Common mistakes people make include:
- letting the furnace or air conditioner salesperson sell them a unit that’s much bigger than they need
- not getting the ducts checked for leakage when installing a new heating and cooling system
- thinking that “since heat rises, we only need to insulate the attic.” Floors over a basement or crawlspace, walls and windows also matter.
- not using ceiling and portable fans to improve comfort in the cooling season. They use very little electricity. Use them to circulate air in the house, to make the house feel cooler by doing this, the thermostat setting for your air conditioner can be raised to 85°F, and still maintain the same comfort as the lower setting.
If your house has central air conditioning, the air conditioner will probably be the biggest user by far. Although used only a few months of the year, the annual cost can be much greater than the annual cost of your refrigerator, which is typically the next largest user. In hot climates, the annual air conditioner cost can exceed a thousand dollars. You can get a very rough idea of what your air conditioner is costing you by subtracting the electric portion of your bill in a spring month when you aren’t using your air conditioner from the electric portion of the bill in the summer when you do use it. This gives you the monthly cost. Multiply this by the number of months you use your air conditioner to arrive at your approximate annual cost.
Refrigerators are typically the largest users in houses without air conditioning or in climates where the air conditioners are used only a few days of the month during the cooling season. If your refrigerator is more than ten years old should consider replacing it. New efficiency standards went into effect in 1992, and older refrigerators are typically two to three times more expensive to run than a new unit. For more information, go directly to the American Council for an Energy-Efficient Economy’s list of most efficient refrigerator-freezers.
There are a number of factors that cause differences in energy bills, so comparing your bill to someone else’s is like comparing apples to oranges. The ages of major appliances, especially refrigerators and air conditioners, can make a dramatic difference in your bill. In addition, if your house leaks air like a sieve while your neighbor’s house was just weatherized and insulated, you will have much higher heating and cooling bills. Other factors that can result in significant differences in bills are the number and kinds of lighting fixtures, thermostat settings for heating and cooling, the number of loads of laundry, old refrigerators out in the garage, and hobbies which result in electricity use.
Whether you should insulate or replace your furnace first depends on the situation in your house. Factors that influence this decision are the age and efficiency of your furnace, and the amount of insulation currently present in the house.
In general it is more cost-effective to upgrade insulation than it is to upgrade your furnace. However, if your furnace is old, and you are planning on replacing it anyway, you might want to upgrade the furnace if you have to choose between the two options. The average lifetime for a furnace is between 15 and 20 years. The efficiency of furnaces has increased over the years, so the older a furnace is, the more likely that furnace is to be inefficient. The average efficiency of new furnaces has increased from 63% in 1972 to 83% in 1995. Older furnaces and furnaces which are used a lot are more cost-effective to replace than newer or infrequently used furnaces. Also, if you insulate your house at the time of furnace replacement, you might be able to buy a smaller capacity furnace and save money on the price. The same holds true for A/C and other heating and cooling equipment.
Yes, programmable thermostats can reduce the energy used for air conditioning or heating by 5 to 30%. Programmable thermostats, while not always digital, save money by turning the air conditioner to a higher setting (or heater to a lower setting) when no one is present in the house or in the evenings when it is cooler. You can achieve the same savings without the programmable thermostat, but you would have to remember to change your thermostat every day when you leave the house, and turn it down every night when you go to bed. In addition, if you are using the thermostat to regulate your heater, you would wake to a cold house. The programmable thermostat does all of the remembering for you once it is set. A sample of a heating schedule you might program into a thermostat is:
Wake up 6:00 am – 9:00 am 68°F
Leave 9:00 am – 5:30 pm 60°F
Evenings 5:30 pm – 11:00 pm 68°F
Sleep 11:00 pm – 6:00 am 60°F
This way your house is always comfortable and you can save money on heating. You can make a similar schedule for air conditioning.
Wake up 6:00 am – 9:00 am 75°F
Leave 9:00 am – 5:30 pm 80°F
Evenings 5:30 pm – 11:00 pm 75°F
Sleep 11:00 pm – 6:00 am 78°F or off