Questions to Ask HVAC Technician When Installing New System

Did you know that more than half of all new HVAC system in the United States do not live up to their efficiency ratings? This is due to improper installations by HVAC contractors. In fact, a faulty installation can reduce performance by up to 30%!

These frequent installation mishaps not only raise your utility bills unnecessarily, but they also contribute to discomfort and a variety of indoor air problems, such as insufficient dehumidification, dust from leaking ductwork, and ventilation problems.

This is all to say that you should be very careful when shopping around for HVAC contractors. It may cost more upfront to have the installation done properly, but it is well worth it. A high-efficiency HVAC system means little if it is not installed according to ENERGY STAR Quality Installation Guidelines:

Questions to Ask HVAC Technician Before Installing New System


  • Do you offer ENERGY STAR qualified equipment?
  • Will you measure my home and calculate the correct size for my equipment using Manual J?¹
  • Will you install a properly matched indoor coil and outdoor unit?² (AC & heat pump only)
  • Will you test to determine the maximum system size that can be installed with my existing ductwork?
  • Will you install new refrigerant lines rather than reusing existing lines?
  • Will you install and help me to set up a programmable thermostat (if not already in use)?
  • Will you consider if zoning, with separate temperature controls for different areas, would be appropriate for my home?
  • Will you provide me with information on any local rebate programs for which I might be eligible?


  • Will you check for damage to existing ductwork and duct insulation, and make repairs if necessary?
  • If insulating ducts, will you seal all duct seams first?
  • Will you test to confirm that duct leakage does not exceed recommended levels?³


  • Will you show me how to replace the air filter(s) in my new system?
  • After installation, will you leave all manuals with me and provide documentation of installation procedures, including Manual J calculations, AHRI certificate, and records of any measurements or testing?
  • Do you offer third-party verification that my system was properly installed and set up?
  • Will you confirm proper levels of refrigerant and airflow across the coil? (AC & heat pump only)

1. Proper equipment size is vital for maximizing efficiency and comfort. To size your new system, the contractor should calculate your home’s heating and cooling loads using the Air Conditioning Contractors of America (ACCA) Manual J or equivalent.

2. Your contractor should provide an Air Conditioning, Heating and Refrigeration Institute (AHRI) certificate to document that your system was properly matched.

3. Duct sealing is essential to the operation of your heating and cooling system. In most cases, it is recommended that total duct leakage be no more than 20%.

Replacing your HVAC system is not as simple as swapping out your old equipment for a new one. Any HVAC contractor that gives you a quote before conducting a thorough inspection of your existing system, ductwork, insulation and ventilation, simply is not doing it right.

For more tip tips and tricks for saving money and energy, read our other blog posts:

Call Larry & Sons for professional HVAC replacements done according to ENERGY STAR’s Quality Installation Guidelines.

Whether you need a home zoning solution, are interested in sustainable energy solutions like geothermal, or are simply looking for a new high-efficiency air conditioner, look no further.

We’re happy to answer all of your questions! Just give us a call today at (301) 733-5428.

We stand behind our 100% Satisfaction Guarantee  and are committed to providing top quality HVAC installation services in Hagerstown, Frederick MD, and the surrounding areas.

We service Hagerstown, Frederick, and the surrounding Maryland areas. We also service parts of West Virginia and Pennsylvania.

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