Is it more expensive to maintain a house at 72 degrees vs 68 degrees, or is the initial ramp up the only cost?

Question

So, I am visiting my parents in NJ, 36 degrees outside. They heat the house to 68 degrees, primarily with the thought that it is less expensive than heating the house to 72 degrees. HOWEVER my thought is that once you reach your desired indoor temperature, it is no difference to maintain the house at 72 degrees than it is at 68 degrees, at least when the outside temperature is that far away from your desired inside temperature. Is this logic true, is it going to take more energy to maintain the inside temperature at a higher degree, or is it just the initial closing of the gap where the cost is?

Thank you everybody for your responses... so much for making my argument with my wise mother...

Answer 1

The greater the temperature difference, the more energy you will use to maintain that difference. The higher the delta temp, the faster the heat will transfer through the existing structure and the more often the heater will have to kick on to maintain the desired temperature..

Answer 2

Follow up question:

Per Cambridge007's question, approximately how much more in heating dollars?
O.K., too many variables for anything exact, but ...

If a February heat bill is $250 when the thermostat is set to a constant 68 degrees,
how much more would it have been if the thermostat had been set to 72?
(Let's say the average outside temperature is 30 degrees.)

If it's going to cost a dollar a day or less, the additional comfort may make it worthwhile.

It is simple to understand raising the temperature to a higher temperature uses fuel.
A bit harder to comprehend that heat loss will increase based on the inside versus outside differential when there is significant insulation in-between. Or is the differential primarily at windows and doors?

But the real question is how much will it cost to be more comfortable?

Answer 3

It costs more to keep the temperature higher. The idea is that the rate of heat loss is proportional to the temperature difference between the inside and outside. It's called Newton's Law of Cooling.

I keep my house at around 62 degrees and I try to turn it down into the upper 50's at night and bundle up tight. I think I'm even getting used to it. No pneumonia yet...

One way people screw up is by cranking up the thermostat when it's really cold out. That's when you should actually do the opposite -- you save the most when you minimize the difference between inside and out.

Trying to plug up places where heat leaks is also very important.

Answer 4

Yes you will see and increase and yes it makes a big difference raising the temperature from 68 to 74..that is a huge raising of temp. You said radiant heat...I have infloor radiant and you cannot just change the temps daily..you have to set the temp allowing the slab to raise or lower taking a good 24 hours to do so, so infloor is very different from other heating systems. If you are chilly, you can try raising the temp 2 degrees, but I really suggest you don't raise it anymore than that unless you are prepared to fork out some dollars to your gas company. Your money..your choice. I would choose a sweater before raising the temp.

Answer 5

I keep my house at a steady 70 degrees. Originally I was lowering the temp when I was not home but it takes more energy (electric) to heat the house back up. At a lower temperture the heat will have to kick on more often to maintain the desired temperture

Answer 6

The efficiency of heat transfer across a gradient (temperature difference) increases with the gradient. You lose heat faster to cool surroundings the higher you set the indoor temperature, so it costs more to keep the place at a higher temperature.

Answer 7

Yes it is more expensive. The other answers are correct. Your reasoning would only apply if you were talking about a perfectly insulated environment where no cold air comes in/warm air escapes. This is not the case in homes.

Answer 8

Your logic would be correct if there were no heat loss to the outside.