CUB Energy Saver

Energy Reference

Space Heating

Space heating is generally the single largest category of energy use in the house. Homes are generally heated using natural gas, electricity, fuel oil and, in more rural areas, occasionally propane. In general, the cheapest, cleanest, and most efficient home heating fuel is natural gas, which is also the fuel used by most households in the state. Electricity tends to be the most expensive way to heat your home, simply because you are adding the additional step of burning fuels at a power plant to generate electricity, which you then convert to heat in your furnace.

The best way to reduce your home heating use is to turn down the thermostat a few degrees in the winter. Its somewhat counterintuitive, but the first few degrees you lower your thermostat can save a disproportionately large amount of energy and money. Similarly, you can use a programmable thermostat to automatically turn the heat down at night and during times when you are away from home.

The thermal envelope of your home is essential to keeping heat inside and reducing heating costs. Homeowners can improve their thermal envelope by reducing air leaks and improving insulation. In both cases, you may be able to request a free in home energy audit from your utility that will help identify air leaks and places in your home where more insulation would be useful.

If you have a home furnace older than 15 years, especially if its an electric furnace, it might make sense to replace it with a more efficient model. A 20 year old gas furnace, for example, is only about 68% efficient, while a brand new Energy Star™ certified gas furnace can be up to 97% efficient, and replacing your old furnace with a more efficient one could pay for itself in less than 7 years.

Water Heating

The hot water from your home’s water heater is used in a number of different places in your home, including showers/baths, washing clothes, dishwashers, and faucets. There are cheap and easy ways to reduce the amount of water you use for each of these.

For saving water in the shower, you can install a low flow showerhead that gives you the same shower strength with around 30 percent less water used. You can also take shorter showers, take showers instead of baths, or lower your shower temperature a bit.

For washing clothes, you can use a cold rinse cycle and a warm or cold wash cycle in your washing machine to save a surprising about of energy and money. You can also wash larger loads of clothes, since the amount of water needed is usually the same no matter how full the washer is. Finally, you can invest in a new high-efficient Energy Star™ certified front-loading washing machine, which will use less water and energy than old top-loading models.

For dishwashers, you can wash dishes by hand using warm or cold water rather than hot. You can also try and wash larger loads of dishes, or run your dishwasher on an efficiency setting or at a lower temperature.

For faucets, you can install an aerator on your kitchen or bathroom sinks that reduces the flow while maintaining the water pressure. When you are washing dishes in the sink, you can fill up the sink rather than leaving the water running the whole time. You can also scrape and only lightly rinse dishes before putting them in the dishwasher.

Finally, there are a number of steps that you can take to reduce the energy used by your water heater itself. The easiest is simply turning down the temperature from 130 or higher to 120 or 115, since most water heaters are set to a temperature that is higher than you will ever really need. You can also buy a water heater blanket to improve its insulation, and also insulate your hot water pipes. The hot water heater itself can be replaced with a solar water heater, a tankless water heater, or a more efficient natural gas water heater.


Cooling (air conditioning) is a major source of energy for homes in areas with warm summers. Even in temperate places, air conditioning can add a few hundred dollars to your summer electricity cost. Homes generally use energy for cooling via central air conditioning (AC) units, window ACs, and fans.

Central ACs tend to be the most energy intensive, simply because it is more difficult to limit what parts of the house you cool. Fans, on the other hand, only use a tiny fraction of the energy that ACs use. The amount of cooling energy your home needs depends largely on the outdoor summer temperature, the size and number of rooms in your home, and temperature setting of your thermostat if you use one.

There are a number of ways that you can save money and reduce your cooling energy use. First and foremost is simply turning up the thermostat a few degrees. A few degrees can make a big difference in the size of your bill! If you use window ACs, try to only turn them on in rooms that you need to cool. Shutting the door to and closing the vents in rooms that you don’t to cool can also reduce your cooling energy use.

Fans can make a room feel quite cool without requiring any real air conditioning. In general, a fan can make a room feel about 7 degrees cooler than it otherwise would, so if you are comfortable at, say, 72 degrees than you would likely be fine only using a fan when its 79 degrees outside.

For homes with a central AC unit, you can often use a single programmable thermostat to control both heating and cooling. This will let you automatically turn down the AC when you leave for work or overnight.

Improving your home’s thermal envelope by sealing leaks can also reduce cooling needs. Closing your blinds during summer days or using reflective solar screens in your windows can help keep the sun’s heat out.


In the average U.S. home, lighting accounts for about 20% of the electric bill. You can cut this usage by over two thirds, and save hundreds of dollars a year, simply by switching to more efficient lighting.

A high-efficient compact fluorescent light bulb (CFL) will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75 percent less energy and lasts about 10 times longer than conventional incandescent (filament) bulbs.

CFLs need a little more energy when they are first turned on, but once the electricity starts moving, use about 75 percent less energy than incandescent bulbs. A CFL’s ballast helps "kick start" the CFL and then regulates the current once the electricity starts flowing.

There are CFL models suited for almost all possible home light fixtures. The only place where CFLs may not be appropriate is for lights on dimmers, though new (and somewhat expensive) models can work on dimmable fixtures.

Additional ways to reduce lighting energy use include turning of the lights when you leave rooms, using solar-powered outdoor lights, and using more natural light via windows and skylights.

Large Appliances

A number of large appliances use a significant portion of total appliance energy use in the average home. These include the refrigerator, freezer, stove/oven, microwave, clothes washer, clothes dryer, and dishwasher. While all of these can be improved by buying new, high-efficient Energy Star™ certified appliances, there are also a number of ways that you can reduce your large appliance energy use through simple steps.

Refrigerators have become considerably more efficient over the last 20 years. A refrigerator in 1980 used close to three times more energy than a similar-sized refrigerator today. Unless your fridge is quite old, it probably doesn’t make sense to buy a new one solely to improve its efficiency. However, you can improve the performance of your current fridge by not overfilling it, keeping the door closed whenever possible, and letting hot foods cool in the air before putting them in the fridge.

Many people have an old extra freezer in their basement of garage. These can be huge energy hogs, and if you can unplug them for all or part of the year you can save up to a few hundred dollars.

Gas ovens and stoves tend to be more efficient and cheaper to operate than electric ones. Self-cleaning electric ovens, in particular, tend to use a lot of energy, and you can save money by cleaning them by hand if you have the time. Microwaves use considerably less energy than ovens and take less time to cook, so microwaving food when possible is another good way to save.

Ways to reduce the energy used by clothes washers and dishwashers are discussed in the water heating section, since the majority of energy used by these machines usually comes from the home’s water heater. Dryers also use quite a bit of energy, and you can save up to $100 a year by using a drying rack or clothes line instead.