Swapnil Shah pointed out five major cooling efficiency myths related to cooling, but I have my own opinions to add on four of them. I think everyone needs to know these.
#1: Air Conditioners Must Run All The Time To Maintain A Cool Temperature
This is only true in certain situations. For example: An undersized air conditioner won’t be able to cool a room off, therefore it has to run all the time. An adequately large unit (for example: a 24,000 BTU unit in a 200 square-foot room) definitely does not need to run all the time, and should be allowed to cycle off sometimes, as this will save energy. I see people virtually chilling their offices and homes with A/C very often, and that wastes a great deal of electricity (according to Shah, up to 20% can be saved on energy costs by cycling the air conditioner off if you’re cool).
My addition to this advice: Don’t buy a unit that takes too long to cool, as it will encourage you to leave it on all the time (no one wants to wait hours for their undersized air conditioner to cool off when they turn it back on).
#2: Having High-End Modern Equipment Means That You Won’t Have To Worry About Energy Efficiency
Even if all your appliances have the best energy efficiency certifications, that doesn’t mean you should leave your windows or doors open. Air conditioners will always consume a great deal of energy if your door or window is left open, under any circumstance.
#3: Building Operators Only Need To Worry About Cooling During Summer
This one surprised me a bit. Sometimes people turn on heat during the summer because they’re ‘cold’. It is extremely wasteful to use A/C and heating at the same time. Even if the A/C is on, turning on the heat during such a hot time of year is still wasteful.
#4: The Building Is So Big That Having One Window Open Won’t Affect Efficiency Much
The rest of the staff who have their windows open could say that too. Central air conditioning system efficiency can be profoundly affected by this because a single unit circulates cool air all throughout the building, one open window is an air leak for the entire building.
Source: Green Tech Media.