect

What I wasn't expecting was that when we connected to the big tank, we had even more pressure! The difference wasn't huge, but it was noticeable - everything just burned a little hotter still.

It's most obvious when we have multiple appliances running at once, a common scenario in winter when we might have the propane furnace, water heater and stove running all at the same time.

Bottom Line: If you have a high capacity propane regulator, you may find you have a little more gas pressure available with a larger propane tank.

Flexibility

OK, this seems like a lot of benefits to having a big propane tank delivered, but there are a few downsides. First, is flexibility.

While we plan to spend this year focusing on our house build, we still want the ability to take our RV and go places - weekend trips, camping with friends or even maybe a vacation!

Full House...of Approved Permits!

Just 2 weeks before we return to Vermont to start construction, we finally have all the permits we need to clear trees and break ground!

Full House...of Approved Permits!

With the small tanks on our RV, that's no issue whatsoever. With a large, standalone tank it's a little trickier. It's certainly possible to disconnect and reconnect the tank when you want to move the RV, the propane company would much prefer to do it for you (and charge you a call-out fee) instead, and while I did do it myself fairly easily a few times last year, it's a bit of a pain to be honest.

Plus, at some point this year we're hoping to move our RV to a location further up the driveway. That will mean calling the propane company to disconnect the tank, relocate it to a new position, and then reconnect it. Additional hassle and expense.

Bottom Line: Small tanks mean we're not shackled to one spot but can move the RV wherever we want, whenever we want.

Cost

Right, the big one. Cost.

Last year, one of the reasons we chose to get a big 100 gallon propane tank was cost - buying propane in bulk was cheaper than refilling our 7 gallon tanks each time.

Things have changed a little since then and propane prices have risen...fast!

Our local propane supplier quoted us around $4.70 per gallon, which factors in the cost of tank rental, refilling, etc! In addition to the per gallon pricing, there may also additional installation charges and call-out fees associated with propane deliveries - depending on exactly what you need.

By contrast, Tractor Supply charges $3.95 per gallon to refill our tanks - and that's an area we pass through regularly so filling the tanks doesn't require a special trip or significant detour. Better yet, a local neighbor pointed us towards West Lebanon Feed & Supply who charge just $2.74 per gallon!

Pro Tip: One thing to watch for - it's not something we've seen elsewhere before, but around here in Vermont several stores charge for refills based on the size of the tank, regardless of how much propane they put in. Bearing in mind the point from before about residual propane liquid being left in the tank in cold weather, this may mean you pay for 7 gallons but only get 5 gallons!

Fortunately both Tractor Supply and West Lebanon Feed & Supply charge by the gallon, not by the tank size.

Bottom Line: A 100-gallon tank would cost around $470 in propane alone (not to mention other fees), where the same amount of propane would cost just $274 if we use our own 30lb tanks and refill them at a local supply store. That's a saving of almost $200!

Summary

Every situation is unique, and what made sense for us a little over a year ago doesn't make sense for us now. When we went through the pros and cons of each option, here's where we landed:

Advantages of Large Standalone Propane Tank

  1. Convenience: never have to worry about running out or refilling propane
  2. Pressure: a large tank maintains maximum pressure regardless of weather conditions or how many appliances we're using simultaneously

Advantages of RV's 30lb Propane Tanks

  1. Flexibility: we can move the RV whenever and wherever we want without having to worry about disconnecting and reconnecting the propane
  2. Cost: based on the current pricing, we could stand to save $$ by refilling our own tanks

While the weather right now in Vermont is cold, the weather will only get warmer on average over the next few months, which equates to lower propane consumption and less refilling. Refilling the tanks is an extra chore, but I don't have a problem lifting the tanks, they're easy to transport in the truck bed, and we've got several good (affordable) options nearby for refilling the tanks.

We went back and forth on the topic a few times, but eventually decided to stick with our own tanks and refill those. Before next winter we plan to either move the RV up to the house site if we complete the utility building, or head south for the winter - so either way, a large tank would need disconnecting and relocating or removing before winter.

If we find our plan doesn't work then we have the option to change at any time - we just call the local propane supplier and they can have a tank on-site within a couple of days. If we do move the RV up to the house-site and spend next winter on the property, then we'll almost certainly opt for the large propane tank as our usage during the cold winter months will be significant.

If you are relying on small tanks, especially in cold conditions when they'll need refilling more often, you may want to consider some propane tank level sensors too.

Photo by EJ Strat on Unsplash.

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