I was glad to see your question. We often field questions concerning small wind and/or photovoltaic systems but seldom hear anyone ask about potable hot water.
I am a huge fan of solar water heating systems because of their relative simplicity, return on investment and life expectancy.
First you will need to decide what type of system you want to install. Some of your options include
- flat plate collector,
- evacuated tube,
- direct exchange, and
- indirect exchange.
Flat plate collectors are the least expensive. They require the least amount of maintenance. Evacuated tubes are more expensive but offer higher temperatures and efficiencies. Direct exchange may be an option in Central Florida if there is little chance of freezing temperatures (no actual freezes in the past 25 years). Indirect exchange involves recirculating antifreeze through the collector and exchanging the heat with a heat exchanger in the water storage tank.
I live in Michigan and have an indirect exchange, flat plate collector system. It has been in service since 1974. The only maintenance requirement is an antifreeze change every 5 years ($100). I'm getting close to replacing the storage tank, but that's not bad for a system that is 37 years old.
You can purchase a package system from companies like Rheem, Velux or Solar Roofs.com for around $8,000.
- Or you can do a little research and put your own system together for about half that.
- Solar Roof's system also has a solar power pump.
- Many solar water heating systems are eligible for a federal tax credit of 30%. Make sure the equipment you order has approved certification to qualify.
If you were to build your own system using a variety of components found on the Internet, you could save money in upfront costs but the design, install and service costs may be higher over the life of the equipment. Make certain the components qualify for any tax incentives and or rebates available in your state.
For a family of five in your zone, you will need about 75 square feet of collector plate and 100 gallons of storage.
If you have a typical 20 gallons per person per day hot water usage, this system has the capacity to provide 100% of your hot water needs.
Picking a solar hot water contractor
It is prudent to exercise the same caution in dealing with solar installers that you would in dealing with any contractor.
- Make sure they are experienced, licensed and carry the appropriate types of insurance.
- Take a look at their installations.
- Ask for references and talk with their former clients.
I like to check the references from clients that have had the equipment installed for at least two years. This gives me an idea of how much experience the contractor has as well as how they deal with problems that come up from time to time.
Good luck -- I'm sure you'll be thrilled with your solar water heating system if you do the necessary homework in selecting a contractor and equipment.
For more information:
Read "I've heard solar water heaters are expensive and easily damaged by winter freezes. Is this true?" a Q&A answered by Cameron Habel.