Portable water heater

Hot water wherever you want it – even far from home

Whether you’re on the road or far off the road, a portable water heater can give you the comfort of a hot shower and the convenience of hot water for dishes and other washing far from home. In this article I will cover the main types of portable water heaters and the advantages and drawbacks of each.

First, let’s clear up what we mean by portable water heaters: a device that can heat a small flow of water and that can easily be moved around. If you’re looking for information on tankless water heaters (which are permanently installed in a house or apartment, and heat water with electricity without using a water tank) you might want to check out my Electric tankless water heater page instead – or see Point of use water heaters for information on plug-in water heaters that provide hot water to a single indoor tap such as a bathroom faucet or kitchen faucet. And while they aren’t a main topic of this page, I do discuss immersion heaters briefly below. These are small electrical heating elements designed to be submerged in water in a coffee cup, or a bucket, or even a hot tub, depending on how much water you are trying to heat (and how big the immersion heater is).

Here are the main topics I will cover:

• Types of portable water heaters
• Heat sources
• Water pressure and flow
• Solar showers
• Immersion heaters
• My pick for best portable water heater

Types of portable water heaters

You can differentiate between types of portable water heater based on whether they heat a water flow or a water storage unit; the heat source; the cost of operation; and other factors. I cover many of these topics in more detail below so let’s start with the basics:

Flow-based or volume-based: Some types of portable water heater are used to heat a flow of water, typically coming from a pressurized source, while others heat a volume of water, such as the water inside a small tank. A third type combines flow and volume by having a storage area that sits atop the heater, and uses gravity to force a flow of water from the storage area through the heater.

Common flow-based portable water heaters are designed to connect to a length of garden hose. This type of portable water heater can work well if you are car camping at a campground that offers individual water hookups, or if you are near a body of relatively clear water that you can run a hose into, and you have an electrical hookup and a water pump to push a flow of water into the heater. One caution: if you’re using a pump you’ll need to ensure the pump pressure rating is enough to meet the requirements for the portable water heater. There’s no point getting a high flow rate water heater and coupling it with a weak pump; your water will run down to a trickle. The Eccotemp L5 portable water heater, described below under My pick for best portable water heater, is an excellent choice in this category.

A volume based portable water heater consists of a storage tank or bag, a heat source, and an outlet. For example Coleman makes an on demand portable water heater with a 5 gallon collapsible water bag. Fill the bag with water – or just put the hose in a bucket of water or other water source – and connect the pump. Then turn the dial on the heater. Within a few seconds hot water comes out the tap. Because the burner goes on and off withou a pilot light, and allows you to get small amounts of hot water in short bursts, this portable water heater is handy for doing dishes and washing hands as well as showering.

Heat sources for a portable water heater can be propane, electricity, solar power, or even the heat from a campfire. Since this is one of the most important differentiators between types of portable water heater I cover heat sources in a separate section below.

Operating cost: You should consider the cost of the unit itself (and anything else you need to buy to get it working, such as a water pump, hose, extra connectors etc.) as well as the energy costs: both for the heat source and for the water pressure, if you need, for example, to power a water pump with a battery. For example, the Coleman on demand portable water heater requires Coleman canisters (or a propane tank) for the heat source, but comes with a custom rechargeable battery to operate the pump. But if you’re away from an electricity source or a week or more at a time, or make a lot of use of the heater, you’ll need additional rechargeable batteries to run the pump. Add up all these costs and you can be up above $300 for the portable water heater, accessories, and heat source for the first few showers. If you wind up not using the shower for more than a few days every summer during an annual camping trip, those can be pretty expensive showers!

Heat sources

Propane portable water heaters are the most popular because they provide instant heat, because propane is a compact and very portable energy source, and because they don’t require you to be near an electricity supply (or have access to strong sunlight). Propane is also the most costly heat source – especially if you buy the small camping canisters of propane – but most portable water heater units that use a propane heat source do come with an adapter to hook them up to a larger propane tank. Just don’t try dragging a big propane tank over a portage! Also, bear in mind that propane is a fossil gas that produces CO2 when burned, so using it contributes to climate change – but for the amount you’ll be showering or washing dishes on a camping trip, it probably contributes far less than a gasoline-powered car would take to get you to the trailhead!

Electricity is a cheap and convenient heat source if you will be hooked up to the grid when using your heater, but because most electric portable water heaters operate at 110 volts and need to operate at relatively low amperage, you won’t get a lot of heat output from them, which means their ability to heat water is limited: you will either find you get hot water at a trickle, or a steady flow of luke-warm water. Also, none of the electric portable water heaters I survey in this article are designed for outdoor use – they might be okay for a permanently installed outdoor shower or outdoor kitchen at a summer home, but the heater itself needs to be kept out of the elements.

Your best bet from an energy efficiency and operating cost point of view is a solar portable water heater. A solar shower consists of a large plastic or vinyl bag and a shower hose; you fill the bag with water and then leave out in the sun for an hour or so to let it warm up, then when you’re ready to shower, you hang the bag up above the shower area, for instance from a sailboat mast or a tree (depending on where you are) and gravity pulls the sun-heated water from the bag down through the hose.

You can even buy a fire powered portable water heater, for trips where you have a campfire and want hot water to do dishes in the evening, for example. The ZODI Outback Gear fire coil water heater (appears to no longer be available for purchase) consists of a looped coil of metal piping connected to a hose at either end. You can connect each end to a water tank such as a Coleman plastic bag water tank. Fill one tank with water and place it above both the coils and the other tank. Then place the metal coils into the heat of a campfire. Gravity pushes the water down through the coils and, through the siphon effect, back up to the second container. It may take a couple of runs through (reversing the upper and lower tanks) to get the water hot enough.

While this sounds like a creative invention, I’m not convinced this is a great investment even at a mere $40 or so, since you have to buy the two containers, have to move heavy containers of water up and down to get enough pressure to push water through the coils for heating, and have to worry about maintaining the fire (and possibly scalding yourself if the water gets too hot!). I’ve done many camping trips, and we never had a problem making hot water with our version of a portable water heater – the biggest pot in the pot set, put over the fire. A hot fire can boil 2-3 gallons of water in under ten minutes! The main problem we usually have is not getting the water hot, but remembering to dilute it with cold water before we start on the dishes, so we don’t burn our hands!

Water pressure and flow

A typical portable water heater is designed to operate at relatively low water flows, because you normally have a limited heat source, and pumping a lot of cold water past a weak heat source tends not to warm it very much. But while low flow is the norm for a portable water heater, you may still need strong pressure, particularly for the propane-based units which often shut off when insufficient water pressure is detected.

Providing that steady water pressure can be a challenge in a camping environment, but if you do have an electrical hookup you can augment the normal pressure of your water supply with a water pump. In fact you can even set the pump up to draw water straight out of a lake or river – as long as you put a strainer on the intake before the water gets to the pump, and you’re careful not to use the output of the heater for cooking or drinking. Another option for a more permanent installation – such as the backup portable water heater for a cabin – is to install a one-way valve and pressure tank between the pump and the heater, so that the pump can pressurize the tank when there is power, and after a power outage you have enough pressure left over, when power fails and the pump stops, to provide a 10-minute shower. Another alternative for areas prone to longer power failures is to use a battery powered pump, although you will need plenty of battery juice to keep such a pump operating.

Finally, you can use the approach that folks have used for generations at summer cottages: build yourself a miniature water tower, and pump water from the lake or river up into the water tower. If the water tower is far enough up a hill you’ll have plenty of water pressure, and if it’s big enough you’ll have enough water for weeks of showers and dishwashing even if the power is out the whole time.

Solar showers

You’ll get not much more than a trickle of hot water from most solar showers, but if you’ve ever been on a week-long canoe trip as I have, you can imagine how good that trickle of hot water feels towards the end of the trip when your entire body is caked in campfire soot, pine sap and grime from portages, and your fingers are stained a dark purple from too many blueberries!

My aunt was a missionary in Thailand for forty-five years, and for much of that time she used an early incarnation of the solar bag shower in her hut in a small Yao village, If you don’t have access to running water or a heat source like propane or electricity, and you can get by with a very modest flow of hot water, a solar shower is a great investment: for $30 to $50 and about 1 lb of packed weight, you can carry luxury with you wherever you go. Just don’t try using it for an early morning shower, unless there’s been a full moon! (Just kidding – you do want to make sure to leave it out in strong sunlight for an hour or so before using it, unless you like your showers cold. Lunar heating just isn’t a thing!)

Some of the best solar showers on the market are of the Advanced Elements Summer Shower brand, which come in sizes ranging from 2.5 to 510gallons. These are sturdily built solar showers that warm up quickly (because of their relatively small capacity) but still provide enough hot water for up to 5 showers in a row (if each person showering focuses on getting clean, not on soaking up the comfort of all that hot water!). For a small group travelling lightly, a Summer Shower is a great investment both from a money perspective and a weight perspective. The SunShower 5.0 (5 gallons) weighs around one pound. I’ll happily carry that over several mile-long portages so that I can have a hot shower on day 5 of a summer canoe trip!

For a bigger group, you can either pack several small solar showers, or pack one Summer Shower and take turns on different days (and pray for sunshine every day), or if you want everyone to shower every day (a good idea when you’re leading a trip of teenage boys across the arctic, and it’s too cold for swimming but you do have 24 hours of sunlight), you could pack the Advanced Elements 10 gallon summer shower, which even lets two people shower at the same time from separate hoses.

If you set up the shower as soon as you arrive at a campsite, and you ration the water carefully, you can get 4 or 6 people through one 10-gallon installment of solar-heated water.

Immersion heaters

An immersion heater typically consists of a coiled resistance heater that you plug into a line voltage power supply, and that heats up the element and the water it is immersed in. The smallest versions are often 12-volt DC units you can use to heat up a cup of water in your car – so you can make tea or instant coffee on a long drive without stopping. (Don’t try this if you’re the driver – let a passenger do the wet work for you!) Larger units are often called bucket immersion heaters, and are handy for heating up water outdoors enough that you can dip your hands in it without freezing your fingers solid. Immersion heaters aren’t really great for camping (unless you’ve got an electrical hookup) but they are handy around a house or cabin where you are close to a power supply but far from the hot water tank.

Immersion heaters are also good for specialized applications such as brewing beer (heat up the mash with a larger bucket immersion heater) or even a (very small) hot tub, if you don’t want to spend a fortune on a specialized hot tub heater. Be forewarned, however, that you should never immerse yourself (or any part thereof) in a water container while the immersion heater is in there. While they are designed to prevent electrocution, a little bit of loose wire or a badly made component may be all that separates you from the hereafter if you try that. And you might burn yourself too! No point becoming a boiled lobster.

My pick for best portable water heater

One of the best portable water heaters in this category is the Eccotemp L5. At just over $100 the Eccotemp portable water heater is a compact, lightweight heater that easily fits into a small section of your trunk storage if you’re travelling with it; you can also use it as a backup water heater if you have a remote cabin or cottage and normally heat your water with an electric water heater but need backup for those inevitable power outages. While it’s fairly heavy at 13 lbs – and the liquid propane tank you’ll need to bring with it is even heavier – it’s easy to install semi-permanently, and even easier to put up temporarily – just hang it up, install the 2 D-cell batteries (used to light the pilot light), connect the input water hose and the output shower head, and attach the gas line to the propane tank, and within 10 minutes you can be showering.

The Eccotemp L5 comes with a garden hose hookup, and as long as you can provide a steady flow of 20 to 80 PSI of water pressure, you will get a steady output of 1 to 1.5 gallons per minute of warm to scalding hot water. If the water supply is very cold, the unit will heat it to an almost comfortable temperature, while a warmer water supply can provide anything from comfort level to very hot depending on how you adjust the temperature setting.

Be careful if you go with a combination Eccotemp L5 portable water heater and water pump, to size the water pump appropriately. A low-capacity pump such as a 10 PSI 1 GPM pump can be made to work with the Eccotemp but with some difficulty. Such a pump is probably acceptable as a backup water pressure source for a cabin where you normally have pressurized tapwater when the power is running, but you’re better to go for a more powerful pump if that will be your main source of water pressure.

The Eccotemp L5 is solidly built, comes with a one-year warranty, and gets rave reviews from owners, especially folks who spend months at a time in a remote cabin or cottage, and those who do frequent car or RV camping.