The Three Components That Make Up Your Air Comfort System

If you find yourself cold during winter or hot during summer, the first place you go is to your thermostat to turn on your heating and cooling system. But how does this important appliance keep your home comfortable when the weather outside is anything but? Few people know the ins and outs of how this complex and intricate system actually works, and that’s what we’d like to explain in this blog. Your HVAC system is kind of like a three-legged stool: each of the three legs needs to work together or the entire thing collapses. If a problem happens with one leg, the other two simply can’t do their job properly, and your air comfort ultimately falls apart. The three components are your HVAC equipment, your air distribution system, and your building envelope.

HVAC Equipment

The term “HVAC” stands for “heating, ventilation, and air conditioning,” and is an inclusive term to refer to all of the various equipment and components that make up your indoor and outdoor units, as well as the lines that connect the two of them. That means your blower fan, your evaporator coil, your condenser, your heat exchanger, and plenty of other parts as well all fall into this envelope.

When you refer to your heating and cooling system, this is what the majority of people think of, and for good reason: when something goes wrong, there’s a strong chance that this is where the problem is. The HVAC equipment features a number of moving parts and components that need to operate under some fairly extreme conditions. It also includes the electrical components that make your HVAC equipment work properly. Because mechanical parts can and do eventually fail, this is where you will find the majority of the major problems you encounter.

Air Distribution System

Here’s the thing with your HVAC equipment: it produces a lot of wonderful, conditioned air, but it doesn’t really have any ability to do anything with it once it does. That’s what your air distribution system is for. Your air distribution system is responsible for taking this conditioned air and spreading it around your home quickly and efficiently, and this is usually done through a duct network. The majority of air ducts are made from sheet metal and fiberglass duct board with flexible wire helix branch lines. If located in unconditioned space, they should always be insulated to minimize heat loss, and should be built in a way that they can withstand the pressure created by a blower fan, creating a “forced air” system without leaking.

Air ducts have no moving parts, so naturally, it’s easy to ignore them as a potential site for problems. However, ducts can and do experience issues. Animals love to break into ducts, particularly during summer months, as they are dark, cool, and sheltered from the world around them. They typically get in by breaking holes in the wall of your duct system, creating a large air gap that reduces airflow and allows conditioned air to escape. However, ducts can wear out even without interference from pests. Moisture in the air can cause sheet metal to rust and rot if it isn’t treated properly, and shifting through either expansion and contraction or inadvertent adjustment can create gaps and cracks that let air out that you would rather have kept. If your energy bills are absurdly high for reasons you can’t quite place, or your HVAC system can’t seem to keep up with the heat or the cold any longer, then your ducts might be the issue you’re dealing with.

Building Envelope

Your building envelope is the term used to describe the outer limits of your home’s structure, or the walls and planes that form it. In other words, your walls, floors, and roof. Your building’s envelope is not a perfectly sealed surface—you probably have windows, doors, vents, and other gaps that can create a way for conditioned air to escape. That’s why we have air seals like weather stripping and insulation. However, these materials wear out over time.

Checking your building envelope is something we recommend each and every year. Notably, check around your windows and doors for any signs of a draft to make sure air isn’t escaping. We also recommend sealing any gaps in your ceiling and having a professional roofer change any damaged or worn-out flashing that might be creating an obnoxious energy leak in your attic.