HVAC & plumbing terms, explained

A heat pump is one outdoor unit that both cools and heats your home by moving refrigerant in either direction, replacing the need for a separate furnace.

The traditional split-system AC with an outdoor condenser, an indoor coil, and a separate furnace or air handler that distributes cooled air through ductwork.

The gas-fired or electric heating component of a split HVAC system that warms air and pushes it through your ducts during cold months.

A ductless system with one outdoor unit serving one or more indoor wall-mounted heads, ideal for additions, casitas, garages, or rooms the central system can't reach.

An all-in-one HVAC system that lives on your roof, with condenser, coil, blower, and often gas heat in a single cabinet — common on Vegas single-story homes.

A heat pump paired with a gas furnace as backup. The heat pump handles cooling and mild heating; the furnace kicks in only on the coldest nights.

An HVAC system whose compressor or blower can run at many speeds instead of just on or off — better humidity control, quieter operation, and lower bills.

A heat pump engineered to deliver full heating capacity down to 5°F or below — overkill for most of Las Vegas, but worth it for higher-elevation neighborhoods.

The traditional 40-, 50-, or 75-gallon water heater that keeps a reservoir of hot water ready at all times, fired by natural gas or electricity.

A water heater that heats water on demand instead of storing a tank of it — endless hot water, smaller footprint, longer lifespan, higher upfront cost.

An electric water heater that pulls heat from the surrounding air to warm water in the tank — three to four times more efficient than a standard electric tank.

Replacing the supply piping inside your home — galvanized, polybutylene, or failing copper — with modern PEX or copper, usually because of recurring leaks or pressure loss.

The buried pipe that carries waste from your house out to the city main — a single failure point that handles every toilet, sink, tub, and washing machine drain.

The supply and drain lines run inside or beneath the concrete foundation slab — the part of the plumbing system that's nearly impossible to access without breaking concrete.

A central plumbing distribution hub where one cold and one hot trunk line split off into individual PEX runs to each fixture — like a breaker panel for your water.

Any pipe that carries used water away from a fixture by gravity — sink traps, toilet flanges, tub drains, washing machine standpipes — eventually feeding the sewer line.

The mechanical heart of any AC or heat pump — pressurizes refrigerant so it can shed heat at the condenser and absorb heat at the evaporator.

A small cylindrical component that gives the AC compressor and fan motor the surge of voltage they need to start up — and the #1 cause of summer no-cool calls in Vegas.

An electromechanical relay that connects high-voltage power to the AC compressor and condenser fan when the thermostat calls for cooling — and breaks the circuit when the call ends.

The indoor coil that absorbs heat from your home's air — refrigerant evaporates inside it, cooling the air your blower pushes across the fins.

The outdoor coil that rejects heat to the air outside — refrigerant condenses inside it, dumping the heat the evaporator absorbed from your home.

A precision valve that meters the exact amount of refrigerant entering the evaporator coil — the throttle that keeps the AC running efficiently at every load.

A connected thermostat with scheduling, occupancy sensing, remote control, and often NV Energy rebate eligibility — typically saves 8-15% on cooling costs versus a manual setback.

A sacrificial magnesium or aluminum rod inside your water heater that corrodes instead of the tank — the single most important $30 part in your plumbing system.

A spring-loaded valve at your home's water entry point that reduces the high pressure from the street main down to a safe 50-65 psi for your plumbing.

A small tank installed near the water heater that absorbs thermal expansion — required by Clark County code on any closed plumbing system with a PRV or check valve.

The network of insulated metal or flex ducts that carries conditioned air from your HVAC system through your home — the silent partner that determines whether a perfect AC actually feels cool.

The resistance air encounters as it moves through your duct system — too high, and the system runs hot, runs loud, and dies young.

The ACCA-standard engineering calculation that determines exactly how many BTUs of heating and cooling your specific home actually needs — the only correct way to size an HVAC system.

The companion to Manual J — once you know the load, Manual D calculates the duct size, layout, and static pressure required to actually deliver that air to every room.

The path your home's air takes back to the HVAC system to be re-cooled or re-heated — too small a return is the most common hidden cause of weak cooling in older Vegas homes.

Water with a high concentration of dissolved calcium and magnesium — Las Vegas tap water averages 280-330 ppm, putting us solidly in the very hard range.

An ion-exchange system that swaps the calcium and magnesium in hard water for sodium — eliminating scale, extending appliance life, and cutting soap usage roughly in half.

A point-of-use filtration system, usually under the kitchen sink, that pushes water through a semi-permeable membrane to strip out salts, minerals, and most dissolved contaminants.

A point-of-entry filter that treats every gallon of water entering the house — typically removes chlorine, sediment, taste, and odor, but does not soften.

A check-valve assembly that stops water from flowing backward into the city main — required on any home connection where contamination could siphon backward, including irrigation and pools.

The total weight of dissolved minerals, salts, and metals in your water, measured in ppm — Las Vegas tap water typically reads 600-700 TDS; RO output is closer to 10-30.

The updated efficiency rating for new central AC and heat pump systems — measures seasonal cooling efficiency under more realistic test conditions than the old SEER.

Annual Fuel Utilization Efficiency — the percentage of a furnace's fuel that becomes useful heat versus what's lost up the flue. A 96% AFUE furnace wastes only 4 cents per dollar of gas.

The heating efficiency rating for heat pumps — the heating-mode counterpart to SEER2, measuring BTUs of heat delivered per watt-hour of electricity over a heating season.

The updated peak cooling efficiency rating — measures how efficiently a system runs at a single hot-design moment (95°F outdoor), the metric that matters most on a 110°F Vegas afternoon.

The standardized efficiency rating for water heaters — replaced the older EF rating, and the higher the UEF, the less you pay to heat a given gallon of water.

A federal certification program that identifies the most efficient products in each category — ENERGY STAR HVAC and water heaters are typically the threshold for NV Energy rebates.

British Thermal Unit — the standard measurement of heating and cooling capacity. One BTU is roughly the energy required to heat one pound of water by one degree Fahrenheit.

HVAC capacity expressed in tons — one ton equals 12,000 BTU/hr of cooling. A typical Las Vegas single-family home needs 3 to 5 tons of cooling capacity.

The sole electric utility for the Las Vegas valley — sets the rate structure, runs the rebate programs that cover most HVAC and water heater upgrades, and operates the Cool Share peak-demand program.

The HFC refrigerant that powered residential AC and heat pumps from roughly 2010 through 2024 — manufacture of new R-410A residential systems ended January 1, 2025.

The lower-GWP refrigerant replacing R-410A in new residential AC and heat pumps starting in 2025 — about 78% lower greenhouse impact, with slightly different system pressures and safety requirements.

The federal American Innovation and Manufacturing Act of 2020 — directs the EPA to phase down high-GWP HFC refrigerants like R-410A by 85% by 2036, driving the R-454B transition.

A federal income tax credit that covers up to 30% of the cost of qualifying high-efficiency HVAC and water heaters — currently up to $2,000 per year for heat pumps and heat pump water heaters.

The mechanical or plumbing permit issued by the Clark County Building Department for HVAC replacements, water heater swaps, and most plumbing modifications — required by code on every reputable install.

NV Energy's residential demand-response program that cycles your AC briefly during peak grid hours in exchange for a bill credit — typically $25-$100 per summer for participating households.