Home Improvement Glossary
Your complete guide to home improvement terminology. Understanding these terms will help you make informed purchasing decisions for plumbing, HVAC, electrical, and home improvement projects. See also our FAQ page and buying guides for more help.
A
ADA Compliant
Definition: Products meeting Americans with Disabilities Act accessibility standards. ADA compliant toilets are 17-19 inches in height (comfort height) making them easier to use for individuals with mobility challenges. See our Toilet Buying Guide for more on ADA options.
Air Gap
Definition: A physical separation between a water outlet and potential contamination source. Required by plumbing codes on dishwashers to prevent backflow of dirty water into clean water supply.
Amp (Ampere)
Definition: Unit measuring electrical current flow. Home circuits typically run 15-20 amps. High-draw appliances like dryers need 30-50 amp dedicated circuits. GFCI outlets are required near water sources.
B
Ball Valve
Definition: A shut-off valve using a rotating ball with a hole through its center. Quarter-turn operation makes ball valves quick to open/close. Commonly used for main water shut-offs.
BTU (British Thermal Unit)
Definition: Unit measuring heating or cooling capacity. One BTU heats one pound of water by 1 degree F. Air conditioners are rated in BTUs - a 12,000 BTU unit cools approximately 500 sq ft.
Backflow
Definition: Reverse flow of water from a potentially contaminated source back into the clean water supply. Backflow preventers are required on irrigation systems and some appliances. Related: Air Gap.
C
CEFIONTECT
Definition: TOTO's proprietary glaze technology that creates an ultra-smooth, ion-barrier surface on toilet bowls. Prevents waste and bacteria from sticking, reducing cleaning frequency. Learn more in our TOTO Brand Guide.
CFM (Cubic Feet per Minute)
Definition: Measures airflow volume in ventilation. Bathroom exhaust fans are rated in CFM - calculate 1 CFM per square foot of bathroom space. A 100 sq ft bathroom needs a 100 CFM fan minimum. See our Bathroom Fan Buying Guide and shop Broan-NuTone fans.
Comfort Height Toilet
Definition: Toilets with seat height of 17-19 inches (vs standard 15 inches). Also called ADA height or right height. Easier to sit and stand, especially for taller individuals or those with mobility issues. TOTO offers many comfort height options.
Compression Fitting
Definition: Plumbing connection using a nut and ferrule to create watertight seal without soldering. Common for water supply lines to faucets and toilets. Easy for DIY installation.
D
Delta P (Pressure Drop)
Definition: Decrease in water pressure as water flows through pipes, fittings, or fixtures. High delta P means reduced water flow at the fixture. Related: PSI, GPM.
Dual Flush
Definition: Toilet with two flush options - low volume (0.8-1.1 GPF) for liquid waste and full volume (1.28-1.6 GPF) for solid waste. Saves water compared to single-flush toilets. See our Toilet Buying Guide.
E
Elongated Bowl
Definition: Toilet bowl shape measuring approximately 18.5 inches from front to mounting holes (vs 16.5 inches for round). More comfortable for adults but requires more space. Most TOTO toilets are available in both shapes.
ENERGY STAR
Definition: EPA certification for energy-efficient products. ENERGY STAR appliances use 10-50% less energy than standard models. Look for the blue ENERGY STAR label. Broan-NuTone offers many ENERGY STAR certified fans.
EPA WaterSense
Definition: EPA certification for water-efficient products. WaterSense toilets use 1.28 GPF or less (20% less than federal standard). WaterSense faucets use 1.5 GPM or less.
F
Flapper
Definition: Rubber valve at bottom of toilet tank that lifts when flushed, releasing water into bowl. Common cause of running toilets - inexpensive to replace. Related: Flush Valve.
Flow Rate
Definition: Volume of water passing through a fixture per unit time, measured in GPM (gallons per minute). Federal limits: showerheads 2.5 GPM, faucets 2.2 GPM. See Kitchen Faucet Buying Guide.
Flush Valve
Definition: Opening at bottom of toilet tank where water exits into bowl. Standard size is 2 inches; larger 3-4 inch valves provide more powerful flush. TOTO's TORNADO FLUSH uses optimized valve design.
G
GPF (Gallons Per Flush)
Definition: Water volume used per toilet flush. Federal standard maximum is 1.6 GPF. High-efficiency toilets use 1.28 GPF or less. Ultra-high-efficiency models use 1.0 GPF or less. Learn more in our Toilet Buying Guide.
GPM (Gallons Per Minute)
Definition: Water flow rate for faucets and showerheads. Higher GPM means more water flow. Federal limits: kitchen faucets 2.2 GPM, showerheads 2.5 GPM. Shop Hansgrohe and Grohe faucets.
GFCI (Ground Fault Circuit Interrupter)
Definition: Electrical outlet that shuts off power when it detects current leakage (potential shock hazard). Required in bathrooms, kitchens, outdoors, and near water sources. Essential for WASHLET and bidet seat installation.
H
Hose Bib
Definition: Outdoor water faucet (spigot) for connecting garden hoses. Frost-proof hose bibs have the valve inside the wall to prevent freezing.
HSPT (High-Speed Propulsion Technology)
Definition: Toilet flushing technology using directed water jets for powerful bowl cleaning with less water.
I
Induction Cooktop
Definition: Cooking surface using magnetic fields to directly heat pots and pans. Requires induction-compatible cookware (magnetic stainless steel or cast iron). More efficient than gas or electric.
L
Low-Flow
Definition: Fixtures designed to use less water than standard models. Low-flow showerheads use 2.0 GPM or less. Low-flow faucets use 1.5 GPM or less. Related: EPA WaterSense.
M
MaP Score (Maximum Performance)
Definition: Independent testing score measuring toilet flush performance in grams of waste removed. Higher is better. Minimum recommended: 350g. Top performers exceed 1000g. TOTO toilets consistently score 1000g+.
N
NPT (National Pipe Thread)
Definition: U.S. standard for tapered pipe threads. Ensures compatible connections between pipes and fittings. Sizes refer to inside diameter (1/2 NPT, 3/4 NPT, etc.).
O
One-Piece Toilet
Definition: Toilet with tank and bowl manufactured as single unit. Easier to clean (no gap between tank and bowl), sleeker appearance, but heavier and typically more expensive than two-piece. See our Toilet Buying Guide.
P
P-Trap
Definition: P-shaped pipe under sinks holding water to block sewer gases from entering home. The water seal must remain intact - dry P-traps allow odors to escape.
Pressure-Assist
Definition: Toilet using compressed air in sealed tank to power flush. More powerful than gravity-fed, uses less water, but louder and more expensive to repair.
PSI (Pounds per Square Inch)
Definition: Unit measuring water pressure. Residential water pressure typically 40-80 PSI. Below 40 PSI causes weak flow; above 80 PSI can damage fixtures. Related: Delta P, Flow Rate.
R
Rough-In
Definition: Distance from wall to center of toilet drain. Standard rough-in is 12 inches. Older homes may have 10 or 14 inch rough-in. Must match toilet specifications. Critical measurement covered in our Toilet Buying Guide.
R-Value
Definition: Measure of insulation's thermal resistance. Higher R-value means better insulation. Recommended attic insulation: R-38 to R-60 depending on climate zone.
S
SEER (Seasonal Energy Efficiency Ratio)
Definition: Efficiency rating for air conditioners and heat pumps. Higher SEER means lower operating costs. Minimum federal standard is SEER 14; high-efficiency units reach SEER 20+.
Siphon Jet
Definition: Toilet flushing mechanism using water jet directed into trapway to initiate siphon action. Creates powerful, quiet flush.
Sone
Definition: Unit measuring sound level of bathroom fans and range hoods. Lower is quieter. 1.0 sone equals quiet refrigerator hum. Look for fans rated 1.0 sone or less for quiet operation. See our Bathroom Fan Buying Guide and shop Broan-NuTone.
Supply Line
Definition: Flexible tubing connecting water shut-off valve to fixture (faucet, toilet). Common materials: braided stainless steel (most durable), reinforced polymer, chrome-plated brass.
T
Tankless Water Heater
Definition: Water heater that heats water on-demand rather than storing hot water. Also called instantaneous or on-demand heaters. More energy efficient but higher upfront cost.
TORNADO FLUSH
Definition: TOTO's rimless flushing technology using dual-nozzle jets creating centrifugal water action. Cleans entire bowl surface more effectively than conventional rim-fed designs. Learn more in our TOTO Brand Guide.
Trapway
Definition: S-shaped channel in toilet base where waste exits to drain. Larger trapway diameter (2 inches or more) reduces clogging. Glazed trapways with CEFIONTECT flush more efficiently.
Two-Piece Toilet
Definition: Toilet with separate tank bolted to bowl. Easier to transport and install than one-piece. Tank-to-bowl connection requires gasket seal.
U
UPC (Uniform Plumbing Code)
Definition: Plumbing code standard used primarily in western U.S. states. Dictates requirements for plumbing installation, fixtures, and drainage.
V
Vitreous China
Definition: Ceramic material used for toilets and sinks. Clay fired at high temperature with glass-like glaze. Durable, easy to clean, resistant to staining and scratching. Enhanced by glazes like CEFIONTECT.
W
Wall-Hung Toilet
Definition: Toilet mounted to wall with concealed tank inside wall. Saves floor space, easier to clean underneath, modern appearance. Requires in-wall carrier frame installation. TOTO and Grohe offer wall-hung options.
WASHLET
Definition: TOTO brand name for electronic bidet toilet seat. Features include warm water cleansing, heated seat, warm air dryer, and deodorizer. Requires electrical outlet near toilet (GFCI recommended). See our Bidet Seat Buying Guide.
Water Hammer
Definition: Banging noise when water flow stops suddenly (valve closes quickly). Caused by momentum of water hitting closed valve. Water hammer arrestors absorb shock to eliminate noise.
Wax Ring
Definition: Wax seal between toilet base and floor flange creating watertight connection to drain. Replaced when reinstalling toilet. Wax-free alternatives available. Related: Rough-In.