Filtration is especially important in HVAC system because your indoor air is up to 5 times more polluted than outside air! Why? Any pollution and contaminants that are in the home stay in the home. Newer homes that are very tightly constructed are even more susceptible to this. Fortunately, there is a solution. The heating and cooling system's duct work pulls all of the air in the home through the return a certain amount of times per hour depending upon your system design. As long as the fan is operating, it is cycling air through the filter. We will go over the different types of filters, how often you should replace them, and their advantages and disadvantages.
Standard
The 1" fiberglass filter
Replace every 30 days
Chances are, this is the type of filter you currently have installed. It is usually 1" wide and sits on the side or just inside of your furnace. Contractors choose this filter because it is the least expensive to initially install. We never recommend using a 1" fiberglass filter as it is more of a "golf ball catcher" than a filter. At minimum, we recommend using a 1" pleated filter.
Advantages:
- Inexpensive
- Easy to replace
Disadvantages:
- Low arrest rate - it really does not filter any contamination and pollution from your home
- Frequent changing (about every 30 days) is required
Good
The 1" pleated media filter
Replace every 30-90 days
You can easily replace your 1" throw-away filter with a 1" pleated media filter. The pleats allow for more surface area and in result a higher arrest rate. At minimum, we suggest that these type of filters be installed. You may notice that a lot of real estate at big box stores is now being dedicated to replacement 1" filters. There are so many types, which one to choose can be confusing. We recommend going with a medium priced filter about $6-8 each. The "higher end" 1" filters that claim to last 90 days typically have a very high pressure drop, sacrificing airflow and fan power for filtration. If you upgrade to a 4" filter, you can have both.
Stay tuned, we are going to have a video lab test on 1" filters to determine which one is best!
Advantages:
- Better arrest rate than the throw-away - filters more contamination and pollution from your home
- Easy to replace
Disadvantages:
- More expensive than a throw-away filter
- Frequent changing (about every 60 days) is required
- May have high pressure drop - fan has to work harder to pull air through the filter
Better
The 4" pleated media filter
Replace every 60-180 days
Similar to the 1" pleated filter, this filter requires a filter box installed on the side of the furnace designed to hold the wider filter. This filter has even more pleats allowing for more surface area and in result a higher arrest rate.
Advantages:
- Excellent arrest rate- filters a significant amount of contamination and pollution from your home
- Easy to replace
- Change only every 60-180 days
- Even though the filter is more expensive, it lasts longer so filter cost ends up nearly the same as the 1" pleated
- Higher initial cost for installation
Disadvantages:
Best
Replace filter every 365 days.
The electronic air cleaner is a whole different animal. It has 2-3 different stages of filtration. Large debris is captured by the pre-filters. Next, an ionizing section positively charges the remaining particles. Aluminum plates in the collecting section are alternately charged negative and positive and collect the particles. Some systems have a post-filter to collect anything that missed the collecting section. End result, extremely clean air entering your home.
Advantages:
- Excellent arrest rate- filters a significant amount of contamination and pollution from your home
- Washable
- Change only every 90-180 days
Disadvantages:
- Higher initial cost for installation
- Requires cleaning
- You will need to purchase pre-filters and post-filters in some models.