Buying an Air Purifier for the Home

If you’re looking to address air quality in your home you first need to decide if you’re looking to improve air quality in

• your whole house or
• a single room

Improving air quality in a whole house

Skip to Single Room Air Purification

Houses, even small apartments contain a lot of air. A 1,000 sq. ft. apartment with 8 ft. ceilings contains 8,000 cubic ft. of air. A 3,000 sq. ft. home with 10 ft. ceilings contains 30,000 cubic ft. of air. That’s a lot of air!

So, if your goal is to purify all the air in your home we recommend the following strategy:

1. Get good quality reasonably high MERV filters for your HVAC system.

We recommend going all the way up to MERV 13 if you can. This will go a long way in lowering the overall particle concentration of the air in your home.

2. Put air purifiers only in the rooms where they will be most beneficial.

Most HVAC systems cannot accept an air filter better than MERV 13. HEPA is the equivalent of MERV 17. There are many other limitations to how well an HVAC system (even equipped with a high MERV filter) can purify the air in your home. We won’t get into them here but suffice it to say that an air purifier provides an entirely different level of air purification as compared to an HVAC system.

The problem is that air purifiers can be expensive – not only to purchase initially but also to maintain (primarily because of the cost of replacement filters).

So, if cost is a concern for you we recommend prioritizing rooms where an air purifier is going to be most beneficial. This includes rooms:

Note that you also have the option of moving a single air purifier between different parts of your home. For example, you may want to operate a single unit in your living room during the day and in your bedroom at night.

In this case, you may feel like portability should be a concern for you as you make a purchase decision. The good news here is that this really doesn’t need to be a concern for you. Almost all air purifiers on the market are light enough and easy to carry.

3. Put individual air purifiers in all rooms

If cost is not a concern for you we recommend placing air purifiers in all of the rooms in your house. We still recommend installing a high MERV air filter in your HVAC system as it will essentially act as a pre-filter for the air purifiers’ HEPA filters – keeping them from “saturating” as fast and thus reducing filter replacement costs.

4. Install a whole house air purifier

As a last resort you can consider installing a whole house air purifier.

We generally do not recommend these units as

Improving air quality in an individual room

Improving the air quality in a single room is a much easier task than doing so for a whole house.

To start, first determine if the room can be sealed (can you close all doors and windows). If it can be sealed you’re in great shape. A sealed room is going to be able to get to much lower particle concentration than a non-sealed room.

The reason is simple: An air purifier processes a set amount of air. Sealing the room allows it to re-process the same air over and over again. As it does so, particle concentration will eventually reach 0 in a sealed room. In a non-sealed room new particles are constantly entering the room. The air purifier will never be able to achieve super low particle concentration in such an environment.

The bottom line:

In a sealed room - you’ll be able to achieve super low particle concentration which is the goal of running an air purifier in the first place. So prioritize sealing the room – leaving windows/doors closed as much as possible.

In a non-sealed room - do not expect this to ever be the case (achieving super low particle concentration), even if you’re constantly running even the highest CFM (output) air purifier in the room.

Second, determine the size of the room. A bit of good news here: We recommend the same “size” air purifier no matter the size of the room. So, the size won’t determine which air purifier you buy – just how you’re going to operate it.

No matter what the size of the room we recommend a top rated 250 CFM unit. These units provide the best combination of value, energy efficiency, and low noise output.

In a small room (up to 150 sq. ft.) – you can run a top rated 250 CFM unit on the 2nd highest speed. This equates to about 100 CFM of output which is sufficient for such a size room. On this setting these units will offer peak energy efficiency and will be very quiet as well.

In a larger room (up to 300 sq. ft.) - you will need to run a 250 CFM unit on its highest setting to get to super low particle concentration in the room and then you can set it to its 2nd highest setting to maintain that low concentration. Do note though that particle concentration in the room will slowly creep up if you leave the unit on the 2nd highest setting for too long. So we recommend that you run it on its highest setting as much as possible.

In an extra large room (well over 300 sq. ft.) – we recommend you run multiple 250 CFM units. Doing so will provide superior coverage in the room at a lower price than buying a single higher CFM unit.

3 types of contaminants you may need to remove from the air in your home