10 DIY Solar Water Heater Plans That Cut Down Your Electricity Bills

If you’re looking for an efficient way to heat your water using solar, there are several DIY plans to consider.

The beauty of these DIY hacks is that they can save you from high energy bills while you enjoy a warm shower.

Some of these hacks don’t require glue or soldering, and for others, no technical know-how is needed.

Try These DIY Water Heater Plans

1. Beginner’s Solar Water Heater Plan

If you don’t have much electrical know-how and you’re a first-time DIY-er, this water heater could be the place to start.

The items you need:

  • Hose
  • Plywood
  • Tubing

First, coil the tubing and then attach it to the plywood. The length of the hose can be 100 feet or more.

Place the whole ensemble in a strategic place for maximum sunlight at a slanting angle.

The water can reach temperatures up to 133 degrees Fahrenheit after 30 minutes of sun exposure.

If you allow the hoses to get up to 90 minutes of sunlight, the water can heat up to 150 degrees Fahrenheit.

You can have one part of the tubing running to the house and the other coming out through a garden hose.


2. Solar Water Heater for Public Bathrooms


Usually, the water in a public bathroom can be chillingly cold. But, this heater ensures you have some warm water trickling on your hands in a public bathroom.

The materials you need:

  • Wooden box
  • Coil
  • Primer
  • Paint

The first step is to build the collector, which absorbs the sun’s heat and warms the fluid. You can use any type of wooden box to build a collector. Prime the box and then paint it.


Next, solder the coils onto the collector.

For efficiency, use glass to cover the collector box.

Check out the plan here.


3. Water Heater Using Plastic Bottles


Ever wonder what to do with your plastic bottles once you empty them?

One thing you can do is set up a water heater. Three people can comfortably use this water heater to shower.

What you need:

  • 20 plastic beer bottles
  • Hose pipes

How does it work? The beer bottles are joined to hose pipes. The sun heats the water from the hose pipes as it passes through the bottles into the shower.


4. Batch Solar Water Heater Plan


This solar water heater looks like a giant bathtub, and it does the job.

What you’ll need:

  • The core of a gas water heater (you can buy a used one)
  • Cattle trough
  • Frame
  • Pipes
  • Mirror

Make a frame inside the trough.

Place the core inside the frame so that it does not touch the sides of the trough. Drill three holes through which the pipes will run.

Fasten a big mirror onto the side of the trough so that it can reflect light as necessary. You can attach the mirror to the plywood. However, handle the mirror carefully to avoid cracks.

To get maximum sunlight, you can tilt the whole heater and support it underneath with a car jack.


If you want to increase the temperatures to about 210 degrees Fahrenheit, you can cover the trough with foil paper.

The batch option is a passive water heater. Passive water heaters are cheaper than most conventional types.

The only downside to a passive water heater is that it might not be as efficient as an active one. However, a passive heater is more reliable.

Check out the plan here.


5. Homemade Flat Panel Solar Water Heater


This water heater option offers a solar-thermal copper coil option.

The materials:

  • Plywood
  • Board
  • Wooden rods
  • Copper pipes
  • Glass
  • Copper tubings
  • Flatheads
  • Pipe to garden hose adapters
  • Nails
  • Dowels
  • Zip ties

You first arrange the copper tubing on the board in a circular pattern. Drill holes around the board and secure the copper tubing to these holes using zip ties.

Next, build the frame using dowels and plywood.

Then insert the board carrying the coils inside the frame. Drill holes through which the pipes will pass.

You then cover the frame with glass. You can use standard window glass or whatever works, depending on the frame size. Next, add the pipe to the garden hose adapters to the pipes for a neat finish.

Lastly, paint the collector box black.

You can add a handle if you want to carry it around easily.

It can heat water up to 171 degrees Fahrenheit.


6. Thermosiphon Water Heating System


For this water heating system, all you need is the sun and gravity. It works without a pump.

What you’ll need:

  • A collector box
  • Collector manifold
  • Copper grid
  • Aluminum roll
  • Insulation sheet

Once you’ve built the collector, make sure it’s connected to the storage tank in a sloping direction for efficiency.

As the sun rays hit the solar panel, the water in there heats up.

Now dense, the water rises to the storage tank.

Cool water then moves from the storage tank to the panel through the collector.


The upside of this option is that the water flow stops when the temperature in the collector is lower than in the tank.

The disadvantage of this water heater is that you can only use it in areas that do not freeze. Why? It doesn’t have freeze protection.

Learn more about this DIY hack.


7. Solar Water Heater Using Plastic Bottles


With this DIY hack, you can hit two birds with one stone. One, have a heating system for your home. Two, recycle plastic waste.

Besides, this system does not use pumps.

So, what do you need?

  • Plastic bottles
  • Cartons
  • 100mm PVC pipe and one of 20mm
  • PVC glue
  • PVC connectors, elbows, and end caps
  • Paint
  • Tape

Cut off the bottom of the bottles and run the pipes through them, creating a series.

The panels can be placed below the tank on a roof that is exposed to maximum sunlight.

For maximum efficiency, replace the bottles every five years, because the bottles are likely to become opaque over the years preventing maximum heat absorption.

Check out more details here.


8. Barrel Solar Water Heater Plan


You can easily convert a 45-gallon barrel into a water heater.

What you’ll need:

  • A barrel
  • Polycarbonate sheet
  • 5 inch PVC pipe
  • 2 caps
  • 2 reducer caps
  • Black paint
  • Bungs


Fix two bungs at the top and bottom of the barrel to attach to the solar panel.

Attach the PVC pipes to the top and bottom of the barrel. Fix the panel between the two PVC pipes. Seal the PVC type with a silicon bead.

Always ensure the water level in the barrel is higher than the top bung.

The polycarbonate allows water to flow to the top of the barrel.

Follow this plan to make your own barrel solar heater.


9. Solar Water Heater (Using an Old Fridge)


You probably didn’t know that you can use parts of your old fridge to make a solar water heater.

The materials you require:

  • Old fridge parts
  • Dowels
  • Glass
  • Aluminum foil
  • Rubber doormat
  • Hoses
  • Some tape

The back of a fridge absorbs a lot of heat because it is painted black, making it a perfect collector box for your water heater. You’ll need to cut out the grill before you start working.

Create a frame using the dowels.

Do the pipework, cover the collector with the glass, and seal any cracks using caulk, or use tape if caulk is unavailable. Use the doormat as the backing material.

Fix the hose to the end and entry ports.

This system can heat your water up to 110 degrees Fahrenheit.

You can use this DIY hack to make a water heater using old fridge parts.


10. Portable Solar Water Heater


If you’re always on the move and often find yourself off-grid, a portable solar heater might come in handy.

Here are the materials you’ll need:

  • Five-gallon bucket
  • Hose spit
  • Clear hose
  • Brass fitting
  • PVC fitting
  • Temperature gauge

Make your own portable solar water heater using these steps:

  1. Make a hole in the lid to avoid air locking.
  2. Fix the temperature gauge on the lid.
  3. Make holes in the bucket and fix the gasket on one of the holes.
  4. Attach the clear hose on the outside of the bucket.
  5. Screw a cord to the bucket from your solar panel.

Final Thoughts

DIY solar water heater plans are fun to build and save you the high costs of paying for hot water through electricity bills.

If you have never done a DIY, you can settle on the beginner’s solar plan.

But if you’re looking to build a bigger plan, go for the batch solar water heater.

Should you be working on a budget, create a solar water heater using plastic bottles, an old barrel, or parts of a discarded fridge.

The temperature of the water depends on the duration of sunlight exposure and the capacity of your system.

It’s time to cut down those energy bills and enjoy a free shower.


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