On Tuesday, March 12, 2013 8:57:24 PM UTC, kerrygirl wrote:

I purchased a windowsill heat mat. It says it will heat to 20oC but it
does not have a thermostat. If I connect a timer to it, how many minutes
should I set it at to keep the temperature even.

Temperature rise (above ambient) is proportional to average heater power, so if your timer switches it on and off once a minute, you get half the average power used and half the temp rise.

20C is meaningless unless it also states what temp it was before using the mat.


NT