Healthy HVAC systems maintain a comfortable environment for human beings to live, work and play in commercial and residential settings. But as in any job, HVAC contractors do run into problems. Here are the most common challenges related to HVAC systems and the most effective ways to tackle them:

Poor Indoor Air Quality (IAQ)

A poorly-designed or improperly maintained system can make people susceptible to a wide range of health problems, including asthma, fatigue, rashes, headaches, and eye, nose and throat irritation.

For example, according to The American Journal of Respiratory and Critical Care Medicine, cases of chronic asthma might be cut by 55-60 percent when biological contaminants — such as dust mites and cat allergens — are kept under control.

HVAC contractors dealing with this issue should always evaluate the design of a structure's ventilation system. Solutions to faulty ventilation might be as simple as moving ductwork or relocating intakes. Humidity control is another factor. Without consistent maintenance, sediment can clog condensate and drain lines, trapping moisture. This allows for potentially dangerous mold and bacteria to collect and breed.

Other IAQ troubleshooting strategies include:

• Replacing filters that haven't been changed in a long time
• Regular inspection and cleaning of air ducts
• Ongoing maintenance and cleaning of AC coils
• Often, central air purification systems or ultraviolet air purifiers are the best fix for poor IAQ.

Energy Inefficient Systems

Operation and maintenance of HVAC systems can be expensive — more so with old or ineffective systems. Modern ACs use 30 to 50 percent less energy as those from the 1970s, according to Energy.gov. By replacing ACs that are only 10 years old with an up-to-date, energy-efficient model, you can save 20 to 40 percent in cooling costs.

Other sources of HVAC energy inefficiency include:

• Dirty air filters
• Malfunctioning condensers or evaporators
• Particle-clogged ducts
• Improperly maintained chillers with damaged or leaky tubes

Effective strategies to boost energy efficiency include installation of a variable speed drive that analyzes a structure's necessary load demand and matches motor speed to meet that demand, and advising property and office managers to install energy-efficient lighting and windows, insulation and ENERGY STAR-certified office equipment.

Retrofitted Systems

In an attempt to cut high-energy costs and improve performance, many owners and property managers of older structures opt for retrofitted HVAC systems. These can pose challenges for HVAC contractors brought in as consultants or advisers prior to the retrofitting process.

It's important for managers to ensure everything is already in place and at maximum efficiency, prior to retrofitting. Otherwise, some planned alterations may not be required or may not result in the desired outcome.

To offset this challenge, contractors should recommend extensive testing and balancing of the "old" system. This can be particularly useful if a contractor already knows the structure's HVAC system and can offer input.

Just as importantly, contractors can urge managers and owners to design an all-encompassing retrofit strategy for the building in question as opposed to making piecemeal changes along the way. Without a master plan, unforeseen HVAC-related issues may arise — and they can be expensive.

HVAC contractors are often uniquely positioned to offer strategic advice about meeting HVAC challenges. Taking a proactive role can make your services more appealing to both current and future customers.