(BPT) - – Those statistics about indoor air pollution and it’s relation to respiratory problems convinced you it was time to get your heating, ventilation and air conditioning system (HVAC) cleaned. You were even looking forward to the increased energy efficiency that a clean system can provide. But $49 and one very noisy service call later, you’re still sneezing and you haven’t seen any dip in your energy bill.

What happened?

“A very low service charge may indicate the service provider isn’t performing a thorough cleaning and maintenance of your home’s entire HVAC system,” says Matt Mongiello, president of NADCA, the HVAC Inspection, Maintenance & Restoration Association. “He or she may have done nothing more than blow air through the ducts and clean off vent grills inside the home. A cleaning performed to NADCA standards – which are cited by the EPA as a best practice – encompasses much more than just the ductwork.”

HVAC companies are among the top 10 industries with the most complaints, according to the Better Business Bureau. So how can a homeowner know if a service provider is doing a good job, or just blowing hot air?

The EPA recommends you interview companies to ensure they have experience working on your type of system, that they will take steps to protect your home and everyone in it from contamination, and that they comply with NADCA’s air duct cleaning standards.

NADCA members carry general liability insurance, have at least one person on staff trained and certified as an Air Systems Cleaning Specialist, and clean and restore heating and cooling systems following the association’s standards and guidelines. A job done to NADCA standards should include:

* A thorough inspection of the HVAC system before doing any work, and full disclosure of any problems discovered during the inspection.

* Examination of metal ductwork at several random sites to ensure the interior surfaces are free of visible debris.

* Cleaning of both the supply and return air ductwork.

* Removal, cleaning and resetting of all supply registers, return air grilles and diffusers.

* Cleaning of the supply and return air plenums.

* Inspection and/or installation of access panels.

* Cleaning of the air-stream side of the heat exchanger and cleaning of the secondary heat exchanger.

* Removal, cleaning and reassembly of the blower motor.

* Cleaning and inspection of the blower blades and blower compartment.

* Cleaning of the evaporator coil, drain and pan. If the cooling coil is clean, light should shine through it when you point a flashlight at the coils.

* Inspection and repair of the coil fins if needed.

* Replacement of air filters.

* Washing of the air cleaner.

While some companies may tout “duct-cleaning” for very low prices, be wary of these offers,

Mongiello, advises. “A cleaning typically costs between $450 and $1,000 per heating and cooling system, depending on the services offered, the size of the system, how easily accessible it is, the climate in your region and how dirty it is,” he says.

Many of those variables will influence how long the job takes, too. Before you hire a contractor, contact at least two NADCA member companies to provide you with a time estimate for the job. “You’ll get an idea of how long the job should take,” Mongiello says. “But in general, a service provider who’s in and out of your home in an hour or less may be leaving out some steps that are necessary to do the job right.”

Finally, Mongiello advises, feel free to stick around while the technicians do their job. “As long as the homeowner’s presence isn’t compromising anyone’s safety, there’s no reason a consumer can’t observe how a job is done,” he says.

To find a NADCA-certified HVAC cleaning company in your area, visit www.nadca.com.