Portable Air Conditioners and Energy Efficiency

ecolightbulbIn the stifling summer heat, a portable air conditioner can take the edge off of a hot room, either as a supplement or substitution for central air conditioning. Because they're compact and fully mobile, they are the perfect cooling solution for any room in your home, office, work site, or even a computer server room.

But portable ACs cost money to run, and this age of rising electric costs and shrinking budgets, you might be worried about how keeping your home cool will affect your utility bills.

We've got you covered. Here's what you need to know to make the most cost-effective choice to meet your cooling needs.

BTUs and EER - Important Numbers to Consider

When choosing a portable air conditioner, there are two very important factors to consider: BTU's and EER.

  • BTU's = British Thermal Units, which measures how much heat is removed from a space in an hour. The larger the number, the more powerful the air conditioner, and the bigger the space it can keep cool.
  • EER = Energy Efficiency Ratio and measures how efficiently an air conditioner operates under specific conditions (usually 95 degrees Fahrenheit). It is a ratio of cooling output compared to energy input. National appliance standards currently require room air conditioners to have a minimum energy efficiency ratio of at least 8, but many models offer EERs of 11, 12 or even 13.

If you're concerned with energy costs, knowing the EER rating is absolutely crucial in determining whether the unit you're buying is an energy saver...or an energy guzzler.

How to Calculate EER

Calculating the EER for a mobile AC involves a little basic math: the simple formula puts divides the BTU's the unit produces by the Watts of electricity used to power it. The higher the result, the more energy efficient the unit will be.

For example, let's consider a portable air conditioner producing 10,000 BTUs that uses 1,200 watts:

BTU's / Watts = EER
10,000 / 1,200 = 8.3
EER = 8.3

In contrast, a second 10,000 BTU air conditioner uses 1,000 watts:

10,000 / 1,000 = 10
EER = 10

The second unit with an EER of 10 can produce the same amount of cooling but uses less energy to do it. Since this saves you money on your electricity bill, it is probably the unit you'll want to purchase - with one caveat.

A higher EER rating is usually accompanied by a higher price tag. Before you make your final purchase, it might be worth your time to figure out if you'll save enough on your energy bills to justify the more expensive unit.

green-piggy-bankEnergy Savings Over Time

To find out if the more expensive AC will pay for itself in energy costs over time, you'll need to perform a few more simple calculations. To find out the energy savings the more expensive unit will offer, you'll need two pieces of information:

  1. The approximate number of hours the portable air conditioner will be operating
  2. The amount a kilowatt-hour (kWh) costs in your particular area

For the purposes of our example, we'll assume the following:

  1. You will use your portable AC for four months out of the year, six hours per day
  2. The kilowatt-hour costs $0.10.

For the two AC units described above, the difference in energy consumption is 200 watts, which means that every five hours of operation, the less expensive unit will consume will one additional kWh. At $.10/kWh, it will take 1000 hours to make up a $100 price difference between the two units.

That's approximately 5 ?? months of use at 6 hours a day before your energy savings are realized. Since a reliable air conditioner will give you years of use, it is usually worth the extra initial cost to buy the more energy-efficient unit. This is especially true if you will be operating the unit for extended periods of time.

If you have questions about the most energy-efficient portable air conditioners available, contact our air conditioning experts. We'll be happy to help you choose the best energy-saving product for your home. To see our complete selection, click here.

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