Solar Hot Water Systems

Table of Contents

  1. Description of the Technology
  2. State of the Industry
  3. Is a Solar Hot Water System Right for Me?
  4. Basic Numbers
  5. Benefits and Drawbacks
  6. Planning Issues and Regulations
  7. Setting Up and Operating a Solar Hot Water System
  8. Additional Resources

Description of the Technology

Solar hot water panels can be highly efficient, converting about 80 per cent of the energy that hits them into heat. Even on a cloudy day, they will produce some hot water, especially if they are oriented south or southwest to take maximum advantage of the sun's rays.

They can be used to provide at least a portion of the hot water you use for showers, dishwashers, clothes washers, farm operations and even in-floor heating.

A typical system consists of:

  1. A solar collector that can be mounted on roofs, walls or the ground
  2. A heat exchanger that extracts the heat that has been gathered
  3. A pump
  4. A storage tank for the heated water

Freeze-protected solar water heaters will keep generating hot water even when the mercury dips well below zero.

State of the Industry

Commercial solar hot water systems have been used for more than a century, and technology continues to improve. Each year, thousands of new systems are installed around the world.

Is a Solar Hot Water System Right for Me?

You'll need clear southern exposure from at least 10 am to 3 pm to make the most of the sun's energy. You'll also need enough room for a storage tank. If you're handy with tools, a simple panel isn't hard to create, or you can buy a more efficient commercial model.

Basic Numbers

According to the Integration of Renewable Energy on Farms website, a domestic hot water system costs $800-1,400 per person, installed and will pay for itself in savings over a period of 5 to 10 years. The average system has a life expectancy of 20 to 30 years.

Benefits and Drawbacks

Benefits:

  • Substantially reduces the amount of fuel you need to heat water
  • Requires minimal maintenance

Drawbacks:

  • Requires some form of supplementary heat (gas, electricity, wood, etc.) to meet all your hot water needs, particularly in the winter

Planning Issues and Regulations

Contact your local municipality to find out about any local approvals or permits required. If your solar collector measures 5 m2 or more, you may need a building permit. You'll also need a building permit to change your plumbing system.

Setting Up and Operating a Solar Hot Water System

Make sure your system is installed to CSA standards. If you have some experience in electrical systems, plumbing and carpentry, this is a job you may be able to handle yourself. Check to see whether installing the system yourself will affect the manufacturer's warranty.

Alternatively, choose a professional installer. The Canadian Solar Industries Association has a list of certified domestic hot water system installers.

Once your system is installed, check it monthly to make sure the pump is operating when the sun shines and the pipes are warm. If you have an antifreeze-filled collector, check the antifreeze every year or two, depending on the manufacturer's recommendation, and top it up or replace it as necessary.

Additional Resources

Publications and Websites

Natural Resources Canada has produced several excellent publications:

As well, you'll find good information on the Clean Air Foundation's Go Solar website, in OMAFRA's Solar Water Heating Systems, in the Solar Thermal Community Action Manual and on the solar water heating pages at the Integration of Renewable Energy on Farms website.

Online Maps and Tools

Natural Resources Canada provides online solar resource maps as well as WATSUN software, which models the performance of commercial and residential solar water heating systems.

Associations


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 22 April 2009
Last Reviewed: 22 January 2014