Glossary of HVAC Definitions and Terms I-Z

Glossary of HVAC Terms

Lien Release - Once the HVAC contractor finishes the work and is paid in full, the homeowner should be sure to get a signed document that releases and protects the homeowner from any potential liens.

R-Value - A rating of insulation capacity. The higher the R-value, the more insulation and the less loss or transfer of energy - for example through walls or roofs. Without sufficient R-value it is possible to heat or cool a structure but still lose the heating or cooling energy as it leaks out of the building.

Refrigerant - Most consumers refer to refrigerant as Freon. It is a liquid that converts into a gaseous state by evaporation at low temperatures. The refrigerant draws heat and humidity or moisture from the atmosphere and by doing so it creates a cooling effect.

SEER - Another rating or measurement similar to the AFUE, the SEER is an industry rating that indicates how well a heating or air conditioning unit performs. The higher the SEER rating, the more powerful the unit, so consumers generally pay more for higher rated units but get better performance as a return on that investment. Lower ratings are below 10, whereas high-performance units offer ratings of as high as 17.

Subcontractor - When a contractor hires someone else to do work that person is a subcontractor. General Contractors often "sub-out" HVAC jobs to HVAC specialists. Homeowners should check credentials of all "subs" used on a project.

Ton - A unit of freezing power that is used by HVAC professionals to measure the capacity for cooling a home. One ton of air conditioning power removes 12,000 BTUs of heat per hour, so knowing the tons an A/C system generates helps to calculate its practical performance.

Worker's Comp - Worker's Compensation Insurance or "workman's comp" is a specific kind of insurance that covers workers in the event of an accident or injury on the job. Homeowners should insist that all contractors carry their own Worker's Comp policies, otherwise if a worker is hurt while on the owner's property the homeowner could be liable for damages.