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Debunking Energy Myths, Part III


Every superhero has a nemesis, and I’ve got several to fight! With the many myths and questions you are sending my way, I’m going to need a new super power – typing faster than a speeding bullet.

Myth #1: Washing dishes by hand uses less energy than running an electric dishwasher.
Answer: No! The electric dishwasher wins.

In this instance the modern machine beats the old-fashioned method: washing dishes by hand several times a day can be more expensive than operating an energy-efficient dishwasher. You can consume less energy with an energy-efficient dishwasher when used properly and when operating with full loads.

Additionally, most modern dishwashers don’t require pre-rinsing of dishes, according to Consumer Reports, a practice that wastes up to 20 gallons of water per load without getting dishes any cleaner.

Truth is, I love my dishwasher! So, just to make sure I’m doing right by my wallet and the planet, I run my dishwasher only when it is full, use the most efficient setting for the load, and air dry the dishes when I can.

Tune in next time when I take on detergents!

Myth #2: If an appliance breaks and it’s more than about 6 years old, are you better off buying a new one rather than repairing it?

Answer: Probably.

It is true that the cost to repair is very important, but so is the appliance.

When trying to determine whether to replace or repair a broken appliance, factor in the energy savings you’ll see with a more efficient appliance. Additionally, consider the cost and nature of the repair, both the old and new appliances’ efficiency ratings, and how often you use the appliance. In today’s economy, your cash flow is probably the most important factor.

For me, trying to figure it out sounds like a lot of thinkin’. Luckily, an online appliance calculator will tell me if my current appliance is wasting enough energy and money to make an upgrade worth my while and, if so, what the pay back period would be.

Myth #3: Do whole-house power factor correction boxes save you money. Myth or no?

Answer: Myth – with a catch. And thanks to Eric for the great question.

For Xcel Energy residential customers, whole-house power factor correction boxes will not help you save money on your electric bill. The science behind this process is a bit complicated (but I’ll do my best to explain in very broad terms).

It is true that power factor correction devices do reduce the current “upstream” of the devices (i.e. appliances), and therefore reduce line losses. However, the devices have no impact on energy consumption other than reducing line losses. We bill our residential customers based solely on energy use and do not charge a power factor penalty when their power factor is low. Therefore, there is no impact on our customers’ energy bills.

So while these devices may provide other benefits for residential customers, such as prolonging the life of equipment, they do not save on energy bills.

If you’d like more information, then check out what the NIST has to say about correction boxes.

Myth #4: Are slow cookers are more energy efficient than a traditional oven or range?

Answer: Yes, when you consider the amount of energy slow cookers use (and thanks for the question, Elizabeth!)

While it’s difficult to find direct comparisons of slow cookers, range tops and ovens, I can provide figures on watts.

The medium-sized element on an electric range top uses approximately 1,650 watts, and 1 hour of cooking uses 1.65 kWh of energy. A crock pot uses around 150 watts and 8 hours of cooking uses 1.2 kWh of energy.

The crock pot uses about 37% less energy.

Either option is more energy efficient than a standard oven, which comes in at a whopping 3,000 watts.

Keep using that crock pot, Elizabeth, and check out these tips for saving even more energy in the kitchen:

  • Match the size of your pan to the size of the burner when cooking on the range – if the burner is bigger, you’re wasting heat.
  • Reheat leftovers in the microwave or toaster oven instead of the oven.
  • Use ceramic or glass pans for baked items – you can set the oven 25 degrees cooler but the food will cook at the same rate.
  • Don’t peek and open the oven because you can lose up to 25% of the oven’s heat.
  • Plug small appliances like the coffee maker and blender into a power strip and turn it off when the appliances aren’t in use.

I hope you’ve enjoyed reading this installment of Mythbusters as much as I’ve enjoyed writing it. Thanks for reading, and I’ll type you in 2012!

And don’t forget to keep your comments coming, and I will dedicate myself to debunking energy hoaxes, thwarting scams and educating energy users everywhere. (Cue patriotic music)

It is true that power factor correction devices do reduce the current “upstream” of the devices (i.e. appliances), and therefore reduce line losses. However, the devices have no impact on energy consumption other than reducing line losses. We bill our residential customers based solely on energy use and do not charge a power factor penalty when their power factor is low. Therefore, there is no impact on our customers’ energy bills.

So while these devices may provide other benefits for residential customers, such as prolonging the life of equipment, they do not save on energy bills.

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