Joolca Hot Tub

[turnitdown]

There are a bunch of threads about the Joolca hot tap system, but I haven't found anything about the hot tub. Has anyone seen one of these in action, or heard anything (positive or negative) about it?

It's basically an inflatable hot tub made of that same rugged material stand-up paddle boards, inflatable kayaks, etc are made of. You use the Joolca Hottap to fill it and recirculate the water.It comes with a pump so you can draw water from a lake or stream, you don't need all that water on-board.

My use case would be wild camping in Scotland, specifically a hot tub under the stars after a hard day on the Munros. If would be awesome if it all works as advertised. I've found some YouTube reviews but they are very unsophisticated, e.g., no info about the temperature of the water going into the unit, for example, which is important.

If I got the hot tub, I'd get an underslung lpg tank (easy to fill here in Scotland). If I just get the shower, I'd use the 907s. So that would be an extra expense. But if I were sitting under the stars in Glen Affric in a hot tub in winter, I'd never think about the money.

The main things that I wonder about:

- how good it is at drawing water from lakes/streams in terms of hose length and rise

- how good it is at getting water hot when the water coming in is, say, 4C.

- whether there is a heating unit similar that works with salt water. There's a lot of ocean coast in Scotland and it would be brilliant to be able to use it instead of freshwater (maybe with a quick freshwater rinse afterward if need be)

 

[secret lemonade drinker]

It would be cheaper to rent a glamping pod with one attached, and wood fired

 

[turnitdown]

It would be cheaper to rent a glamping pod with one attached, and wood fired

Sure, if I only planned to use the hot tub a few times. That said, the appeal is partly to be in the middle of nowhere, not at a commercial campsite with other people, artificial lighting, tacky decorations, etc.

 

[lohr500]

Just my opinion and it doesn't help with your questions, but I think it is too bulky to transport around in a Cali where space is already at a premium, especially if matched to the Hot Tap water heater.
And then there is the practicality of finding a wild camping spot somewhere with a stream or lake to pump the water from.

I used a quick calculator on google to work out that you need 14.7kW to heat 350 litres from 4C to 40C assuming 100% efficiency.
No idea how efficient the Hot Tap heater is or what thermal losses you would get from the pipework and tub with the lid left on, but let's say 75%.
So you would need around 20kW of energy to heat it from 4C to 40C
1Kg propane equates to around 14kW, so roughly 1.4kG of gas for the initial heating.

I'm not smart enough to work out how long it would take the heater to raise the temp from 4 to 40 based on the heater specs!!

 

[turnitdown]

Just my opinion and it doesn't help with your questions, but I think it is too bulky to transport around in a Cali where space is already at a premium, especially if matched to the Hot Tap water heater.
And then there is the practicality of finding a wild camping spot somewhere with a stream or lake to pump the water from.

I used a quick calculator on google to work out that you need 14.7kW to heat 350 litres from 4C to 40C assuming 100% efficiency.
No idea how efficient the Hot Tap heater is or what thermal losses you would get from the pipework and tub with the lid left on, but let's say 75%.
So you would need around 20kW of energy to heat it from 4C to 40C
1Kg propane equates to around 14kW, so roughly 1.4kG of gas for the initial heating.

I'm not smart enough to work out how long it would take the heater to raise the temp from 4 to 40 based on the heater specs!!

Thanks. The space thing doesn't worry me much because these would be solo trips, and just for a night or two, rather than something where there'd be a whole family, weeks of stuff, and so on. I realise the thing is bulky but I would have minimum kit aside from it.

I do wonder more about the camping spots with lakes and streams. My sense is there are loads of wild camping spots like that in Scotland, especially if salt water is okay, but it could be a hassle. A lot would depend on just how close you need to be too, e.g. it's one thing to find a stream, it's another to be able to park within 6 metres of it (if indeed that were needed).

Joolca says "A 9kg gas bottle can get up to 15 hours of use and a 4kg up to 7 hours, this is on the gas being set to the highest settings." That's 0.6kg per hour and they say it takes 2 hrs to fill/heat the hot tub. If that's right it pretty closely matches your calculations. This would be too much £ if you were using 907 bottles but dirt cheap if you were using propane in an underslung tank.

Another option would be to forget about the underslung tank and get a refillable tank. That would make it easier to bring the hot tub to the water as well. But it involves yet another thing to transport plus I'm not crazy about having a refillable tank bouncing around in the Cali. That said, I'm on Edinburgh and it would be amazing to drive 20 minutes to the beaches in East Lothian, set up a hot tub 20 feet from the water, go for a swim and climb in the tub afterward. Over the years I can easily see getting a lot of value out of this set up even if it's still a niche application, not something I'm using or carrying with me all the time.

 

[Georgeo]

Just my opinion and it doesn't help with your questions, but I think it is too bulky to transport around in a Cali where space is already at a premium, especially if matched to the Hot Tap water heater.
And then there is the practicality of finding a wild camping spot somewhere with a stream or lake to pump the water from.

I used a quick calculator on google to work out that you need 14.7kW to heat 350 litres from 4C to 40C assuming 100% efficiency.
No idea how efficient the Hot Tap heater is or what thermal losses you would get from the pipework and tub with the lid left on, but let's say 75%.
So you would need around 20kW of energy to heat it from 4C to 40C
1Kg propane equates to around 14kW, so roughly 1.4kG of gas for the initial heating.

I'm not smart enough to work out how long it would take the heater to raise the temp from 4 to 40 based on the heater specs!!

Surely these calcs need a time component like kWh

 

[lohr500]

Surely these calcs need a time component like kWh

Agree. They do and that's the bit I can't work out from the hot tub heater specifications.
As an example, if it needs 20kW to heat the tub from 4c to 40c and the heater is capable of outputting 5kWh then it would take 4 hours to heat up.

 

[Mehdime]

Keep us updated if you ever give it a try. It’s unlikely I’ll ever try it myself as I suspect it’s far too much faff. But having a shower outdoor in the middle of nowhere overlooking some gorgeous scenery has been one of the greatest luxuries I've been able to enjoy with the California. A hot tub would be truly spectacular and I see why you’d want to give it a try.

Looking at the Joolca hot tub, the only thing I’d say is that it seems to be poorly designed from an enjoyment point of view (unless the goal is intimate time). It’s shaped like a regular bath - long and shallow. So you’ll have your bum wet and the rest of you outside freezing.

What you want from a small hot tub is something short and tall like this so that you’re sitting and fully immersed in water: https://amzn.eu/d/fs2SqUY

That’s actually what we had for years in our garden (and it was glorious) until we went ahead and installed a proper Japanese-style deep bath and hot water tap outside.

 

[turnitdown]

Agree. They do and that's the bit I can't work out from the hot tub heater specifications.
As an example, if it needs 20kW to heat the tub from 4c to 40c and the heater is capable of outputting 5kWh then it would take 4 hours to heat up.

They say it's 37,500 BTU output (in the UK), which is 11 kWh.

 

[turnitdown]

Keep us updated if you ever give it a try. It’s unlikely I’ll ever try it myself as I suspect it’s far too much faff. But having a shower outdoor in the middle of nowhere overlooking some gorgeous scenery has been one of the greatest luxuries I've been able to enjoy with the California. A hot tub would be truly spectacular and I see why you’d want to give it a try.

Looking at the Joolca hot tub, the only thing I’d say is that it seems to be poorly designed from an enjoyment point of view (unless the goal is intimate time). It’s shaped like a regular bath - long and shallow. So you’ll have your bum wet and the rest of you outside freezing.

What you want from a small hot tub is something short and tall like this so that you’re sitting and fully immersed in water: https://amzn.eu/d/fs2SqUY

That’s actually what we had for years in our garden (and it was glorious) until we went ahead and installed a proper Japanese-style deep bath and hot water tap outside.

Thanks. I hadn't registered the tub isn't very high. That's not ideal, although it's so long that it would be quite easy to lie back and be fully submerged, depending on how comfortable that position is.

It does strike that as not an ideal shape for one person, like do I really need 350 litres of water?

What I'd really like is a box that could be mounted on a tow bar that serves three purposes: box for transporting extra gear, on-site bench (so a lid that's good for sitting on), and an interior with l x w x d and interior lining that makes it suitable to use as a bath. I don't think this can be purchased off the shelf and I'm not sure how much hassle it would be to get one fabricated (probably a lot of hassle).