Potential and Electric Heating Efficiency
Name: Brian O.
Date: March 2004
Working on our physics project, we are designing an
energy-efficient home and are considering installing radiant electric
floor heating. We have determined it's more efficient (relative to the
house itself) to use electric resistance heating cables buried in
high-mass concrete rather than a water-based system. The question we
cannot answer is it more efficient to use 240 volt cables or 120 volt
cables? And by efficient, we mean the cost to operate the heating
cables over a typical Washington, DC winter.
For the cables in the floor it makes no difference, because all the power
you dump there goes into heating. For transmission to/from the floor,
you would like to minimize the resistive losses (I*I*R). For a given power
P=VI, you can lower the resistive losses by increasing the voltage.
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Update: June 2012