Hi,
we have a 90l fridge, no hot water and occasionally use the stove. Our 9kg bottles last between 20 and 28 days.
I have not read of anyone getting substantially more than 28 days.
So, based on my experience and that of
@Drover, a gas bottle will last between 8 and 28 days. How long you get will be based on a number of factors.
The most important is personal usage. Most of your gas usage will most probably be due to the fridge.
Note that three-way fridges are quite often not installed correctly and this has a major impact on the gas usage AND the performance of the fridge in hot weather.
A gas fridge does not have anywhere near the recovery capacity of a compressor fridge. So one cannot open the door all day, put in a slab of hot beer at midday after it has been baking in the boot of the car all day and expect it to be cold by 5pm.
Other questions you might like to ask, all of which will most probably have been answered many times and in great detail in other posts on the forum are:
1: How to ensure your fridge has been installed correctly?
2: Does having a shade cloth on the off-side of the van to keep the sun off improve the fridge performance? (YES!)
3: If my fridge does not have fridge fans in the back, should I install them? (YES!)
4: Does ice buildup on the fins in the refrigerator compartment affect the fridge performance? (YES!)
5: Can I reduce the ice buildup and keep the inside of the fridge at a more even temperature and avoid having vegetables (especially lettuce) from freezing? (YES!)
6: What performance should I get from the fridge on 240V and 12V?
7: Can I run my fridge on 12V from the van battery? (NO!)
7A; Can I run my fridge from the tug battery? (Definitely, but only if you understand what is needed OR find an auto electrican that can be trusted to do the job correctly)
8: What practices do people employ to get acceptable performance with a gas fridge?
9: Do I need to have, read, and understand the fridge manual? (YES, especially if you want to decrease your chances of having to cut a camping trip short because all the food in the fridge has gone off)
10: Should I get a temperature gauge to monitor the fridge/freezer temperatures? (Definitely recommended)
11: When operating the fridge when stationary, do I need to have the van level to have the fridge work correctly and avoid damaging it? (YES!)
When you get to the end of this list your last question might be: Why the hell did I not order the van with a 240V/12V compressor fridge? That is a very good question, unfortunately there is, at the moment, no simple answer. There are many possibilities and people are often quite passionate about the particular solution they have adopted.
My solution, at the time of purchase of our Penguin, 15 months ago, was to give the three-way fridge a go. With a bit of effort, we are quite happy with the performance. My personal feeling (and others will have different opinions, yet we are all basically correct) is that whether I go 3-way or 2-way they each have pluses and minuses:
three-way fridges:
It is good to know that once I have a new gas bottle, I am good to go for 20 or more days.
It is bad that once the outside temperature climbs above 35C, we have to be very careful and observant, otherwise the fridge temperature will climb past 6C.
2-way fridges:
It is good that they recover quickly and handle hot days MUCH better than a three-way fridge.
It is bad, that you will need to become an expert in keeping the 12V supplied to the fridge. This will most probably entail multiple batteries, a good working knowledge of solar panels and regulators, probably a combination of roof-mounted and portable panels, considering van position to ensure the panels get enough sun, a portable generator for when all else fails, and monitoring battery charging and usage currents, voltage and State of Charge.
So, in the end, you will be spending time and effort in one choice or the other.
A very common solution, is to have a bet both ways: Keep the three-way in the van, but also put a suitably sized Waeco/Engle portable in the back of the tug (usually to keep the beer, cider, and chardonnay cold).
cheers
Mike