Angie's List: How can I improve indoor air quality?

Paul F. P. Pogue
Angie's List
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You may have heard of a variety of potential services or additions you can install in your HVAC system or elsewhere in your home that will boost air quality. Here are some of the available options and their pros and cons.


Average cost: $530

Where you might need it: Particularly dry areas

Humidifiers, which keep your air moisture balanced, come in a variety of models. Steam units are usually the best to use in a residential system, because they are efficient and the least prone to mold. Less-expensive models include drum and flow-through styles.

If you install a humidifier, consider a humidity gauge or a humidistat to track moisture levels. Experts recommend maintaining a humidity level between 30 and 50% in your home.

Filters are one method to improve air quality in your home.


Average cost: $1,400

Where you might need it: Warm, damp climates

On the flip side, too much moisture can attract mold and pests and seriously impact your comfort. Air conditioning helps with humidity, but some climates present too much of a challenge to the system. You can use portable dehumidifiers to work on specific rooms, but if humidity is an ongoing problem, invest in a whole-house unit connected to your HVAC system that draws moisture out of the air.

Newer models of two-stage air conditioners, combined with smart thermostats, can automatically adjust humidity levels. A two-stage system generally costs about $1,000 more than a comparable standard unit.


Average cost: $1,500

Where you might need it: Hot or humid climates

If your air ducts contain mold, or members of your family suffer from serious allergies, an HVAC pro may recommend installing an ultraviolet light to kill microbes as they pass through the system.

UV lights are very effective in their particular range. They kill organic growths, such as mold or bacteria, but have no impact on dust, pet dander or other allergens. Usually, pros install them near the coils, where all the air passes through. They’re particularly effective in humid climates, where evaporator coils can easily get wet.

You’ll want to replace the UV light bulbs once a year, at a cost of about $100.


Average cost: $10 to $100

You can also remove particles form the air with other kinds of cleaners. Most air cleaning devices use one of two methods. Mechanical air filters capture particles on filter materials – at the most basic level, this is the filter you regularly replace in your HVAC system. Electronic (or electrostatic) air cleaners use ionization to draw air particles towards a metal plate.

Mechanical air filters are ideal for larger particles such as dust, pollen, mites, some mold and animal dander.

When selecting a filter, look for the MERV rating, which is a number between 1 and 20. MERV ratings between 1 and 4 are very basic and not particularly good at capturing airborne dust and allergens. Filters rated between 5 and 13 are reasonably efficient, and those rated between 7 and 13 are very good at controlling airborne particles. The highest efficiency home filters are rated from 14 to 16. (Filter rated above 17 are very rare in residential settings.)

Electronic filters are extremely effective on small particles. They cost more than mechanical filters and need to be carefully maintained, however.

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