Energy Efficiency



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Frequently Asked Questions :: Energy Conservation and Efficiency

Q: Can a setback thermostat save money?

A: A thermostat is an on/off switch that tells your furnace to heat your home when the temperature drops below a set point. The thermostat's job is to maintain the temperature indoors within a narrow range. It works the same way for central air-conditioning in the summer.

According to EPA's ENERGY STAR program, homeowners can save about $180 a year by properly setting their programmable thermostats and maintaining those settings. See Programmable Thermostats for more information on this topic.

NorthWestern Energy is currently offering rebates to homeowners who purchase and install ENERGY STAR setback thermostats in their homes. For details, visit Programmable Thermostat Rebates.

Q: How can I find out what energy efficiency measures make sense in my home?

A: A home energy audit is the first step to assess how much energy your home consumes and to evaluate what measures you can take to make your home more energy-efficient. An audit will show you problems that may, when corrected, save you significant amounts of money over time. During the audit, you can pinpoint where your house is losing energy. Audits also determine the efficiency of your home's heating and cooling systems. An audit may also show you ways to conserve hot water and electricity.

You can easily conduct a home energy audit yourself. With a simple but diligent walk-through, you can spot many problems in any type of house. When auditing your home, keep a checklist of areas you have inspected and problems you found. This list will help you prioritize your energy efficiency upgrades. For more information on areas to check and how to do it, see Do-It-Yourself Home Energy Audits at

A professional auditor can carry out a more thorough audit, using a variety of techniques and equipment to determine the energy efficiency of a structure. Thorough audits often use equipment such as blower doors, which measure the extent of leaks in the building envelope, and infrared cameras, which reveal hard-to-detect areas of air infiltration and missing insulation.

There are several places where you can locate professional energy auditing services. Your state or local government energy or weatherization office may help you identify a local company or organization that performs audits. They may also have information on how to do your own audit. Your electric or gas utility may conduct residential energy audits or recommend local auditors. Also check your telephone directory under headings beginning with the word "Energy" for companies that perform residential energy audits.

RESNET, the Residential Energy Services Network, certifies energy raters who can conduct an energy rating and qualify a home for ENERGY STAR certification or federal energy credits. For a list of RESNET certified raters in your state, visit

For more information, visit these links:

NorthWestern Energy's EFFICIENCY PLUS (E+) Energy Audit for the home is available to customers who heat their homes or water primarily with electricity or natural gas delivered by NorthWestern Energy. The E+ Home Energy Survey is available to customers who use electricity delivered by NorthWestern Energy for lighting and household appliances. Call (800) 823-5995 for eligibility details.

Q: Where are the biggest air leaks in my home?

A: Many air leaks are easy to find because they are easy to feel - like those around windows, doors, and through electrical outlets. But hidden air leaks in attics, basements, and around chimneys are often more significant sources of energy loss. Consider addressing these big leaks first because they will have a greater impact on improving your comfort and reducing your utility bills. ENERGY STAR's Home Sealing Do-It-Yourself Guide has great pictures and suggests places to look for these leaks. Visit ENERGY STAR Home Sealing for more information. (Source:

Q: Can ENERGY STAR qualified CFLs be used with dimmer switches?

A: Yes! Always read the packaging of the CFL to be sure of its proper application, but there are a wide variety of ENERGY STAR qualified CFLs that are designed for use in most fixtures in your home or business. Product types include:

  • Incandescent shape (or A-shaped) and Globes, both are good in fixtures where the bulb is exposed or in fixtures with clamp lamp shades
  • Reflectors are intended for non-dimmable track lighting and recessed cans, and some weather protected outdoor spot lights
  • Candle shapes can be used in some porch lights, in wall sconces and in some chandeliers
  • Spirals, and mini-spirals are getting smaller and smaller in size and can be used in almost any fixture, especially table and floor lamps with harped shades

There are a few qualified 3-way and dimming CFL models that can be used for 3-way fixtures or in dimmable recessed cans or track lighting. (Source:

Q: How should I maintain my heating and cooling equipment?

A: Maintain your equipment to prevent future problems and unwanted costs. Keep your cooling and heating system at peak performance by having a contractor do annual pre-season check-ups. Contractors get busy once summer and winter come, so it's best to check the cooling system in the spring and the heating system in the fall. To remember, you might plan the check-ups around the time changes in the spring and fall.

A typical maintenance check-up should include the following:

  • Check thermostat settings to ensure the cooling and heating system keeps you comfortable when you are home and saves energy while you are away.
  • Tighten all electrical connections and measure voltage and current on motors. Faulty electrical connections can cause unsafe operation of your system and reduce the life of major components.
  • Lubricate all moving parts. Parts that lack lubrication cause friction in motors and increases the amount of electricity you use.
  • Check and inspect the condensate drain in your central air conditioner, furnace and/or heat pump (when in cooling mode). A plugged drain can cause water damage in the house and affect indoor humidity levels.
  • Check controls of the system to ensure proper and safe operation. Check the starting cycle of the equipment to assure the system starts, operates, and shuts off properly.

Cooling Specific

  • Clean evaporator and condenser air conditioning coils. Dirty coils reduce the system's ability to cool your home and cause the system to run longer, increasing energy costs and reducing the life of the equipment.
  • Check your central air conditioner's refrigerant level and adjust if necessary. Too much or too little refrigerant will make your system less efficient increasing energy costs and reducing the life of the equipment.
  • Clean and adjust blower components to provide proper system airflow for greater comfort levels. Airflow problems can reduce your system's efficiency by up to 15 percent.

Heating Specific

  • Check all gas (or oil) connections, gas pressure, burner combustion and heat exchanger. Improperly operating gas (or oil) connections are a fire hazard and can contribute to health problems. A dirty burner or cracked heat exchanger causes improper burner operation. Either can cause the equipment to operate less safely and efficiently.

Actions To Do Yourself

  • Inspect, clean, or change air filters once a month in your central air conditioner, furnace, and/or heat pump. Your contractor can show you how to do this. A dirty filter can increase energy costs and damage your equipment, leading to early failure. (Source:

Q: How can I reduce water-heating costs in my home?

A: There are a number of ways you can reduce the amount of energy used to heat water. According to NorthWestern Energy, the following measures can help save money:

  • Repair leaky water faucets.
  • Limit showers to five minutes or less.
  • Only use dishwashers, clothes dryers and washing machines when they are full.
  • Install low-flow and faucet aerators and save about 18,250 gallons of heated water per year.
  • Set the temperature of water heaters to 120°F. Use a candy thermometer to check the temperature of hot water running from a tap.
  • Install an insulating blanket on your hot water heater. Follow installation directions.
  • Hot water pipes in unheated areas should be insulated. If located in a heated area, the first 10-feet of hot water pipe from the water heater tank should be insulated.
  • Choose energy-efficient hot water heaters when purchasing a new one. NorthWestern Energy recommends an energy factor of at least .59 or better for 40-gallon gas or propane heaters. New 40-gallon electric water heaters should have energy factors of at least .91. Larger water heater tanks will have slightly lower energy factors.
  • Turn your gas water heater thermostat to "pilot only" to save energy when you are away for several days. If it is an electric heater, turn it off. Write a note to remind yourself to turn it back on.
  • Drain water from the bottom of the tank at least every three months to avoid sediment accumulation and maintain energy efficiency. To drain the tank, open the drain valve at the tank bottom and allow the water to run until clear (one or two buckets of water usually will do).
  • Use cold water for laundry. Almost all detergents clean clothes effectively in cold water.
  • Skip the dry cycle on the dishwasher when possible. Open the door slightly so dishes dry naturally. This measure can save about one-half the power consumed in a normal cycle.

Q: How can I reduce lighting costs?

A: NorthWestern Energy offers these useful tips:

  • Turn off lights when not in use. If fluorescent lights will be unused for 15-20 minutes, turn them off, too.
  • Consider installing motion sensors or timers on exterior lighting. Indoor occupancy sensors automatically turn off lights a short time after you leave a room and turn them on when you enter.
  • Replace traditional incandescent bulbs with compact fluorescent lamps (CFLs) where possible. CFLs have improved significantly in recent years. They are smaller and can fit almost everywhere standard incandescent bulbs are used. CFLs use about a third as much energy to create the same amount of light as incandescent bulbs, and they last 8 to 10 times longer. Choose a CFL with lumen output close to that of the incandescent bulb you use currently.
  • Avoid using long-life or extended-life incandescent bulbs. They give off less light than a standard bulb and use more energy.
  • Replace halogen torchieres with energy efficient CFL torchieres that operate at a much lower temperature, use less energy and are dimmable. Halogen versions can reach temperatures up to 1,000 F, creating fire hazards.

Fore more information on energy-efficient lighting, visit ENERGY STAR: Lighting Products.

Q: Are there inexpensive ways to save energy?

A: You bet! While many energy conservation measures require an investment, there are just as many no- or low-cost measures that can result in substantial energy savings. Consider these tips from the U.S. Department of Energy:

If you haven't already, conduct an energy audit to find out where you can save the most.

Take Advantage of Heat from the Sun

  • Open curtains on your south-facing windows during the day to allow sunlight to naturally heat your home, and close them at night to reduce the chill you may feel from cold windows.

Cover Drafty Windows

  • Use a heavy-duty, clear plastic sheet on a frame or tape clear plastic film to the inside of your window frames during the cold winter months. Make sure the plastic is sealed tightly to the frame to help reduce infiltration.
  • Install tight-fitting, insulating drapes or shades on windows that feel drafty after weatherizing.
  • Find out about other window treatments and coverings that can improve energy efficiency.

Adjust the Temperature

  • When you are home and awake, set your thermostat as low as is comfortable.
  • When you are asleep or out of the house, turn your thermostat back 10°–15° for eight hours and save around 10% a year on your heating and cooling bills. A programmable thermostat can make it easy to set back your temperature.
  • Find out how to operate your thermostat for maximum energy savings.

Find and Seal Leaks

Maintain Your Heating Systems

  • Schedule service for your heating system.
  • Find out what maintenance is required to keep your heating system operating efficiently.

Furnaces: Replace your furnace filter once a month or as needed.

Wood- and Pellet-Burning Heaters: Clean the flue vent regularly and clean the inside of the appliance with a wire brush periodically to ensure that your home is heated efficiently.

Reduce Heat Loss from the Fireplace

  • Keep your fireplace damper closed unless a fire is going. Keeping the damper open is like keeping a window wide open during the winter; it allows warm air to go right up the chimney.
  • When you use the fireplace, reduce heat loss by opening dampers in the bottom of the firebox (if provided) or open the nearest window slightly—approximately 1 inch—and close doors leading into the room. Lower the thermostat setting to between 50° and 55°F.
  • If you never use your fireplace, plug and seal the chimney flue.
  • If you do use the fireplace, install tempered glass doors and a heat-air exchange system that blows warmed air back into the room.
  • Check the seal on the fireplace flue damper and make it as snug as possible.
  • Purchase grates made of C-shaped metal tubes to draw cool room air into the fireplace and circulate warm air back into the room.
  • Add caulking around the fireplace hearth.
  • Find out more techniques to improve your fireplace or wood-burning appliance's efficiency.
  • Learn tips for safe and efficient fireplace installation and wood burning.

Lower Your Water Heating Costs

Water heating can account for 14%-25% of the energy consumed in your home.

  • Turn down the temperature of your water heater to the warm setting (120°F). You'll not only save energy, you'll avoid scalding your hands.
  • Find other strategies for energy-efficient water heating.

Lower Your Holiday Lighting Costs

Are ENERGY STAR qualified appliances worth the extra cost?

Yes. When buying an appliance, remember that it has two price tags: what you pay to take it home and what you pay for the energy and water it uses. ENERGY STAR qualified appliances incorporate advanced technologies that use 10–50% less energy and water than standard models. The money you save on your utility bills can more than make up for the cost of a more expensive but more efficient ENERGY STAR model.

For top performance, premium features, and energy savings, look for energy-efficient clothes washers, refrigerators, dishwashers, room air conditioners and dehumidifiers that have earned the ENERGY STAR. This mark may appear on the appliance, the packaging or the EnergyGuide label.

Does turning off computers really save energy?

Though there is a small surge in energy when a computer starts up, this small amount of energy is still less than the energy used when a computer is running for long periods of time. For energy savings and convenience, consider turning off:

  • the monitor if you aren't going to use your PC for more than 20 minutes
  • both the CPU and monitor if you're not going to use your PC for more than two hours.

Make sure your monitors, printers, and other accessories are on a power strip/surge protector. When this equipment is not in use for extended periods, turn off the switch on the power strip to prevent them from drawing power even when shut off. If you don't use a power strip, unplug extra equipment when it's not in use.

Most PCs reach the end of their "useful" life due to advances in technology long before the effects of being switched on and off multiple times have a negative impact on their service life. The less time a PC is on, the longer it will "last." PCs also produce heat, so turning them off reduces building cooling loads.

For cos- effectiveness, you also need to consider how much your time is worth. If it takes a long time to shut down the computer and then restart it later, the value of your time will probably be much greater than the value of the amount of electricity you will save by turning off the computer.

Power-Down or Sleep Mode Features

Many PCs available today come with a power-down or sleep mode feature for the CPU and monitor. ENERGY STAR® computers power down to a sleep mode that consume 15 Watts or less power, which is around 70% less electricity than a computer without power management features. ENERGY STAR monitors have the capability to power down into two successive "sleep" modes. In the first, the monitor energy consumption is less than or equal to 15 Watts, and in the second, power consumption reduces to 8 Watts, which is less than 10% of its operating power consumption.

Make sure you have the power-down feature set up on your PC through your operating system software. This has to be done by you, otherwise the PC will not power down. If your PC and monitor do not have power-down features, and even if they do, follow the guidelines above about when to turn the CPU and monitor off.

Note: Screen savers are not energy savers. Using a screen saver may in fact use more energy than not using one, and the power-down feature may not work if you have a screen saver activated. In fact, modern LCD color monitors do not need screen savers at all. (Source: EERE Energy Savers)

How do I know whether I should insulate my home?

Checking your home's insulation is one of the fastest and most cost-effective ways to use a whole-house approach to reduce energy waste and make the most of your energy dollars. A good insulating system includes a combination of products and construction techniques that protect a home from outside hot or cold temperatures, protect it against air leaks, and control moisture. You can increase the comfort of your home while reducing your heating and cooling needs by investing in proper insulation and sealing air leaks.

Insulate your home when:

  • You have an older home and haven't added insulation. Only 20% of homes built before 1980 are well insulated.
  • You are uncomfortably cold in the winter or hot in the summer—adding insulation creates a more uniform temperature and increases comfort.
  • You build a new home, addition, or install new siding or roofing.
  • You pay high energy bills.
  • You are bothered by noise from outside—insulation muffles sound.

Where to Insulate
Adding insulation in the areas shown above may be the best way to improve your home's energy efficiency. Insulate either the attic floor or under the roof. Check with a contractor about crawl space or basement insulation.

(source: DOE Energy Savers)

What home energy improvements are the best investment?

A: An energy audit's purpose is to identify places in the home where energy is being wasted and prioritize the projects needed to fix them.The end result is intended to reduce the amount of energy the home needs to operate and keep occupants comfortable. While the word “audit” may sound ominous, a home energy audit is just the first step in the process of lowering energy bills by making a home more efficient. Energy audits range from simple walk-throughs you can do yourself, to more elaborate services performed by trained professionals. Which is right for you will depend on your situation, abilities and interest level.

If you own the home, there is a clearly defined benefit for your efforts. You'll start saving money on your energy bills as soon as you identify and fix energy wasters. If you rent or lease, it's a good idea to check with your landlord early on to see if the audit findings can be acted on. A landlord who pays the utility bills is more likely to invest in the process knowing that there will be savings through lower utility bills down the road. If you are a tenant and pay the utility bills yourself, you'll benefit immediately from no-cost and low-cost measures uncovered by an energy audit. Improvements requiring an investment in the building itself or its systems should be carefully evaluated since you don't own them and won't be taking them with you if you move to another property.

The Internet has brought consumers many new conveniences and tools, including help evaluating your home's energy use. Online calculators let you enter information about your home and appliances and compute your energy costs. Such calculators can be helpful as part of an overall energy plan to help you assess and analyze your best savings opportunities. (Source: NorthWestern Energy)

For more information, visit these links:

Perform Your Own Audit
Professional Energy Audit

Q: Are there any energy-efficiency opportunities when replacing my roof?

A: Energy-savings opportunities can be achieved by carefully choosing roofing materials and by purchasing ENERGY STAR qualified roof products when possible. Some areas that should be considered when upgrading your roof include:

  • Insulation: When specifying or replacing a roof, insulation can be placed under the roof.
  • Radiant Barriers: In addition to traditional insulation, radiant barriers save energy both in the summer and winter by re-directing radiant energy in the facility.
  • Cool Roofing: These systems lower heat gain for facilities by reflecting the sun's radiant energy, saving energy on air-conditioning. Consult your roofing and HVAC professionals to learn if cool roofing is an option for your facility.

To learn more about energy-efficiency opportunities for roofing visit:

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