Is my house making me sick?

Stasis Home ResearchEvery claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated July 2026

Maybe, and the usual causes are ordinary, not mysterious. If your headaches, grogginess, congestion, or brain fog ease within a day of leaving home, the building is a likely driver. The common culprits are poor ventilation, off-gassing from new materials, damp and mold, and fine particles. One, carbon monoxide, is a true emergency: get a CO alarm today.

The tell: do your symptoms ease when you leave?

A headache that lifts on the drive to work, grogginess that disappears on vacation, congestion that clears after a weekend away. When symptoms track the building rather than the season or a passing bug, the house is worth investigating. This pattern has a name, sick building syndrome, and the honest science is less dramatic than the phrase sounds. It is rarely one hidden toxin. It is usually a few ordinary things stacked together: a home sealed tight enough to trap what gets made inside it, not enough fresh air reaching the rooms, new materials still off-gassing, or a damp spot quietly feeding mold. The good news is that each of these is identifiable and fixable, and the list of real culprits is short. The rest of this page walks the common symptoms back to their likely source, starting with the one that is a genuine emergency.

First rule out the emergency: carbon monoxide

One cause is not a slow-burn comfort issue, it is a medical emergency, so clear it first. Carbon monoxide is a gas you cannot see or smell, produced whenever fuel burns: a furnace, a gas stove or water heater, a fireplace, a car warming up in an attached garage. It causes headaches, dizziness, nausea, and confusion, and at high levels it can be fatal. Two tells separate it from ordinary bad air: symptoms often cluster in colder months when the heating runs, and more than one person or a pet in the home feels sick at the same time. Because you cannot detect it with your senses, the only protection is a carbon monoxide alarm. If your home has any fuel-burning appliance or an attached garage and no working CO alarm, that is the single most important thing to buy today. If an alarm sounds, or several people feel sick at once, get everyone outside into fresh air and call 911.

Match the symptom to the source

Once carbon monoxide is ruled out, the everyday causes sort by symptom. Grogginess after a full night's sleep and a bedroom that feels stuffy by morning usually mean carbon dioxide from your own breathing building up behind a closed door in a tightly built home. It is not toxic at these levels, but it is a reliable sign the room is not getting fresh air, and it costs you deep sleep. A new-carpet, fresh-paint, or new-furniture smell paired with headaches, watery eyes, or a scratchy throat points to volatile organic compounds off-gassing from those materials, a group that includes formaldehyde, a known human carcinogen, which is why a lingering chemical smell in a new build or recent renovation is worth taking seriously. A musty or earthy smell with congestion, sneezing, sinus trouble, or asthma that is harder to control points to damp and mold; the settled harm there is respiratory, not the 'toxic black mold' panic online, and the real fix is finding the water, not testing the air. Eye, throat, and airway irritation that spikes when you cook, or during wildfire smoke or heavy nearby traffic, points to fine particles, PM2.5. A HEPA filter genuinely helps with those particles, but it does nothing for the gases above, and nothing for carbon monoxide or radon.

The one with no symptoms, and why guessing fails

One serious cause gives you no symptoms at all. Radon is a radioactive gas that seeps from the soil into a home, invisible and odorless, and the leading cause of lung cancer among people who have never smoked. There is no headache, no smell, no stale-air feeling to warn you, so the only way to know is to test, and a test is inexpensive. That is the larger lesson of this whole page. The symptoms overlap, several causes feel the same from the inside, and the fixes are different for each: a carbon dioxide problem needs ventilation, a mold problem needs the leak found, a particle problem needs a filter, and radon needs a soil-side fix. Guessing wastes money on the wrong device. A few days of measurement, or a proper home audit, tells you which driver you actually have before you spend anything.

Where to start

Put a carbon monoxide alarm on every level of the home if you have any fuel-burning appliance or an attached garage. This is the one that can save a life, so do it first.
Ventilate: open the bedroom door or a window when outdoor air is clean, run the kitchen and bathroom exhaust fans, and flush the house for fifteen minutes in the morning.
Find and fix moisture: check under sinks, around the toilet base, the HVAC condensate drain, and any musty-smelling corner, and dry or repair the source within a day or two.
Test for radon. It has no smell and no symptoms, so a test is the only way to know it is there, and the kits are cheap.
Use an indoor air monitor, or a home audit, to find the actual driver before buying any device. A filter does nothing for gases or radon, so measure first.

The science behind this

AIRCarbon dioxide (CO2)The carbon dioxide your breathing builds up behind a closed door. Not toxic at home levels, but the clearest sign a room is starving for fresh air, and the usual cause of morning grogginess.AIRVOCs and formaldehydeThe gases off-gassing from new paint, flooring, and furniture, including formaldehyde. The source of that new-build chemical smell and the headaches and irritation with it. A HEPA filter does not touch them.AIRMoldWhat the research actually shows on damp, mold, and health, where the evidence on breathing symptoms is solid, and where the 'toxic mold' claims run past it.AIRPM2.5 (fine particulate matter)The fine particles from cooking, smoke, and traffic that irritate eyes and airways and reach deep into the lungs. The one problem on this list a HEPA filter genuinely fixes.AIRRadonThe radioactive soil gas with no smell and no symptoms, and the leading cause of lung cancer in people who never smoked. The reason testing beats guessing.AIRIndoor humidityThe dryness or damp behind a lot of vague symptoms. Too dry dries out your nose and throat; too damp feeds mold. The comfortable band is 40 to 50 percent.

What actually works

Method

Mechanical ventilation (ERV / HRV)

Method

HEPA air purifiers

Common questions

Can my house really make me sick?

Yes, and usually through ordinary causes rather than one hidden toxin. Poor ventilation, gases off-gassing from new materials, damp that feeds mold, and fine particles from cooking or smoke can all produce real symptoms. The clearest sign it is the building is that your symptoms ease within a day or two of leaving home. One cause, carbon monoxide, is a true emergency and should be ruled out first with an alarm.

What are the symptoms of a house making you sick?

The common ones are headaches, grogginess or fatigue that does not improve with sleep, congestion and sinus irritation, watery or scratchy eyes and throat, and trouble concentrating. None of these points to a single cause on its own, which is why they get confused with allergies or a lingering cold. The pattern that matters is timing: symptoms that lift when you leave the house and return when you come back point at the building rather than at you.

Is my old house making me sick?

It can, though the reasons differ from a new home. Older houses skew toward moisture and mold from aging roofs, windows, and plumbing, and toward carbon monoxide risk from older or poorly maintained fuel-burning appliances, so a CO alarm and a moisture check matter most. Newer, tightly sealed homes have the opposite problem: they trap the carbon dioxide you exhale and the gases from new materials because so little fresh air gets in. Age cuts both ways, so match the check to the house.

What is sick building syndrome?

Sick building syndrome describes a pattern where people in a specific building get headaches, tiredness, or irritation of the eyes, nose, and throat that ease once they leave it. The honest science is that it rarely traces to one mystery toxin. It is usually several ordinary factors together: too little fresh air, gases from materials and furnishings, humidity that is off, and dust or particles. Because the causes stack, the fix is to work out which ones are present in your home rather than to hunt for a single culprit.

Why do I feel better when I leave the house?

Because you are stepping out of the exposure. If a headache clears on your commute, or grogginess lifts on a weekend away, whatever is driving it is concentrated indoors and diluted the moment you leave. That is the single most useful clue you have that the building, not a virus or the season, is the source. It does not tell you which cause it is, but it tells you where to look.

How do I find out what in my house is making me sick?

Start by ruling out carbon monoxide with an alarm, since that one is an emergency. After that, measurement beats guessing, because a stuffy room, a musty smell, and a chemical smell can feel similar but need different fixes. A few days with an indoor air monitor, or a full home audit, shows whether the driver is ventilation, humidity, particles, gases, or something in the soil. Testing first keeps you from buying a filter that does nothing for the problem you actually have.