In the age of COVID, over the past two years, the talk about clean air has become even more prevalent. While mask mandates are lifting and people are returning or already returned to the office, there are more people than ever working from home. Are you one of those people still working from home? While you are setting up your home office and taking those “gram-ready” pics of your freshly cleaned and organized desk, while kicking your dirty laundry out of site, are you considering how clean the air is inside of your home?
We breath air every minute of every day, shouldn’t we make healthy air a priority? Let’s talk about what could be in your air and what are some options you can take to clean your air.
Types of Air Pollutants
Unfortunately, there are more than a few things that can be in our air. For the sake of this article, I am going to focus on particles and filtration. What I am leaving out are gases and types of air sanitization. I’ll cover those later. So what can be in our air? I’m sure a lot of these things won’t come as news to you but what may be of interest are their size and if they are being filtered. Take a look at the Legend & Reference to compare the sizes to some more familiar things.
Types of Particles & Sizes
- pollen: 10 – 200 microns, average is about 25 microns
- dander & dust: 5 – 10 microns
- Fire smoke: 1 micron
- cigarette/cigar smoke: 1 micron
- bacteria: 0.3 – 60 microns
- viruses: range from 0.005 – 0.5 microns
- mold: 3 – 12 microns
- insulation: 1 – 1000 microns
- asbestos: 0.7 – 90 microns
Legend & Reference
microns = micrometer
hair = 17 – 180 microns
spiderweb = 2 – 3 microns
mist = 70 – 350 microns
Filtration & MERV Ratings
A MERV rating is used to categorize air filters. The ratings determine how much and what size particles the filters capture. Below is table from the EPA website for your reference. Beyond MERV rating is a HEPA filter. A HEPA filter is a high efficiency filter, often used in hospitals.
| MERV Rating | Average Particle Size Efficiency in Microns |
|---|---|
| 1-4 | 3.0 – 10.0 less than 20% |
| 6 | 3.0 – 10.0 49.9% |
| 8 | 3.0 – 10.0 84.9% |
| 10 | 1.0 – 3.0 50% – 64.9%, 3.0 – 10.0 85% or greater |
| 12 | 1.0 – 3.0 80% – 89.9%, 3.0 – 10.0 90% or greater |
| 14 | 0.3 – 1.0 75% – 84%, 1.0 – 3.0 90% or greater |
| 16 | 0.3 – 1.0 75% or greater |
BUT WAIT! Before Increasing Your MERV Rating
The biggest caveat when deciding whether you’d like to increase the MERV rating of your filters is considering what your HVAC unit can handle. When replacing a filter with a higher MERV rating, the system is able to capture more and smaller particles. The downside of this is the static pressure has also increased, essentially increasing the air friction through the filter making the fans work harder to push air through. Just like it would be easier to blow through a 2 in pipe versus trying to blow through a coffee stirring straw.
I think you know what is coming at this point…it is important to look at the specifications of your unit or to call the manufacturer to see how high you can increase the MERV rating of the filter without causing unwanted issues and maintenance to the unit.
However, I understand this warning alone does not motivate some people to read the manual. Occasionally, I am that person, so let’s go over what will happen if you decide to install a higher than recommended rated MERV filter.
Initially, if the unit is left the same and the higher filters are inserted, the first thing you may notice is that the space isn’t able to reach your set point temperature. This is happening because the air is being restricted. Reference coffee straw analogy.
To account for this, you’ll probably head over to the thermostat to adjust the temperature further up or down. Now, the energy consumption is increasing and you may be wasting energy. In order to maintain comfortable temperature in the space, your fans are working harder to push air through to the occupied space but because they are designed to a certain static pressure limit, there may be a backdraft. This means the fans are trying to push a certain amount of air through but it’s not all able to fit, this is wasted energy.
Additionally, even if the unit is able to reach the set point during moderate temperature days, but is now working harder to do so, it may no longer be able to provide for the more extreme weather days because it has already reached it’s capacity. With the filter installed for some time, this will also cause further wear and tear on the mechanical components causing more maintenance or sooner replacement.
So what are some alternative options to better filter your air? Great question!
Other Filtration Option
Electrostatic Filters
Electrostatic Filters are aluminum filters that have a current of electricity run through them. Particles are then attracted to the filter by static electricity, similar to how your hair sticks to a balloon if you rub it on your head. This allows the spaces through the filter to be larger as to not restrict the air. Since the filter is aluminum, it is also washable, making it reusable and therefore more sustainable.
Many electrostatic filters still only capture large particles, so you may be capturing more, but still allowing a lot of the smaller elements to pass through.
A downside to this filter type is a byproduct is ozone generation. Ozone even at relatively low levels is a lung irritant, people with allergies could also be sensitive, causing coughing, throat irritation, and congestions. At higher levels or consistent exposure it could cause bronchitis, emphysema, asthma, and permanent scare tissue.
There are a handful of other air purification, cleaning, sanitizing products to make our air healthier. Let me know if you have any in your home.
When was the last time you replaced your filter?