Should I Get a Whole House Air Purifier?


When I was looking for a way to purify the air in my own home, it was difficult deciding whether I’d need just a few portable air purifiers or a whole house air purifier.

So, should you get a whole house air purifier? For most homes, the answer is no. This solution can be expensive, especially with the duct-based, standalone units. A less expensive option is to add a special filter to the HVAC furnace. However, once all the pros and cons of a whole house air purifier system are taken into account, a portable air purifier system will likely be a better choice.

Manufacturers are creating portable air purifiers that are becoming more advanced each time. These purifiers are also tested and regulated more, making them a more trustable source when it comes to purifying the air in a home.

Whole House and Portable Air Purifying Options

Let’s take a look at the options you have when it comes to purifying the air in your home.

Whole House – replacement filtersYou’d replace your regular HVAC filters with special filters that claim to be “whole house air-purifying filters.” There are various kinds, but essentially, it’s an upgrade from a basic fiberglass filter to one that’s slightly better (i.e. pleated filters, extended media filters, electronic filters, UV filters).
Whole House – duct-based, standaloneLarge, stand-alone units are ducted and incorporated into the already existing duct lines with the rest of your HVAC system. They are installed professionally in between the supply air and return air ducts and use the fan to filter out more air.
PortableMultiple portable air purifiers are used strategically in several areas in your home. They operate independently from the HVAC system. Many have advanced filters that can be stacked up for maximum air cleaning capabilities.


Whole House Systems Using Replacement Filters

There are air filters that are advertised as having the ability to purify the air in your home while working together with your already existing HVAC furnace system. It’s quite convenient – next time you’re getting ready to replace the air filters in your HVAC, simply pick up these specialty replacement filters instead of the ordinary, cheap ones.

Sounds too good to be true?

Actually, it might be. While these filters are better quality, the problem is that the average HVAC system isn’t designed to purify the air. An HVAC system simply takes up the air in your home and gives it back at a different temperature. In other words, an HVAC system’s primary function is to cool or heat the already existing air.

Don’t get me wrong – I’m all for better quality filters. In fact, I’ve written rave reviews on this very blog about upgrading to a better air filter with a higher MERV rating, while taking care not to obstruct airflow. (By the way, MERV stands for minimum efficiency reporting value and is a way to rate the ability for air filters to filter out certain pollutants.)

But you should know what this upgrade means. The basic fiberglass air filter is only rated MERV-1 to MERV-4, meaning that it can only trap some dust and pollen. In fact, the rating is so low, many dust and pollen particles will constantly cycle through the HVAC system and never get trapped in the filter.

These basic filters don’t catch dust mites or pet dander at all because they aren’t rated to do so. In fact, the purpose of these filters isn’t to purify the air in your home, it’s to protect the HVAC system. In other words, the filter is intended to trap large particles that may break the HVAC unit, not filter out pollutants that may make you sick.

However, once you upgrade to a filter like a MERV-11 rating, the filter will be able to trap those pollutants, along with some other things like smog, smoke, and mold.

The MERV-11 is the highest rating that I’ve found will work in a residential setting without overly constricting the airflow.

Now, an upgrade to a MERV-11 filter sounds like a whole house air-purifying system, doesn’t it?

Technically, it does work in your whole house (that’s what most HVAC systems ideally do). Even though this is a choice I personally made in my own home, an upgraded air filter on an HVAC furnace is a far cry from what some of the portable air-purifying units do.

If you compare an average MERV-11 air furnace filter to a good quality portable air purifier like this one from Honeywell, you’ll start to notice the difference. First, it has a True HEPA filter, which, if it could be rated using the MERV system, would have an equivalent to a MERV rating of 17 to 20. Very different from a MERV-11 rating, to say the least.

Many portable air purifiers nowadays also have several filters built in. For example, a pre-filter traps the larger pollutants first, so that the HEPA filter can then work at better efficiency to trap the finer particles. Even a HEPA filter doesn’t catch everything, so a third filter using activated carbon is often added to trap the finer pollutants like VOCs, smog, and smoke, for example.

So, in conclusion, you may have an improved air filter on your HVAC system, but how good is its ability to circulate the air in your entire home when it cannot trap the smaller particles like some of the portable air purifiers can?


Duct-Based Whole House Systems

This is the most expensive option. Not only does it require a large standalone unit, it also requires professional installation. Here, a large air purifying unit is ducted and inserted into the ductwork system of the rest of your HVAC system.

The air cleaner is inserted in between the supply air and return air ducts. The idea is that while the pollutants are moving through the air ducts, they will be trapped by this whole house air purifier.

This is probably a better option than the replacement filter option from above since it’s custom-fitted to work with the HVAC system. However, it is pricier and may fit everyone’s budget.

Some of the added cost will also come from your energy bill. You’ll find that a ducted whole-house air purifying system is constantly on. After all, air can’t be purified unless the unit is turned on, so the unit will become more active. Even when the temperature is maintained at the set thermostat level, the fan will still be on in order to continue filtering out the air in the home.

The good news with these units is that they have the option of using a HEPA filter. Again, keep in mind that replacing HEPA filters for large units like this can get expensive, and it isn’t for everyone.


Can Portable Purifiers Become a Whole House Air-Purifying System?

Yes, they can, but you’ll need to figure out how many air purifiers you need, which special features each must have for each room, and where to place them. Here’s a resource that may be able to help.

The good thing about portable air purifiers is that they can vary across each room in your house. A whole house system, on the other hand, doesn’t provide this variation.

For example, you can select air purifiers that can pick up the VOCs and smoke in your kitchen while cooking, while focusing on selecting a good air purifier and dehumidifier combo for the bathrooms and basement. When it comes to the bedrooms, you may perhaps select a low-noise air purifier and turn off the ionizing feature, so that the heavy ions don’t fall on your bed while sleeping.

There are quite a few nuances when it comes to selecting the right features of an air purifying system. Just know that a portable air purifier will allow you to select the features that work for each room.


Related Questions

How much does a whole house HEPA filter system cost?

Depending on the square footage of the home and some other considerations, this system will roughly cost somewhere between $1,500 to $5,000, including installation. However, it isn’t unusual for the cost to be higher for large homes with a large square footage.

Besides the upfront cost to purchase and install the unit, you’ll also need to factor in an increase in the energy bill. The HVAC won’t only be on when it needs to cool or warm the air. Its fan will continue to work in order to clean the air.


Can portable air purifiers be harmful?

Generally speaking, as long as you use your air purifiers as instructed, they shouldn’t be harmful. However, many experts advise against the ionizing function on an air purifier, as this can create ozone. When purchasing a portable air purifier, it’s best to look for the ability to turn off this function. Unfortunately, many air purifiers can have this option on by default, without the ability to turn it off.


Do HEPA filters remove viruses?

A HEPA filter can remove some, but not all viruses. A HEPA filter should be able to trap particles that are 0.3 micrometers in diameter and larger. While this includes many viruses, it isn’t uncommon for other viruses to only be 0.1 micrometers in diameter. There are also some other smaller pollutants that fall in this small range of fine particles, including some mold, bacteria, smoke, VOCs, among others.