Air Duct Sealing: Why It Matters and How It Works in East Metro Detroit

Here’s a scenario a lot of East Metro Detroit homeowners will recognize: the furnace kicks on, runs for what feels like forever, and the upstairs bedroom is still cold. The instinct is to blame the equipment. Usually, though, the real story is simpler — air is leaking out before it ever reaches the room it was meant for.

That leak can happen in one of two places: inside the ductwork that carries heated and cooled air through your house, or in the building envelope around your living space — the attic, the walls, the crawl space, all the little gaps where conditioned air slips out and outside air sneaks in. People tend to lump these two things together under “air sealing,” but they’re not quite the same job, and knowing the difference matters if you’re trying to fix the problem instead of guessing. Below, we’ll walk through both. Koala Insulation of East Metro Detroit handles the whole-home side of this, and you can get a free estimate to see where your house is actually losing energy.

What Is Air Duct Sealing?

Duct sealing means closing up the gaps, holes, and loose connections in the ductwork itself  the metal or flexible tubing that pushes conditioned air from your furnace or AC to every room in the house. It sounds like a small thing until you see the numbers. ENERGY STAR estimates that in a typical home, somewhere between 20 and 30 percent of the air moving through the duct system never makes it to its destination — it just leaks out into the attic, the crawl space, or wherever else the ducts happen to run.

That shows up in ways you’d notice without any technical explanation: bills that feel too high for the size of the house, rooms that never catch up to the thermostat, or a faint musty smell drifting out of the vents.

Sealing this kind of leak usually means an HVAC technician applying mastic sealant — a thick, paint-like compound — or specialized foil tape to the seams and joints along the duct run. It’s detailed work, partly because ducts are often buried behind drywall or tucked into hard-to-reach attic space.

What Is Whole-Home Air Sealing?

Whole-home air sealing is a different animal, even though it’s chasing the same basic goal. Instead of targeting the ductwork, it targets the building envelope — the boundary between your conditioned living space and the outside world. Think about where a house actually leaks: around recessed lighting, at the rim joists where the foundation meets the framing, through gaps left by plumbing or electrical work, along the spot where an attic hatch meets its frame. None of that has anything to do with your ducts, but it adds up to the same result   conditioned air escaping and your HVAC system working harder than it should.

This is the service Koala Insulation of East Metro Detroit actually provides. The team identifies where a home’s envelope is leaking and seals those points so your insulation can do the job it was installed to do in the first place.

How the Two Actually Work Together

It’s worth being honest here: sealing one without the other usually leaves money on the table. A perfectly sealed duct system still won’t solve a drafty attic — the air arrives fine, then leaks right back out through a gap near the eaves. And a well-sealed envelope won’t help much if half your conditioned air never made it out of the ductwork to begin with.

So you may need two different specialists here. An HVAC contractor is generally the one to call for leaks inside the ductwork itself. For everything happening in the walls, attic, and crawl space, that’s where Koala Insulation of East Metro Detroit comes in — pinpointing exactly which envelope gaps are causing the problem, rather than guessing.

How Much Does Air Sealing Cost?

We’re not going to pretend there’s a single number that applies to every house, because there isn’t. What a whole-home air sealing project costs comes down to things a technician has to see in person how big the home is, how many gaps need attention and where they’re located, and how easy or difficult those areas are to access. An attic with a tight, low-clearance crawl space is a different job than an open, walk-up attic, even in two houses of similar size.

The only way to get a number that means anything is a home efficiency assessment. Koala Insulation of East Metro Detroit will walk through your home and put together an estimate based on what’s actually going on — not a guess made over the phone. Get a free estimate to find out what your project would actually involve.

Is Air Sealing Worth It?

For most homes dealing with drafts, uneven temperatures, or bills that just feel too high, yes  and there’s data behind that, not just a sales pitch. The Department of Energy has pointed to meaningful whole-house energy savings from comprehensive air sealing, and ENERGY STAR notes that sealed ductwork alone can improve heating and cooling efficiency by as much as 20 percent. Past the utility bill, there’s a comfort argument too: fewer drafts, less dust pulled in from the attic, better air quality overall.

Where it’s less of a slam dunk is a newer home built tightly to begin with, where there isn’t much air leakage to fix. That’s really the whole argument for getting an assessment instead of assuming — a 1960s ranch and a 2015 build aren’t the same project, even at the same square footage.

When Should You Hire a Professional?

A few things tend to mean it’s time to call someone rather than keep living with it:

• One or two rooms that are always harder to heat or cool than the rest of the house
• Drafts near outlets, baseboards, or the attic hatch that don’t go away
• Energy bills that don’t match up with the size or age of your home
• Dusty or slightly musty air that seems to come from the vents, basement, or crawl space
• An HVAC system that seems to run longer, or more often, than it used to

The honest reason to bring in a professional here is that finding the actual leak is harder than it sounds. You can feel a draft near a window and assume that’s the problem, when the real air loss is happening somewhere you’d never think to check — behind a soffit, around a bathroom fan vent, in a rim joist you’ve never seen. A trained eye evaluates the whole envelope instead of chasing the one symptom you happened to notice.## The Koala Insulation Process

Koala Insulation of East Metro Detroit runs a pretty straightforward process for air sealing work:

1. Free home evaluation. A technician walks through your home to find where air is actually escaping.
2. Home efficiency assessment. They review what they found and explain why certain fixes matter more than others.
3. Personalized plan. Recommendations get built around your specific home, not a generic package.
4. Sealing service. The team seals up identified gaps and cracks using proper materials and technique.
5. Final walkthrough. The work gets reviewed to confirm it actually solved the problem.

The East Metro Detroit team covers the surrounding area too, including Farmington Hills, Rochester Hills, and Royal Oak.

Frequently Asked Questions

What is air duct sealing?

Air duct sealing closes gaps and loose connections in HVAC ductwork so conditioned air doesn’t escape before it reaches your rooms. It’s a different job from whole-home air sealing, which deals with gaps in the building envelope itself — the attic, walls, and crawl space.

How much does air duct sealing cost?

It depends on your home’s size, how many gaps or leaks there are, and how accessible those areas turn out to be. Since every house is different, the only real way to get an accurate number is a professional assessment. Request a free estimate to get a recommendation specific to your home.

Is air duct sealing worth it?

ENERGY STAR has found that sealing a leaky duct system can boost heating and cooling efficiency by as much as 20 percent, which makes it a solid investment for a lot of homes with forced-air systems. Whole-home air sealing offers a similar payoff by closing the gaps that let conditioned air out and outside air in.

When should I call a professional?

If you’ve got rooms that never seem to hit the right temperature, drafts that won’t quit, bills that feel too high, or an HVAC system running more than it used to, it’s worth calling someone. A professional can actually track down where the air is escaping instead of leaving you to guess.

Conclusion

Whether your home is losing conditioned air inside the ductwork or through gaps in the walls and attic, the end result looks the same  higher bills, less comfort, an HVAC system working overtime. Knowing the difference between duct sealing and whole-home air sealing means you can fix the right problem instead of throwing money at the wrong one.

If drafts, high bills, or uneven temperatures have you looking into air sealing, get a free estimate from Koala Insulation of East Metro Detroit and find out exactly what your home needs.