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Introduction
Benefits
Equipment & Services
Hiring Contractors
1. Introduction
Solar heating systems have been used since the 19th century. Nowadays the use of solar heat is widespread, with about seven million households world wide presently using solar hot water systems. According to the U.S. Department of Energy (DOE), heating water today accounts for up to 14 percent of the average household’s energy use, and nearly four percent of total U.S. energy consumption.
2. Benefits
Energy Savings
By installing a solar water heating system, a typical household can meet 50 to 80 percent of their hot water needs. And though they cost a little bit more up front to install, the system will save you money in the long run as the fuel source (the sun’s energy) will always be free. With regular inspection, the system will operate for 20 to 30 years with minimal maintenance and costs.
Conservation
Installing a solar hot water system provides the satisfaction that you are doing your part to use renewable sources of energy, extending our current energy supplies, while reducing carbon emissions and environmental pollution.
Increased Home Value
Because Colorado experienced over twenty years of relatively low natural gas prices, during those years having an appliance on one’s roof that required maintenance was not a selling point. But now that natural gas prices have skyrocketed and are widely expected to stay high in to the foreseeable future, a solar hot water system should increase a home’s resale value.
3. Equipment & Services
Solar water heating systems typically cost between $2,000 and $5,000 installed, depending on the type and size of system. A typical solar water heating system includes the flat plate collectors, a collector tank, a thermosiphon valve, piping, shutoff valves, and relief valve. An installer will include an estimate of energy savings, will install the equipment, provide warrantees, and may offer a maintenance package.
According to the National Renewable Energy Laboratory, the most popular type of solar collector for water heating is the flat panel design (other types include evacuated-tube, concentrating, and integral collector storage). A flat panel collector is an insulated weatherproof enclosure with an absorber plate, flow tubes, and a transparent cover. Once the solar energy is collected, it is commonly employed with the pumped indirect solar water heating system.
An indirect system pumps heat-transfer fluids (usually a non-toxic propylene glycol-water antifreeze mixture) through collectors and into to a storage tank. Heat exchangers transfer the heat from the fluid to the household water stored in the tanks. Many indirect system designs also incorporate an external heat exchanger. The drain-back system is another system where the water in the collectors and exposed piping drains into an insulated drain-back reservoir tank each time the pump shuts off.
Placement
The optimal orientation of a solar panel for overall annual production is tilted at latitude and facing due south. The placement of the solar panels however is often determined by the characteristics of the available roof area. While it is possible to tilt the panels at an optimal angle rather than at the pitch of the roof, this causes issues with wind loading and aesthetics. In Colorado the optimal angle is 40°; a tilt of 55° optimizes winter gains while a tilt of 25° maximizes summer gains.
Number of Solar Collectors
The number of solar panels needed for a specific application depends on a number of variables; the hot water load of the home, the geographic location, the type of panels, and the estimated efficiency of the chosen orientation. In general you want to size the system to meet the load on the sunniest day under optimal conditions to avoid over-sizing and the poor economics associated with this.
4. Hiring Contractors
Download our solar hot water comparison form (Acrobat reader .pdf format). Find solar hot water installers from our list of solar contractors.
Twenty-five years ago there were combined state and federal tax credits available for solar systems installed in Colorado. Many companies rushed into the market to serve the demand. Unfortunately, quite a few of them had little or no experience with the technology, selling untested equipment and providing little maintenance. This gave the word “solar” a black eye. Within a few short years after the credits were offered, they were removed and over time things have changed for the better. The companies and equipment that are now in the market have withstood the test of time.
Questions to ask
Use the checklist of questions that we have provided to hire an experienced solar contractor.
Certifications
Ask if they have been certified by Colorado Solar Energy Industry Association (COSEIA).
References, licensing, insurance
It is always important to speak with previous customers, check with the Better Business Bureau and ask for verification of the necessary licensing and insurance requirements.
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