Pre-Christmas cold snap leads to higher bills this month

Though it only lasted a few days, the cold snap that hit right before Christmas caused a spike in electric usage for some CoServ Members, who might be noticing higher bills this month.

Members who have electric heating can look at their electricity usage on SmartHub to see how much they used in the days leading up to Christmas Day. The average temperature for December 2022 was 10.6 degrees cooler on average than December 2021. The average high temperature was also 12.6 degrees cooler.

Utilities use a metric called Heating Degree Days to measure heating usage in the winter. Click here to learn more about Heating and Cooling Degree Days.

The Heating Degree Days increased by 158 percent in December from the same period a year ago with the majority of those occurring on December 22-24.

Here’s a usage example from one CoServ Member. The usage for December 23 alone was 231.92 kilowatt-hours. That’s nearly four times the average December usage for that account, according to SmartHub.

So why the spike in usage? For answers, we talked to Josh Sterling, CoServ’s Manager of Energy Solutions and Efficiency.

It starts with the average outside temperature, which for December 23 was 14 degrees Fahrenheit. Then consider that the thermostat for your home was likely set somewhere in the 60s or 70s. That means there’s about a 50-degree difference between the outside temperature and the temperature you’re setting to be comfortable in your home. That requires any heater, gas or electric, to work harder and more often.

Looking specifically at electric heaters, there are two types: heat pumps and resistance heaters.

Resistance-style heaters use coils that are heated up by electricity and then a fan blows air past them, sending heat into the house. These traditional heaters use more electricity than heat pump systems.

Most newer-built homes that have electric heating use heat pump systems, including from the Member in the example above. A heat pump uses the compressor outside but it runs the cycle in reverse so it extracts heat energy from outside and transfers it into your home. This works by lowering the pressure of the refrigerant so it absorbs the heat.

Modern heat pumps are much more efficient than traditional coil heaters but they do have limitations when the temperature is below 40 degrees Fahrenheit, as it was during the December cold snap. They pull heat out of the air but there’s very little heat when it’s that cold.

That’s why homes that have heat pumps also have emergency or auxilliary heaters, which use the traditional resistance-style heating technology. When the temperature dips into the 20s, the emergency heat works in conjunction with the heat pump to warm the house.

Because the emergency heaters use less efficient coil heating, Members will notice a spike in usage on days when it runs.

However, not manually turning on the emergency heat wastes electricity because the heat pump will run constantly without reaching the desired temperature so it could run almost nonstop.

“Setting the thermostat to 68 degrees, the recommended temperature for heating, is the best thing you can do during the winter, especially when it gets below freezing. The closer you get the inside temperature to the outside temperature, the less energy that will be used,” Josh said. “Avoid using space heaters as they are designed for intermittent personal use only and much like the central heating unit but on a smaller scale, they are resistance heaters, too.”

Want more tips on how to conserve energy this winter? Be sure to check out CoServ’s Winter Savings Series.