Pure Maintenance Austin TeamWhat does this glossary cover?
Talk with an HVAC tech or read about indoor air, and you'll run into terms that rarely get explained. This glossary defines the words we use most in our guides, in plain English and in alphabetical order, with notes on how each one plays out in Central Texas homes. If a word you need isn't here, give us a call and we'll add it.
A to C
Air changes
How many times the full volume of air in a home or room is replaced, or passed through a system, in one hour. You'll often see it written as ACH, for "air changes per hour." More air changes usually means stale air gets diluted or filtered faster.
Allergen
Anything in the air or dust that can bother some people. Common indoor allergens in Central Texas homes include pollen (cedar in winter, oak in spring, ragweed in fall), dust mites and pet dander. Medical questions belong with your doctor. Our indoor allergens guide has more.
Bio-load
Our name for the microscopic particles and microbes that build up in a home's air, on its surfaces and inside its HVAC system over time. Dust, dander, pollen, cooking residue and tiny living things all add to it. You can't see a bio-load, but you often notice it as stale odors or extra dust. See What Is Your Home's Bio-Load?
Condensate drain line
The pipe that carries water away from your AC's indoor coil. On a humid Austin day, an AC can pull gallons of water out of the air. If the line clogs, that water backs up and can overflow into a ceiling or closet, so the line should be flushed during regular HVAC service.
D to H
Dander
Tiny flakes of skin shed by pets (and people). Dander is so light that it floats in the air, clings to fabrics and settles in ductwork. It's one of the most common indoor allergens.
Dew point
The temperature at which air holds all the moisture it can, so water starts to condense into droplets. When a cold surface, like an AC vent or a window, sits below the dew point, it "sweats." Austin's summer dew points often sit around 70°F, which is why the air feels so sticky.
Dry fog
A fog made of droplets so small that they float in the air instead of landing on and soaking surfaces. Our whole-home treatment uses the patented Pure Maintenance VaPURE dry fog system to reach every room, surface and closet, plus the ductwork, without getting things wet. See Dry Fog Treatment.
Evaporator coil
The part of your AC that sits inside the home, on top of or beside the furnace or air handler. In most Austin homes, that's up in the attic. Refrigerant makes the coil cold, so warm air passing over it cools down and drops its moisture. Because it stays cold and wet while the AC runs, it collects dust and grime and needs periodic cleaning. Gold Eagle Services handles coil cleaning.
HEPA
Short for "high-efficiency particulate air." A true HEPA filter catches nearly all of the tiny particles that pass through it. You'll find HEPA filters in vacuums and portable air filters, but most home HVAC systems can't push enough air through one.
M to P
MERV
Short for "minimum efficiency reporting value," a rating from 1 to 16 for how well an HVAC filter catches particles. Higher numbers catch smaller particles, but a filter too dense for your system can choke airflow. Many homes do well with a MERV 8 to 11 pleated filter; ask your HVAC tech what your system can handle.
Micron
A unit of size equal to one-millionth of a meter. A human hair is roughly 50 to 70 microns wide. The particle sizes behind filter ratings, along with dust, pollen and fog droplets, are measured in microns.
Positive pressure
Pushing more air into a space than leaves it, so air flows outward through every gap and opening. During a dry fog treatment, we use positive pressure to carry the fog into closets, behind furniture and through the whole home, not just the room where the machine sits.
P-trap
The U-shaped bend of pipe under a sink, tub, shower or floor drain. It holds a little water that blocks sewer gas from coming up into your home. If a drain goes unused for weeks, that water dries up and you may smell sewer gas; running water for a few seconds refills it. See Smelly Drains and Dry Traps.
Q to V
Quat
Short for "quaternary ammonium compound," a common ingredient in household and commercial cleaning products. Quats can cling to some cotton and microfiber cloths, which leaves those cloths less effective than people expect. See What's a Quat?
Relative humidity
How much moisture the air holds compared with the most it could hold at that temperature, shown as a percent. For comfort and a lower bio-load, keep indoor relative humidity between about 40% and 50%. A simple hygrometer, a small humidity gauge, shows where you stand. Our Central Texas humidity guide explains more.
Return vent vs. supply vent
A supply vent blows conditioned air into a room; you'll feel air coming out of it. A return vent pulls air back to the HVAC system to be filtered and conditioned again. Returns are usually larger, and in many Austin homes the filter sits right behind the return grille. Keep both clear of furniture and rugs so air can move freely.
VOC
Short for "volatile organic compound," a chemical that turns into vapor at room temperature. New paint, furniture, carpet, cleaning products and air fresheners can all release VOCs, which is where much of that "new" smell comes from. Airing out a room and choosing low-VOC products help.
Putting it all together
Most of these terms come back to four habits: hold relative humidity near 50%, keep air moving through a filter your system can handle, keep the coil and condensate line clean, and give the house a deep refresh when the bio-load builds. The first three are HVAC work. The last is where a dry fog treatment fits, and a phone call can sort out which one your house needs.
Get a free phone consultation
Pure Maintenance Austin, brought to you by Gold Eagle Services, serves all of Central Texas, out to College Station (about 2.5 hours), including Round Rock, Georgetown, San Marcos, Bastrop and Marble Falls. Book a free phone consultation: a Comfort Advisor calls you, learns what's going on in your home and sends a written quote based on square footage. Call 512-904-4646 or email IAQ@goldeagleservices.com. We're open Monday through Saturday, 7am to 7pm.