19x21x1 Air Filters
WHY YOU SHOULD REPLACE YOUR AIR FILTER
Reduce your energy costs with clean filters
A dirty filter in your furnace or AC system will raise your energy bills. A dirty filter restricts the air flow into your system's air handler, causing it to work harder to cool or heat your home.
Improve airflow & efficiency of your furnace
A dirty clogged filter can restrict furnace or AC airflow and potentially cause problems with the system. They also cease to filter allergens and other particulates out of your air.
Increase the longevity of your furnace or AC system
Dirty, unchanged filters can make your furnace or AC system fail completely. Repairing a broken system can end up costing you a pretty penny.
WHAT DO MERV RATINGS MEAN?
Allergies, pets, odors and smoking all can greatly affect the quality of your indoor air. Discount Filters offers many different types of discount air filters to help you breathe better air inside your home based on your specific needs.
We carry discount air filters in 1-2 inch standard sizes, and 3-5 inch media sizes. Our air filters are great and work well in HVAC systems, furnace and air conditioner systems. If you are looking for a custom size air filter you can request that we make a special size for you. As always, we offer Fast Shipping & Free Returns on all of our discount furnace filters.
- MERV 8: The most basic air filter a homeowner will need is a MERV 8. A MERV 8 filter offers excellent air filtration for their home. A MERV 8 air filter would be good for a family that doesn't smoke, doesn't have pets, and doesn't have bad allergies.
- MERV 11: People with pets and/or light allergies, would greatly benefit from a more advanced filtration level called a MERV 11. A MERV 11 filter reduces pet dander, dust, pollen and other particles that are present in your home.
- MERV 13: A MERV 13 air filter however will capture even smaller dust particles, dirt, pollen, mold spores, pet dander and more from your home's air. A MERV 13 air filter is great for people with regular allergies and who own multiple pets. The MERV 13 filter is typically more expensive and will also put more strain on your HVAC system, however the high quality filtration you will get will be well worth it.
Frequently Asked Questions
I'm looking for a 19x21x1 filter for my furnace - will an air conditioning filter work?
Depending on where you live, you might refer to the filter one way or the other. The good news is - it doesn't really matter. All forced air heating/cooling systems use a filter - which serves to keep your equipment clean and to promote good indoor air quality in your home.
How often should I change my furnace / air conditioner filters?
It's important to change your 19x21x1 air filter to keep your heating and/or cooling system operating at peak efficiency. There are general guidelines for filter change intervals: Replace 1" fiberglass/polyester filters every 30 days. Replace 1" and 2" pleated filters every 90 days. Replace 4"-5" filters every 6 months.
What is an HVAC filter?
HVAC stands for Heating Ventilation and Air Conditioning. "HVAC system" refers to the system that regulates (heats/cools) and moves air throughout your home. In addition to keeping your HVAC system clean, your filter removes airborne particles and allergens from the air in your home.
How do I choose my whole house air filters?
The industry standard for rating the efficiency of air filters is "MERV", which stands for Minimum Efficiency Reporting Value. Manufacturers and retailers have attempted to simplify things by creating different comparison systems. Examples: FPR (Filter Performance Rating), or MPR (Micro Particle Rating), or even a good/better/best/ultimate system. At DiscountFilters.com - we organize our filters into different categories - "Dust", "Allergy", "Health" and "Odor". We provide information on the common contaminants that each filter category removes on our product pages.
How do I know what air filter to purchase?
The first things to consider when looking for an air filter are dimensions. Most air filters will have dimensions printed on the side of the filter frame. The "nominal size" is the size you see printed on the filter; it originates from the actual size, which is rounded up to the nearest whole inch.
What 19x21x1 air filters do you recommend for my furnace and/or air conditioning system?
We carry a huge selection of filters in many different sizes. We stock many more sizes than the local "big box" or hardware store. In most of the common sizes - we might have 5 different choices ranging in price and efficiency. We recommend the AIRx "Allergy" filters (MERV 11) as these offer the best combination of performance and value.
Which Heating and Cooling Systems Are Compatible With 19x21x1 Air Filters?
19x21x1 air filters are compatible with most forced air heating and cooling systems, including:
- Central air conditioners
- Furnaces
- Heat pumps
- HVAC systems
- Air handlers
A system that forces and circulates air through ductwork, into the rooms, and back through the system requires an air filter, such as a 19x21x1.
Why Does Air Filter Size Matter?
The 19x21x1 air filter dimension is no accident. Manufacturers create filters this size for several reasons:
- Structural integrity: Larger filters have less structural stability due to their construction. Most frames are made from cardboard, which can bend or tear with enough air pressure. A 19x21x1 filter is small enough to stay intact.
- Adequate air filtration: Filters for this size are large enough to provide proper filtration over a 30 to 90-day period before requiring a replacement.
- Compatible with certain systems: 19x21x1 air filters are compatible with certain furnace and air conditioner brands and models.
That is why air filter size matters. If you want optimal performance, you need to match the right filter with your furnace or air conditioner.
What Are Furnace Filters?
Furnace filters are the first defense against airborne dirt and dust particles that harm HVAC systems and contribute to dirty indoor air. The filter prevents the dust from building up in the heating components inside the furnace and circulating into the rooms. Filters are referred to as “furnace filters” when they are used in heating applications, but in most cases, they are the very same filters used in air conditioning applications.
How Long Does a Furnace Filter Last?
The main thing you need to consider when considering furnace longevity is thickness, which translates into surface area. For instance, a 1" thick furnace requires replacement every three months. A 4-5" thick filter can last up to nine months or even an entire year.
Do Furnaces and ACs Share Filters?
A traditional HVAC system combines a central air conditioner and a furnace. Both heating and cooling systems distribute air through the same ductwork, which circulates the air through your home. Since both units share the same ductwork, they may also share the same air returns. If so, both the air conditioner and the furnace use shared filters. The same filter cleans the air regardless of which system you turn on. There are some benefits of using shared filters:
- Less hassle when shopping for filters
- More bundle options, more savings
- No more searching for different sizes
- Consistent replacement schedule
- Replaceable and washable options are available
The Importance of Changing Filters for AC and Furnace Units
Americans now spend around 90% of their time indoors, where air can be 2-5 times more polluted than outdoor air, according to the EPA. Air filters are the primary component that helps you maintain a cleaner environment in your home. For this reason, they are a core part of AC and furnace maintenance. Here are five practical benefits of changing filters according to manufacturer specifications:
1. Improve the Air Quality in Your Home
An air filter traps dust, pollen, pet dander, mold spores, and other airborne particles, resulting in cleaner air. Changing the filter allows it to trap particles more effectively.
2. Get Higher Efficiency from Your System According to the Department of Energy, regularly changing your air filter can save you 5-15% of energy consumption and utility bills. Preventing dirt buildup allows the air to flow more smoothly so that the unit doesn't have to work harder than necessary.
3. Extend the Life of Your System Most air conditioners and furnaces last ten to 15 years. However, you must provide ongoing maintenance if you expect them to last that long. Doing something as simple as changing the filter reduces wear and helps the moving parts last longer. It can also prevent you from voiding your warranty if you have a problem with your AC or furnace.
4. You Pay for Fewer Repairs A furnace or air conditioner needs repair mainly because it has moving parts. These include a blower motor, compressor, evaporator coil, condenser fan, and heat exchanger. Dust and dirt buildup make it difficult for the parts to move. Eventually, they need repair. A filter can reduce buildup, allowing the parts to last longer with fewer repairs.
5. You Achieve More Temperature Control When the air is cleaner, the HVAC can regulate airflow. As a result, you can maintain the desired temperature more consistently. You get balanced airflow coming through every vent in the house. Plus, you get more accurate readings on your thermostat.
How Often Should I Change the Furnace or AC Filter?
Both HVAC manufacturers and technicians replace the filters every 90 days. If you change the filter sooner than that, you may waste money. If you change it later, you get a dirty system. You must consult the furnace or AC owner manual, as each system has specified requirements. If you opt for washable air filters, you only need to change them once every five years. The tradeoff is that you need to clean the filter. How often?. At least once a month. Again, check with the HVAC or filter manufacturer for the best replacement schedule for HVAC efficiency.
Air Grill Filters: What Are They?
You may notice grated vents called return air grills on your walls or ceilings. They're a part of your HVAC system.
What Is a Return Air Grill Filter?
An air grill filter allows air from your rooms to flow back into your home's HVAC system to be heated or cooled again. Some return air grills have a filter slot where you can insert a filter. The filter catches dust, pet hair, and other particles before the air re-enters the HVAC system. Regularly replacing these filters is important because clogged filters make your HVAC system work harder, wasting energy and money. They also prevent dirt and dust from building up inside your HVAC equipment.
Do I Need Both a Furnace Filter and a Return Air Grille Filter?
You will normally use one or the other - but not both. Return air grille filters are typically used in parts of the country where the HVAC equipment is not easily accessible - like an attic or crawlspace.
Common Types of Filters and Their Uses
When HVAC technology changes, new filters are required to accommodate the latest models; as a homeowner, you will benefit from a wide range of advanced filters designed to work with your system. Here are some of the most popular air filters available today.
What Are the Different Types of AC and Furnace Filters?
HEPA Filters HEPA (High-Efficiency Particulate Air) filters are made of dense mats of fine fiberglass fibers. They can remove at least 99.97% of airborne particles as small as 0.3 microns. HEPA filters have very high MERV ratings, typically between 17 and 20.
HEPA filters are commonly used in hospitals, cleanrooms, and homes of people with severe allergies or respiratory issues. However, if not properly sized for the HVAC system, they can significantly restrict airflow. Therefore, they are almost never used in residential HVAC applications.
Electrostatic Filters
Electrostatic filters use static electricity to attract and capture particles from the airstream. They don't restrict airflow as much as other high-MERV filters. The average MERV rating for electrostatic filters is around 10-16. Some electrostatic filters are washable and can be reused for long periods of time. When properly maintained, they can effectively remove pollen, dust, smoke, and smog particles.
Carbon Filters
Carbon filters contain activated carbon or charcoal that helps remove odors, gases, and larger airborne particles. They have relatively low MERV ratings, around 4-8. Carbon filters are often combined with particle filters to improve indoor air quality. Their main purpose is absorbing volatile organic compounds (VOCs), smoke odors, and other gaseous pollutants rather than particulate matter.
Pleated Air Filters
Compared to flat panel fiberglass or polyester filters, pleated filters increase the surface area available for particle capture. They also allow higher MERV ratings for residential use, typically between 7 and 13. The pleated design also reduces airflow resistance. Pleated filters can remove pollen, dust mites, mold spores, lint, and pet dander. Higher MERV pleated filters may require more frequent changing to avoid excessive pressure drop.
How Do You Maintain AC and Furnace Filters?
Regarding filter maintenance, you have two main choices for AC and furnace filters: replaceable and washable. Both types of filters offer pros and cons. For instance, you don’t have to clean replaceable filters. Conversely, you don’t have to keep buying washable filters. Let’s look at best practices for maintaining each type of filter and the impact of maintenance on HVAC system longevity.
What Are the Best Practices for Filter Maintenance?
Disposable Filters As a rule, you want to replace most air filters every 90 days. For most filters, the three-month mark is when the filter has reached capacity for filtering out particles while not restricting airflow. Ninety days is typically the standard for pleated filters. Fiberglass and polyester panel filters should be replaced monthly.
Washable Filters Clean the filters every month, depending on your home environment and the type of filter you have. If you have pets or allergies or live in a dusty area, you’ll want to clean the filters more often. Follow the manufacturer's instructions for cleaning the filter.
Air Conditioner Filter Replacement: 5 Signs That Your Current Air Filter Needs Replacing
If your AC or furnace isn't cooling/heating as effectively as before or the airflow weakens, a clogged filter could restrict proper operation. A dirty filter forces the HVAC system to work harder, leading to higher energy bills without changing thermostat settings. Here are some common signs that you need to replace or clean the filter:
- It’s a dirty air filter with visible dust and dirt buildup on the filter
- Poor system performance
- Increased energy consumption
- Unusual noises from the HVAC unit
- Musty or unpleasant odors
Strange sounds like humming or rattling can indicate strain on the system from a blocked air filter. Dirty filters can accumulate damp debris, bacteria, and contaminants that produce stale, musty smells when the system runs.