Two homeowners call us in the same week. One says the vents look filthy and the house is dusty no matter how often she vacuums. The other says his bills climbed all summer and the back bedroom never really cooled down.

Both are asking about their ductwork. They need opposite services.

Duct cleaning and duct sealing get talked about interchangeably, often by companies selling one of them very aggressively, and the distinction is worth understanding before you spend money.

What Duct Cleaning Is For

Cleaning removes what has accumulated *inside* the ducts: dust, construction debris, pet dander, insulation fibers, the occasional evidence of rodents.

It is genuinely worthwhile when there is a reason for it:

After a remodel or new construction, when drywall dust has been pulled through the system
After rodent or insect activity in the attic or crawlspace
Visible mold at the registers or a persistent musty smell when the system starts
Visible debris blowing out of the supply vents
After a house sits vacant for a long period, or after smoke damage

It is not, despite the marketing, an annual necessity for a normal home, and it will not fix a high utility bill. Air moving through a duct at speed does not deposit much on the walls of a properly sealed system. If someone offers to clean your ducts for $79 and shows up with a shop vac, you have found the version of this service that exists to sell you something else once they are in the attic. A real cleaning uses negative-pressure equipment on the trunk lines and takes hours. Our air duct cleaning page sets out what our process involves.

What Duct Sealing Is For

Sealing addresses air escaping *from* the ducts, at joints that have separated, at connections where the original tape has dried out and let go, at boots that were never properly fastened to the register.

This is the one that costs you money every month. Duct systems in Sacramento-area homes typically run through the attic, which in August is well over 130 degrees. Cooled air leaking out of a supply duct up there is air you paid for, delivered to your insulation. Worse, leaks on the return side pull that superheated attic air, plus dust and, in September, smoke, into the system and distribute it through the house.

The symptoms are different from a cleaning problem:

Utility bills climbing without a change in habits
Rooms furthest from the equipment never reaching temperature
The system running almost continuously in the afternoon
Noticeable dust when the filter is clean and new
Uneven temperatures between floors or wings

Our post on signs your ductwork is leaking cool air goes through how to spot this from inside the house, and why your air conditioner is always running covers the run-time side.

Why Now Is The Right Time To Look

Two reasons this is a September conversation.

The first is that your ducts have just come through a full Sacramento summer of maximum thermal stress, and problems that developed in July are still there in October, quietly waiting to cost you on the heating side. Leaks do not care which direction the air is being conditioned.

The second is smoke. Return-side leaks are the most common reason a house that has been closed up all week still smells like fire, and sealing them is one of the few structural improvements to your indoor air quality that also lowers your bill.

What We Would Tell A Neighbor

If your vents look clean and your bills are high, stop shopping for duct cleaning. Get the system assessed. If there is visible debris, a smell, or you have just finished a remodel, cleaning is legitimate and worth doing properly.

And if anyone quotes you either service without going into the attic first, get a second opinion.

Want to know what is actually in your ducts? Contact Absolute Comfort or call (916) 224-7159. We serve Fair Oaks, Carmichael, Citrus Heights, Orangevale, Gold River, Rancho Cordova, Folsom, Roseville and Granite Bay.