Is leaving the fridge door open for, say, 10 seconds a "big deal"?

Question

To use an example, say I need to take out a carton of milk from the fridge, add some milk to my tea, then put the carton of milk back. There are two methods:

Method A:

1. Open fridge door.
2. Take out milk.
3. Close fridge door.
4. Add milk to tea.
5. Open fridge door.
6. Put back milk.
7. Close fridge door.

Method B:

1. Open fridge door.
2. Take out milk.
3. Add milk to tea.
4. Put back milk.
5. Close fridge door.

Say Method A means leaving the fridge door open for 10 more seconds than Method B. In terms of energy wastage, is this a "big deal"?

(Against this must be weighed what to me is the obvious benefit of Method B --- convenience. But perhaps Method A has other costs too, such as additional wear-and-tear of the fridge door.)

Answer 1

It is common knowledge that hot air rises and cold air sinks. Inside a fridge the coldest air will be in the bottom of the fridge.

As soon as the fridge door is opened cold air from the bottom of the fridge drops out onto the floor of the room where the fridge is located. This air is replaced by room temperature air entering the top of the fridge space.

The longer the fridge door opens the greater the amount of cold air falls out of the fridge and is replaced by room temperature air.

Opening the fridge door for the least amount of time possible is the best way to retain cold air in the fridge. However, opening the fridge too often, even if briefly, in a short period of time will drain the fridge of the cold air inside it.

The best thing to do is know what you want to get from the fridge, get it as quickly as possible and close the fridge door as soon as possible and leave it closed.

Answer 2

No, leaving the fridge door open for about 10 seconds is not a "big deal". I figure it "wastes" about 3,000 joules of heat energy, or about 1,000 joules of electrical energy, which is equivalent to leaving a light on (60 watts) for about 20 seconds. For full analysis, see my post here: Should I Leave the Milk Out?.

Answer 3

your fundamental logic is all wrong in your question. My limited brain cell matter suggests that Method B means the fridge door is open 10 seconds longer than Method A?!!! If you reverse the question you might be able to apply some maths theory to find the correct answer.....! I agree that keeping fridge door open as short a time as possible will help contribute to a significant reduction in global energy usage. I refer you to study by Dr Dr. Claus and Barthel Thomas Götz http://www.bigee.net/media/filer_public/2012/12/04/bigee_doc_2_refrigerators_freezers_worldwide_potential_20121130.pdf . They report about 1,4 billion domestic refrigerators and freezers are in use world- wide. With an average annual electricity consumption of 450 kWh each, altogether they account for almost 14 % of the total electricity consumption from the residential sector and cause worldwide annual greenhouse gas emissions of 450 million tons of CO2eq. Households all round the world are currently using 1,4 billion refrigerators, fridge freezers and freezers. The average annual consumption of all these cold appliances amounts to about 453 kWh. In total, this causes an annual electricity consumption of 649 TWh, which is more than the total electricity consumption of Germany, for example. Now will you close the fridge door as soon as possible ?!!!!