On Thu, 29 Oct 2009 20:20:32 -0400, mm wrote:

On Thu, 29 Oct 2009 13:53:18 -0400, jeff_wisnia
wrote:


Poll question:

How many guys here have wives who mistakenly think that when warming up
a cooled down house the rate of temperature increase of a typical home
heating system will be faster if they shove the thermostat setting all
the way up to 90F than if they just move it to the appropriate setpoint.

No it won't, but what about when boiling water. Shouldn't the temp be
all the way up when one is in a hurry? Even though on my electric
stove with a medium sized pot of water, water will continue to boil
when the knob is at 6 out of 10.

I think with most electric stoves the temperature of the heating element
is directly proportional to the dial setting (regardless of whether the
stove's altering the resistance of the system or cycling power on and off
like a furnace) - there's not necessarily any feedback from the heating
element to the controller via a thermostat.

So for a stove, yes giving it full power until it boils and then turning
it down to maintain boiling *is* quicker than just boiling it at the lower
setting (unless you're using coated pans, because you'll kill the
non-stick coating by giving them full power :-)

Now, a thermostat-controlled system is a different matter...

1) Is the heating device capable of variable heat according to demand?
Most aren't - but I'm sure there are some furnaces out there (for example)
that can switch in extra burners and produce a hotter output if the
difference between current temperature and 'desired temperature' (as set
by the 'stat) is great - in those cases turning the stat up to 11 might
actually make a difference :-)

2) The dynamics of the system if there's just one 'stat (and the
system design's poor) might be tricky - the area with the 'stat in might
reach desired temperature before the rest of the building feels warm, so
turning the thermostat way up could result in a situation where the rooms
that the people are actually in feel warmer sooner than they would if the
thermostat were just set to desired temp (and the room with the stat in
will end up feeling too hot until the temperature of the whole building
evens out)

In other words, it's not quite clear-cut I think...

cheers

Jules