DIY Solar Hot Water System

About This Project

A big chunk of your utility bill comes from your hot water usage. With this simple DIY solar hot water system, you can greatly reduce or even eliminate your costs for hot water. 

This is my favorite DIY solar project that we have had much success with. Since installing this hybrid system at my own home, we have only paid an average of $3/month to the grid for hot water! The payback time for this system is much quicker than most solar projects.

This is a simple PV direct system that requires no batteries, charge controllers, inverters, etc. It also requires no pumps, piping, or plumbing, making it extremely easy to install.

While some folks are okay with connecting the solar directly to the water tank, I have found that the hot water controller is necessary to maximize production and prevent thermostat arcing. You will get a lot more heat for your investment with the controller!

Installation Video

How it Works

This simple PV Direct system provides you with solar hybrid hot water. Solar energy runs to the controller, which provides MPPT and prevents arcing for your thermostat. The controller is wired directly to the lower part of the heat tank which acts as a heat storage battery. 

You can use the heat produced by the PV Direct system for all of your hot water, and only rely on the grid when your usage exceeds what your solar is producing. If you’ve never done a solar DIY project before, this is a great place to start!

solar hot water


  • Affordable – if you’re starting with no supplies, it will cost just over $1,000 for a complete kit. This is extremely affordable compared to fluid based systems that can run at over $5,000
  • Simple – No batteries, inverters, or charge controllers, No pipes, pumps, or plumbing.
  • Saves money – Greatly reduce or even eliminate your hot water bill 
  • Reliable – The charge controller makes sure that you have hot water even on cloudy days, and no pipes means no freezing!
  • Upgradeable – Add more panels or units as you go, or take it completely off-grid
  • Eco-friendly – Using solar reduces CO2 emissions. Solar power is free, clean, and requires no fossil fuels to product

Materials List

  • 3-4 300W Panels (max 1400W)
  • Panel mounting + hardware
  • Hot water tank (existing tanks in most homes work)
  • Solar direct hot water controller
  • Heat sink (for controller)
  • PV cable (100 ft) and connectors
  • Disconnect

Installation Follow-Up

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