Why Is Duct Size So Important?

When selecting a new air conditioner, your HVAC sales consultant will likely emphasize just how important it is that you choose a unit that’s the right size for your home. Select a system that’s too small and it’ll run for hours on end while struggling to keep your home at the ideal temperature. Select one that’s too big and it’ll create air pressure issues in your home, short cycle, and waste a ton of energy as well. Finding the right balance is something you need to focus on intently in order to see optimal results.

However, what many people don’t often think about when replacing their heating and cooling system is what connects the unit with the rest of their home: their ductwork. This network of air passageways also needs to be the correct size in order for your new air conditioner to work at its most efficient and for your home to receive the cooled or heated air you’re asking it to create. Just like your HVAC system, ducts that are too small or too large can lead to all sorts of issues, so you need to make sure these are the ideal size as well.

What if My Ducts Are Too Big?

Bigger ducts means more airflow right? Not necessarily. While your ducts might be larger and capable of handling more air, that doesn’t mean your HVAC system can pump any more air into them than its already capable of. And this could lead to issues with your home getting the treated air once it’s been produced. Your HVAC system relies on creating a certain amount of air pressure in your duct network so that it can push the air into the various rooms of your home.

Think of it like water flowing through a hose. If you hook an industrial-size fire hose to your typical garden tap, you’re going to sit there for what feels like ages waiting for your garden tap to spit out enough water to fill the hose and eventually start flowing out the nozzle end. Now imagine there’s a small hole in your hose—the water may never come out the other end at that point. There isn’t enough pressure to overcome it. As a result, your HVAC system will run and run for hours on end and produce a ton of cold or warm air that you’ll never feel inside your home because it can’t force the air through your excessively large ducts. This not only wastes energy (and money) but forces your system to run longer, which leads to a higher chance of breaking down.

What If My Ducts are Too Small?

On the other hand, too much pressure in your ducts isn’t a good thing either. When your HVAC system blows air into your duct system and your ducts are too small to handle the amount being pushed through, the air will eventually back up in your system and create added resistance against your blower fan, making it more difficult for your system to operate. This places a ton of extra stress on your blower motor, causing it to waste a ton of extra energy, and significantly increasing the chances that it breaks down entirely, forcing you to call for a costly repair.

Think of it this way: take a regular drinking straw, place it between your lips, and try to breathe through it. It’s suddenly a lot more difficult, right? This is because the straw itself doesn’t have the volume necessary to handle the influx of air that your lungs are either demanding to draw in or push out after. You’ll also notice that when you breathe out, the air that comes out of your ducts does so at a much higher speed. The same applies to your HVAC system: ducts that are too small can actually cause the air to come zipping out of your vents, creating drafts and air currents in your home. While small currents are normal, more severe ones can actually cause papers to go flying or even blow over possessions. You could also create an air pressure difference between the inside and outside of your home, which could lead to things like unwanted door slamming and even unwanted air loss through any tiny gaps in your doors and windows.

If you need your ductwork serviced or you need your existing ducts replaced, contact the Kerrville heating and cooling services team from 72 Degrees Air Conditioning & Heating by dialing (830) 302-3140 today!