My energy bill went way up, what’s up?

Posted on November 26, 2018

Ouch! Did your actual or projected energy cost go through the roof? Big changes in the weather are usually the primary cause!

Your (projected) energy use is way up. Why might this happen?

Your energy bill may go way up. Or perhaps you received an email from Duke Energy telling you that your projected use is way up, like the image above. What’s up with this?

If this happens in late fall, or early winter, this is likely perfectly normal.

2018s weather, for example, set everyone up for what may have been an unpleasant surprise. We had unseasonably temperate temperatures for most of fall. This means you were not using either your AC or your heat very much, and if you did, it didn’t have to work very hard. So… that’s great: low energy bills!

Then Winter hit pretty hard!

From unseasonably nice, to very cold: Recipe for big energy use changes!

But then we had temps drop below freezing, in fact well below freezing, almost record breaking. That means, ladies and gentleman, fire up your heat! And not just a little… we went from not much use at all… what a lovely fall it is… to wow, its cold!

Very cold=even more costly to heat.

Note: the colder it is outside, the harder it is for heat systems (other than gas) to warm the home, not just because of the temperature difference, but also because heat pumps, which are usually more efficient, don’t work well when the temps go well below zero and they have to fall back on emergency (heat strip) heat. This is normal, but means it costs even more to heat when it gets to be very unseasonably cold… See the chart. We dropped WELL below zero (and well below the green “normal”).

Energy usage may double or more…

So, since HVAC is the most significant use of energy in a home, that means your energy bill likely doubled or possibly tripled when the temps drastically changed. How much it went up depends on how much you used your AC before hand, how much “other stuff” you have drawing energy in the house, and how warm you set it to when you turned on the heat.

About that “average” Duke may report…

The two graphs on this page are from actual 5 and 2 bedroom units and there increased usage. Big increases, but not unusual when temps change markedly. Note, the $270 above average DOES NOT MEAN the increase is higher than other people in the area. It means the amount is higher than that particular home’s average, and of course this is true because peak winter (and peak summer) are always much more expensive energy-wise.

What can you do?

For many of our places, you have double hung windows. They rock. You can open them up… but if they aren’t closed right, they can let a lot of air in (plus they won’t lock). Check out our FAQ about double hungs!

A few other tips about saving on Heat from Duke Energy:

  • Check your furnace filter monthly and replace it when it appears dirty.
  • Lower your thermostat temperature to the lowest temperature that is comfortable to your family. You may save as much as 3 percent on your energy bill for each degree you lower your thermostat. Reduce your thermostat setting at night and when you are away.
  • The “auto” thermostat setting on central heating systems may save you money.
  • If you have a heat pump, keep the outdoor unit clear of grass, leaves and especially drifting snow around the outdoor coil.
  • Never switch a heat pump to the “emergency heat” setting on the thermostat, unless the unit is malfunctioning. This switch will turn off your energy-efficient heat pump. Using only your backup electric or gas furnace without the heat pump could double your heating costs.

Never below 60 (or off!)

BUT! Don’t ever set the thermostat to below 60 (or to off!) if you will be away because frozen pipes will cost you a lot more than the energy bill! Bad things. Expensive things. Thousands of dollars…

Even smaller places will see similar projected big changes. These happen most frequently when weather goes from nice to very hot or cold in a short period, like May and November. Toward summer, we might jump from no HVAC to high speed AC, and in winter to a need for a lot of heat!