How do you heat water without electricity? What are the methods to heat water on your homestead? Can you build a DIY off grid water heater?
We are used to traditional water heating methods that use tons of electricity or natural gas. Both of these energy sources are not conventionally available in an off grid setting. However, there are so many ways to heat water naturally on your homestead, that by the end of this article you will feel confident that building an off grid water heater is not only easy, its pretty cheap as well!
We have become accustomed to having hot water at the turn of a faucet, but that nicety hasn't been around for long in our human history. The first gas water heater was invented in the 1890s, and the appliance didn't get mass adoption until the 1930s.
It is completely doable to live without a hot water heating system. You can boil water in a kettle, or simply go without.
But who wants to live without hot water?
As you will find out in your off-grid journey, anything requiring energy is expensive, time-consuming, and can break down. Energy is the most complicated piece of the off-grid puzzle, with heating and cooling usually being the biggest challenges.
This article discusses the best, most energy-efficient methods for off-grid hot water heater systems. Some of them are expensive, and some of them you have to build yourself. Some could be a temporary measure while you work on installing an upgraded water heating system.
Make sure to bookmark this article as there are several linked articles in this article that relates to each water heating method.
Off Grid Water Heater Energy Sources
As noted above, HVAC systems require tons of energy and are the most challenging systems in relation to the off grid lifestyle. As a homesteader, we strive to be independent of municipal utilities. However, running cooling and heating systems will require manufactured sources of energy, depending on how comfortable you want to live.
Every situation is different, so you have to decide what is right for you, what you can afford, and your resources.
How to Heat Water Without Electricity:
1. Propane - A convenient gas that can be delivered to your homestead but is not technically "off grid"
2. Direct Solar Heating - Using the power of the sun to directly heat up water in a collector
3. Wood Burning - The most off grid solution but you must stoke a fire whenever you need hot water
4. Electric Solar Conversion - Using solar panels and battery bank to run an electric water heater is possible
Using wood to heat your water is the most primitive and cost-effective energy resource. However, it is very time-consuming, and wood may not be readily available on your property.
Solar is also a cost-effective strategy for heating water, depending on how you plan to capture the solar. Some places do not have a lot of sun during the day, which could be problematic. And your water will cool off at night, so you will need a holding tank that keeps the water warm.
Propane is a fantastic energy source used by many off-grid folks for water heating. But propane is not cheap, and you have to either fetch it in town or have a company deliver it to you.
Electricity is not a good option for water heating as the appliances take up a TON of energy, which is a pretty big no-no when living off the grid. Although, I have come up with an electric method that may work for you if you have spare energy.
Let's dive into each energy system and discover the best methods for heating hot water off the grid for your situation.
1. Off-Grid Propane Hot Water Heater
Overview: I believe propane water heating is the most balanced method between living off the grid and having convenient comfort.
Although propane "technically" is not off the grid because you have to rely on another entity to provide you with energy, it is a very effective method for heating your water, and many off-grid folks use it. That is what I use to heat my hot water!
Propane tankless water heaters are readily available and not all that expensive. Many rural communities have local, private propane distributors that will install a large propane tank on your property and travel to your location to keep your propane tank full. You can also transport your propane tanks to the shop for refilling, but that is way less convenient.
Unfortunately, propane is getting more expensive as the demand for gas increases, especially over the winter. However, you can offset this cost by learning to live with less hot water.
One easy way of using less hot water is to turn off your water intermittently in the shower. You can get a showerhead with a pause button and pause the water when you are soaping up. This is what I do, and I save a TON of water and propane!
Here is a highly rated and affordable pausing shower head - product link.
Off-Grid Propane Tankless Water Heater
Propane tankless water heaters have become very popular due to their energy-saving design and on-demand hot water.
When you use a tankless heater, you have endless hot water. This is because the water goes through super hot coils to heat up instantly compared to traditional waters heaters where the water just sits in a tank and gets depleted as you use it.
Since tankless propane water heaters are on-demand, you use less energy as the appliance only heats the water when in use.
Tankless propane water heaters last almost twice as long as traditional water heaters do, and they usually come with a solid factory warranty for several years.
Note that you will need professional installation unless you are a licensed gas plumber.
How much propane does an indoor propane tankless water heater use?
There are several factors dictating how much propane your tank will use. The water heater heats up to 120 degrees. How many BTUs it takes to get to that temperature is mainly based on your climate. It is all about your groundwater temperature.
Let's use the Northern USA region as an example. It takes an average of 650 BTUs to heat one gallon of water through a tankless propane water heater at an average groundwater temperature of 42 degrees.
The average person in USA uses 12 gallons of hot water per day.
Multiply your BTUs by gallons:
650 BTUs X 12 gallons = 7,800 BTUs per person per day
Next, we figure out how many BTUs are in one pound of propane - it is 21,548 BTUs. Divide your BTUs per gallon of propane by daily personal usage:
21,548 / 7,800 = Around 3 days of usage per person, per pound of propane.
With these calculations, one pound of propane provides three days of hot water to the average person.
This figure can vary greatly depending on your region, seasonal water usage variations, how many people you have in your household, how many appliances are using the hot water, and how much hot water each person uses. So take the time and calculate your hot water usage to determine if a propane tankless water heater is right for your off-grid lifestyle.
Indoor VS Outdoor Propane Tankless Water Heater
As you start to shop around for propane tankless water heaters, you will notice that there are indoor models and outdoor models. The main difference is that outdoor models do not have to be vented because they are installed outdoors. However, if you purchase an indoor model, you will need to vent the water heater properly, which means boring holes through walls.
Another factor when choosing between an indoor or outdoor water heater is condensation. Indoor water heaters not only need to be vented, but condensation has to drain out as well, which means another hole in the wall.
Outdoor propane tankless water heaters do not require venting and can be cheaper than their indoor counterparts.
However, outdoor water heaters require more propane to heat the water in colder climates, especially throughout the winter. It could freeze the unit and cause irreparable damage. Not good!
Suppose you are building a new home and live in a cold climate, choosing an indoor tankless water heater that you install while building makes sense. If you add a tankless water heater to an existing build and live in a milder climate, then an outdoor heater makes good sense.
Want to know more about propane tankless water heaters? Read my article: Propane Tankless Water Heaters for Off Grid Living.
Indoor Propane Tankless Water Heater Product Recommendation
The Rinnai V65iP Propane Tankless Hot Water Heater provides a 6.5 GPM flow rate, accommodating a small to medium-sized cabin.
Outdoor Propane Tankless Water Heater Product Recommendation
Rinnai also makes a comparable outdoor tankless water heater. The V65eP model also provides a 6.5 GPM flow rate and works great in warmer climates.
Best Temporary Hot Water Heating Solution for Off Grid Living
This portable outdoor propane tankless water heater is excellent for very small cabins, camping trips, RVs, and temporary hot water while you are building your homestead. I actually own this unit and I love it. Just make sure to drain the water out of the unit if temperatures reach freezing points.
Let me know if you use a propane tankless water heater in your cabin or homestead by leaving a comment below!
2. Solar Hot Water Heater Systems
Watch my video on solar hot water heater systems!
Heating your water with the power of the sun is completely free and super effective. You would be amazed how BOILING HOT your water gets when it sits in the sun. I am sure you have experienced super hot water coming out of a hose that has sat in the sun all day. Imagine if the hose was black, it gets even more hot!
A great example of solar water heating comes from the country of Israel. A whopping 85% of citizens use a "dud shemesh", or sun boiler, which is a simple device that heats a panel full of water in the direct sunlight. That heated water is then circulated into a tank through convection. Less than 1% of Americans use a solar water heater, despite the push to become more energy efficient (source).
A solar collector circulates hot water through tubing that sits in the sun, and then sends the heated water into your pre-existing water heater, or to a special water heater built specifically for the system.
These prebuilt solar collectors can be quite expensive and some require professional installation.
Some systems are easy to install and plug right into your hot water system. The nice thing about solar hot water heaters is that there are no moving parts that can break down, so the unit is virtually maintenance free. You can also get a clean energy rebate for your purchase (check with your local jurisdiction for energy rebates).
Learn even more about solar hot water heaters in my new article!
Building a DIY Solar Hot Water Collector with a Holding Tank
To build a solar hot water heater, you will need a few key components such as a collector to capture the sun's energy, insulation materials to reduce heat loss, and a storage tank to hold the hot water.
First things first, let's build that collector! You'll need to mount a metal or glass panel on a frame, add some insulation to the back and sides, and angle it just right so it can soak up as much sunshine as possible. Then, connect it to the storage tank with pipes. Don't forget to wrap the tank some insulation so the heat doesn't escape. You can also store the tank indoors or build a small insulated housing unit around the tank to keep the warmth from escaping.
Finally, you'll want to install a system to circulate the water between the collector and the storage tank. This can be done using a pump or by utilizing gravity. If you do want to use gravity, you will need to embrace the process of convection.
Convection happens when water is heated. When the water heats up, it rises and carries the heat with it, creating a continuous cycle of flow. As you can see in the photo above, the tank must be placed above the collector in order for the hot water to rise up and be collected.
Solar Water Heating Panels For Sale
Although there are not many models available in the USA, I have found a couple that are worth mentioning.
The Sunbank makes a 40 gallon hot water heating panel system that has no moving parts, does not use glycol, and is insulated so the heated water stays hot all throughout the night.
It is an easy installation for a handy person knowledgeable about basic plumbing techniques. The unit is a couple of thousand bucks, but is eligible for a 30% tax rebate, so check with your local jurisdiction for that hefty rebate.
The Heliatos hybrid hot water solar panel kit plugs directly into your existing hot water heater. Its a hybrid system, so you can still use your original water heater on cloudy days. This solar water heater is less than a thousand bucks and would work well with a small cabin. You can always add more solar hot water heating panels if your hot water needs demand so.
You can use a solar water heating system that is designed for pools, just plumb it into a holding tank. the water should get nice and hot, especially if you place them on top of a pitched roof. I wouldn't necessarily drink the water directly from this system, although it is poly which is a common water pipe material. The water should be completely safe for washing and bathing.
Off Grid Project: DIY Solar Hot Water Heater
Don't want to spend thousands on a manufactured solar heating panel system? Build one yourself for pennies!
The method is quite simple:
- Find a used, broken traditional water heater. You can find one for free at landfills, building supply stores, and local appliance shops. They can't even give these things away!
- Strip away all the bits and pieces until you are left with a bare tank.
- Paint that tank completely black.
- Place the tank in a wooden frame, lined with reflectix. Place a pane of glass on top, you can salvage one from an old window, or sliding glass door.
- Connect a hose into the tank and fill it with water. You can connect an output hose that gets pumped into your pre-existing hot water heater.
- Let that baby bake in the sun, and you will have piping hot water!
3. Off the Grid Wood-Burning Hot Water Heater
A wood burning hot water heater is a great choice for those living off-grid as it provides a reliable source of hot water without relying on electricity or other fuel sources. It is a self-sufficient and sustainable option that allows you to utilize readily available resources such as fallen trees or branches. Additionally, wood is a renewable fuel source that is often cheaper and more accessible than other heating options.
There are big disadvantages to using a wood-burning DIY hot water heater as your primary source of water heating. The primary drawback is the time and effort required to gather and chop wood, store it properly, and then load it into the heater. This can be especially challenging during harsh weather conditions. In addition, wood burners require regular cleaning and maintenance to keep them in good working condition and to prevent chimney fires.
Wood burning hot water heaters can be less energy efficient than other options and may require more fuel to achieve the desired temperature.
However, I think this option is great for a secondary backup to water heating if you lose access to propane, power, or sun for an extended time frame.
How to Build a DIY Wood Fired Hot Water Heater
There are so many creative DIY methods of building a wood fired hot water heater, but the basics always stay the same.
Basically, you have a coil that is heated by burning wood. Cold water enters the coil, gets heated by the hot smoke of the burning wood, and is routed into a pre-existing hot water heater, a hot water storage tank, or a range boiler.
A range boiler is an antiquated, yet highly effective, way of routing cold water into the heating coils of your wood burning stove and routing the hot water back into the tank for use.
The cold water in the range boiler sits at the bottom of the tank, while the hot water rises to the top of the tank. Convection replaces the need for water pumps.
Range boilers are not so easy to come by, so you can build one yourself with a discarded hot water heater. You can read this article about how to adapt an old hot water heater tank into a range boiler.
Here is a real life example of the wood fired hot water heater using a homemade range boiler:
There are many other methods for making a DIY wood fired hot water heater. Let's go over some more simple designs for off grid hot water heater systems.
This is a primitive coil water heating method for heating up water in a hot tub. It uses basic convection like a range boiler does. The cold water sinks to the bottom of the tub, routes through the coils, gets heated up, and circulates the hot water back into the tub.
This old guy got really creative and put a couple of metal barrels on top of a kiln to make off grid hot water. Instead of using coils, you can directly heat a tank of hot water for the same effect.
You can use a rocket stove to heat up water by placing the copper tubing in the chimney of the stove.
As you can see, there are so many great ways to build a diy off grid wood burning hot water heater. The only downside is that you will have to stoke the fire first before you get any hot water. It takes a little bit of time to get the water to temp, so make sure to preemptively plan your hot showers.
4. Electric Water Heating Systems for Off Grid Living
As someone who's been in the off-grid living game for a while, I've seen a lot of changes in the world of hot water heaters. One development that's been particularly exciting is the improvement of electric tankless water heaters. When I first started out, electric tankless heaters weren't really an option for off-grid use because they required too much power. But these days, they've become much more energy efficient, making them a viable choice for those of us living off the grid.
Not only do these new electric tankless heaters use less power, but they also provide a steady flow of hot water, so you don't have to worry about running out in the middle of a shower. And because they don't have a tank, they take up less space, making them a great option for those with limited room. Plus, with no tank to worry about, you'll never have to deal with the hassle of replacing a leaky or rusty tank.
Electric tankless hot water heaters are now a viable option for small hot water uses, such as in a cabin or RV.
Calculating the Draw of a Tankless Electric Water Heater on an Off Grid Battery Bank
Before you get too excited about having an electric tankless water heater in your cabin, you need to accurately calculate how big you battery bank will need to be to support the electrical draw from the water heater.
In this example, we will look at the EcoSmart ECO 11 Electric Tankless Water Heater which needs 13KW at 240 Volts.
Number of batteries = Total power draw in Watts / (Battery voltage x Battery capacity in Ah)
Assuming a 12V battery, the number of batteries can be calculated as follows:
Number of batteries = 13,000 Watts / (12 Volts x 100 Ah)
Number of batteries = 13,000 / 1200 = 10.83
Therefore, you would need at least 11 100 Ah batteries to support a 13 kW draw.
Now this is just covering the battery bank. You will also need the proper electrical infrastructure to ensure you don't blow your expensive off grid solar power system. Here are the electrical specifications required for the 13KW electric tankless water heater:
Now I am not an electrician and I struggle with understanding my own solar power equipment, so I cannot give you advice on how you would set up the infrastructure in your off grid electric system in order to facilitate a tankless electric water system. However, just a few years ago this type of water heater didn't really exist with the efficient capacities as we see now. So its definitely an option for those that are interested!
Electric Tankless Water Heater Product Recommendation
As used in our example above, I recommend the EcoSmart electric tankless water heater.
This water heater has a compact design that saves space, heats water on demand for energy efficiency, and provides enough hot water output for a small cabin or homestead.
Point-Of-Use Mini Tank Electric Water Heater
You can also look into one of these mini tank electric water heaters that would work for sinks and smaller water heating installations.
These mini tank water heaters range from holding 2.5 to 7 gallons of hot water and use 1400 watts for heating. These could be used for a small cabin, installing one for the kitchen and one for the bathroom.
More than two point-of-use heaters could add up to a heavy electrical load if you are not careful about when you are running the hot water.
It does use 13KW of electricity which is still quite a bit, but it is a whole lot less than older generation electric tankless water heaters and there is a smaller option that uses only 8KW.
Bosch Electric Mini-Tank Water Heater
This is a 4 gallon point-of-use water heater that comes in under $200. This uses 1440 watts, which is a manageable electric load.
That is a lot of solar panels just to power the water heater! This does not account for energy loss from converting the power into A/C, nor does it account for cloudy days. As you can see, a traditional hot water tank is just not all that feasible for the off grid lifestyle.
Traditional Electric Tank Water Heaters on Solar Power
Using a traditional electric tank water heater on solar power can work for off grid installations, if you don't mind adding more panels to your system. .
It's important to consider the size of your electric tank water heater and your solar panel setup to ensure that you have enough power to consistently heat the water. A properly sized system can provide a steady flow of hot water, even on cloudy days.
While traditional electric tank water heaters may be less energy-efficient than tankless options, they still offer a convenient and reliable hot water source when powered by the sun. And with the added bonus of being able to store hot water for later use, it can be a practical choice for those living off-grid.
Traditional Tank Water Heater Solar Power Calculation
According to energyusecalculator.com, a traditional tank water heater uses 4,000 watts per day and runs for about 3 hours per day.
A 250-watt solar panel will provide 250 watts per hour when the sun is providing full direct sunlight for about 4 hours per day, equaling about 1000 watts per day output.
We divide our water heater watts per day usage by how many watts the solar panel provides:
4,000 / 1,000 = 4 250-watt solar panels
You also need to make sure that your battery bank can provide the 4,000 watt draw. As a rough estimate, if you have a 12V system and plan to discharge the batteries to 50% of their capacity, you would need around 8 100Ah batteries in parallel to support a 4000 watt draw for a few hours.
Here's a six gallon mini tank water heater that is good for quick showers and washing dishes. If you live in an RV, you know how to stretch six gallons of hot water!
In conclusion, there are many options for an off-grid water heating system, each with its own pros and cons. Whether you choose a solar hot water heater with a collector, a wood-burning system, an electric tankless option, or a traditional electric tank powered by the sun, you'll want to carefully consider your needs, budget, and the resources available to you.
Remember, the goal is to have a reliable and energy-efficient hot water source that will meet the needs of your household, so take the time to research, compare, and find the right solution for you. And don't be afraid to reach out to professionals for advice and installation help, especially when it comes to gas powered and electric appliances.
In the end, you'll be glad you did, because nothing beats a warm shower after toiling on the property all day!
If you have any questions or comments, please feel free to leave them below.
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