Solar Water Heating

How do they work?

Solar hot water systems use solar collectors or panels to absorb energy from the sun. Heated fluid circulates through a solar storage tank, where it transfers its heat to the water in your hot water tank. The solar fluid never touches this water. Water heated by the sun can reach temperatures exceeding 212º F, however the normal temperature for household use is only 120º to 130º F. 

We use solar hot water tanks that have been proven to last longer than conventional water heaters, which means you’ll still be enjoying hot water free from the sun for years after your neighbors have to replace their conventional systems.

These hot water tanks are extremely well insulated and are fitted with an electric or gas back up that heats the water on days where sunlight is insufficient.

Solar Water Heating Panels, sometimes called Domestic Hot Water (DHW), collectors, are made of glass, copper and insulation. They are designed to heat relatively small amounts of water (40 to 80 gallons in a home) quickly, to high temperatures suitable for bathing, laundry and dish-washing.   

The Drain Back System

A fail-safe method of ensuring that collectors and collector loop piping never freeze, is to remove all water from the collectors and piping when the system is not collecting heat. This is a major feature of the drain back system, (see illustration) Freeze protection is provided when the system is in the drain mode. Water in the collectors and exposed piping drains into the insulated drain-back reservoir tank each time the pump shuts off. A slight tilt of the collectors is required in order to allow complete drainage. A sight glass attached to the drain-back reservoir tank shows when the reservoir tank is full and the collector has been drained.

Solar water heaters can also be used to heat your home. The same set of solar collectors will provide hot water to a water-to-air heat exchanger that can be installed inside your HVAC unit. Greater tax incentives are available when you use hot water to heat your home.

Add an instant hot water circulation system to avoid wasting hundreds of gallons of water whilst waiting for the water to get hot. 

What are the benefits

Water heating accounts for about 30 percent of an average household's total greenhouse gas emissions and about the same proportion of total household energy use. Installing a solar water heater can greatly reduce your energy bills as it will use energy from the sun to heat water at zero cost, and will not produce any harmful greenhouse gas emissions.

A solar water heater can provide between 80-90 percent of your total hot water requirements, depending on the climate and the model of heater. The upfront cost of a solar water heater (including installation) is higher than electric or gas water heaters, but energy bill savings will quickly compensate for this over time.
Not only great for the environment but you will save on your power costs, using the sun’s free energy. A family of four with a solar hot water system can save up to 3 or 4 tons of greenhouse gas emissions compared to a conventional electric water heater. That’s the same as taking a small car off the road, so you can imagine the benefits for our future generations and the future of the planet.

How much one saves will depend upon the size of the system, the needs of your family, and the way you currently heat your water. The average annual cost for water heating can be over 30% of a household's entire annual electric bill, especially in those homes with teenagers or shower hogs. In an average home a person uses between 15 to 25 gallons of hot water a day so a family of four could well be using over 35,000 gallon in a single year

Significant State and Federal Tax Credits for Renewable Energy

The State of North Carolina is currently paying a rebate that covers up to 35% of the total system cost. In addition to the State rebate, the Federal government has placed a 30% federal income tax credit on residential solar systems. By utilizing both State and Federal incentive programs, the total system cost maybe reduced by up to 50%. This makes solar power a great home investment.

If the water heating system is used in a business there is accelerated depreciation (MACRS) which will offset the financial impact of an installation quicker.

Return on Investment

Solar heating does have a payback, and it can vary from four to ten years. But it may be more useful to think of solar as an investment that yields an annual return, much as a bank savings account provides interest. A solar water heater will generate savings that can equal a bank account generating a twenty percent (20%) annual return, and the savings are not taxed as income, as is the interest you earn at the bank.
The truth is, if you want hot water... you will be paying for that heat. You may prefer to pay the utility bill forever, or you may wish instead to go solar, and become your own utility. It is quite similar to the reason you once decided to buy your home and stop renting. Solar is simply one of the best investment available today.