Furnaces and other heating equipment get a good workout when temperatures dip as low as they have in the Minot region the past few days.
Natural gas usage on Sunday was about 50 percent greater than normal for this time of year, according to Montana Dakota Utilities. Sunday's high was minus 10 and the low was minus 21 in Minot.
Public buildings can be more heavily affected by cold weather due to their square footage and the amount of activity.
Kevin Sickler, property superintendent for the City of Minot, said a cold spell in January 2013 caused natural gas costs to go up about $1,000 for the month at the Public Works Building complex.
The city shop and equipment storage at the complex are primary areas where the city takes pains to keep costs down. Limiting the amount of time that large overhead doors are open when equipment is moved in and out is critical. Sickler said employees are drilled to be "very diligent when they run the overhead doors up to have somebody there the minute you are through the doorway to get things closed."
Once crews are out for the day and the storage areas are vacated, the heat is kept turned down, Sickler said.
Many city-owned buildings have thermostat setbacks for hours when the buildings aren't in use. Often, the setbacks are programmed to take place automatically.
Sickler said the public works building also received an insulation upgrade a few years ago as part of a re-roofing program.
Last winter, the city shop replaced ceiling-mounted, individual infrared heaters with tube-style heating using natural gas. Sickler said the new heating is more uniform and appears, so far, to be saving money.
Scott Collins, director of the Minot Municipal Auditorium, said the amount of heat used at the auditorium depends on the events that are going on because heat is turned back when areas aren't in use. The impact of one cold day also can be insignificant to the monthly bill if balanced by warmer days during the month, he said.
Randy Renfandt, superintendent of buildings and grounds for Minot Public Schools, agreed that it's difficult to measure the direct impact of a brief coldsnap on energy bills.
The district needs to keep the buildings comfortable for students and staff, Renfandt said, but like the city, the district takes steps to conserve energy. Thermostats are set back when buildings aren't in use, and when reroofing or remodeling occurs, extra insulation is added.
Colder weather has been making its mark on Ward County's energy bills. The natural gas bill for the Courthouse in December was $2,075, up from $1,397 in November. The natural gas bill at the jail more than doubled from $768 to $1,580.
Leona Lochthowe, building supervisor for Ward County, said the heating equipment runs harder and there's more wear resulting in breakdowns when the weather is colder. Strategies to control heating bills have included keeping inner doors closed to avoid outside air from sweeping through the building as people leave and enter and turning thermostats down at night.
Trinity Health operates round the clock in its hospital buildings so can't set thermostats back. The natural gas bill for the Trinity and St. Joseph's hospitals totalled about $6,700 for Sunday through Tuesday, compared to about $3,000 for those same three days last year. Trinity spokesman Randy Schwan said a price increase accounted for 27 percent of the difference but gas usage was up 77 percent.
Schwan said Trinity tries to control energy use by advising employees to use a single entrance, putting barriers between garage and building-entry doors and encouraging people to shut doors behind them as quickly as possible. Still, there's noticeable energy loss with automatic doors and with main clinic doors that happen to be on the north. Employees who work next to lobbies have learned to dress warm, he said.
As for homeowners, the effect that the cold temperatures have on energy bills varies depending on factors such as square footage, number of people in the home, the direction the home faces, square footage of windows and thermostat-setting behavior.
Xcel Energy recommends setting thermostats to 68 degrees during the day and setting them back at night, noting that a homeowner can save 1 percent of a heating bill for each degree the thermostat is set back during an eight-hour period.
MDU recommends customers consider balanced billing to help alleviate big swings in their utility bills each month. Information is available at (www.montana-dakota.com) in the customer service section.