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| Off-Peak Heat and Water |
| by Kim Kinrade |
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| In a previous article, I reviewed the basics of the time-of-use (TOU) power structure and how off-peak electrical use can benefit homeowners who are willing to slightly alter their usage habits. Large savings, for example, can be achieved just using a clothes dryer outside the peak times of electrical use on the grid. |
| How about heating your home? Electric Thermal Storage (ETS) heaters are a great partner for the TOU program. ETS units use ceramic bricks to store heat provided by elements inside the heater unit and a microprocessor adjusts the heat depending on the outside temperature. |
The unit takes nine bricks made of high-density iron oxide ceramic to hold a maximum amount of heat without taking up a lot of space. In one unit, made by Steffes Corporation, each brick measures only 7" by 8" by 1-3/4" high but weighs 10 pounds! The heating elements automatically turn on during the off-peak period and transfer heat to the bricks. It is the special composition of the ceramic material that allows for such long storage and even distribution of heat.
The maximum temperature of the bricks when fully charged is around 1,400 degrees. When used daily, they rarely get below 250 degrees. This means that even during colder periods they don't have to start from 'stone cold' every night. |
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| The cabinets of the ETS heaters are simply painted sheet metal with heavy insulation on the inside.. This enables the bricks to retain the heat for the duration of the peak time and no one can burn their hands on the cabinet. |
Two types of insulation are used. The first is a tightly woven blanket of an aluminum silicate compound. Following this is a composite containing the same material used for the tiles providing protection on the space shuttles. Together they keep the outside cabinet temperature less than 180 degrees F.
When the TOU changes to day time use rates the charging of the bricks stops and the stored heat is then released gradually throughout the day. One or more fans inside the heater (depending on the size of the unit) circulate air around the heated bricks and out into the room.
Steffes Corporation is a manufacturer of this type of ETS unit and forced-air and hydronic furnaces as well. These operate on the same TOU system using bricks to either heat air, which is then transferred through the heating ducts, or water that is pumped to separate zones in the home. Either unit can be fitted into the appropriate existing central heating system. |
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The upside of ETS?
- Lower cost heating option
- Safe form of heating
- No need to remember to fill an oil or propane tank
- No gas emissions which negates the need for a carbon monoxide detector
- No routine maintenance outside of changing air filters (or regular plumbing checks with the hydronic systems)
- Clean and reliable
- No house chimney required
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The downside for the units is the front-end cost. They start at approximately $3,000 installed for the medium-to-large-sized room units, and $1000-$1500 for the bedroom-sized. So to install an ETS unit in every room is a substantial initial investment.. Count on about double the price of central air or hydronic systems. As well, remember to factor in the cost of the off-peak meter, switching microprocessor and any upgrade to the electrical system. |
| As well, let’s not forget that power companies are not infallible and interruptions occur. This might not bode well for a prolonged power outage during a January cold-snap in Minnesota. |
| In time the ETS units may compliment a “green” system made up of equal parts of passive and active solar energy melded with wind power. |
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| Compare FREE Estimates From Heating and Ventilation Contractors NOW! |
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