Saving Energy at Home Simply by Not Wasting It

There are many common myths or misunderstandings which lead people to inadvertently waste a lot of energy in their homes. Let's examine a few-if you find one that applies to you, you could start saving energy immediately!

Opening the windows to get fresh air in the house even while the air conditioning is on won't hurt - False! In the air conditioning season the outside air is usually more humid than what you want your indoor air to be, and it will make you feel warmer than the dryer air (due to evaporative cooling). Not only that , but letting in more humid air actually makes the air conditioner work harder to keep the air cool, because removing that moisture from the air takes extra energy. So remember, even if the air outside is lower in temperature than the inside air for a portion of the day, it will usually not save you energy to open windows for part of the day and use the A/C part of the day. (Exception: if you happen to live in a very dry climate then mixing in cooler outside air will not hurt, as long as it is very dry air.) So when the temperatures and humidity levels start to rise, keep that A/C on 24/7 and the windows closed and it may actually run less than it would if you keep switching!

If I keep a ceiling fan running it will lower the air temperature in the room- False! Many people are confused about fans - they know that they feel cooler when the air is moving so they falsely think the air is actually cooler. This is not usually the case - it is not the motion of the air that makes it cooler but rather the interaction of the moving air and your body. So when your body is not in the room there is no cooling going on! You see, the movement of air across our skin makes us feel cooler due to evaporative cooling of the small amounts of moisture always present (even when we don't feel "sweaty"). So turn off those ceiling fans when you're not home, and in rooms you are not using - at those times they are energy-wasters. But when you are in the room, such fans can save you energy by making you feel cooler and thus allowing you to keep the A/C thermostat a little higher than otherwise.

If I turn the thermostat way down, then my air conditioner will cool the house faster- False! It will just waste energy by running longer and probably cooling the house farther than needed. With most systems, the rate of cooling is constant independent of the temperature setting - that is, the system is either on or off with the thermostat turning it on when actual temperature is above your set point and off when it gets down to the set point. So, for a specific example consider this: John and Mary have two identical houses next to each other and both come home and find the indoor temperature to be 80 degrees. John turns his A/C on and sets the thermostat as low as he can, hoping to speed up the cooling process: he sets it to 60 degrees. Mary sets hers to the temperature she wants the house to be at: 75 degrees. A half our later John's house is 75 degrees. What is the temperature in Mary's house? The same: 75 degrees! But then comes the real problem: if John does not manually adjust his thermostat back to a reasonable setting like 75 degrees, his A/C will continue to run and waste energy cooling the house more than he really wants (perhaps even uncomfortably cool). Note that an exception to this is that some heating and cooling systems (this is more common with heating systems) actually do work differently when the set point is far from the actual temperature - these are usually referred to as "two-stage" systems. But with these it is even more important not to set them to unreasonable temperatures, because even though they may cool (or heat) faster when you do that, they will waste a lot of energy doing so. It is best to keep the thermostat set at the actual temperature you want to maintain.

Another point of confusion is the best temperature at which to set your home's hot water heater. You may have seen the recommendation to lower the setting to save energy - to around 120 degrees. But then if you have a dishwasher you will notice that the owner's manual tells you the hot water must be at least 140 degrees for it to work properly! What to do? Well this is further complicated by the fact that some dishwashers have their own built-in water heater, which will kick in whenever the incoming supply water is not hot enough. So, you might think that in that case you can get away with turning your hot water heater down because the dishwasher will take care of its own water heating, right? Well it's not that simple, because the dishwasher probably uses electricity to heat the water, whereas your water heater may use natural gas which is a much more efficient way to heat (or even solar heat, which is even better and greener!). In that case, it is better to keep the water heater at 140 or higher so as not to rely on the electric heater in the dishwasher. But if your water heater is electric, then by all means turn it down and let the dishwasher heat its own water; that will save energy (and money!)