Once you have your home properly sealed and insulated, your work isn't done. Homeowners willing to get their hands dirty with cleaning and minor maintenance tasks can improve their home's energy efficiency. Below are some guidelines on how periodic cleaning can add up to saving you money.
Cleaning Refrigerator Coils Regularly
The coils underneath and behind a refrigerator are dust magnets. Refrigerant is pumped and circulated through the coils as a fan blows room air across them. The moving air removes heat from the refrigerant inside the coils. As the fan sucks air from underneath the refrigerator, it brings along with it dust and dirt that stick to the coils. Removing the access panel from the lower front of the refrigerator can reveal a startlingly filthy sight if the coils haven't been cleaned in a while.
In addition to being unsightly, the dust on the coils acts as insulation that prevents the fan from efficiently removing heat. Cleaning the refrigerator coils a couple of times a year with a vacuum cleaner and an elongated brush helps the refrigerator operate at its maximum efficiency. Moving a refrigerator away from a wall so air can circulate behind it will increase its energy performance, as will keeping it out of direct sunlight and away from heat sources like a radiator or a range.
As energy-saving tips go, cleaning the coils under your refrigerator probably produces little economic effect compared to the amount of effort required to do the job. But it's still a task worth undertaking, if only for the hygienic benefit.
Replacing the Furnace Filter
The filter on a forced-air furnace performs a valuable function in the home. It strains bits of dust, dirt, and debris from the air stream as it passes through the furnace. This not only improves air quality, but it also protects the inside of the furnace (and air-conditioning evaporator coil, if there is one). Without a furnace filter in place, dirt would build up on the back side of the heater exchanger and inside the evaporator coil. That dirt would act as insulation and interfere with the efficient transfer of heat from the furnace or cooling from the air conditioner to the air passing through it.
But a furnace filter also slows the passage of air through the furnace -- especially when it is dirty. The best way to keep your furnace operating at its maximum efficiency is to keep a clean filter inside. That's one of the only things you as a homeowner can do to maintain your furnace.
Filters can be purchased in bulk and replaced every 30 to 45 days, or they can be vacuumed at those same time intervals. People who own pets may find that their furnace filters need to be replaced or cleaned more frequently, due to pet dander, hair, and dirt brought in from outside.
It is important to remember that in most homes that have a central air-conditioning system, the furnace's blower is used to distribute cool and dehumidified air during the summer months. Therefore, air passes through the furnace -- and the furnace filter -- during those months as well. That's why homeowners with central air-conditioning systems need to change or clean filters in the summertime at roughly the same intervals as they do during the winter. The more freely air can pass through the furnace, the more heat and cooling it can distribute while wasting less energy.
Tuning Up Heating and Cooling Equipment
Furnaces, boilers, and air-conditioning systems all have mechanical, moving parts in addition to electrical components. Over time these parts can go out of adjustment and need lubrication and cleaning. Like an automobile, your heating and cooling equipment runs best when it is "tuned up" and all the parts are working together as they were designed.
Tuning up heating, ventilation, and air conditioning equipment, especially the newer, more complicated systems, should be attempted only by service people who have the training and the equipment to do the work. How often should you call for service? For oil-fired systems, the recommended interval is a year. Gas-fired furnaces and boilers and air-conditioning systems should be checked at least every two years.
Just as tuning up a car can yield better gas mileage, the money you spend on servicing your HVAC equipment will pay off in better efficiency -- and will also extend the life of the components.
Removing Dirt From Baseboards
Hot water baseboard and electric baseboard heating systems run at maximum efficiency only if the baseboard convectors and radiators are kept clean. These systems depend on air flowing through the many fins that surround the pipes or heating elements. Obstruction of that air -- either from dirt and dust buildup or from something covering the top or bottom of the heating units -- compromises the performance of the entire system. As is the case with a forced-air furnace, freely flowing air contributes to better efficiency and energy conservation.
Removing or opening the covers that surround baseboard convectors exposes the fins that distribute heat from hot water inside the pipes or heating elements. Vacuuming and brushing the fins, and straightening any that are bent, ensures efficient airflow -- and thus efficient heat transfer to the air.
Checking Ducts for Leaks
Duct sealing: Keeping ducts clear of dirt will help heat and air conditioning flow properly to all rooms. Scheduling an annual service cleaning also will provide an opportunity to check for leaks. Here's a startling statistic: Professional heating, ventilation, and air-conditioning organizations estimate that 25 percent of the air traveling down a poorly installed forced-air duct system winds up somewhere other than where it was intended to go. In other words, some duct systems leak 25 percent of the air passing through them. That leakage might occur in basements, crawl spaces, duct chases, or attics. The bottom line is that you're not getting all the heating and cooling for which you are paying.
The solution to leaky ducts is duct sealing. While it is tempting to use a product called "duct tape" to do this job, regular duct tape is actually poorly suited for duct sealing. The adhesives in cloth duct tape break down in the presence of heat; eventually the tape fails and falls off the duct.
A product better suited for the task is duct-sealing mastic, available in tubs at heating supply houses, hardware stores, and home centers. To apply duct mastic, dip a gloved hand into the tub, scoop out some mastic, and smear it all around every single joint you can find in your ductwork. The mastic has the consistency of pancake batter, and once it cures it stays on the duct and doesn't leak.
There are plenty of opportunities in most forced-air heating and cooling systems to upgrade the performance of the ducts. Loosely fitting joints and gaps large and small also should be sealed as soon as possible.
After a sealing job is complete, diverter vanes inside the ducts (if they are installed) might have to be rejiggered and cleaned because air that was supposed to go to a certain area will finally be doing so. The result might be that a formerly cold room is suddenly the warmest one in the house. Also, the furnace or A/C compressor might not come on as often once the conditioned air is getting to where it was designed to go. Duct mastic is inexpensive, the time it takes to seal up your ducts is minimal, and the results can be dramatic.
Duct wrappers: After duct sealing is complete, it's time to think about upgrading your forced-air delivery system even further.
Any ducts passing through unheated crawl spaces or attics should be insulated. Heat and cooling thrown off by the ducts in such areas is completely wasted, but if that heat and cooling were retained, the furnace or air conditioner might not have to work so hard to condition the house.
Duct insulation is available in both wrapping and sleeve types. Sleeves are more effective because they have fewer seams, but may require temporary disassembly of the ducts in order to slip them into place.
Maintaining a Clear Path for the Air Conditioner
Air-conditioning systems work by moving refrigerant from inside the house to outside. Inside the furnace evaporator coil, the refrigerant absorbs heat from the air passing through the blower compartment. The refrigerant is then pumped outside and flows into a heat-transfer assembly called the condenser. The condenser coils resemble an automobile's radiator. As refrigerant flows through small tubes in the condenser coils, thin metal fins attached to those tubes extract heat from the refrigerant.
A fan inside the condenser moves air past all the tiny fins and tubes, accelerating the transfer of heat from the refrigerant to the outside air. But this cooling flow of air can take place only when the pathways to the compressor are unobstructed. Landscape plantings, ivy, decks, or benches built over and around the compressor restrict the free flow of air through the system, reducing its efficient transfer of heat. So, to get the most for your A/C dollar, it's a good idea to keep the outside compressor unit cleared of nearby obstructions.
Because airflow through the condenser is important for the efficient function of a central air-conditioning system, carefully examine the outside of the condenser unit from time to time. The thin metal fins are fragile and can bend if something comes in contact with them -- a baseball, lawn mower tire, or edge of a rake, for example. "Fin combs" are inexpensive at heating supply stores and home centers, and they can straighten several rows of bent fins at once.
Cleaning and minor maintenance aren't the only steps you can take around the house to help improve energy efficiency. In the next section we'll talk about strategies for more effective water conservation.