[thedoc (OP)]

Pauline Andre  asked the Naked Scientists:
   
Hi Chris
 
I have this argument with my husband every Winter!!!
 
I want to put the undertile and undercarpet heating on a low setting (15C) and keep it on until the end of August (or whenever it starts to warm up). My husband wants to turn the lounge one off at night and then put it on in the morning; the children's one off while they're at school and then on just before they go to bed.
 
He says my way consumes more electricity because it's on all the time. I maintain that it takes more energy to get the temperature up after being off for so long and therefore I feel my way consumes less electricity. Also I hate to be in a cold room!!
 
This year my husband agreed to keep the heating on through my persuasive argument, but warned me of a huge upcoming electricity bill. Are we consuming more electricity my way. Please solve our debate!!
                                                           
Regards
Pauline

What do you think?

[Geezer]

It depends  :-)

If your home is very well insulated it should not cost much more to leave the heat on (and it will be a lot more comfortable). If it's poorly insulated, leaving the heat on will probably waste more energy.

If possible, use some sort of "set-back" thermostats to control the temperature in each room. If you can reduce the temperatures in unused rooms, even by a few degrees, it will save energy, but it won't take very long to return the room to a comfortable temperature when it becomes occupied again. Letting a room get really cold may save some money, but only because the room is uncomfortably cold, and possibly unusable, until it warms up again.

[syhprum]

As Geezer says you can never fail to save money by switching things off but it will be at the expence of comfort.

[chris]

The higher the temperature in any room, the greater the thermal gradient relative to the outside; so the rate at which heat energy flows away increases with temperature. In other words, the warmer it is the faster you are losing heat and throwing away money. Running a room at a slightly lower temperature will lead to a slower rate of heat loss, saving money; turning off the heating altogether will save the most money, but you'll be cold while you wait for the room to re-warm. You won't, however, somehow burn off more energy re-heating the room from cold than had you let the room remain warm. As the above two posters have suggested, it's a compromise between cost and comfort.

[CZARCAR]

will the cold room be heated faster by using a fan?

[Lynda]

It would be better to have it on low - to avoid draughts when the heat comes on.

[syhprum]

all the poster,s take the simplistic view that electricity for heating costs the same what ever time of day you buy it which of course is not the case.
The best arrangment is to buy power at night when it is at its cheapest but there is a problem generally you don,t want the indoor temperature as high inside at night but but higher during the day this would seem to call for a considerable delay being needed between the heating elements being on and the heat seeping thru to the house which is fine if the day time temperature is predictable but can be a problem in England where January daytime temperatures can commonly vary by 20°C over a couple of days.   

[Geezer]

The best arrangment is to buy power at night when it is at its cheapest

Not always an option, and not available in these parts. That's probably a consequence of the whopping great lake I can see which is more that 2000 feet above sea level