How Does Insulation Impact HVAC Efficiency?
If you’re concerned with how much it costs to heat and cool your home, you’re not alone. You may even be considering an HVAC upgrade to a more efficient system to cut those costs. However, your HVAC equipment isn’t the only factor in your home’s heating and cooling equation. How well your home keeps conditioned air inside it can also have a massive effect on its heating and cooling costs. That makes insulation a key topic when discussing HVAC efficiency. Here’s everything you need to know about how insulation impacts HVAC efficiency and can even reduce the need for heating and AC repair services.
What Is Insulation and How Does It Work?
When you think of insulation, you likely equate it with a thick, comfortable blanket that keeps you warm. However, insulation’s fundamental role isn’t to keep you warm; it’s to slow or prevent heat transfer. In other words, it works just as effectively to keep heat energy out of your home as in it. To understand why, you need to understand the science behind heat transfer.
The first thing to know is that heat energy spontaneously moves from warmer substances to colder ones. It never moves on its own in the other direction. Your HVAC system exploits this fact to heat and cool your home’s air. Your AC does it by pushing cold refrigerant through a heat exchanger while passing your home’s cooler air over it. Gas furnaces do the opposite by blowing cool air over a heat exchanger while hot combustion gases flow through it. Both use a method of heat transfer called conduction. In that case, the heat exchanger’s metal conducts the heat energy.
There are two other methods of heat transfer, however. One is convection, which relies on the air as a heat transfer mechanism. The other form of heat transfer is radiation, which transfers heat energy through visible and non-visible light wavelengths. Insulation, then, must work to slow or halt all three methods of heat transfer to remain effective.
How Fiberglass or Wool Insulation Works
Fiberglass and wool insulation both use the same primary method of slowing heat transfer. They’re both dense and fibrous, which helps trap pockets of air between and inside them. Those pockets remain isolated from each other by the material fibers, which don’t readily transmit heat energy. That means both insulation types create a gauntlet that heat energy must travel through to pass through them.
How Foam Insulation Works
Foam insulation works similarly to fiberglass or wool, relying on trapped gases within itself to slow heat transfer. However, foam can have some added benefits as an insulation material. Some foams are even better at resisting heat conduction, improving their thermal performance relative to fiberglass or wool. Spray foam applications also have the added benefit of sealing air leaks. So, if you use spray foam insulation on an exterior wall, for example, it’ll work its way into any gaps and close them.
Understanding R-Values
R-value is the basic unit of measure used to denote insulation’s ability to slow heat transfer. In fact, the R stands for resistance. The scale is easy enough to understand and applies to insulation of every type. Basically, the higher the R-value assigned to insulation, the better job it does slowing down heat transfer. You will also find that higher R-values typically come from adding thickness to your insulation.
How Much Can Insulation Improve HVAC Efficiency?
There are too many variables to provide an exact amount of efficiency improvement you might expect from insulation upgrades. For example, upgrades will only be marginally effective if you live in a well-insulated home. However, most homes aren’t as well insulated as they should be. Seattle didn’t even have a comprehensive energy efficiency building code until 1980. The first residential insulation guidelines only appeared in 1974. They’ve both had substantial upward revisions in the intervening years. However, if your home is older than both, there’s a good chance it’s under-insulated.
According to the Department of Energy, upgrading the average home’s insulation to modern standards can trim 20% of its HVAC system’s costs. To achieve that in your Seattle home, you must meet some minimum insulation R-values:
- R38-R60 in attic
- R25-R30 in floors
- R5-R10 sheathing on above-ground walls
- R15-R19 sheathing or batt insulation on below-ground walls
Where to Upgrade First
It may seem like a big job if you’re interested in upgrading your home’s insulation to improve its HVAC efficiency. And in truth, addressing every part of your home’s insulation can be difficult. For that reason, some insulation upgrades make more sense than others. The first place to upgrade is your attic insulation. There are two main reasons for that. One is that your attic is where your home likely loses the most heat. The other is that it’s the easiest part of your home’s insulation to upgrade.
To bring your home’s attic insulation up to modern standards, you can install new insulation on top of what’s there. If your attic has loose-fill insulation, you must aim for a depth of between 13 and 20 inches to reach the recommended R-value. You can measure the depth of your insulation with a ruler to estimate your need. It is also possible to add loose fill insulation over existing roll insulation. You can check your existing roll insulation’s R-value by looking at its paper backing. Most brands print their R-values conspicuously there. However, it’s necessary to ensure that your roll insulation isn’t damaged or degraded before making upgrades.
Your home’s exterior walls are the next place to target for insulation upgrades. The process starts with a professional estimate of your existing wall insulation’s R-value. Most of the time, doing so is possible without damaging your home’s finished walls. If your home benefits from upgrades, adding loose, blown-in insulation is the least-destructive method. It only requires a few small holes cut into your finished walls to allow access. Those holes will let the installation team blow insulation into the wall’s interior. After completion, they’ll patch the holes and repaint to restore each wall.
Finally, you can upgrade the insulation in your home’s interior walls and floors. Doing so typically uses the same methods as exterior wall upgrades. Installing better insulation in those spaces can help your HVAC system heat and cool your home more evenly. It prevents heat from moving between the rooms and floors of your home. It can also reduce the pressure on your attic insulation by keeping conditioned air where your HVAC system delivers it.
Seattle’s HVAC Efficiency Experts
If you’re looking for a more efficient HVAC solution for your Seattle home, Brennan Heating & Air Conditioning can help. We’ve served local homeowners for over 30 years and understand the unique climate challenges of the Pacific Northwest. We’re also a Lennox dealer, carrying the latest quality heating and cooling systems. Our HVAC technicians are NATE-certified. We’re also a recipient of the Angi Super Service Award in recognition of our superior service quality. To top that off, we’re Better Business Bureau accredited with an A+ rating. We even offer an ironclad workmanship guarantee, and we’ll treat your home with care and respect.
If you want to improve your home’s efficiency in Seattle with services like duct sealing, indoor air quality products, and more, contact Brennan Heating & Air Conditioning today!
