Over the past couple of years, I've tried three different types of camp shower - the Solar Camp Shower, which is sold under a number of different brand names from many outlets, the Sea to Summit Pocket Shower, and the Ortlieb Water Bag with optional shower head. These are all black water containers that can be left in the sun for two or three hours, then hung up to provide a slow running but warm shower. If you search the web, you will find pictures of all of them. All three do the job, but there are differences in price, capacity, quality, and convenience of use.
On a sunny day during our UK summer, there is easily enough solar heat - about 1 kilowatt per square metre - to warm up the water in these bags. Instructions written on the Solar Camp Shower warn that, on really sunny days, the water can get too hot. I can confirm this. But what about the colder months? At home, I place the bag in a box lined with expanded polystyrene, and put a sheet of glass over the top. This increases the heat gain and final temperature, so a hot shower is available from March to October, as long as the sun shines for a few hours.
These are intended for use while camping or trekking, so a bit weird to talk of using one at home? If you have a secluded garden, and a tree or pole to hang it from, you can have a shower outdoors. It's a bit like having children, you can't really know what it's like until you have one. No need for shampoo, no need to get hair out of the plug hole, no clearing up to do. As long as you can arrange shelter from the wind, it's a refreshing experience. You might decide to give it a try.
The Solar Camp Shower is the cheapest of these three. If you search the web, it can be had for around £5 delivered, or you can pay more if you want to have a prestigious brand name printed on it. This device is a flat bag made of plastic which has a capacity of 20 litres - easily enough for two showers. The kit contains the bag, a tap and pipe attached to a small plastic shower head, a length of dowel to strengthen the top of the bag and help it maintain its shape, and a hook and line from which the bag can be suspended from a tree branch or building. The assembled kit can easily be rolled up for stowage and transport.
It is tricky to add water to this bag. If you can find a way of suspending the bag while filling it, things will be much easier, especially if you want to fill it to capacity. Remember that 20 litres of water weighs 20 kilos, and holding the bag up yourself while trying to pour water into it is quite a challenge unless you are a weight-lifter. You can put it down on its `back', but then the hole through which you have to fill it needs to be held above the rest of the bag. When you have got the water in, you still have to close the filler cap, which needs to be pressed onto the bag. If you don't get the bag in the right position, the water tends to squirt back out again when you press. Once full, it needs to be lifted above your head (obviously), and you will not be able to do that by throwing the line over a branch and pulling - you need to push the bag up at the same time, especially if it is anywhere near full.
There is not much to complain about at this price level. The line you get to suspend it from is quite thin, but it has proved strong enough. The tap is similar to the ones you find on a water butt - you turn a lever through 180 degrees to turn it on. The clear pipe through which the water runs before reaching the small shower head is quite long. This allows you to direct the water to any part of your body. The water pressure decreases during your shower because the level of water in the bag decreases, but there is no accurate way of altering the pressure by altering the flow through the shower head. The weakness of this system only emerges after a year or so. The tap begins to seize, and I have broken off the lever on one of these while attempting to turn it on. I have not been able to buy a replacement tap.
Sea to Summit make a `pocket shower' which is, as the name suggests, very compact. It is a black fabric tube with a 10 litre capacity, closed at one end by a small shower head, and open at the other end. This large opening is very easy to fill, and it is closed by folding over the top several times round a semi-rigid strap and securing it with a pinch-clip. This construction resembles the water-tight containers familiar to canoeists. You will not find a lighter camp shower than this, or one that packs smaller. It can be suspended from two small rings mounted on the strap next to the pinch-clip. The flow rate can be adjusted by rotating the shower head, and it makes a water-tight seal when closed. Other reviewers have mentioned that the head contains an O-ring, which will leak if over-tightened, so care is required. The cylindrical shape of this bag makes it more difficult than the others to lay flat so that it heats up effectively, though it can be done if don't want to use its full capacity. This is a high quality device that can be got for around £18, delivered, by shopping online.
The most expensive of these showers comes from Ortlieb, a German company probably best known for expensive waterproof cycle panniers. They manufacture a 10 litre Water Bag, made of extremely light but waterproof fabric. A matching shower head can be purchased for a couple of pounds. I got the bag and shower head together on-line for just over £25. A pair of straps with pinch-clips allow the bag to be hung either way up. This bag has only one opening. A large screw-on cap contains the spout and thus serves as a filler cap and a dispenser. The shower head is easily screwed onto the spout, turning the water bag into a shower. Being flat, the bag heats up quickly in the sun. It can be hung one way up to fill it, then hung the other way up to turn it into a shower. The spout adjustment can be used to regulate the flow rate. This, too, is a high quality shower, and I would expect it to last for many years.
All three devices work well, though the flow-rate is feeble. They deliver water at a rate of one to two litres a minute. If you expect these to rival a mains-fed shower (6 litres per minute from an `eco' shower head, and up to 30 litres per minute from a power shower), you will be disappointed. But with any of these, you can have a warm refreshing shower almost anywhere, as long as you can find five or ten litres of clean water and a few hours of sunlight.
If you just want to take one car-camping for the summer holidays, it's hard to fault the Solar Camp Shower. It will probably last a couple of seasons and it won't take up much space when you pack it. At some point, the tap will stick, and you will have to throw it out. If you are looking for versatility, longevity, lightness, and quality, and can afford to pay, then go for the Sea to Summit or the Ortlieb. If you anticipate filling the shower with water you have heated yourself, with a Kelly Kettle, say, then the Sea to Summit will meet your needs admirably as it is by far the easiest to fill. It is also packs the smallest, and if you are back-packing, this will suit you well. The Ortlieb has slightly bulkier fittings, but is less fiddly to use, having only the one opening. Whichever you choose, showering outdoors is a luxury you will learn to appreciate.