How to Improve Your Home's Air Quality Without Breaking the Bank

Improving indoor air quality in a New Hampshire home does not require a $5,000 whole-home filtration system. For most homes, the highest-impact improvements are cheap or free: changing the filter on schedule, running exhaust fans, managing humidity, and avoiding the indoor pollution sources that are easy to control. Adding a higher-quality filter or an in-duct UV light brings additional gains, but the foundation matters first.

Here is what actually helps, ranked from free to professional install.

Free steps

Change your HVAC filter on schedule

The single biggest IAQ improvement most homeowners can make at zero ongoing cost beyond filter purchase. A clogged or low-quality filter does almost nothing for indoor air quality.

• 1-inch filters: check monthly, replace every three months
• 4 to 5-inch media filters: replace every six to twelve months
• Aim for at least MERV 8; MERV 11 to 13 captures meaningfully more
• If you have allergies or pets, MERV 13 in a thick filter cabinet is the sweet spot

Run exhaust fans appropriately

Bathroom and kitchen exhaust fans pull moisture, cooking odors, VOCs, and particulates out of the home. They are typically already installed but underused.

• Run bathroom fans during and for 20 minutes after showers
• Run the range hood while cooking, especially when frying or browning
• If a bathroom fan is not vented to the outside, it is just moving moisture into the attic; have the venting checked

Open windows briefly when outdoor air quality is good

NH air quality is generally good outside of summer ozone alerts. A few minutes of cross-ventilation refreshes indoor air and dilutes accumulated VOCs and CO2.

Address obvious moisture sources

Mold and dust mites both thrive at indoor humidity above 50 percent. Fixing leaks, drying out basements, and using exhaust fans properly addresses the source.

Reduce indoor pollution sources

• Avoid harsh cleaning products with high VOCs; choose lower-VOC alternatives
• Air out new furniture, mattresses, and carpets in a garage or ventilated space before bringing them into living areas if possible
• Skip candles, especially heavily scented ones, which release substantial VOCs and particulates
• Take shoes off at the door (reduces tracked-in pollutants and pesticides)

Low-cost upgrades (under $300)

Upgrade your filter

Switching from a basic 1-inch MERV 4 filter to a 4 to 5-inch MERV 11 to 13 media filter dramatically improves what your existing HVAC system actually filters out. Equipment cost is modest; ongoing replacement cost is similar to standard filters.

Confirm your system can handle a higher-MERV filter without restricting airflow excessively. Newer systems usually handle MERV 13 fine; older or marginal systems may not.

Add a portable HEPA air purifier in problem rooms

A quality portable HEPA unit (Coway, Levoit, Honeywell, Blueair) costs $150 to $300 and works well for individual rooms (bedroom, nursery, home office). True HEPA captures 99.97 percent of particles down to 0.3 microns. Useful for allergy sufferers, smoke events, or any time someone is sick.

Add a portable dehumidifier for damp basements

A basement that stays above 55 percent humidity supports mold and dust mite growth and feels musty. A quality 50-pint dehumidifier costs around $200 to $300 and addresses the root cause in most cases.

Buy a digital hygrometer

Under $20 for a battery-powered hygrometer that tells you actual indoor humidity. Aim for 30 to 45 percent in winter and 45 to 55 percent in summer.

Mid-investment professional upgrades

Whole-home UV air treatment on the HVAC duct

A duct-mounted UV light at the indoor coil inactivates mold, bacteria, and some viruses as air circulates. Particularly effective at preventing biofilm buildup on the coil itself. Installed cost is typically $500 to $1,000; bulbs need replacement every 12 to 24 months.

Electronic air cleaner

A duct-mounted electronic air cleaner uses an electrical charge to capture particles on washable collector plates. More effective than even MERV 13 media filtration for the smallest particles. Installed cost is typically $1,000 to $2,000; collector plates wash periodically rather than requiring replacement.

Whole-home dehumidifier or humidifier

For homes with chronic humidity issues (too damp in summer, too dry in winter), a whole-home unit installed on the HVAC duct provides better control than portable units. Installation typically $1,000 to $2,500.

Large-investment upgrades (for serious IAQ needs)

HRV or ERV (heat recovery ventilator or energy recovery ventilator)

For tight modern NH homes, an HRV or ERV exchanges stale indoor air for fresh outdoor air while recovering most of the heating energy that would otherwise be lost. Installed cost typically $2,000 to $4,500. The best solution for homes where CO2 buildup, VOC accumulation, or moisture management is a real concern.

Whole-home HEPA system

A central HEPA bypass system installed in parallel with the duct system delivers true HEPA filtration to the whole house. Installed cost typically $1,500 to $3,500. The gold standard for particulate removal.

What to skip

• Cheap tabletop "ionic" air purifiers: the American Lung Association has noted these are largely ineffective and some produce ozone, which is itself a respiratory irritant
• Ozone generators marketed for home use: never run these in occupied spaces
• Houseplants as a primary air cleaning strategy: the studies showing plants clean air were done in sealed lab chambers. The number of plants needed to meaningfully clean a typical home's air is enormous. Plants are great for many reasons; air filtration is not one of them.

Schedule an IAQ consultation

If anyone in your NH household has allergies, asthma, or other respiratory concerns, or you want a professional look at what your home actually needs, contact A.J. LeBlanc Heating. Serving New Hampshire families since 1928.

Frequently Asked Questions

What is the cheapest way to improve indoor air quality?

Change your HVAC filter on schedule and upgrade to MERV 11 or higher. Run bathroom and kitchen exhaust fans. Both are essentially free and meaningfully improve indoor air.

Are houseplants effective air purifiers?

Not at the scale most people imagine. The NASA studies that popularized this idea used sealed lab chambers; replicating the effect in a typical home would require dozens or hundreds of plants per room. Houseplants are nice for other reasons.

What MERV filter should I use?

At least MERV 8 for basic filtration. MERV 11 to 13 for households with allergies, pets, or asthma. Higher-MERV filters need adequate system airflow, especially in 1-inch thicknesses; a 4 to 5-inch media filter at MERV 13 is the sweet spot for most NH homes.

Do air purifiers really work?

Quality HEPA portable units work well for the rooms they are in. Inexpensive tabletop ionic purifiers do not, and some produce ozone, which is a respiratory irritant.

Is a UV light system worth it?

Useful for biological contaminants (mold on the coil, bacteria, some viruses) but does nothing for particulates. Best used in combination with quality filtration, not as a substitute.