How Do I Choose an Air Purifier After a Renovation?


Air purifiers effectively clean the air inside your home by removing pollutants, dust, and debris, and they can be especially useful after a home renovation.

But how do you choose an air purifier after a renovation? Look for an air purifier with high CADR and ACH ratings, and True HEPA and activated carbon filters. CADR and ACH indicate how much volume of air an air purifier can circulate in a room and how quickly. True HEPA and activated carbon filters together can remove smaller pollutants. An air purifier with all these features is your best choice to be able to effectively remove the smaller, hard-to-reach pollutants that are often found in new building materials like plywood, insulation, laminate, cabinetry, paint, and stains.

Now that you know what’s important and what to look for, let’s take a look and review. Remember, you want to look for these features:

  • a higher CADR and ACH rating
  • a True HEPA filter
  • an activated carbon filter


Why Air Purifiers Even Matter After a Renovation

It is a fact that air pollutants inside the house can be five times higher than outside. The poor indoor air quality of a house can have adverse impacts on the health of the house members, and they might experience asthma attacks or symptoms that are closer to allergies. Others may experience headaches, nausea, dizziness, and flu-like symptoms.

Air purifiers are an excellent way to reduce some of these dangers that are posed by indoor air pollution.

But this is during “normal” times, when your home has already been lived in.

During and after renovation or construction, indoor air quality can pose even higher risks. That’s because most building materials have been infused with volatile organic compounds (VOC)s in the factory and now are introduced into your home.

Volatile organic compounds are very small pollutants on a molecular basis, and the smaller a particle is, the harder it is to remove from a home. So they tend to linger in your home and slowly off-gas from those newly introduced building materials. Some off-gas in days, but others can take years.

And when that happens, we’re not just talking light health symptoms like a headache or dizziness here and there. With VOCs, these symptoms tend to be more severe, and can have major health risks, especially in small, male children.

For that reason, an air purifier that has the ability to remove even the smallest of those pollutants is important. A True HEPA filter will help filter most pollutants, but a heavy activated carbon filter will be especially important to rid your home of VOCs. And an air purifier with high CADR and ACH ratings means that the fan of the air purifier will be powerful enough to reach deep and far enough to pull those pollutants from every corner of the room.

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How Air Purifiers Filter the Air

Air purifiers consist of one or multiple filters and a fan that sucks the air and circulates it. The air sucked by the air purifier moves through the filter, which captures all the pollutants and dust particles present in the air. After purification, the cleaner air flows back into the living space, and the cycle starts anew.

Air filters are usually made from paper, fiberglass, activated carbon, or mesh and require regular maintenance and replacement. Therefore, after purchasing the air purifier, you will have to pay for operating costs and filter replacement costs.

However, the replacement of the air filter depends upon the usage and the type of the air purifier.  Some filters are available in the market that you can wash and reuse, but they require careful maintenance and tend to not work as well after several washes. Therefore, you will not find them on the most effective air purifiers.


Features of a Good Air Purifier

You should keep in mind various things while selecting an air purifier, especially when you want to make your home environment clean from construction dust. The following are some of the essential features that you should consider.


Clean-Air Delivery Rate (CADR)

Small air purifiers usually serve a room up to 299 square feet, while a medium air purifier serves a space between 300 and 699 square feet. Similarly, a large air purifier can serve between 700 to 1,900 square feet of space. In technical terms, this is represented by the clean air delivery rate (CADR).

CADR measures the cleaning speed of an air purifier in which it removes the smoke, dust, debris, and other pollutants from the air. Because air purifiers work differently depending on the size of pollutants, the CADR rating is actually made up of three separate numbers:

  • pollen
  • dust
  • tobacco smoke

Each tells you how many square feet of space the air purifier can work on to remove large particles (i.e. pollen), medium-sized particles (i.e. dust), and small particles (i.e. tobacco smoke). The VOCs found in new construction materials tends to fall in the small particle category of the CADR rating, or smaller.

Note that CADR ratings are for 8-foot ceilings, so you’ll need to buy a larger size if your home has higher ceilings.

Speaking of going bigger, it’s a good idea to go for a higher CADR rating than what you’d usually get to really get rid of those VOCs that are lodged in the building materials. If you have newly painted moldings that are obstructed by doors or walls, for example, you want your air purifier’s fan to be powerful enough to reach even those nooks of your room.

(Important Note: The CADR standard is set by the the Association of Home Appliance Manufacturers’ standards and is represented by a label called the AHAM Verifide label. Always look for it when purchasing an air purifier and stay away from manufacturers that don’t show this label but claim to offer air purifiers that are able to work on questionably large rooms yet are also questionably low-priced.)


CADR Label Example for Air Purifier


Air Change Rate (ACH)

Your air purifier can have a high CADR rating, but if its fan doesn’t move the air fast enough, it’s pointless.

This is why the air change rate (ACH) is important. It tells you how often the given volume of total air in a room will cycle through the fan of an air purifier. An ACH of 4, for example, means that the air will be cycled 4 times per hour, or once every 15 minutes.

You want your air purifier to have a high ACH rate. One with 5 or 6 air changes per hour is ideal after a renovation.


True HEPA Filter

A True HEPA filter is most effective in removing particles like dust, pet dander, pollen, mold, and other allergens. A HEPA filter must remove up to 99.97% of dust, including particles as small as 0.3-micron diameter.

Be careful of filters that are advertised as HEPA-like or somehow similar to HEPA. You’ll miss a lot of the pollutants in your home if you don’t get a True HEPA filter.


Activated Carbon Filter

An activated carbon filter is your best tool to remove small pollutants that the True HEPA filter can’t. An activated carbon filter can help with pollutants like these:

  • formaldehyde found in cabinetry and laminate flooring
  • BTEX (benzene, toluene, ethylbenzene, xylene) found in paint and varnish

Granted, these are molecularly small pollutants, so they will be hard to remove. But if you get a heavy activated carbon filter (one that has heavy granules rather than a thin sprayed on layer of carbon), it should help a lot.

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Guidelines to Control Dust After Renovation

When you are renovating your home to give it a new look or increase its market value, you will encounter a ton of dust in the process. Most of this dust comes from tiny plaster particles, fiberglass, or mold spores (if you’re renovating an older, neglected home).

Similarly, you use all kinds of material during construction, and some of it contains silica dust. Silica dust is hazardous, and if you inhale this compound for a long time, you will have serious health complications, including lung cancer. 

After completing all the construction process, sure, you will clean up the entire place, but what about the tiny dust particles present in the air?

Here are some ideas to implement in addition to the air purifier to keep the air in your home as safe and clean as possible:

  • The first step is to cover the area of construction adequately. You can use plastic barriers and sheeting and for this purpose.
  • During the renovation process, keep on vacuuming your house with a vacuum cleaner that has a high-quality filter (yes, some vacuum cleaners also come with True HEPA filters!).
  • Covering the air vents in the renovation area is essential as it will keep the dust and fumes from spreading through the HVAC system.
  • Another essential thing to consider is opening the windows in the construction area depending upon the season and air pollutants outside.
  • To avoid the paint fumes that can cause breathing cancer, you should use VOC-free and odor-free paints.
  • After completing the home renovation, replace HVAC filters with a good quality filter and check it frequently.
  • With home cleaning, you can also consider cleaning the ductwork of the HVAC system to remove the dust particles that settle there.
  • After completion of the project, test the indoor air quality of your home. An air quality monitor can help you do that.
  • Allow building materials to off-gas outside on the lawn in the sun before allowing them inside the home.


Related Questions

What are the health risks and effects of construction dust?

People who work on construction sites are more likely to possess high risks of health issues. The construction workers usually face lung and airway damages, asthma, chronic obstruction, and many other diseases.

Whether you live near a construction site or have a home renovation, there can be an unsafe amount of dust that you should consider dealing with properly. It is best to avoid the dust from construction entirely as this dust can cause life-changing damages to your body.


How can an air purifier remove dust?

Good quality air purifiers contain a True HEPA filter that captures particles as small as 0.3 microns with an efficiency level of 99.97%. Air purifier sucks the contaminated air and cleans it with the help of a filter. After cleaning the air from contaminants, the air flows back into the environment. Another thing is to check the CADR rating specifically for dust and make sure you’re sizing your room correctly.


Why can’t I just buy an ozone air purifier?

You can do that, but be careful. Ozone is harmful. I’d advise to only use an ozone air purifier if you aren’t living or sleeping in the home yet.