DIY Solar Water Heater

 
 

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Building a DIY solar water heater system is a great way to capture the sun's energy and save money on your hot water heating bill. Professionally installed solar heating systems can cost in the neighborhood of $9,000, but if you enjoy a DIY project you can build your own.

The hot water you collect can be used to fill a pool, hot tub, or even with your traditional heating system. This article will show you how to build a DIY solar water heater and provide you with other useful information you should know.


Soldered copper tubes

How to Build a DIY Solar Water Heater

Do a quick search on the Internet for DIY solar water heaters and you'll find plenty of different types you could build. We chose this style because it didn't require working with expensive copper tubing and soldering joints.

At the end of this article we'll provide you with several different methods so you can choose the type of project you want to tackle.

Buying Materials for DIY Solar Water Heater

Getting Started

Depending on your level of experience, you may have many of the necessary equipment and supplies on hand. 

You can find the material and equipment you'll need for this project HERE.

Trimming 2x4's on a Table Saw

Cut the Wood

  • Cut the plywood to 4' x 6' (the lumber store may do this for you)
  • Mark and cut the 2 x 4's (frame) to fit the plywood (you should have two 6-foot pieces and two 46-1/2 inches)
  • Cut the treated 4 x 4's (legs) to desired height
  • Using a table saw, re-saw the frame 2 x 4's to 3/4-inches - by doing this you'll be able to build two frames, one for the top (tubing) and one for the bottom (legs)
  • To make gluing easier, you can run each of the frame pieces through the table saw again this will straighten one side
Gluing the wood for the DIY Solar Water Heater

Build the Top Frame

  • Lay the plywood on a flat surface
  • Apply a wood glue (such as Titebond III) along one edge of the frame wood
  • Connect the frame piece with glue to the plywood and use a speed square to ensure its aligned properly. Use clamps to hold in place
  • Drill countersink holes through the plywood into your frame wood, and screw the pieces together. This video will explain how
  • Repeat with each piece of your frame and butt joint the joints together. This video will give you several different butt joint options
  • Run a bead of caulking where the frame connects to the plywood
Building the bottom frame

Build the Bottom Frame

  • Drill pocket holes into the bottom frame boards. This video explains how
  • Flip the plywood frame over so you can begin attaching the bottom frame
  • Use your impact driver to ensure all the screw heads are fully embedded from the top frame (bottom of the plywood)
  • Glue and screw the bottom frame pieces into place
  • Run a bead of caulking along the frame and plywood seam
  • Plug the pocket holes with pocket hole plugs, and trim the excess so they are flush. Use a sander or saw 
Paint the Solar Water Heater Frame

Paint the Frame

  • Paint the bottom frame edges where it could come in contact with another surface
  • Paint the outside of the bottom frame. It's not necessary to paint the entire bottom of the frame
  • Flip the frame over and paint all three sides of the top frame
  • Paint the plywood
  • Add a second coat 
Attaching the Zip Ties

Prep for Tubing

  • Find the center of your frame using a measuring tape. Draw a line through the center of the frame length wise and width wise so they meet in the dead center of the plywood
  • Using a small piece of wood, build a template that will allow you to drill the holes into the plywood in a uniform manner
  • For each zip tie, you'll need two holes to hold the tubing in place. One for input and another for output
  • On the center of each side, drill 12 holes so you can insert 6 zip ties
  • Thread the zip ties through the holes
Coiling the Tubing

Installing the Tubing

  • Starting with the zip tie closest to the outside of the frame, begin coiling the tubing. Use caution not to kink or tangle the tubing. This is best done with two people
  • Once you have coiled enough tubing to fill the 6 zip ties, drill more zip tie holes and continue coiling the tubing
  • At some point you will no longer be able to bend the tubing without kinking it. At this point you can switch to an oval shape within the tubing
  • When you have all the tubing coiled in the frame, feed the end through the out-feed hole
  • Use a pair of scissors to trim the zip ties

solar water heater mounted on brick roof

Advantages of Solar Water Heaters

Here are a few of the benefits to owning a solar water heater:

Cost Efficiency

Do you like the thought of free energy? Well a solar water heater will allow you to harness the energy from the sun and reduce your electrical bill as much as 50% for electric water heaters.

If you live in an area where there's plenty of sun shine, such as Texas or Arizona, then your water heating bill could drop as much as 90%!

Carbon Footprint Reduction

Heating your water with a solar water heater will not only reduce your electric and gas bill, it'll also reduce your carbon footprint.

Traditional gas and electric water heaters use and release natural gas or fossil fuel into the atmosphere. Using a solar water heater does neither. Which means you get to save money while helping save the environment. How cool is that!

Fewer Solar Panels

If you want to take advantage of solar energy, but aren't thrilled with the idea of covering your entire roof with solar panels. You can make a huge impact on reducing your energy bills by simply switching your water heating to solar.

One to three solar panels is all it takes to power the average household solar water heater, and with fewer solar panels the installation costs will also be less.

Little to No Maintenance

There's very little maintenance required after you install a solar hot water system.

As a safety precaution, every few years you should replace the circulated antifreeze and hire a contractor to inspect they system. But beyond that, there's really nothing else you need to do.

It's not uncommon to see solar water heaters last over 20 years!

what are disadvantages of solar water heaters

Disadvantages of Solar Water Heaters

Initial Costs

We're not going to lie, adding a solar water heater to your home isn't cheap. Although every install is unique, $9,000 is a good rough estimate. 

The good news is, you maybe able to qualify for tax credits or rebates to help offset the initial costs. Learn more about federal programs here, and there may even be incentives at your state level.

Climate Impacts Performance

Solar water heater systems include either a gas or electric back-up water heater to prevent you from running out of hot water in cloudy or snowy days.

Although you can install a solar system in any climate, it's important to recognize that if you live in a sunny area, like Arizona, your back-up heater won't be used as frequently. 

Only for Hot Water

It may seem like a no brainer that a solar hot water system can only be used for hot water, but it is worth mentioning. You won't be able to power your electric appliances with the solar panels.

In order to attain "usage electricity" to your home from solar panels, you need to install a photovoltaic solar energy system. If you have an electric water heater you may want to consider going this route instead.

tools needed for copper cutting and soldering

How to Make a Solar DIY Water Heater

Tools and Equipment

Electric Drill

Get yourself an adjustable drill as this will work best for accommodating your specific project needs. Make sure that it is suitable for drilling wood, plastic and metal surfaces.

Forstner Drill Bits

Forstner drill bits are great for making holes in metal and plastic materials. These can also be used for drilling holes in the storage tanks, as well as making the holes for your input and output water pipes.

Screwdriver Set

Get yourself a quality screwdriver set that has a variety of screwdriver styles (slow, cross, torx etc..).

Right Angle Clamps

These are optional, but will end up being useful for making precise 90 degree angles that will not need to be held together with your hands.

Saw

Get yourself a simple hand saw that will cut wood and metal effectively. You can opt for a circular electric saw for added efficiency.

Metal Sheet Scissors

These will be great for cutting sheet metal (aluminum, tin etc..)

Copper Tubing Cutter

These will be used to cut copper tubing.

Paintbrush

Grab yourself a good quality paintbrush for painting the copper pipes, inner walls of the collector tank and the absorber plate.

Burner & Soldering Equipment

This equipment will be used to solder the copper tubes together. It will include a burner, soldering equipment and soldering paste flux.

Pipe Welding Equipment

This equipment will be used to weld a variety of pipes throughout the build.

Copper Pipe Bending Tool

This will be used to bend the copper piping into the appropriate shape.

Pipe Cutting Scissors

These specialty scissors are used to cut the specific type of piping involved in the solar water heater build.

Traditional Tools

These will include hammers, measuring tools, meters, scalpel, wrench, clamps etc..

Safety Equipment

This will include safety goggles, gloves etc..

Materials

  • Treated wooden planks
  • Transparent cover glass
  • Aluminum sheet
  • Aluminum L profile
  • Aluminum foil
  • Copper tubes
  • Insulating material
  • Hot water storage barrels
  • Matte glass paint
  • Silicone
  • Screws
  • Check valve
  • Adapters, rubber seals, valves
  • Thread seal paper
  • PP-R pipes
  • Tape and plastic wrap

Step-By-Step Guide

join wood planks
  1. Design and construct the wooden frame for your solar tank. One side should be inclined so that the glazing can have maximum sun exposure.
  2. Now it is time to build the sides or the walls of the heater box using your plywood planks. The inside of the box should be covered with some sort of insulating material (styrofoam, fiberglass, aluminum etc..).
  3. The next step involves figuring out where the plumbing will be installed in your unit before building the heater box itself. You will also need to determine where the designated openings for incoming and outgoing water pipes will be located. Once you have determined all of this, go ahead and install your plumbing system.
  4. Now, you should insulate your piping in order to reduce the amount of heat and energy loss experienced by your system.
  5. This final step involves covering your solar water heater box, which is also known as glazing. There are a few good materials you can use for this such as fiberglass, acrylic and tempered glass. The main point of this step is to maximize the sun’s heat as it passes through the      cover, and a the same time reduce the amount of heat loss experienced. Tempered glass is a great option as it delivers in both of these areas.
  6. Now it is time to determine the efficiency of your solar water heater system. If you are using an older heater, you will need to get ride of the old pipe fittings and check the inside for leftover sediment.

You will also need to install all of your new pipe fittings, drains and your pressure release valve. You will also want to install all connectors in order to concentrate the sun’s light, which includes the insulation shutter and any other heat loss protection.

When you have finished, seal all of the exposed surfaces by distributing a layer of silicone along all joints and connections.

How to Install a DIY Solar Water Heater

Your DIY solar water heater will essentially be circulating solar heated water through a loop of plumbing that runs from the roof-panels to the heat exchanger.

As a result, you will be installing a pump that facilitates this hot water circulation throughout the household to the critical areas that are in need. Fittings tapped into the reservoir allow it to be placed inline between the city’s water source and the cold water inlet pipe that feeds to your water heater.

It is highly recommended that you seek out the help of a professional who can install the DIY solar water heater for you properly.

It is important not to make any mistakes during installation as this could cause damage to the property and end up costing a lot more than you stand to save with a DIY solar water heater project!

Finding The Perfect Location For DIY Solar Water Heater

Finding the Perfect Location for DIY Solar Water Heater

Finding the perfect location for your DIY solar water heater will involve determining where your water heater system’s collectors should be facing. This will depend on where you are geographically, and as a result where they will receive most exposure to the sun on a consistent basis.

A south facing location for the collectors will often provide the ideal set up in order to maximize energy potential. East and west facing locations can also be effective, but they will sometimes need some sort of tilt kit in order to provide the ideal angle that can take on maximum sunlight exposure.

It is also important to consider any shade producing structures, whether they are natural or man made, that will block the sun from reaching your solar water heater system’s collector tanks.

Things like trees, bushes, fences, buildings or anything else that may get in the way of direct sunlight should be considered and avoided when deciding on the location for your DIY solar water heater.

Conclusion

Water heaters are an incredibly important part of any household that is in need of a consistent flow of hot water to function.

Some water heaters will inherently be more effective, efficient and expensive than others, depending on their style.

In this article we talked about solar water heaters, and more specifically, DIY solar water heater systems. We covered the relative advantages and disadvantages of solar water heaters, and discussed the reasons why building your own DIY solar water heater can be very beneficial.

Next, a detailed guide that outlines the tools, materials and actionables required to build your very own DIY solar water heater system from start to finish was provided.

We hope that you have learned everything you need to know about building a DIY solar water heater.

Thanks for reading!

References


Drilling holes for the legs

Attaching the Legs

  • Find the center of the board, use a 1/2" spacer identify the spot where you will drill a 3/8" hole that will go through the lumber
  • Connect each leg to the frame with a 3/8" lag bolt
  • You can add a 2 X 4 on each side to prevent the legs from wobbling if necessary
  • Attach a small 2" x 4" in the center of the tubing and paint it black
  • Paint the four legs black

Acrylic Sheet

  • Leaving the protective film on the acrylic sheet, place it on top of the frame
  • Use a plastic drill bit to drill holes through the acrylic sheet 
  • Then, using a regular drill bit, re-drill the holes into the wood
  • Remove the acrylic sheet and vacuum out the inside of the tubing area
  • Remove the one side of the protective film from the acrylic sheet and place it back on top of the frame
  • Secure it in place using 1-1/4" deck screws
  • Remove the protective film from the top of the acrylic sheet
  • Attach hose connectors to the in-feed and out-feed of the solar panel heater

After building your solar panel you can use it to heat water for a pool, hot tub, or even store it in an old water heater tank to use for your home. 

An old electric water heater can be used. Simply remove the outer shell and insulation and old pipe fittings. While you have the tank stripped down, it's a good idea to flush it out to remove any sediment that might be inside.

Next, paint your tank flat black. This will increase the heat absorption.

Replace the pipe fittings, temperature/pressure relief valve, and the drain. Then seal joints and connections with silicone, and connect the heater to your solar panel.

Your DIY solar water heater will heat the water as it flows through the panel and collect in your water heater where the sun will keep it warm.

Watch the Video

Material List

  • One 4 x 8 Sheet of 1/2" exterior plywood 
  • Four kiln-dried 2 x 4 x 8 (for the frame)
  • Four treated 4 x 4 x 8 (for the legs)
  • Wood glue (we recommend Titebond III)
  • Caulking
  • Pocket hole plugs
  • Exterior Latex Rustoleum - Flat Black
  • 500-foot role of irrigation tubing
  • Zip ties
  • Lag Bolts (4)
  • Acrylic Sheet (1/16" thick)
  • 1-1/4" deck screws
  • Hose connectors

Equipment List

  • Table Saw
  • Skill or miter saw
  • Speed square
  • Clamps
  • Drill
  • Countersink bit
  • Pocket tool jig kit (guiding tool and bit)
  • Impact driver
  • Sander (optional)
  • Tape Measure
  • Scissors
  • Plastic drill bit

Alternate Method

How does a solar water heater work

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