Home Maintenance Glossary

The terms that show up in inspection reports, contractor quotes, and your maintenance schedule, defined in plain language. Every definition is consistent with how the term is used across SeasonKeep's guides and articles.

A

AFCI (Arc-Fault Circuit Interrupter): A breaker or outlet that shuts off power when it detects the electrical arcing that starts fires — the kind caused by damaged wires or loose connections. Modern codes require them on most living-area circuits; they have a test button you should press periodically.
Anode rod: A sacrificial metal rod inside a tank water heater that corrodes so the tank itself doesn't. Inspecting it yearly and replacing it once it's more than half consumed can dramatically extend the tank's life.

B

Backflow preventer: A valve that stops irrigation or other outdoor water from flowing backward into your drinking water supply. Many municipalities require an annual test by a certified tester.
Blower motor: The fan motor inside a furnace or air handler that pushes conditioned air through the ducts. Clogged filters make it work harder, which shortens its life.

C

Caulk: Flexible sealant applied to joints and gaps — around windows, tubs, siding transitions — to keep water and air out. It dries out and cracks over time, so inspecting and renewing it is a recurring task rather than a one-time job.
Circuit breaker panel: The metal box (also called the service panel) where your home's electrical circuits originate, each protected by a breaker that trips when a circuit is overloaded. Know where yours is and label the breakers; anything beyond resetting a breaker belongs to a licensed electrician.
CO detector (carbon monoxide detector): An alarm that senses carbon monoxide, the odorless gas produced by fuel-burning appliances. Most codes require one near sleeping areas in homes with fuel-burning appliances, fireplaces, or an attached garage; test it regularly and replace units every 5-7 years (check the manufacture date printed on the back).
Condensate drain line: The small pipe that carries away the water an air conditioner or high-efficiency furnace produces. Algae clogs it easily, causing water damage or system shutdowns; flushing it is a quick recurring task in cooling season.
Condenser: The outdoor unit of a central air conditioner or heat pump. It needs clear airflow — leaves, grass clippings, and cottonwood fluff on its coil make the system work harder and cost more to run.
Creosote: The flammable tar-like residue that wood smoke deposits inside a chimney. It's the fuel for chimney fires, which is why wood-burning fireplaces need periodic professional sweeping.

D

Dehumidifier: An appliance that pulls moisture out of indoor air, most often used in basements. Keeping indoor humidity in a healthy range discourages mold, dust mites, and musty odors; the unit's own filter and tank need periodic cleaning.
DIY difficulty rating: SeasonKeep's per-task rating of how approachable a job is: easy (basic tools, no special skills), moderate (comfortable with a ladder and simple repairs), or professional-only (gas and refrigerant work, chimney sweeps, roof inspections, and jobs requiring certification like backflow testing).
Downspout extension: A pipe or flexible sleeve that carries roof runoff from the bottom of a downspout several feet away from the foundation. Without one, gutters concentrate water exactly where it does the most damage.
Dryer vent: The duct that carries hot, moist air from a clothes dryer outside. Lint accumulates inside it, making the dryer slow and inefficient — and lint in a hot duct is a genuine fire hazard, which is why the full duct run deserves cleaning on a schedule.

E

Efflorescence: The white, chalky mineral deposit that appears on concrete, brick, or block walls when water moves through the masonry and evaporates. It looks cosmetic, but it means water is moving through the wall and is worth investigating.
Evaporator coil: The indoor coil of an air conditioner or heat pump where the refrigerant absorbs heat from your air. Dust buildup insulates it and can freeze it solid, so it's cleaned as part of routine HVAC service.
Expansion tank: A small tank on a water heater or boiler that gives heated water somewhere to expand, protecting pipes and valves from pressure spikes. Its internal air charge can fail silently, so it's checked during annual water heater service.

F

Fascia: The vertical board along the roof edge that gutters attach to. When gutters overflow, water runs down its back side, and rotted fascia can no longer hold gutter brackets.
Flashing: Thin metal installed where a roof meets anything that interrupts it — chimneys, vents, walls, valleys — to steer water away from the seams. Failed flashing, not failed shingles, is behind many roof leaks.
French drain: A gravel-filled trench with a perforated pipe that intercepts groundwater and carries it away from the house. A common fix for chronic yard drainage or basement moisture problems.

G

GFCI (Ground-Fault Circuit Interrupter): An outlet or breaker that cuts power in a fraction of a second when electricity leaks to ground — for example through a person. Required anywhere water is near power (kitchens, baths, outdoors); test the buttons periodically to confirm they still trip.
Grading: The slope of the ground around your foundation. Soil should fall away from the house so rain drains off; soil that has settled and slopes toward the walls sends water straight to the foundation.
Gutter guard: A screen or cover that keeps leaves out of gutters. Guards stretch the cleaning interval — they don't eliminate it, since fine debris still gets through and accumulates below them.

H

Heat pump: An HVAC system that moves heat rather than generating it, cooling in summer and heating in winter by reversing direction. It runs year-round, which makes filter changes and periodic service matter more than for single-season equipment.
Home Health Score: SeasonKeep's 0-100 score reflecting how current a home is on its maintenance across all systems, updated as tasks are completed or skipped.
Hose bib (sillcock): An outdoor faucet. In freezing climates it must be winterized — hose removed, supply shut off or frost-free valve verified — because a frozen hose bib can split the pipe inside the wall.

I

Ice dam: A ridge of ice at the roof's edge, formed when attic heat melts the upper roof's snow and it refreezes at the cold eaves. The dam blocks meltwater, which backs up under shingles and into ceilings; prevention lives in the attic (air sealing and insulation) and in clean gutters.
IECC climate zone: The International Energy Conservation Code's division of the U.S. into zones 1 (hottest) through 8 (subarctic), with letters for moisture: A humid, B dry, C marine. Your zone determines which maintenance tasks apply to your home and when they're scheduled.
Irrigation blowout: Forcing compressed air through sprinkler lines in fall to purge water before it can freeze and crack pipes, valves, and heads. A standard pre-winter task in freezing climates.

M

MERV rating: A 1-16 scale for how finely an air filter captures particles. Higher numbers filter more but restrict airflow more; most homes do well in the MERV 8-13 range that balances air quality against strain on the blower.

P

Pipe insulation: Foam sleeves on water pipes in unheated spaces — crawl spaces, garages, exterior walls — that slow freezing. In cold climates, checking it before winter is one of the highest-stakes cheap tasks there is, because a burst pipe floods the house.
Preventive maintenance: Servicing systems on a schedule to catch small problems before they become failures, as opposed to reactive repair after something breaks. The economics favor prevention because small fixes cost a fraction of the emergencies they prevent.

R

Radon: A naturally occurring radioactive gas that seeps from soil into homes and raises lung cancer risk over long exposure. It's invisible and odorless, so testing is the only way to know your level; homes with mitigation systems should verify the fan is running.
Refrigerant: The working fluid that carries heat through an air conditioner or heat pump. A system low on refrigerant has a leak — topping it off is a symptom patch, and handling refrigerant legally requires certification, so this is professional territory.
Ridge vent: A vent running along the roof peak that lets hot, moist attic air escape, working with soffit vents that draw fresh air in at the eaves. Good attic ventilation fights both summer heat load and winter ice dams.
R-value: The measure of how well insulation resists heat flow — higher is better. Attic insulation depth translates to R-value, and an under-insulated attic shows up as high energy bills and, in snowy climates, ice dams.

S

Sediment (water heater): Minerals from the water supply that settle at the bottom of a tank water heater. A sediment layer makes the burner work harder and accelerates corrosion from the inside, which is why tanks get flushed on a schedule.
Shingle granules: The gritty mineral surface of asphalt shingles that protects them from UV. Granules accumulating in gutters signal aging shingles; bald patches mean the roof is losing its protection.
Shutoff valve: The valve that stops water flow to a fixture or to the whole house. Every homeowner should know where the main shutoff is before a pipe bursts, and valves should be exercised occasionally so they don't seize open.
Soffit: The underside of the roof overhang. Its vents supply the intake air for attic ventilation, so they need to stay unblocked by insulation, nests, or paint.
Sump pump: A pump in a basement or crawl-space pit that ejects groundwater before it floods the space. It sits idle for months and then matters enormously, which is why testing it — and its battery backup — before the wet season is a standard task.

T

TPR valve (temperature and pressure relief valve): The safety valve on a water heater that opens if temperature or pressure climbs dangerously, preventing tank rupture. It's tested by briefly lifting the lever; a valve that won't open or won't reseal needs replacement.
Tuckpointing: Repairing the mortar joints between bricks by grinding out failing mortar and packing in new. Sound mortar keeps water out of masonry walls and chimneys.

U

Underlayment: The water-resistant layer between roof shingles and the deck beneath them — the roof's second line of defense. Its condition is part of what a professional roof inspection evaluates.

V

Vapor barrier: A plastic or foil sheet that blocks ground moisture from migrating into a crawl space or through walls. A torn or missing barrier under the house shows up as damp air, mold, and musty smells above.

W

Weatherstripping: The flexible seals around doors and windows that block drafts. They compress and crack with age; renewing them is one of the cheapest comfort-and-efficiency tasks a home offers.
Winterization: The set of fall tasks that protect a home from freezing: draining outdoor water lines, shutting off hose bibs, insulating pipes, servicing heat before the first cold snap. In cold climates these are the most consequential tasks of the year.

Definitions are a start; a schedule is better. SeasonKeep turns your home's zip code, age, and systems into a personalized maintenance calendar with these tasks already timed and explained. Start free, no credit card required.