SEER is useful for comparing one model to another much in the same way that a car's calculate MPG is useful. It's not an accurate prediction of exactly how efficient the system is, but it can tell you which one is more efficient. Also, since SEER is based on a "cooling season", what region you live in will determine how long or short your cooling season is.
Many homes have a forced-air HVAC system. Both the heating and the central air conditioning units share a ductwork system where they either push in or pull out warm or cooled air. There are also heating and cooling systems that don’t require ductwork — such as ductless mini-splits — but work on the same principles of heat exchange. The national average to hire an HVAC specialist is $2,920-$3,670, with costs varying depending on the work you need done and the equipment you are installing.
The key to the continued and efficient operation of your heating and cooling system is periodic maintenance. Cleaning the air duct vent system, and servicing you heating and cooling equipment will keep the system operating at its peak performance. Air ducts are cleaned for two reasons. One: to prevent debris from entering furnace and air conditioning components. Two: to prevent debris from cycling through the home. The air duct cleaning contractor needs to employ cleaning methods which successfully removes debris, and ensures that debris does not enter the occupied space. Most contractors can verify the results of the cleaning through video or pictures.
I originally took off one star because of the SNAFU with getting the part ordered.  When Alberto called me on the phone he admitted the person had "gotten busy with other things" and apologized.  THAT was taking the high road and I was impressed by that.  Sadly, for reasons I won't guess at, Alberto has decided to take the low road in his comments and imply that they got the part as quickly as possible.  Well, we called at 2:30 so did someone spend six and a half hours finding the part??  That seems very doubtful.
Many central air conditioning systems use the furnace blower to distribute cool air through the home. If you do not have a central heating system installed, it is cost-effective to install a heating and air conditioning system at the same time. If you already have central heat, you can use the existing fans and duct system for the central air system.
Despite Bergendahl's experience, Vinick says NADCA's certification standards have improved the situation. "A lot of [service companies] weren't going about it the correct way," he says. “We have an anti-fraud task force, and we’ve gone after some fraudulent duct cleaners with the help of state attorneys general.” He suggests that in addition to NADCA membership, homeowners make sure their cleaners are an established business, have appropriate insurance and are registered to do business in their state and locality.
If not properly installed, maintained and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.
Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants that have the potential to affect health, such as mold, fungi, bacteria, and very small particles of dust. The removal of such contaminants from the HVAC system and home should be considered as one component in an overall plan to improve indoor air quality.
EPA does not recommend that air ducts be cleaned except on an as-needed basis because of the continuing uncertainty about the benefits of duct cleaning under most circumstances. EPA does, however, recommend that if you have a fuel burning furnace, stove, or fireplace, they be inspected for proper functioning and serviced before each heating season to protect against carbon monoxide poisoning. Some research also suggests that cleaning dirty cooling coils, fans and heat exchangers can improve the efficiency of heating and cooling systems. However, little evidence exists to indicate that simply cleaning the duct system will increase your system's efficiency.
Manufacturers of products marketed to coat and encapsulate duct surfaces claim that these sealants prevent dust and dirt particles inside air ducts from being released into the air. As with biocides, a sealant is often applied by spraying it into the operating duct system. Laboratory tests indicate that materials introduced in this manner tend not to completely coat the duct surface. Application of sealants may also affect the acoustical (noise) and fire retarding characteristics of fiber glass lined or constructed ducts and may invalidate the manufacturer's warranty.
Most people are now aware that indoor air pollution is an issue of growing concern and increased visibility. Many companies are marketing products and services intended to improve the quality of your indoor air. You have probably seen an advertisement, received a coupon in the mail, or been approached directly by a company offering to clean your air ducts as a means of improving your home's indoor air quality. These services typically — but not always — range in cost from $450 to $1,000 per heating and cooling system, depending on: