How to Build a Solar Water Heater at Home – Basics

Discover tips and ideas on how to build a solar water heater (SWH). What you should know for a simple, almost free, and exciting homemade solar DIY project.

Building a solar water heater can be a great way to save money on your energy bills, but it can also be expensive, unsuccessful, and time-consuming if not done properly. That is why it is crucial to follow the expert and manufacturer’s instructions.

One of the ideas on How to Build a Solar Water Heater at Home

You can use materials you already have for this homemade DIY project, which is a more cost-effective option. Alternatively, you can purchase a kit that comes with proven results and detailed instructions on how to build your solar water heater. This is especially helpful if you’re new to DIY projects or don’t have much experience with solar energy.

How to Build a Solar Water Heater: Considerations

Basic Tips

To successfully build a solar water heater, proper planning is essential. You must be able to visualize and design a solar heating system, have a basic understanding of carpentry, plumbing, welding, or soldering, have the necessary tools and help, and be willing to learn.

So, how can you build a simple solar water heater?

One of the simplest ways is to use discarded drums or barrels painted with flat black paint. These drums can absorb the sun’s energy and heat the water inside. This idea can be improved by making it more efficient, such as by placing them in an insulated box with a glass or fiberglass cover and making small additions.

For more advanced units, consider building a solar water heater with a movable base that can change the angle and have better sun exposure during the day or a season. Additionally, the heater can be installed horizontally, vertically, or diagonally, depending on your preference, location, design, and viability.

When building your solar water heater, choose a location that is easiest for you to make and install, such as a garage or backyard. It’s best to build it in sections for easy transfer and assembling. For easier assembly, you can also purchase a mounting hardware kit.

How to Make a Simple and Almost Free Homemade Batch System

batch water heater is a type of passive solar water heating system where the storage tank and collector are combined into one unit. It is also known as an integrated collector storage (ICS) system.

The water is heated by the sun’s energy, which is absorbed by the collector and transferred to the water in the storage tank.

Batch water heaters are simple and cost-effective to build and maintain, making them a popular choice for DIY solar water heating projects. However, they are less efficient in cold climates where the water can freeze.

If you’re looking to save money on your energy bills and build a solar water heater, do your research and follow the instructions carefully.

Required Materials

Here is a list of materials needed to build a basic solar water heater:

  1. Solar collector (e.g., copper tubing, aluminum sheet)
  2. Insulation (e.g., fiberglass, polystyrene foam)
  3. Water tank (e.g., an old electric water heater, a custom-made tank)
  4. Glazing material (e.g., tempered glass, acrylic, polycarbonate)
  5. Wooden frame (e.g., 2×4 inch wood)
  6. Plumbing fittings (e.g., pipes, valves, connectors)
  7. Reflective material (e.g., aluminum foil, Mylar)
  8. Paint (e.g., flat black paint for the tank)
  9. Tools (e.g., saw, drill, screwdriver, pliers, wrench)
  10. Sealant (e.g., silicone, caulk)

Step 1

The first step in building a solar-powered water heater is to create a wooden frame for the solar tank and collector, using 2×4 inch lumber. When designing the frame, it’s important to consider the standard size of the insulation, cover, and other components that will be used. Additionally, the frame must provide strong support for the storage tank. One side of the frame should be angled to optimize sun exposure for the glazing.

Step 2

Build the walls or sides of the heater box using plywood or if you have any other material handy. The inside of the box should be covered with the materials like fiberglass insulation, Styrofoam, or aluminum.

Step 3

Before building the heater box, plan and design where to install the plumbing, including the opening for incoming water and exiting pipes. Consider how to connect it to the heating system and house plumbing.

Install plumbing fittings and pipes at the bottom of the tank for water coming from the house, and another set on the top of the sun-powered water heater in the backup unit, for example.

During and after building the heater, always check for leaks. When filling the heating system with water, make sure to remove all the air from the tank. Install a bleed valve and temperature relief valve in your heater. The drain pipes should run downhill consistently for easy drainage.

Step 4

Insulate the pipes to reduce energy and heat loss, so your built solar heater can be more energy efficient.

Step 5

The final step in your DIY solar water heater project is to cover the box. There are many effective materials available for glazing, such as acrylic, polycarbonate, fiberglass, glass, or tempered glass. The goal is to increase the sun’s heat through the cover while reducing heat loss.

We recommend using tempered glass as a cover because of its great characteristics. Talk to your local store to see what sizes they can provide so you can accurately design the solar heater box. If you order custom-made glass, it may cost more.

Step 6

In this step, you should focus on the details that will determine the efficiency of the system.

If you are using an old electric heater, strip off the outer enclosure and insulation, remove the old pipe fittings, and check the inside for sediment buildup. Clean the tank if necessary.

Paint the tank in flat black to increase heat absorption, and install pipe fittings, a drain, and a pressure release valve.

Seal all exposed surfaces, apply silicone along joints and connections, install reflectors to concentrate sunlight, and include insulation or a shutter at the top as heat loss protection. Then, your homemade solar hot water heater will be ready to use.

Videos on How to Build a Solar Water Heater

How to Build a Solar Water Heater Using Copper Pipes

How to Install a Cheap and Cost-Effective SWH Using a Black Hose

How to Build a Batch System

How to Build a Thermosyphon Water Heater System

The DIY solar hot water system described above is known as an integrated solar heating system, or simply the batch water heater, where the collector and storage tank are combined into one unit.

These systems are useful in warmer southern areas, while in colder northern climates, they are much less efficient and not recommended, as the water inside the tank can freeze.

Another option is to build a system where the solar panels or collectors are separate from the storage tank. These are usually called thermosyphon systems.

Here are the general steps to build a thermosyphon solar water heater:

Step 1

Gather materials: You will need a solar collector, storage tank, pipes, insulation, and plumbing fittings. The collector can be a flat-plate or evacuated tube collector, and the storage tank can be made of metal or plastic.

Step 2

Install the collector: The solar water heating system with panels can be installed on the roof, in the backyard, or wherever it is viable and where the site has excellent sun exposure.

The collector should be installed at an angle facing the sun, and connected to the storage tank with pipes.

Solar panels are made of black-painted copper pipes installed in the insulated collector box and covered with glazing made from clear plastic or window glass.

Again, it is important to orient the glazing almost perpendicular to the sunlight. As the water becomes warmer, it rises to the top of the panel and from there to the storage tank, using pipes.

Step 3

Install the storage tank: The storage tank should be installed at a higher elevation than the collector so that heated water can naturally flow from the collector to the tank.

It can be reused from an old electric heater and modified to accommodate a new design. If it is located outside, paint it black to attract even more of the sun’s heat, along with the panels.

Step 4

Connect plumbing fittings: Connect the incoming and outgoing water pipes to the storage tank, and install a drain valve and temperature relief valve.

Step 5

Insulate the system: The pipes, storage tank, and collector should be insulated to reduce heat loss.

Step 6

Test the system: Fill the system with water and check for leaks. Bleed the air from the system and make sure the temperature relief valve is working properly.


In conclusion, building a solar water heater can be a rewarding and cost-effective project, but it’s crucial to do your research and follow instructions carefully. Whether you decide to build it from scratch or use a kit, with the right guidance and materials, you can create an efficient and eco-friendly way to heat your water at home.

If you have other ideas on how to build a solar water heater, please click on this link and submit your ideas, designs, or help others achieve their goals in using renewable energy for water heating.

For more examples, plans, and additional information, please refer to the Wiki page.

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