Posted: July 2010

Water Heaters

Some water heaters can affect water quality, and some can also affect indoor air quality. Installation and operating costs vary, depending on the equipment chosen. In a combo system, a boiler can be used to provide both hot water for domestic use, and hot water for heating the house.

Some water-heater tanks have a plastic lining, but sensitive people generally prefer glass-lined tanks because they tend to be slightly more inert. The insulation, which is between the inner water tank and the outer sheet-metal shell, is either fiberglass or a foam product, both of which can outgas into the room’s air when the tank gets hot. One way to minimize outgassing from either kind of insulation is to set the water heater’s thermostat on high—while increasing the ventilation to the area—to speed up the outgassing rate. After a few days of outgassing, the thermostat can be turned back down to a normal setting.

Many water heaters contain a magnesium anode rod to inhibit corrosion. With some water supplies, the reaction between the water and the rod can result in the hot water having a “rotten egg” odor. This problem can be minimized by filtering the water, choosing a water heater with a plastic liner which doesn’t require an anode, or by removing the anode—something that can shorten the life of the heater.

Solar

Solar water heaters can be a healthy option. Most are considered pre-heaters to be used in conjunction with a conventional water heater. There are two basic types of solar water heaters, but there are variations of each. Batch water heaters consist of a water tank mounted outdoors in an insulated box with a glass top. Sunlight warms the water in the tank, then it flows indoors into a conventional water heater to be heated up to a usable temperature. This is the lowest-cost and simplest approach. A flat-plate collector consists of a dark-colored outdoor panel that absorbs heat from the sun and transfers it to a fluid (usually antifreeze) which is pumped to a heat exchanger which, in turn, transfers the heat to the water in a conventional water heater. Some flat-plate collectors, if they are located lower than the water heater, don’t require pumps.

Solar water heaters can be expensive to install—sometimes as much as $4,000. But they tend to be less costly to operate than other water-heating approaches. If you are considering a solar water heater, reducing your consumption should be a priority. This can be done by installing low-flow shower heads, etc. If you use less water, you lower your energy needs, thus the cost of the system. 

The primary health consideration with solar water heating has to do with the potential for leaking antifreeze, but if a system is installed conscientiously, this shouldn’t be a problem.

This article was provided courtesy of the Healthy House Institute (www.HealthyHouseInstitute.com).