HVAC Resources

for Marble Falls, Kingsland, Granite Shoals, Burnet, Horseshoe Bay, and Cottonwood Shores Since 1978
Below you will find a collection of helpful terms and definitions for the HVAC industry. If you can’t find a term or become overwhelmed contact us today for help!

A.F.U.E.
Annual Fuel Utilization Efficiency applies to furnaces – both gas and oil.  It describes the percentage of heat produced for every dollar of fuel  consumed.

A.H.R.I.
The Air Conditioning, Heating, and Refrigeration Institute is the authority  on HVAC ratings such as SEER, EER, HSPF, and AFUE

Air Balancing
The process of installing dampers in ductwork to direct airflow throughout a building. The dampers allow the contractor to adjust the amount of air that enters a Room.

Air Cleaning
An IAQ control strategy to remove various  airborne particulates and/or gases from the air. The three types of air  cleaning most commonly used are particulate filtration, electrostatic  precipitation, and gas absorption.

Air Conditioner
A device used to control temperature and  humidity of the air.

Air Conditioning
In HVAC it is the control of the quality,  quantity, and  temperature-humidity of the air in an interior space.

Air  Handler or Air  Handling Unit (AHU)
Used instead of a  furnace for  electric heating applications. The equipment that includes a  blower or fan,  heating and/or cooling coils, and related equipment such as  controls, condensate drain pans, and air filters. Does not include ductwork,  registers or  grilles.

Allergen
A substance capable of causing an allergic reaction  because of  an individual’s sensitivity to that substance.

Ambient  Air
The air external to a building or device.

Attic Fan
A fan mounted on an attic wall used to exhaust warm  attic air to the outside.

Attic Vent
HVAC term for a passive or mechanical device used  to ventilate an attic space, primarily to reduce heat buildup and moisture condensation.

Blower
The device  in an air conditioner that distributes the filtered air from the return duct  over the coil/heat exchanger. This circulated air is cooled/heated and then  sent through the supply duct, past dampers, and through supply diffusers to the living/working space.

British Thermal Unit (BTU)
The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit, equal to 252 calories.

Carbon  Monoxide (CO)
A colorless, odorless but poisonous combustible gas with the  formula CO. Carbon monoxide is produced in the incomplete combustion of  carbon and carbon
compounds such as fossil fuels (i.e. coal, petroleum) and their products (e.g. liquefied petroleum gas, gasoline), and biomass.

CFC
Chlorofluorocarbons are ozone-depleting chemicals and are being phased out by the Environmental Protection Agency. HVAC refrigerant R-22 is an example of a CFC that is being phased out and replaced by an HCFC.

Compressor
A device used to compress air for mechanical or electrical power  production, and in air conditioners, heat pumps, and refrigerators to  pressurize the refrigerant and enabling it to flow through the system.

Condenser Coil
The device in an air conditioner or heat pump through which the  refrigerant is circulated and releases heat to the surroundings when a fan  blows outside air over the coils. This will return the hot vapor that entered  the coil into a hot liquid upon exiting the coil.

Condenser or Condensing Unit
The component of a central air conditioner that is  designed to remove heat absorbed by the refrigerant and transfer it outside the conditioned space.

Conditioned Air
Air that has been heated, cooled, humidified, or dehumidified to  maintain an interior space within the “comfort zone.” (Sometimes  referred to as “tempered” air.)

Cooling Capacity
The quantity of heat that a cooling appliance is capable of  removing from a room in one hour.

 









 
 
 
 
 
 




 
 
 


Dampers
Controls that vary airflow through an air outlet,  inlet, or duct. A damper position may be immovable, manually adjustable or  part of an automated control system. Different types of dampers are used in air balancing and zoning

Dehumidifier
A device that reduces the level of humidity in a room or home.

Diffusers  and Grilles
Components of the ventilation system that distribute and return  air to promote air circulation in the occupied space. As used in this  document, supply air enters a space through a diffuser or vent and return air  leaves a space through a grille.

Duct(s)
The round or rectangular tube(s), generally constructed of sheet metal,  fiberglass board, or a flexible plastic-and-wire composite, located within a  wall, floor, and ceiling that distributes heated or cooled air in buildings.

EER
Energy Efficiency Ratings (EER) measure the efficiency with which a product  uses energy to function. It is calculated by dividing a product’s BTU output  by its wattage.

Electronic Air Cleaner
An electronic device that filters out large particles and  contaminants in indoor air. It then electronically pulls out tiny particles  that have been magnetized, such as
viruses and bacteria, drawing them to a  collector plate.

Environmental Agents
Conditions other than indoor air contaminants that cause stress, comfort, and/or health problems (e.g., humidity extremes, drafts, lack of air  circulation, noise, and
over-crowding).

Exfiltration
Occurs when air escapes an area, specifically a building, and is the opposite of infiltration.





 
 
 
 
 
 




 
 
 


EER
Energy Efficiency Ratings (EER) measure the efficiency with which a product  uses energy to function. It is calculated by dividing a product’s BTU output  by its wattage.

Electronic Air Cleaner
An electronic device that filters out large particles and  contaminants in indoor air. It then electronically pulls out tiny particles  that have been magnetized, such as
viruses and bacteria, drawing them to a  collector plate.

Environmental Agents
Conditions other than indoor air contaminants that cause stress, comfort, and/or health problems (e.g., humidity extremes, drafts, lack of air  circulation, noise, and
over-crowding).

Exfiltration
Occurs when air escapes an area, specifically a building, and is the opposite of infiltration.

HCFC
Hydrochlorofluorocarbons are the safer refrigerant alternative to chlorofluorocarbons, or CFCs, which deplete the ozone layer. R-410a is a HCFC.

Heat Loss
The heat that flows from the building interior, through the building  envelope to the outside environment.

Heat Pump
A product that works just like an air conditioner in cooling mode;  however, in heating mode, the refrigerant flow is reversed and heat is  extracted from the outside air too heat your home.

Heat Load
The rate of heat flow required to maintain a specific indoor  temperature; usually measured in Btu per hour.

HEPA
High efficiency particulate resistance (filters).

Humidity
A measure of the moisture content of air; may be expressed as absolute,  mixing ratio, saturation deficit, relative, or specific.

HVAC
An acronym for heating, ventilation, and air-conditioning

 
 
 
 
 




 
 
 


IAP
Indoor air pollutant: Particles and dust, fibers, mists, bio-aerosols, and  gases or vapors.

IAQ
HVAC acronym for Indoor Air Quality

Load Calculation
A series of studies performed to determine the heating or  cooling requirements of your home. An energy load analysis uses information  such as the square footage of your home, window or door areas, insulation  quality and local climate to determine the heating and cooling capacity needed by your furnace, heat pump or air conditioner. When referring to cooling this is often known as a Heat Gain Analysis, since a home’s cooling requirements are determined by the amount of heat absorbed through the roof, entry way and walls.

Matched System
A heating and cooling system comprised of products that have been  certified to perform at promised comfort and efficiency levels when used  together, and used according to design and engineering specifications.

Organic Compounds
Chemicals that contain carbon. Volatile organic compounds  vaporize at room temperature and pressure. They are found in many indoor  sources, including many common household products and building materials.

Particulate Matter
A state of matter in which solid or liquid substances exist in the  form of aggregated molecules or particles. Airborne particulate matter is  typically in the size range of 0.01 to 100 micrometers.

Particulates
Fine liquid or solid particles such as dust, smoke, mist, fumes, and fog  found in air and emissions.

Plenum
HVAC term for an air compartment connected to a duct or ducts.

Preventive  Maintenance
Regular and systematic inspection, cleaning, and replacement of  worn parts, materials, and systems. Preventive maintenance helps to prevent  parts, material, and systems failure by ensuring that parts, materials and systems are in good working order.

Programmable Thermostat
A type of thermostat that allows the user to program into the devices’  memory a pre-set schedule of times (when certain temperatures occur) to turn  on HVAC equipment.

Puron  Refrigerant
Puron® refrigerant is an environmentally sound refrigerant  designed not to harm the earth’s ozone layer. Federal law requires that all  manufacturers phase out ozone depleting refrigerants in the next few years.  Puron refrigerant is approved by the US Environmental Protection Agency as a  replacement for R-22 a.k.a. Freon.

R-22  Refrigerant
R-22 is a single component HCFC refrigerant with low ozone  depletion potential. It has long been used in a variety of air-conditioning  and refrigeration applications in a variety of markets. Per U.S. EPA  regulations, new R-22 cannot be used in new systems effective in 2010,  although service quantities of the refrigerant may be produced until 2020.

R-410a Refrigerant
R-410a is a blend of hydrofluorocarbons also known as HFCs which does not contribute to the depletion of the ozone layer. This is the “new refrigerant” which replaces R-22 systems. R-410a is not compatible with R-22 equipment due to its higher psi operation.

R-Value
A measure of the capacity of a material to resist heat transfer. The  R-Value is the reciprocal of the conductivity of a material (U-Value). The  larger the R-Value of a material, the greater its insulating properties.

Radiant  Barrier
In HVAC a thin, reflective foil sheet that exhibits low radiant  energy transmission and under certain conditions can block radiant heat  transfer; installed in attics to
reduce heat flow through a roof assembly  into the living space.

Refrigerant
The compound (working fluid) used in air conditioners, heat pumps, and  refrigerators to transfer heat into or out of an interior space. This fluid  boils at a very low temperature enabling it to evaporate and absorb heat.

Return Air
Air that is returned to a  heating or cooling appliance from a heated or cooled space.

Return Duct
The central heating or cooling system contains a fan that gets its air  supply through these ducts, which ideally should be installed in every room

Seasonal  Energy Efficiency Ratio (SEER)
A measure of seasonal or annual efficiency of a central air conditioner or air conditioning heat pump. It takes into  account the variations in temperature that can occur within a season and is  the average number of Btu of cooling delivered for every watt-hour of  electricity used by the heat pump over a cooling season.

Split System Air Conditioner
HVAC term for an air conditioning system that comes  in two to five pieces: one piece contains the compressor, condenser, and a  fan; the others have an evaporator
and a fan. The condenser, installed  outside the house, connects to several evaporators, one in each room to be  cooled, mounted inside the house. Each evaporator is individually controlled,  allowing different rooms or zones to be cooled to varying degrees.

Static Pressure
Condition that exists when an equal amount of air is supplied to and exhausted from a space. At static pressure, equilibrium has been reached.

Supply Duct
HVAC term for the duct(s) of a forced air heating/cooling system  through which heated or cooled air is supplied to rooms by the action of the fan of the central heating or cooling unit.

Ton
A unit of air cooling capacity: one ton is 12,000 Btu per hour and 350-450 CFM. Most residential systems are available in 1.5 – 5 Tons.

Two Stage Compressor
Two Stage Compressors are capable of two levels of operation, a low stage and a high stage. Properly sized equipment will operate 80% of the time in low  stage, enhancing efficiency and comfort with lower humidity levels and quieter operation. It’s like getting two air conditioners or heat pumps in one system.

V.O.C.
Volatile organic compounds are found everywhere from cleaning supplies to paint. Look  for ‘Low VOC’ or ‘No VOC’ labels

Variable Speed Blower
Blower motor that changes speeds based on the amount temperature differential from the thermostat setting and ambient temperature of the room. Variable Speed Blower have increased efficiency from Fixed Speed Motors along with greater dehumidification.

Vent
A component of a  heating or ventilation appliance used to conduct fresh air into, or waste air or combustion gases out of, an appliance or interior space.

Vent Damper
HVAC term for a device mounted in the vent connector that closes the vent when the heating  unit is not firing. This traps heat inside the heating system and house  rather than letting it draft up and out the vent system.

Vent Pipe
A tube in which combustion gases from a combustion appliance are vented out of the appliance to the outdoors.

Weatherization
Caulking, weather-stripping,sealing holes and cracks to reduce air infiltration and exfiltration into and out of a building.

Weather-stripping
A material used to seal gaps around windows and exterior doors.

Zone
An area within the interior space of a building, such as an  individual room(s), to be cooled, heated, or ventilated. A zone has its own thermostat to control the flow of conditioned air into the space.

Zoning
The  combining of rooms in a structure according to similar heating and cooling  patterns. Zoning requires using more than one thermostat to control heating,  cooling, and ventilation
equipment.