September 2025 EnergyWiseSM Tip: Degree Days

September 22, 2025

By: NPPD Energy Efficiency Program Manager Cory Fuehrer

Have you ever reminisced about how hot a summer or how cold a particular winter was? It 

seems to be human nature to compare current outdoor temperatures to weather we experienced in 

the past. One of the late Johnny Carson’s favorite ways to set up a weather joke was to start by 

saying, “It was so hot today…” Having seen the routine many times, his audience would 

boisterously reply in unison, “How hot was it?!” Obviously, his reply was the punchline to which 

everybody laughed. But what if there was a way to quantify how hot or cold it truly was in order 

to compare it to other days, months or years in the past? Actually, there is and it’s called a 

“degree day”.


Degree days are a measurement of how cold or warm a particular location was. A degree day 

compares the daily mean temperature (average of the day’s high and low outdoor temperature) to 

a standard temperature. In the U.S., that’s usually 65° Fahrenheit (F). The more extreme the 

outside temperature, the higher the number of degree days. A higher amount of degree days 

generally results in higher energy use for space heating or cooling.


More specifically, heating degree days (HDDs) are a measure of how cold the temperature was 

on a given day or during a period of days. For example, a winter day with a mean temperature of 

30°F has 35 HDDs. Two such cold days in a row have 70 HDDs for the two-day period. If the 

daily mean temperature is greater than 65°F, no HDDs are associated with that particular day.


On the other hand, cooling degree days (CDDs) are a measure of how hot the temperature was on 

a given day. If a summer day had a mean temperature of 80°F, 15 CDDs would be recorded. If 

the next day had a mean temperature of 85°F, 20 CDDs would be assigned to it. The total CDDs 

for the two days is 35 CDDs. By totaling HDDs and CDDs for entire months or years, 

comparisons to previous months or years can be made.


Say you’d like to evaluate an average of how much energy it might take to heat and cool your 

home. Degree days, along with your heating and cooling system’s efficiencies and other factors

can be included in this equation to provide a fairly accurate estimate. Degree days also provide 

possible insight as to why energy bills were higher or lower than anticipated.


The Nebraska Department of Water, Energy, and Environment (NDWEE) provides historical

degree day and degree day normals on a monthly basis for 12 cities around the state in addition 

to the state's overall average degree days. Degree day normals are 30–year averages over a 

baseline comparison period. Currently, NDWEE uses 1991–2020 for the baseline.


Nebraska's overall HDD normal for a year is 6281. The CDD normal for a year is 996. (Note that 

commas are not used degree day data.) In comparison, Hawaii's HDD normal is 1 and its CDD

normal is 4766. Hawaiians use almost no energy for heating but need to use huge amounts if they 

wish to keep indoor spaces below 80°F. In contrast, Colorado's HDD and CDD normals are 7053 

and 329 respectively. While our neighbors to the west use a little more energy than us for 

heating, they require only about one-third of the energy to keep cool.


In the 2024/2025 season, Nebraska's HDD totaled 5956, which was 325 HDD less than normal. 

This indicates last winter in Nebraska was about 5% warmer than normal. 


For the upcoming winter, the “Old Farmer's Almanac” forecasts above-normal temperatures in 

the Cornhusker state. By the end of next June, we should know if the prediction was right. In the 

meantime, when a friend claims the winter of 2018/2019 was the coldest they remember, you can 

prove the winter of 1978/1979 was actually the coldest in more than 50 years.



Regardless of what the upcoming winter is like, your local public power provider, in partnership 

with Nebraska Public Power District, may have an EnergyWiseSM incentive available when you 

upgrade your heating, ventilation and air conditioning system’s efficiency. Contact your local 

utility or visit www.energywisenebraska.com for more details.

May 20, 2026
Southwest Public Power District will be closed Monday, May 25th, in observance of Memorial Day. Normal business hours will resume Tuesday, May 26th. If you need assistance during this time, please call (308)285-3295 to speak with an on-call representative.
May 20, 2026
As vacation season gets started, it’s easy to overlook the small appliances at home that keep using electricity while you’re away. A quick pre-vacation checklist can give them a vacation, too—and prevent them from wasting energy while nobody’s home. So, before you load up the car or head to the airport, start unplugging. First, the kitchen. Ice makers, second refrigerators and extra freezers can quietly run nonstop. If they’re empty or nearly empty, consider turning them off. Adjust your main refrigerator to a slightly higher temperature but keep it within safe food storage limits. Around the house, unplug electronics like televisions, gaming systems, computers and coffee makers. Better yet, connect them to a surge-protecting power strip so you can unplug them all at once. Many devices draw power even when not in use if they’re turned off but still plugged in. Water-related appliances are another common miss. Turn off or lower settings on electric water heaters if recommended by the manufacturer. Finally, adjust your thermostat. There’s no need to keep your home as cool as when you’re there, but don’t turn the system off entirely. A moderate setting helps manage humidity.
May 13, 2026
By: NPPD Energy Efficiency Program Manager Cory Fuehrer Most homeowners who have heat pumps use them to heat and cool their homes. But a heat pump also can be used to heat water. You may have already seen one of these units in a “big box” or appliance store and wondered what it was and how it worked. Here are the details: Heat pump water heaters use electricity to move heat instead of generating heat directly through electrical resistance. It takes a lot less electricity to transfer heat than it does to generate heat. Therefore, heat pump water heaters can be two to three times more energy efficient than conventional electric resistance water heaters. To move the heat, heat pump water heaters work like a refrigerator in reverse. While a refrigerator pulls heat from their interior and dumps it into the surrounding room, an air-source heat pump water heater pulls heat from the surrounding air and moves it into their internal water tank. Another type of heat pump water heater has indoor and outdoor components that move heat from outside the home. Still others are integrated with other space conditioning heat pump systems, which combine all the required equipment into a single unit located inside home. Stand-alone heat pump water heaters, which contain all the necessary equipment in one unit, require installation in locations that remain in the 40º– 90ºF temperature range year-round. Rooms housing heat pump water heaters should provide at least 500 to 1,000 cubic feet (28.3 cubic meters) of air space around the unit. As heat is transferred into the hot water tank, cool exhaust air can be vented back into the room or ducted outdoors. Ideal locations for installation are in spaces with excess heat, such as a furnace room. The temperature of the room in which the unit is installed will drop when it is operating by 2 F° to 6 F° and perhaps even more during periods of high demand for hot water.  The energy to feed the heat pump water heater can come from passive solar gain, heat from a conventional heating system, the warming effect of soil surrounding a basement wall, or any other heat source. The cooling of air while the unit is operating is especially advantageous in the summer. If the unit is installed in a basement located in a humid region, it also removes moisture from the air, which reduces and may eliminate the need for a separate dehumidifier. Since the heat pump water heater operates as dehumidifier, a condensate drain must be available. In their “heat pump only” mode, heat pump water heaters cannot heat water as quickly as electric resistance water heaters. In this mode, they can only generate about 8 to 10 gallons per hour. To make up for this basic deficiency in performance, heat-pump water heaters are equipped with electric resistance elements that are energized whenever the heat pump cannot keep up with the demand for hot water. This feature improves the performance of the unit but does reduce its overall efficiency. Most heat-pump water heaters have controls that allow a homeowner to choose one of three modes of operation: •Heat-pump-only mode (the most energy-efficient). •Hybrid mode (heat-pump operation plus electric resistance backup). •Electric-resistance-only mode (a mode that you could choose during cold weather, when you might not want the appliance to cool the space where it is located). A study in the northeast U.S. revealed that households installing a heat pump water heater could save between $40 and $270 per year when compared to using an electric-resistance water heater. Savings calculations were based on a family household that uses 35 gallons of hot water per day, with an electricity cost of 17 cents/kilowatt-hour. Lower end savings were seen when the heat-pump water heater was installed in a bad location (a small, cold room). Conversely, the high end of the savings scale was seen when the unit was installed in a good location (a large, warm room). Your local public power provider, in partnership with Nebraska Public Power District, wants to help you make the most from the energy you use to produce hot water in your home or business. For more ideas on saving energy while running your business or home, along with possible EnergyWiseSM energy efficiency financial incentives to help with the cost of upgrading to a heat pump water heater, contact your local utility or visit www.energywisenebraska.com for additional details.
May 6, 2026
The days are getting longer, and that means you don’t need your home’s outdoor lights to automatically turn on quite as early. Take a few minutes this weekend to reset outdoor motion sensors and timers to avoid wasting electricity when natural daylight is available. Walk around your property and adjust timers to match sunrise and sunset schedules. Photocell sensors should trigger lights only when it’s actually dark. Motion-activated floodlights should be properly aimed to illuminate paths without lighting empty spaces. While you’re at it, replace any old bulbs with LED alternatives, which can reduce energy use. Consider smart lighting controls that allow scheduling from your phone or tablet.
April 29, 2026
The month or two between cold and warm weather gives you the perfect opportunity to save energy. Milder temperatures mean heating season is winding down, but it’s not warm enough for air conditioning. Some call this a “shoulder season.” Take advantage of the moderate weather by keeping both the heat and the air conditioning turned off. Instead, open windows to draw in fresh air and turn on ceiling fans. Inspect and seal air leaks and clean AC filters. Open blinds, curtains and shades during daylight hours to reduce the need for electric lighting. The shoulder season is brief, so forming smart habits now can keep energy bills lower while the outdoor weather keeps your home naturally comfortable.
April 22, 2026
April is a great time to plant a tree. Arbor Day is April 24 this year, and people all over the world will plant trees in their yards and communities. The day is a reminder that spring is the season to think long term about your home’s energy use. Planting trees, shrubs or climbing vines now can provide natural cooling in the summer and save energy on air conditioning. Deciduous trees—the ones that shed their leaves in the fall—are particularly effective for energy efficiency because their lush leaves shade your home and yard in the summer and then allow sunlight to shine through your windows in the winter after their leaves fall. Position trees on the south and west sides of your house to block harsh afternoon sun. Fast-growing trees, like maples or lindens, offer benefits within a few years, while slower-growing species add long-term value and curb appeal. Shrubs and vines can shade walls and windows while enhancing landscaping. A trellis with vines near sunny windows can reduce heat gain, lowering cooling costs. Beyond energy savings, planting trees improves air quality, supports wildlife and adds value to your property. When selecting plants, consider native species that require minimal water and maintenance. By planting shade this spring, you’ll enjoy cooler indoor temperatures, and you could lower your heating and cooling bills.
April 15, 2026
Spring rain is good for flowers. It is not good for extension cords. Water and electricity, as you know, are a risky mix. April is a smart time to check your outdoor setup before yard work and storm season begin. • Start with your cords. If a cord is cracked, frayed or warm when in use, replace it. Do not tape it. Do not run it through puddles. Keep connections off the ground and out of wet grass. • Plug outdoor tools only into outlets protected by a ground fault circuit interrupter, or GFCI. These are designed to shut off power fast if something goes wrong. Test them each month. Push the “test” button. Then reset. • Using power tools in a damp garage or driveway? Dry your hands. Wear shoes. Keep cords away from metal and standing water. • Never pull a plug by the cord. Grab the plug itself. Yanking the cord can loosen wires and create a shock hazard later. • Store cords indoors when you’re finished using them outdoors. Sun and rain break them down over time. • If you use a generator during storms, keep it outside and far from doors or windows. Never plug it directly into a wall outlet. Small steps matter. A quick check now can prevent injuries later.
April 10, 2026
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April 1, 2026
Lightning, high winds and torrential downpours can put your home and neighborhood at risk of power surges and outages. And those can damage your expensive household electronics. So, prepare for spring storms to protect yourself and your electronics from harm. · First, install surge protectors as a first line of defense. Use them for computers, televisions, exercise equipment and other sensitive devices. Look for protectors with indicator lights that show when protection is active. · During severe storms, unplug electronics and turn them off—excluding things like the refrigerator and medical oxygen tanks. Even the best surge protectors cannot block a direct lightning strike. · If your home experiences frequent outages, consider installing whole-house surge protection, which is installed at the electrical panel. An electrician can explain whether this option makes sense. · Backup power options, such as battery packs or portable generators, can help keep essential devices running in case the power goes out. Portable generators should only be used outdoors and far from windows and doors to prevent carbon monoxide poisoning. · After an outage, wait a few minutes before turning electronics back on. This helps protect devices from voltage spikes as power is restored.
March 26, 2026
As you get to the business of spring cleaning, inspect your tools—vacuum cleaners, pressure washers, carpet cleaners and power tools—to make sure they are in shape for another season. · Before starting any project, inspect cords and plugs for cracks, fraying or exposed wires. Damaged equipment should be repaired or replaced. Using tools with ground-fault circuit interrupter protection is especially important in garages, basements and outdoors. · Follow manufacturer instructions and avoid overloading outlets or power strips. High-powered tools should be plugged directly into a wall outlet, not extension cords, unless the cord is rated for the tool’s electrical load. · When cleaning or repairing appliances, unplug them first. Water and electricity are a dangerous combination, so keep tools dry and avoid using them with wet hands or on damp surfaces. · For outdoor projects, use extension cords labeled for outdoor use and keep connections off the ground. Wear appropriate protective gear, including gloves and eye protection, and keep tools away from children and pets. Taking a few extra minutes to check equipment and follow basic precautions can prevent injuries and electrical hazards while tackling spring projects.
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