You’ve heard us preach over and over about how important it is to change your air filters on a regular basis. But there are so many to choose from these days and prices vary widely!  We’ll help you make sense of it all in this and two subsequent posts on this subject.

What’s the purpose?

The purpose of an air filter is to keep the coils and heat exchanger inside your HVAC system clean. Dirty coils and heat exchangers can make the system work harder and cause it to be replaced earlier, so keeping the filter clean helps prolong the life of your HVAC system. Since the air in your house circulates past these filters, they also affect the quality of the air you breathe. People with allergies or asthma are especially sensitive to airborne particles like pet dander, pollen, mold and dust, and the right filter will filter out these particles.

What is a MERV rating?

When it comes to air filters, the most important thing to look for – besides the correct size for your particular system – is the MERV rating. MERV stands for Minimum Efficiency Reporting Value. It is a measurement standard designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters. The MERV rating is a number from 0 to 20, with most residential air filters in the 4-12 range. The higher the MERV rating, the more efficient the filter is, and the greater percentage of particles it can capture. MERV is an industry standard rating, so it can be used to compare filters made by different companies.

As a general rule, prices are higher for filters with higher MERV ratings. Often HEPA filters are rated in the range of MERV 17 to 20, and are the most expensive types of filters. But here is one instance when the most expensive may not be the best!  Most residential HVAC systems may not have enough fan or motor capacity to accommodate higher efficiency filters, such as those greater than MERV 16. Always check your HVAC manufacturer’s recommendations.

Installation Affects Performance

How a filter is installed also effects its performance. If a filter is installed such that air bypasses the filter, its effectiveness will go down substantially, so make sure the filter is the right size and it’s a snug fit. Plus, most filters are directional, meaning you have to install them facing the right direction. Check for the arrow which indicates the direction of air flow, and install the filter with the arrow pointing towards the duct. Here’s another tip: If you have your HVAC system’s fan set to “auto” then the air is only going past the filter when your system kicks on. By setting it to “on” the fan will continually move air across the filter, so the air you breathe will be continually filtered.

Most Important Thing

The most important thing to remember about home air filters is to change them regularly. Even the highest-quality filter won’t work if it is clogged with particles!  Check the filter manufacturer’s guidelines, as different filters are meant to be changed at different intervals. Plus, if you’re doing remodeling, there is construction going on, or you have pets, you will need to change your filters more frequently to compensate for the extra dust and residue in the air. Mark the date of installation along the filter’s frame, so you can clearly see when it was last changed.

Whether you call them vent covers, floor registers, or air grilles, this article deals with the part of your HVAC’s ducts that you see in the various rooms of your house.  These may be located along the floor, baseboard, or wall, and vary in size depending on the size of the ductwork.  The purpose of a vent grille is to protect the ductwork from damage and tears from things falling into it such as a person’s foot or from scratching by pets or sharp objects – while at the same time allowing air to pass.

A Decorating Statement

It’s become a high-end decorating statement to have vent grilles specially coordinated with your dêcor.  Whether you shop at Home Depot or a boutique home accessories store, you’ll see vent covers in a variety of materials, colors, finishes and designs.  Materials can be brass, bronze, cast iron, metal, steel, or wood, and they can cost anywhere from $3.00 each to $100-200 each!  Regardless, they all serve the same function and there’s more to them than just the aesthetic qualities.

Air Flow Issues

First and foremost, ensure the vents are open and unblocked by drapes or furniture. Vacuuming or stepping on a floor register could inadvertently close the register, making your HVAC system not work properly, so if you’re having uneven heating or cooling, the vents/registers are the first thing to check.

When should vent covers be replaced?

Vent covers only need replacing if they become damaged (bent), corroded (rusted), or will not stay open.  Otherwise, a periodic cleaning is all they need, using a cleaner appropriate for the type of material and finish.

How often should the vent covers be cleaned?

They should be cleaned whenever they need to be, but a minimum of twice per year fall and spring is ideal.  In high traffic or dusty environments, you may want to clean them each time you replace your air filters (minimum of every 3 months).

If you are embarking on a home improvement project, such as painting a room, doing drywall repairs, or sanding/refinishing wood floors, steps must be taken to protect the ductwork from paint, sand/dust, flumes, tools, and damage.   Remove the vent registers prior to beginning work. Then, cover the duct completely with a barrier material that can be taped all around. A large plastic garbage bag also works very nicely. If there is danger of someone walking or positioning a ladder or tools near a duct that is covered in this fashion and thus falling in and damaging the duct put the vent grille back on top of the register.  If you have the high-end designer vents (brass, etc.), consider getting a couple of the cheap vent grilles to use temporarily during your home improvement project, so your “good” vent grilles won’t inadvertently be damaged.  The last thing you want is someone putting a foot through the duct or tools falling in and tearing a hole in the duct!

Why it’s so important

Tears in the ductwork or any holes require immediate attention. They will cause your HVAC system not to function properly, and your system will not cool or heat very well.  The conditioned air (the air you paid to heat and cool) will be leaking out and mixing with unconditioned air, which is then blown back through your house.  Not only is there a lot of lost energy – costing you extra money but your HVAC system will be over-worked and wear out quicker.  You may also develop a pest problem from crawling insects, rodents, or reptiles which can come through the holes in the ducts into your home. Over time, you may also develop an odor and moisture problem.  If you are experiencing any of these issues, a hole in your ductwork may be your culprit!

If you are building a new home or an addition, make sure the contractor seals all the ductwork before the drywall is installed. It is almost impossible to clean drywall dust out of ducts, so the best solution is to keep them protected from sources like this from the outset.  For more information on duct cleaning, see our earlier post.