Electric Thermal StorageElectric Thermal Storage
ETS heaters use high-density ceramic bricks to store heat given off by elements inside the heater. The elements come on during the co-op's off-peak times to heat up the brick. The stored heat is then released throughout the day. Because the heaters use electricity off-peak, you receive a discount on the electric rate for the ETS heater.

ETS is a great replacement for kerosene and fuel oil space heaters and for wood stoves. Many members also use them to supplement their existing electric heating system. While one unit usually won't heat your entire home when it gets really cold, multiple units can be installed to keep you warm all winter long.
Cutaway diagram of an ETS unit.

How Does ETS Work?
It's really simple. ETS cabinets are filled with bricks made of special materials that store heat. Electric elements, similar to those found in electric ovens, pass through the bricks. When the elements are on, or charging, some of the heat is released into the room to provide immediate comfort. The rest of the heat is store in the bricks until it's needed.

Space-age insulation around the core helps the bricks retain stored heat. After the ETS unit has been charged, fans inside the heater move air around the bricks. The air is warmed to 180 to 200 degrees and returned to the room. Since the process is controlled by a wall thermostat, you can get as much or as little of the heat as you want-whatever is most comfortable.

What Makes The Bricks So Special?
High-density iron oxide ceramic bricks surround the elements to absorb heat. A high-density compound accomplishes two things. First, it holds more heat for a longer period of time. Second, it requires less space, and that means a slimmer, more attractive cabinet.

Although a brick measures only 7" by 8" by 1-3/4" high, it weighs 10 pounds. Nine bricks are required for each heating element. The heating elements also are crafted from special long-life material. That enables the manufacturer to offer a full five-year warranty on the elements. Other parts are warranted for three years.

At maximum charge, the core of the ETS unit reaches about 1,400 degrees. The heat is stored in the bricks until you need it. In one test, the core temperature was about 250 degrees three days after the unit was shut off!

But With Heat That Intense, Is It Safe?
Perfectly. When we say space-age insulation, we mean it. Actually, there are two types of insulation used-both highly resistant to heat transfer. One is aluminum silicate spun into a tightly woven blanket. The other is chemically identical to tiles used to cover space shuttles. Their combined resistance to heat loss has obvious benefits to making the unit more efficient, but they also make it safer.

At maximum charge-and remember that the core temperature is about 1,400 degrees-the skin temperature of an ETS heater is about 180 degrees. That sounds high, but compare it to wood stove. The skin temperature of a stove can be as high as 600 degrees. Another way to compare would be to consider that if you accidentally touched an ETS unit with your hand, it would be uncomfortable, but you could react before any burn would occur. With a wood stove, your hand would be burned immediately.

Still, some common sense needs to be exercised around ETS units because of the heat generated. For example, you should allow 1 1/2" clearance on the sides, back and between the top of the unit and any shelf. If the unit is enclosed in a wooden cabinet, side and back clearance should be increased to 2". All fabric items, such as curtains and bed clothes, should be at least 4" from the unit at all times.