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The Ultimate Guide to HVAC Dampers

hvac system air dampers

What exactly is an HVAC damper, and how can it contribute to the comfort of your home all year? If you're asking this question, you are not alone.

To be honest, this is one of the less well-known components of a heating and cooling system. The compressor, air filter, vents, and other HVAC system parts are far more well-known. However, most homeowners are unaware that dampers play an important part in maintaining temperature throughout your home.

Our heating and air conditioning Comfort Advisors Team gets a lot of questions about HVAC dampers, their benefits, and how to properly use them throughout the year along with their heating and cooling system. In this guide, we'll cover multiple common questions, including:

  • What are HVAC dampers?
  • Why are dampers used in HVAC systems?
  • What are the different types of dampers used in HVAC systems?
  • Where are HVAC dampers located?
  • Do all HVAC systems have dampers installed?
  • When should I open and closed my HVAC dampers?

Now let's get started with the most frequently asked question on the subject...

What Is an HVAC Damper? What Does a Damper Do in an HVAC System?

Dampers are an important part of HVAC systems. Consider a dam, for example. When closed, a damper prevents the air from going across it like a dam does with water.

HVAC dampers are an important part of your zoning system. They function as valves in the ducts. Their use determines which portion of your property gets heated/cooled air until desired settings are reached. Since cold air sinks and hot air rises, HVAC dampers control the amount of air that is supplied to different parts of your property.

Different Types of HVAC Dampers

There are various dampers that can be found within an HVAC system, and each particular damper serves a purpose. Let's go ahead and break down what each type of dampener does so you know which one is right for your home.

Butterfly Flat Dish Dampers

These dampeners look like little butterflies sitting up on top of the duct work so they get their name from what they look like. They're super easy to install and they don't take up any space. Their purpose is to keep the airflow going in one direction so if you want dampers that can be used for both heating and cooling, butterfly dampers are a great option because dampers of this type only care about pressure, not which way the air is flowing.

Blade Dampers

Blade dampers come with two blades that look like big fans that close slowly together. The effect these have on your airflow happens at the point where the blades meet each other. This creates more of an abrupt stop of airflow than butterfly dampers do but these also work equally well for heating or cooling purposes.

Inlet Vane Dampers

If dampeners are like tiny little doors that close off the airflow, inlet vanes dampers are like small vents that open up and allow air to flow. They don't dampen or direct your airflow but they do help control the pressure of the air moving throughout your entire HVAC system.

Louver Dampers

Louvers dampen down on their own when there is higher pressure in an area. If you need dampers that can only be used for heating season, louvers dampers might be a good choice for you.

Where Are HVAC Dampers Located?

HVAC dampers are most commonly located in the main trunk line right before and after any major junctions. They can also be located at certain points on multiple system ducts, with two dampers found on every main line 90 degrees apart. Although dampers may vary from manufacturer to manufacturer and even from unit to unit, most dampers share a few common characteristics:

  1. They are round discs made of thick fiberglass or dense cardboard (similar to egg crate bedding)
  2. They have a handle that can be turned either direction to allow or stop airflow through the damper
  3. Some dampers have a pointed metal pin attached for easy grip when turning

Every house is different. Some homes have no dampers at all. A supply duct may travel to the right or left off of your furnace depending on where your home is situated. A damper will generally be inserted in the supply duct that leads to your upper level. Examine all of the runs and see if any have dampers if you have exposed ductwork. Some houses include dampers in every run, which is excellent for air balancing.

When Should I Open and Close My HVAC Dampers?

In most houses, dampers on the upper level are opened in the summer and shut in the winter. In the winter, closing the dampers on your HVAC system to the upstairs allows for heat to rise naturally as it is distributed throughout the home. In the summer, the lower level is naturally cooler, and most people report having hot rooms. In the summer, it's critical to open the dampers on the upper level and block as much air from entering the basement as possible.

If you have someone to assist you, one simple method to see whether the dampers are open or closed is to have someone go up and cover each vent with their hand. By covering a bedroom's vent with your hand, you may check each damper to ensure it is open or shut. It takes some cooperation, but it's a fantastic and easy technique to get maximum comfort for hot and cold spots in your house.

When the weather changes, you must know how to adjust your HVAC dampers. It's a good idea to create an alert on your calendar so you're not caught off guard when the house gets too hot or cold. If you label your dampers correctly, you won't be perplexed as to how to alter them.

Suffering From Hot Spots or Cold Spots in Your Home?

Dampers are fantastic, but they may not be enough to fully eliminate hot or cold air spots in your house. There might be a variety of reasons why you're still having air balance difficulties.

At ARS/Rescue Rooter, our team of HVAC system professionals can diagnose weak air flow or air leaks in your ductwork. We can also help replace or repair any existing control dampers in your home. If your heating or air conditioning is experiencing some air duct damper issue, find your nearest ARS/Rescue Rooter location or call us at 866-399-2885 to book an appointment with us today!

Additional Damper Questions & Answers

What distinguishes automatic dampers from manual dampers?

Automatic dampers are controlled by your thermostat or central control system. Manual dampers, on the other hand, must be adjusted by hand. This makes them a more cost-effective solution but also means you will have less control over the airflow in your system.

What is the primary function of guillotine dampers?

These are designed to provide positive isolation and are used most during maintenance on HVAC systems. They serve as a temporary means of regulating airflow, ensuring the integrity of the system as well as efficiency during repairs. This makes them crucial for HVAC maintenance.

How do inlet vane dampers contribute to HVAC system performance?

Inlet vane dampers are critical for modulating airflow and pressure on the inlet side of your system’s blowers, offering precise control over them. They are perfect for anyone looking to fine-tune airflow management within their systems to optimize their overall performance.

What makes louver dampers popular in HVAC systems, and how are they unique in terms of construction and function?

These are used in many HVAC systems because of their versatility and compatibility with various duct sizes. Many choose them because they also feature high-quality construction and reliability for regulating airflow.

How do HVAC dampers benefit homeowners in terms of comfort and energy efficiency?

They control airflow to different zones, reducing hot or cold spots in the home. They also enhance energy cost savings because they optimize the distribution of conditioned air.

Why may dampers not be enough to fix hot or cold spots at home, and what should you do in such situations?

Dampers may not be enough to resolve all your comfort issues because there may be airflow or ductwork problems. This is why you should have professional HVAC technicians servicing your systems to ensure long-term comfort and efficiency.

Searching for more knowledge to boost your indoor comfort? Sign up for our email newsletter and you'll receive expert tips and advice from our HVAC & plumbing pros. Plus when you sign-up. you'll be entered into a drawing to win a FREE 50 Gallon Gas or Electric Water Heater!

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