What's wrong with my system?

It won't turn on at all

Dead thermostat screen

Likely causes

1. Dead thermostat batteries.
2. A tripped breaker cutting power to the system.
3. A safety float switch (full condensate pan) cutting the low-voltage circuit.
4. A failed transformer or control board.

Safe checks you can do yourself

• Replace the thermostat batteries.
• Check the breaker and reset the AC breaker once if tripped.
• Take a flashlight look at the indoor unit's drain pan — if it's full of water, the float switch is doing its job.

When it's time to call

If fresh batteries don't wake it, the breaker re-trips, or the pan is full. A re-tripping breaker is a fault, not a nuisance — stop after one reset. A full pan means the drain line needs clearing before the system will run again.

Red flags — stop and call now: Breaker trips again immediately → leave it off and call.

Air conditioning repair & service

It runs, but blows warm air

Outdoor unit runs, air stays warm

Likely causes

1. Low refrigerant from a leak.
2. A dirt- or debris-blocked outdoor coil — a classic during SoCal heat waves; the coil can't dump heat.
3. A compressor that runs but no longer pumps.
4. Big duct leaks pulling in hot attic air.

Safe checks you can do yourself

• Replace a dirty filter.
• Clear leaves, dryer lint, and vegetation at least 2 feet around the outdoor unit — don't open anything, just clear around it.
• Feel two vents: if air is cool at one and warm at another, suspect ducts, not refrigerant.

When it's time to call

Refrigerant work is EPA-licensed-only territory — there is no safe DIY here. Honest note: “topping off” refrigerant every summer without fixing the leak is renting a repair; ask any company you call to find the leak, not just refill.

Air conditioning repair & service

Weak airflow from the vents

Weak airflow everywhere

Likely causes

1. A clogged air filter.
2. A coil beginning to ice over — which chokes airflow further.
3. A failing blower motor or wrong blower speed.

Safe checks you can do yourself

• Pull the filter and hold it to a light — if you can't see light through it, replace it.
• Make sure all supply registers are open.
• Listen at the indoor unit: is the blower actually spinning up?

When it's time to call

If a fresh filter doesn't restore airflow within a few hours. Blower motors and iced coils are tech territory; running a starved system stresses the compressor.

Air conditioning repair & service

Ice on the unit or copper lines

Iced coil, airflow-starved

Likely causes

1. A clogged filter or blocked returns starving the coil of warm air, so it freezes.
2. Blower problems doing the same thing.

Safe checks you can do yourself

• Switch cooling OFF and the fan to ON — let it thaw for 2–4 hours (put towels by the indoor unit; melting ice makes water).
• Replace the filter.
• Open every register, then try cooling again.

When it's time to call

If it re-freezes after a thaw and a fresh filter. Repeated freezing with good airflow points at refrigerant, and running an iced system can slug and kill the compressor — the most expensive part in the machine.

Air conditioning repair & service

Water leaking around the indoor unit

Water at the indoor unit or ceiling stain

Likely causes

1. A clogged condensate drain line — algae and dust; the #1 cause.
2. A rusted or cracked drain pan.
3. A failed condensate pump.
4. An iced coil melting off.

Safe checks you can do yourself

• Flashlight look at the pan and the drain-line outlet (usually a small pipe ending outside) — is the outlet bone-dry while the pan is full? That's the clog.
• Put a towel or shallow pan under any active drip.

When it's time to call

Promptly if there's a ceiling stain — attic units drip into drywall and the damage bill outruns the plumbing bill fast. Line clearing is a quick visit.

Air conditioning repair & service

Strange noises (buzzing, screeching, banging)

Outdoor buzzing/humming

Likely causes

1. A failing capacitor or contactor — buzzing that precedes a no-start.
2. A fan obstruction.
3. Loose hardware vibrating.

Safe checks you can do yourself

• Look — don't reach — through the top grille for obvious debris like a twig against the fan.
• Note whether the fan still spins up.

When it's time to call

Soon if the buzz is new or the fan hesitates on start. Catching a $30 capacitor before it strands the compressor on a 100° day is the cheapest AC repair there is.

Air conditioning repair & service

Runs constantly / can't keep up (heat wave)

Can't keep up in a heat wave

Likely causes

1. Physics — most systems are designed to hold about 20°F below outdoor temperature, so 78° inside at 103° outside is on spec.
2. A dirty coil or filter stealing capacity right when you need all of it.
3. Duct leaks dumping cold air into the attic.

Safe checks you can do yourself

• Put in a fresh filter.
• Clear 2 feet around the outdoor unit.
• Close blinds on the sun side.
• Set a realistic target and let it run — short setbacks make it work harder.

When it's time to call

If it can't hold within ~5° of a reasonable setpoint, ices up, or this is new behavior at temperatures it used to handle. Honest read: a struggling-but-running AC in record heat is often normal; a change in behavior is the real signal.

Air conditioning repair & service

Carbon monoxide alarm went off

STOP — safety first: Carbon monoxide alarm is sounding

Likely causes

1. A fuel-burning appliance (furnace, water heater, range) is putting CO into your air.
2. Attached-garage exhaust drifting indoors. CO is invisible and odorless — trust the alarm, not your nose.

Safe checks you can do yourself

• None. Get every person and pet outside immediately.

When it's time to call

911 from outside. Do not re-enter until the fire department clears the house. Afterward, have the flagged appliance inspected by a licensed tech before running it again — that's when a combustion-safety inspection is worth every penny.

Red flags — stop and call now: A sounding CO alarm is the emergency — out of the house, then 911.

No heat — system won't start

Dead thermostat, no heat

Likely causes

1. Dead thermostat batteries.
2. The furnace's service switch flipped off.
3. A tripped breaker.
4. A control or transformer fault.

Safe checks you can do yourself

• Put in fresh batteries.
• Find the switch on or beside the furnace that looks exactly like a light switch — it gets bumped off more than anyone admits — make sure it's ON.
• Check the breaker, one reset.

When it's time to call

If power's confirmed and the screen stays dark. Low-voltage faults are quick diagnostics for a tech and a rabbit hole for everyone else.

Heating services

It runs, but blows cold air

Heat pump air feels cool

Likely causes

1. Nothing — heat-pump supply air (85–92°F) is cooler than furnace air but still well above room temperature; it heats by volume, not blast.
2. A defrost cycle blowing cool air for a few minutes.
3. An actual fault only if the house temperature is falling.

Safe checks you can do yourself

• Hold a thermometer at a vent — anything meaningfully above room temperature means it's working.
• Watch the house temperature over an hour rather than judging by hand-feel.

When it's time to call

If the house can't hold temperature, the auxiliary/emergency heat runs constantly (watch the bill), or the outdoor unit ices over solid and stays that way. Honest read: “cooler-feeling air” is the #1 false alarm we see on heat pumps in mild SoCal winters.

Heating services

Starts, then shuts off, over and over

Lights, then dies in seconds

Likely causes

1. A dirty flame sensor — it can't prove the flame exists, so the control shuts the gas. This is the most common furnace repair, period.
2. A weak igniter.
3. A venting or pressure-switch fault.

Safe checks you can do yourself

• None beyond a filter check — the flame sensor lives behind the burner compartment, and that's not homeowner territory.

When it's time to call

Now-ish; the fix is typically fast and inexpensive. Left alone, the furnace will eventually lock out on a cold night.

Furnace repair

Pilot light / ignition trouble

Pilot won't stay lit after the knob

Likely causes

1. A worn thermocouple — it can no longer prove the pilot's lit, so the gas valve closes the instant you let go.
2. A weak or dirty pilot flame.
3. A failing gas valve.

Safe checks you can do yourself

• A visual only — note the pilot flame's color and size through the sight glass if it lights (steady blue = healthy; weak yellow = starved). Skip repeat attempts; each one releases a little unburned gas.

When it's time to call

This week. A thermocouple swap is a routine, inexpensive visit. If you smell gas at any point, that changes everything: leave and call SoCalGas 1-800-427-2200.

Furnace repair

Burning or odd smell from the vents

Dusty burn-off at first seasonal use

Likely causes

1. Summer's dust layer burning off the heat exchanger — the classic first cold-night smell.
2. A filter overdue for a change adding to it.

Safe checks you can do yourself

• Crack a window, run the heat, and give it 30–60 minutes — the smell should fade the same day.
• Replace the filter if it's due.

When it's time to call

Only if the burning smell persists past the first day, gets stronger, or smells electrical rather than dusty. First-use burn-off is normal; you likely don't need anyone.

Loud noises (boom, squeal, rumble)

Boom on ignition

Likely causes

1. Delayed ignition — gas pools in the burner box for a few seconds before lighting, then ignites all at once.
2. Dirty burners, a weak pilot/igniter, or misaligned burners behind it.

Safe checks you can do yourself

• Stop using the heat.
• A sniff-check for gas odor near the unit (from a respectful distance) — if present, leave and call the utility.

When it's time to call

Before the next use. Small ignition booms crack heat exchangers and singe components; this is a genuine “don't run it until it's looked at” symptom, and we'd tell you the same if you'd bought the furnace yesterday.

Furnace repair

Some rooms stay cold

Same rooms always cold

Likely causes

1. Weak or leaking duct runs to those rooms.
2. Closed or blocked registers.
3. Long duct runs that were never balanced.

Safe checks you can do yourself

• Open the cold rooms' registers fully.
• Close the door and feel for airflow at the vent with the fan ON.
• Clear furniture off vents.

When it's time to call

For a duct inspection and balancing — this is an air-delivery problem, and no thermostat or furnace swap fixes ducts. Honest note: sometimes the fix is as small as a damper adjustment.

Duct cleaning & duct services

No hot water at all

Gas water heater, no hot water

Likely causes

1. The pilot is out.
2. A failed thermocouple/thermopile shutting the gas valve.
3. A gas supply interruption.
4. A failed gas control valve.

Safe checks you can do yourself

• Look through the little sight window near the bottom — is the pilot flame visible?
• Check whether other gas appliances work (isolates a supply problem).
• Confirm the temperature dial isn't turned to “vacation/off.”

When it's time to call

If the pilot's out or the burner won't fire. Thermocouple and pilot-assembly work is quick for a licensed tech; it's gas work, so it isn't a DIY item on this checker.

Red flags — stop and call now: Gas smell anywhere near the unit → leave, SoCalGas 1-800-427-2200 or 911.

Water heater services

Not enough hot water / runs out fast

Hot water shrank gradually

Likely causes

1. Sediment — LA & OC water is hard, and mineral buildup steadily eats tank capacity and insulates the burner from the water.
2. An aging element (electric) losing output.

Safe checks you can do yourself

• Listen during a heating cycle — popping or rumbling is sediment announcing itself.
• Note the tank's age from the serial-number sticker.

When it's time to call

For a professional flush if the tank is under ~8–10 years old. Honest math: on a 12+-year-old tank, a flush can stir up more trouble than it fixes — that's the point where a replacement conversation is the truthful one, not an upsell.

Water heater services

Water is scalding hot

Scalding after a dial change

Likely causes

1. The thermostat dial is simply set too high.
2. Nothing else — this one's usually exactly what it looks like.

Safe checks you can do yourself

• Turn the external dial to about 120°F (often the mark between “warm” and “hot”) and give it a few hours to settle. 120°F prevents scalding — matters most with kids or elders at home.

When it's time to call

Only if the temperature won't respond to the dial — that points at a failed thermostat or gas control, which is a real repair.

It's leaking

Leak at the top fittings

Likely causes

1. Loose or corroded inlet/outlet connections.
2. A weeping flex line.
3. A failing anode-rod port seal.

Safe checks you can do yourself

• If it's actively dripping, close the cold-water shutoff valve on the line feeding the tank (turn clockwise).
• Towel and bucket.
• Photos help whoever comes out.

When it's time to call

Soon but not panicked — top-side fitting leaks are usually repairable without replacing the tank. That's good news worth knowing before anyone quotes you a new unit.

Water heater services

Rusty or smelly hot water

Rust only in hot water

Likely causes

1. A depleted anode rod letting the tank corrode — the anode sacrifices itself for years, then quits.
2. Rusting steel hot-water pipes in older homes.

Safe checks you can do yourself

• Run a hot-only tap into a white cup, then a cold-only tap — confirming it's truly hot-side-only is the whole diagnosis you can do from outside.

When it's time to call

Reasonably soon. If the tank is mid-life, a new anode rod can add years; if it's old, rust is the tank's early retirement notice — better to plan the replacement than have it choose its own moment.

Water heater services

Popping, rumbling, or whining

Popping/rumbling tank

Likely causes

1. Sediment — water trapped under a hardened mineral layer flashes to steam and pops.
2. In LA & OC hard water, this is close to universal on unflushed tanks past a few years.

Safe checks you can do yourself

• None needed to confirm — the sound is the diagnosis.

When it's time to call

For a flush while the tank is young enough to benefit; sediment makes every therm cost more and shortens tank life. On an old tank, honest answer again: flushing can open leaks — a tech should assess before touching the drain valve.

Water heater services

Pilot light keeps going out

Pilot dies at knob release

Likely causes

1. A worn thermocouple — it must feel the flame before the valve stays open; when it weakens, the valve drops the instant you release.
2. A dirty pilot orifice making a too-small flame.

Safe checks you can do yourself

• Look at the flame while holding: healthy is steady blue wrapping the thermocouple tip; weak yellow means starved. Look only — repeat attempts release unburned gas.

When it's time to call

This week — a thermocouple is one of the least expensive gas repairs there is.

Water heater services

Tankless problems (error code, lukewarm)

Tankless error code

Likely causes

1. Scale buildup tripping temperature/flow sensors — the #1 tankless issue in hard-water SoCal.
2. Venting or combustion-air faults.
3. Gas-supply pressure.

Safe checks you can do yourself

• Write down the exact code and look it up in the manual (or the maker's site) — totally safe and it tells whoever you call exactly what to bring.
• One power-cycle at the unit's plug or switch is fine; more than one is denial.

When it's time to call

If the code returns after one power cycle. If the unit's never been descaled and you're past year 2–3 on unsoftened water, assume scale until proven otherwise.

Tankless water heaters

One fixture is slow or clogged

Slow bathroom sink/tub/shower

Likely causes

1. Hair and soap scum matted at the stopper or trap — far and away #1.
2. Mineral scale narrowing older drains.

Safe checks you can do yourself

• Lift out the pop-up stopper or shower strainer and clear what's on it (gross, free, effective).
• A few firm plunges with standing water.
• Skip chemical drain cleaners — they rarely clear hair mats, they damage pipes, and they burn the plumber who works on the drain next.

When it's time to call

If the stopper cleaning and plunger don't restore flow — a proper auger clears the trap arm in minutes. Recurring slowness in the same drain hints at a bigger narrowing worth a look.

Drain cleaning

Several drains are slow at once

Multiple slow drains, lowest first

Likely causes

1. A main sewer line blockage building — tree roots are the top cause in older LA & OC neighborhoods.
2. Heavy scale or grease in the main.
3. A bellied (sagging) section collecting debris.

Safe checks you can do yourself

• Ease off water use — every gallon goes toward the eventual backup.
• Confirm the pattern: multiple fixtures = mainline; one fixture = branch.

When it's time to call

Now, before it becomes a backup on a Sunday night. Ask for a camera inspection with the clearing — seeing roots vs. grease vs. a break changes everything about what you should pay for next.

Drain & sewer services

Sewage backing up

STOP — safety first: Sewage is actively backing up

Likely causes

1. Your main sewer line is blocked — tree roots and aging lines are the usual culprits in older LA & OC neighborhoods.
2. Everything you drain now comes back up at the lowest fixture.

Safe checks you can do yourself

• Stop using ALL water — every flush and shower feeds the backup.
• Keep kids and pets away from the water; raw sewage is a genuine health hazard.
• If it's reached outlets or appliances and your breaker area is dry, switching off breakers to that room is reasonable — otherwise leave the electrical alone.

When it's time to call

Right away — this doesn't self-resolve, and cleanup cost grows by the hour. Ask for a mainline clearing plus a camera inspection so you learn why it happened, not just a temporary hole in the clog.

Red flags — stop and call now: Raw sewage indoors is a health hazard — stop all water use now.

Drain & sewer services

Gurgling sounds or sewer smell

Cross-fixture gurgling

Likely causes

1. A partial mainline or branch blockage forcing air through neighboring traps.
2. Blocked or inadequate venting making drains gasp for air.

Safe checks you can do yourself

• Map it — which fixture gurgles when which one drains; that pattern localizes the blockage better than any guess.

When it's time to call

Soon; gurgling is the early-warning stage where a clearing is cheap and a backup hasn't happened yet. Best-value moment on the whole timeline.

Drain cleaning

Toilet keeps clogging / weak flush

One toilet clogs repeatedly

Likely causes

1. A partial obstruction lodged in the trapway — the toy scenario; it passes water until paper snags on it.
2. A weak flush from a misadjusted tank.
3. Mineral-clogged rim jets on older bowls.

Safe checks you can do yourself

• Lift the tank lid (just a lid) and watch a flush — does the flapper stay up for a full flush or slam shut early?
• Does the bowl's water level look normal between uses?

When it's time to call

A recurring single-toilet clog earns an auger and, if that fails, a pull-and-inspect. Honest note: if the toilet is the problem, a modern one out-flushes it for less than serial service calls.

Toilet repair & replacement

Garbage disposal trouble

Disposal hums but won't spin

Likely causes

1. A jam — something (fruit pit, bone shard, utensil) wedged between the impeller plate and the grind ring.
2. Worn grind components if it jams routinely.

Safe checks you can do yourself

• Switch it OFF first, always. Never put your hand in it, powered or not.
• Insert the hex wrench that came with it (or a 1/4″ allen key) into the socket on the disposal's bottom and work it back and forth to free the plate.
• Press the red reset button underneath, then try again with cold water running.

When it's time to call

If the hex trick doesn't free it, or it jams routinely — bearings and grind components wear, and a persistent hum cooks the motor.

Red flags — stop and call now: Burning smell while it hums → switch off, leave it off.

Garbage disposal repair

I smell gas

STOP — safety first: You smell gas: leave now

Likely causes

1. A gas leak at a line, fitting, valve, or appliance.
2. It does not matter which yet — the smell is the signal.

Safe checks you can do yourself

• None. Do not flip any switch, light anything, or start a car in an attached garage.
• Leave the doors open on your way out if they're already open — never go back inside to open them.

When it's time to call

Now, from outside or a neighbor's. Call SoCalGas at 1-800-427-2200, or 911 if the smell is strong or you hear hissing. Only after the utility clears the property does a licensed plumber's gas-line repair come into play.

Red flags — stop and call now: This IS the red flag — leave first, make the calls from outside.

Dripping faucet or running toilet

Dripping faucet

Likely causes

1. A worn cartridge, washer, or seat inside the faucet.
2. Hard-water scale chewing those parts faster than the brochure promised.

Safe checks you can do yourself

• Confirm which handle side drips (hot/cold).
• If it's maddening tonight, close that fixture's shutoff under the sink until it's fixed.

When it's time to call

At your convenience — but for perspective, one drip per second is roughly 3,000 gallons a year on your bill. Cartridge swaps are quick; on a corroded older faucet, replacing the fixture is sometimes the cheaper honest path.

Faucet repair

Low water pressure

Low pressure at one fixture

Likely causes

1. A scale-clogged aerator or showerhead — hard-water special.
2. That fixture's shutoff valve not fully open.
3. A kinked supply line under the sink.

Safe checks you can do yourself

• Unscrew the faucet aerator (hand-tight fitting at the spout tip) and rinse the grit out — fixes a huge share of these.
• Check the fixture's shutoff valves are fully open.
• Soak a scaled showerhead in vinegar overnight.

When it's time to call

If a clean aerator and open valves don't restore it — then the restriction is inside the faucet body or its supply, a small repair.

Faucet repair

Visible leak / water where it shouldn't be

Leak under a sink

Likely causes

1. A loose P-trap connection.
2. A failed supply line or its connection.
3. The faucet base or sprayer hose leaking down from above.

Safe checks you can do yourself

• Dry everything, lay a paper towel, run the faucet, then fill-and-drain the basin — where the towel wets first tells you drain side vs. supply side.
• If it's a supply drip, close that line's shutoff valve.

When it's time to call

Supply-side leaks deserve fast attention (they run whether or not you use the sink); drain-side leaks only leak when you use it, so you can shut the cabinet and schedule calmly. Braided supply hoses are cheap insurance while someone's there.

Plumbing services

Water bill spiked — hidden leak?

Meter moves with everything off

Likely causes

1. A leaking toilet flapper — the #1 hidden water thief; silent and huge.
2. A slab or underground service-line leak.
3. A stuck water softener or RO unit cycling.

Safe checks you can do yourself

• Food-coloring test every toilet first (dye in tank, 15 minutes, look in bowl) — cheapest suspect, most common culprit.
• Then close the house main: if the meter STOPS, the leak is inside; if it keeps moving, it's in the yard line between meter and house.

When it's time to call

Once your two tests localize it. Inside + no dyed toilets = professional leak detection. Meter-to-house = service-line repair. Either way you'll make that call knowing roughly what it is — which is the point of this checker.

Leak detection

No water, or a trickle, whole house

Whole street is out

Likely causes

1. A municipal main break or utility work — not your plumbing at all.
2. Nothing in your house caused this.

Safe checks you can do yourself

• Check your water utility's outage page or call their line — that's genuinely the whole list.

When it's time to call

The utility, not a plumber — and never let anyone charge you a service call for a city outage. When water returns, run a cold tap a few minutes to flush any stirred-up sediment before using hot water (protects the water heater from a gulp of grit).

Banging or noisy pipes

Water hammer bang

Likely causes

1. Fast-closing solenoid valves slamming moving water to a stop — the shock wave is the bang.
2. It worsens with high house pressure or waterlogged/absent hammer arrestors.

Safe checks you can do yourself

• Identify which appliance triggers it (start a wash cycle and listen).
• If you have a pressure gauge on a hose bib, note the reading — over ~80 psi makes everything worse and is also out of code.

When it's time to call

Worth fixing, not just annoying — repeated hammer stresses joints and hoses until one lets go. Hammer arrestors at the offending appliance are a modest job; if pressure's high, the PRV is the real patient.

Plumbing services

Allergies or congestion worse indoors

Symptoms spike when the system runs

Likely causes

1. A low-grade or overdue filter letting the system redistribute dander, dust, and pollen.
2. Dirty ductwork re-seeding the air each cycle.
3. A dirty evaporator coil.

Safe checks you can do yourself

• Check the filter's condition AND its rating — a builder-grade fiberglass filter stops rocks, not allergens; MERV 11–13 (if your system's manual allows) is a cheap upgrade.
• Look at a supply register with a flashlight for visible dust mats.

When it's time to call

If a better filter doesn't move the needle in a couple of weeks. Honest guidance on duct cleaning: it helps when there's a real contamination (visible mold, vermin, renovation dust) — ask for photo/video evidence of what's in YOUR ducts before paying, and be wary of anyone selling it annually.

Indoor air quality solutions

Musty smell when the system runs

Musty burst at startup

Likely causes

1. Microbial film on the evaporator coil and in the condensate pan — the “dirty sock” smell — blasted loose each startup.
2. A stagnant condensate trap.

Safe checks you can do yourself

• Flashlight look at the condensate pan area for standing water or slime (look, don't disassemble).
• Run the fan a few minutes and note if the smell truly fades — startup-only is the signature of coil film.

When it's time to call

At your convenience — a coil cleaning and pan treatment usually ends it. Mild and common, but it doesn't improve on its own.

Indoor air quality solutions

Excessive dust, no matter the cleaning

Dust puffs from vents

Likely causes

1. Duct leaks on the return side vacuuming attic or crawlspace dust and blowing it into rooms — attic dust plus Santa Ana wind season makes this a SoCal staple.
2. Heavily loaded ducts shedding.

Safe checks you can do yourself

• White-tissue test — hold a tissue over a supply register at startup and see what it catches.
• Check the filter is seated with no bypass gaps around its frame.

When it's time to call

For a duct-leakage check — sealing return leaks fixes the dust at its source and usually pays energy dividends too. Cleaning without sealing refills itself.

Duct cleaning & duct services

Humidity trouble (muggy or too dry)

Muggy while AC runs

Likely causes

1. The thermostat fan set to ON — between cooling cycles the fan re-evaporates moisture off the wet coil and pumps it right back into the house (the sneakiest setting mistake there is).
2. An oversized AC that cools fast but never runs long enough to dehumidify.
3. Big attic-duct leaks pulling humid air in.

Safe checks you can do yourself

• Set the fan to AUTO — genuinely check this first; it fixes more mugginess than any purchase.
• Longer, cooler cycles dehumidify better than short blasts.

When it's time to call

If AUTO doesn't fix it — oversizing and duct leakage are diagnosable, and the honest fix might be duct sealing rather than any new equipment.

Air conditioning repair & service

Stuffy rooms / stale air

Same rooms always stuffy

Likely causes

1. Weak supply airflow to those rooms (duct balance/leaks).
2. No return path — a closed door with no return grille pressurizes the room and chokes its own supply.

Safe checks you can do yourself

• The door test — does airflow improve noticeably with the door open?
• Check for a gap under the door (an inch matters).
• Registers fully open, unblocked.

When it's time to call

For duct balancing or return-path fixes (jumper ducts, transfer grilles) — small-sounding work that transforms stubborn rooms. Equipment is rarely the problem here.

Duct cleaning & duct services

Carbon monoxide or gas safety worry

STOP — safety first: Carbon monoxide alarm is sounding

Likely causes

1. A fuel-burning appliance (furnace, water heater, range) is putting CO into your air.
2. Attached-garage exhaust drifting indoors. CO is invisible and odorless — trust the alarm, not your nose.

Safe checks you can do yourself

• None. Get every person and pet outside immediately.

When it's time to call

911 from outside. Do not re-enter until the fire department clears the house. Afterward, have the flagged appliance inspected by a licensed tech before running it again — that's when a combustion-safety inspection is worth every penny.

Red flags — stop and call now: A sounding CO alarm is the emergency — out of the house, then 911.