As a lifetime Puget Sound resident, I've seen first hand why many homes in our area don't have any air conditioning installed. Our air conditioning "season" is so short it can be difficult for many homeowners to justify the expense of adding central AC. Because of this, many Puget Sound homeowners have opted to purchase portable AC units to cool small areas of their homes during the warmest parts of the summer. I can't say I blame them! The cost of purchasing a portable unit ($400 to $550) is so much less than adding central air conditioning (minimum of $4,000), it appears to be an intelligent solution to "get by" during the summer months. However, if we take a closer look at all of our available options, some better solutions become apparent.

First, let's look at the efficiency of portable AC units. A good place to start would be to take a look at the U.S. government's minimum efficiency standards for portable AC units. This quote is taken directly from the EPA's Energy Star website:

"At this time, portable room air conditioners are not labeled as ENERGY STAR qualified products. The code of federal regulations has no federal standard to regulate the energy consumption of portable air conditioners. ENERGY STAR will determine whether to add portable air conditioners to the program once a federal standard is set."

That's right! There are NO efficiency standards for portable AC units! Of course, the government DOES have aggressive efficiency standards for any air conditioning equipment INSTALLED in a home, driving up the cost of central AC. Because of this discrepancy, our government has inadvertently created a situation where people are incented to purchase low quality, inefficient, portable air conditioning units due to their low upfront cost.

These units have inefficiency built into them by their very design. The worst offenders are the units with a single exhaust hose. These units pull already-cooled air from the room into the unit, where it is heated and exhausted to the outside. Not only this, but when the cooled and re-heated air is exhausted, the room is re-pressurized with hot, humid air from outside the room.

Here in the Puget Sound, this inefficiency alone is probably not enough to convince most people to purchase central air conditioning. We only need air conditioning a few weeks a year. While it does hurt, the inefficiency of a portable unit alone doesn't really hurt enough to justify the expense of an installed air conditioner.

However, there is one air conditioning solution that renders the above a non-debate: the heat pump! People in our area tend to think of heating and air conditioning as two separate functions, but the heat pump handles both with extreme efficiency. In fact, heat pumps and ductless heat pumps handle heating so efficiently they may completely pay for themselves in just a few years, depending on your current heating system. In essence, by adding a heat pump for heating, you are adding air conditioning to your home for free!