On Tue, 20 Nov 2007 02:18:13 GMT, mroberds@xxxxxxxxxxxxxxxx wrote:

<measures> The seat here is wood (I think), about 6 x 1.3 cm in cross-
section and about 100 cm circumference. 0-8376-0333-1 has the densities
of various kinds of wood at 0.50 to 0.72 g/cm^3; take the average of
0.61 g/cm^3 to get about 476 g of toilet seat. The same reference gives
the mean specific heat for those types of wood as 2.1 to 2.9 kJ/(kg * K);
taking the mean of 2.5 kJ/(kg * K) implies that you need about 0.525 kJ
to raise the temperature of the toilet seat by 1 K. The thermometer on
the thermostat says it's about 17 C in here now; I'm guessing that
around 32 C (90 F) might be a butt-compatible temperature. That's a
15 C or 15 K rise, or about 7.9 kJ. Since 1 kWh is 3.6 kJ, that's about
2.2 kWh. That number seems kind of high to me, but I've been awake too
long to figure out where I might have gone wrong.

Unless you want to switch the heater on specifically shortly before you
use the toilet, the more relevant measure might be the heat loss from a
given temperature to the air over time, which is how much it'll cost to
*keep* the seat heated.

Jasper

.

## Relevant Pages

... the mean specific heat for those types of wood as 2.1 to 2.9 kJ/; ... to raise the temperature of the toilet seat by 1 K. The thermometer on ... around 32 C might be a butt-compatible temperature. ... the important question is how rapidly the heat is ...