Question: Why are the bags on the top of the furnace truck floppy?

Furnace cleaning trucks have a very distinct look and sound. When one is operating, you can hear it from a block away. When you see it there are normally several bags sticking out of the top of the truck. Have you ever wondered what those bags are for? 

Generally, people assume that the bags on the top of the furnace truck is the vacuum. When the bags are sticking straight up it must mean that the cleaning is underway, right?

The bags are actually an exhaust dust filter for the vacuum. Think of the little dust filters that you can buy for a shop vac that clip on the exhaust air port to prevent dust from filling the room. The bags are like those, but on a much larger scale.

The vacuum that sucks all the dirt out of your furnace system is actually located inside the truck. It’s very obvious when the vacuum is on and the cleaning is taking place – because you can’t hear anything else! The vacuum makes a very loud humming noise when operating, and as long as the sound is blasting, the vacuum is doing its job (and so are our technicians). 

If the bags aren’t sticking up straight, am I getting as good of a furnace cleaning?

Yes. Another assumption people have about the bags on the top of the furnace truck is that if they aren’t sticking up straight, the cleaning isn’t as good. But this is not the case. 

The bags filter out dust and debris from many houses, and every couple of months we have to clean them out because as you can imagine, they get filthy. The dirtier the bags are the more the airflow is restricted. This is because less air can get through the build up of dust, causing the bags to stick up in the air. 

So when you see bags that look like this:

…you know that a truck with recently cleaned bags is servicing your furnace system!

We proudly maintain our trucks at peak performance level, so whether the bags are floppy or sticking straight up in the air, you can trust that your furnace is getting the best cleaning possible.