How do I improve the indoor air quality in my house?
Improving indoor air quality comes down to four steps in order: filter the air with the right MERV rating for your system, control humidity between 30 and 50 percent, seal the duct leaks pulling attic and crawlspace air into your home, and add ventilation or targeted purification if a specific problem remains. Start with the filter and humidity, because they cost the least and solve the most.
What indoor air quality actually measures
Four things drive how the air in your home feels and how it affects your family: particles you can breathe in, humidity, ventilation, and gases such as carbon monoxide. Most complaints we hear, constant dust, allergy symptoms indoors, musty smells, dry winter throats, trace back to the first three.
Step one: is my filter doing anything?
A filter is rated by MERV, which measures how small a particle it captures. Higher is not automatically better, because a filter that is too restrictive for your blower starves the system and can freeze the coil.
- MERV 8: catches dust, lint, and pollen. Safe in essentially any system.
- MERV 11 to 13: catches finer particles including much smoke and pet dander. Good for allergy households, but confirm your blower can handle it.
- MERV 16 and up: generally belongs in a dedicated media cabinet or air cleaner, not a one inch slot.
The bigger lever is surface area. A one inch filter clogs in roughly 30 days in a dusty Kansas summer. A four or five inch media cabinet holds far more, filters better, and gets changed a few times a year instead of monthly. If you are fighting dust, that upgrade usually beats buying a higher MERV one inch filter.
Step two: what should my humidity be?
Aim for 30 to 50 percent relative humidity year round. Kansas makes you fight both directions.
- Summer. Humid air feels warmer than it is, and above roughly 60 percent you get mold and mildew growth. A correctly sized air conditioner dehumidifies as it cools. An oversized one cools the thermostat fast, shuts off, and never runs long enough to pull the water out. That is why an oversized system leaves the house cold and clammy.
- Winter. Furnace heat drives humidity down. Dry air causes cracked skin, static, sore throats, and gaps in wood floors and trim. A whole home humidifier tied into the ductwork handles the whole house instead of one room.
Step three: where is the dirty air getting in?
This is the step most homeowners skip. Return ducts that leak in an attic or crawlspace pull unfiltered air straight into your air stream. That is attic dust, insulation fibers, and crawlspace moisture, delivered to every room by the system you installed to make the air better.
Signs it is happening: dust reappears within a day or two of cleaning, the air smells like the crawlspace when the system kicks on, and the filter looks dirty on the wrong side of the filter housing. Sealing return leaks often does more for dust than any filter upgrade.
Step four: do I need an air purifier?
Only after the first three steps, and only for a specific problem. Whole home air cleaners and UV systems install in the ductwork and treat all the air the system moves, which beats a portable unit that treats one room. They are worth considering when someone in the home has asthma or severe allergies, when there are indoor pets, or when a musty smell survives after the humidity and duct work is fixed.
Be skeptical of any product sold as a cure all. If the ducts leak and the humidity is at 65 percent, a purifier is treating a symptom.
What about carbon monoxide?
This one is not about comfort. Any home with gas appliances needs working carbon monoxide alarms on every level, especially outside sleeping areas. A cracked heat exchanger can put combustion gases into your air stream, and you cannot smell it. Our maintenance visits include checking combustion safety on the furnace.
What to do next
Do them in order. Right sized filter with real surface area, then humidity, then duct sealing, then targeted purification. A 32 point maintenance visit is $139 for non members and covers the filter, the humidity equipment, and the combustion safety check in one trip. Comfort Club members get seasonal tune ups included.
Frequently asked questions
How do I improve the indoor air quality in my house?
Work in this order. Use the right MERV filter with enough surface area for your blower, hold humidity between 30 and 50 percent, seal duct leaks that pull attic or crawlspace air into the system, and only then add whole home purification for a specific remaining problem such as asthma or pet dander.
What MERV rating should I use in my home?
MERV 8 is safe in nearly any system and catches dust and pollen. MERV 11 to 13 catches finer particles and suits allergy households, but confirm your blower can handle the restriction. A four or five inch media cabinet is usually a better upgrade than a higher MERV one inch filter because it adds surface area instead of restriction.
What humidity level should I keep in my house?
Between 30 and 50 percent relative humidity. Above about 60 percent you risk mold and mildew and the air feels warmer than it is. Below 30 percent in winter you get static, dry skin, sore throats, and shrinking wood trim. A whole home humidifier handles the winter side through the ductwork.
Why is my house so dusty even after I clean?
Dust that returns within a day or two usually means unfiltered air is bypassing the filter. Leaking return ducts in an attic or crawlspace pull dirty air directly into the system, and an undersized or overloaded filter lets the rest through. Sealing return leaks often helps more than any filter upgrade.
Are whole home air purifiers worth it?
They are worth it for a specific problem after the basics are handled, such as asthma, severe allergies, indoor pets, or odors that persist once humidity and duct leakage are fixed. Because they treat all the air the system moves, they outperform a portable unit, but they cannot compensate for leaking ducts or high humidity.
How we know this
This guidance comes from what our technicians find on real service calls across Leavenworth, Shawnee, and the Kansas City metro. Prices shown are our own published rates. Anything that depends on your specific equipment is called out as something we confirm on site.
Licensed, insured and bonded mechanical contractors. EPA certified technicians.
Still not sure what you are dealing with?
Tell us what the system is doing and we will tell you what it means. A real person answers the phone 24 hours a day, and we quote the repair before we start work.
Serving Leavenworth, Shawnee, and the Kansas City metro since 2009. Licensed, Insured & Bonded Mechanical Contractors.