HVAC stands for heating, ventilation and air conditioning, is the technology of indoor and vehicular environmental comfort. The three functions often combined into one system to give comfort. HVAC is a common word in heating and cooling industry. Like lots of other appliances, it has improved in energy efficiency in past years. As a result, we can save lots of money and increase our comfort by proper maintenance and upgrade our HVAC systems. HVAC systems should be installed properly, the operating efficiency of a HVAC system depends as much on proper installation as it does on the performance rating of the equipment. If system will not install properly it will give bad impact on comfort and electricity bills. It will degrade comfort, degrade air quality and it will threaten the health of homeowners. If we feel any problem like this, then we have to hire a contractor.