Last updated: September 27, 2026
Most of us spend the large majority of our time indoors, and EPA studies have found levels of about a dozen common organic pollutants to be two to five times higher inside homes than outside. That's why indoor air quality is important: it affects how comfortable your home feels, how well you sleep, how much you dust, and how people with allergies or asthma feel day to day.
Short answer: The biggest indoor air problems in Vancouver homes are excess winter humidity, stale air in sealed-up houses and wildfire smoke. Keeping humidity at 30–50%, running exhaust fans, upgrading filtration and adding fresh-air ventilation address most of them.
In the Pacific Northwest, the concerns are specific: long damp winters that keep windows shut, tighter modern homes, and wildfire smoke in some late summers. This guide covers what affects indoor air, why humidity matters so much here, and the practical fixes that help.
What pollutes indoor air
Indoor air collects pollutants from inside the home and from outside:
- Particles: dust, pet dander, pollen, and smoke from cooking, fireplaces or wildfires
- Biological contaminants: mold spores, dust mites, bacteria and viruses
- Volatile organic compounds (VOCs): gases released by paints, cleaners, air fresheners, new furniture, flooring and craft supplies
- Combustion gases: carbon monoxide and nitrogen dioxide from gas appliances, fireplaces and attached garages
- Excess moisture: not a pollutant itself, but it drives mold and dust mites
When a home can't bring in enough fresh air, or its HVAC system recirculates air without filtering it well, these build up.
Why Vancouver homes face specific challenges
Closed-up winters. From October through April, most homes here stay sealed against the rain and cold. Showers, cooking, drying laundry and simply breathing add moisture and pollutants that have nowhere to go.
Tighter houses. Newer homes and older homes with energy upgrades leak less air. That's good for heating bills, but without planned ventilation, stale air stays in.
Cottonwood and pollen. Spring and early summer bring heavy pollen and cottonwood fluff.
Wildfire smoke. In some years, smoke from regional fires settles over Clark County for days in August and September. Fine smoke particles get indoors easily.
Humidity: the part most people overlook
The EPA recommends keeping indoor relative humidity below 60%, and ideally between 30% and 50%.
Too humid (above 50–60%)
This is the more common problem in Vancouver winters. Signs include:
- Condensation on windows, especially in the morning
- Musty smells in closets, basements or crawlspaces
- Mold on window sills, bathroom ceilings or behind furniture on outside walls
- Air that feels clammy even when it's warm
High humidity feeds mold and dust mites, both major allergy and asthma triggers, and over time it can damage drywall, window frames and wood.
Too dry (below 30%)
This is less common here, but it happens during cold, dry east-wind spells or in homes heated for long stretches. Signs include:
- Static shocks
- Dry skin, eyes and throat
- Cracking wood floors or furniture
How to measure indoor humidity accurately
An inexpensive digital hygrometer from a hardware store tells you where you stand, if you use it the right way:
- Place it well: at about chest height in a main living area, away from bathrooms, the kitchen, exterior doors, windows and supply vents.
- Let it settle: give it 30 minutes after moving it before you read it.
- Check more than one room, more than once: winter mornings usually read highest, and bedrooms and basements often run higher than the rest of the house.
- Check its accuracy with a salt test: seal the hygrometer in a zip-top bag with a small dish of table salt dampened to a paste, and leave it 8–12 hours. An accurate meter reads about 75%. If yours reads 72%, add 3 points to its readings.
If readings stay above 50–60% through the winter even with exhaust fans running, it's time to look at ventilation. We can measure your home's humidity and airflow and recommend a fix.
Are you in need of professional services for your home’s indoor air quality?
Contact Tri-Tech Heating, Inc. for expert solutions today!
Signs your home's air quality needs attention
- Dust comes back soon after cleaning
- Allergy or asthma symptoms are worse at home than elsewhere
- Musty or stale smells that return
- Window condensation or visible mold
- Stuffy rooms, or rooms that feel different from the rest of the house
- Headaches or fatigue that ease when you leave home
- Smoke, cooking or pet odors that linger
If you ever experience headaches, dizziness or nausea together with gas appliances in use, treat it as a possible carbon monoxide problem: get fresh air and call 911. Every home with gas appliances or an attached garage should have working CO alarms.
What helps: practical steps
Things you can do today
- Change your filter on schedule, every one to three months, and sooner during smoke events or if you have pets.
- Run bathroom fans during showers and for 20 minutes after. Use the range hood when cooking, especially on a gas stove.
- Vent the dryer outdoors, and avoid drying laundry indoors in winter.
- Keep return grilles clear, since your system can only clean the air it can reach.
- Choose low-VOC products for paint, cleaning and home projects, and air out new furniture.
- On smoky days, keep windows closed, run the system fan to filter indoor air, and consider a portable HEPA purifier for bedrooms.
HVAC solutions Tri-Tech offers
Upgraded filtration. Moving from a basic filter to a higher-efficiency media filter captures much finer particles, including many smoke and allergy particles. The EPA suggests MERV 13 or as high as your system's fan and filter slot can handle, so it's worth having your system checked.
Fresh-air ventilation. A ventilation system exhausts stale indoor air and brings in fresh outdoor air in a controlled way. That helps tight homes clear moisture, odors and VOCs without opening windows in the rain.
Microbial reduction. A photohydroionization (PHI) probe installs in the ductwork and is designed to reduce mold, yeast and viruses in the air moving through your system.
Air Scrubber Plus with ActivePure Technology. An in-duct system designed to reduce airborne pollutants, VOCs and surface contaminants throughout the home.
Low wall returns. Adding or relocating a return near the floor helps pull dust-laden air into the system before it circulates at breathing height.
Barometric dampers. These let make-up air in to replace air removed by exhaust fans, dryers and range hoods, so the house isn't pulling unfiltered air through cracks and gaps.
Duct sealing. Leaky return ducts in crawlspaces and attics can pull in dust, insulation fibers and damp air. Sealing them improves air quality and efficiency.
Which of these makes sense depends on your house, your system and what's bothering you. A visit that looks at humidity, airflow, filtration and ventilation together usually points to the right fix. See our indoor air quality services.
Breathe easier at home
Tri-Tech Heating, Inc. installs filtration, ventilation and air-cleaning systems for homes across Vancouver, Camas, Salmon Creek and Clark, Cowlitz and Skamania Counties and the Portland metro area. Our work is 100% guaranteed.
Explore our indoor air quality services, our seasonal maintenance checklist and our HVAC terms glossary, or contact us.
Our office is open Monday through Thursday, 8:00am to 5:00pm, and Friday, 8:00am to 4:00pm, and a call to (360) 891-2002 during those hours reaches a person. After hours, call the same number and a live person from our answering service will take your information. They'll text our on-call technician right away, or, if you'd rather wait, pass your request to our office and we'll respond by 9:00am the next business day. Licensed HVAC #TRITEHI952LL, CCB #161426.
Are you in need of professional services for your home’s indoor air quality?
Contact Tri-Tech Heating, Inc. for expert solutions today!
Frequently Asked Questions
Does my furnace or heat pump clean the air?
Only as well as its filter. Standard filters mainly protect the equipment. Higher-efficiency filtration and air-cleaning add-ons are what improve the air you breathe.
How do I know if I need a ventilation system?
Frequent condensation, lingering odors, stuffiness or a newer, tightly built home are good signs. A technician can check your home's humidity and airflow.
Company Information
Tri-Tech Heating, Inc.
6406 NE 116th Ave Unit C
Vancouver, WA 98662
Phone: (360) 891-2002