The curse of having a dryer that vents up through the attic is that lint can and will build up within the vent, restricting the airflow and cause the dryer to work poorly. I recently had this experience, and much to my dismay, it was my wife and not myself that finally diagnosed the root of the problem.
Symptoms: The dryer runs normally, cloths heat up but do not dry without running them three or more times. Even then, the cloths may still be damp. The built-in dryer filter may collect less lint than normal. You may also notice that hot air is blowing out of the dryer filter slot when the filter is removed for cleaning.
The buildup of lint in the dryer exhaust vent is normally a slow process. It may take ten years for the lint buildup to become a noticeable problem. Unfortunately, the symptoms noted above are not obvious until the vent is severely blocked. Before you take on the task of dismantling your dryer vent, first check that the flexible vent hose is not kinked or clogged. That may be your only problem. Perhaps you might find that missing sock you have been looking for?
My first thought was that I had a problem with the flexible vent hose. I removed it and found a large amount of damp lint within the hose. Although I did not find any mates for my collection of orphaned socks, I did find an earring my wife was missing. Cleaning and shortening the vent hose seemed to cure my problem for a while, but it was misleading. Little did I realize at the time that the vent hose split while I was re-installing it. These flexible metal vent hoses are easily damaged. The cloths dried, but the dryer was now dumping some portion of the hot moist air into the laundry room. It was not until I installed a new vent hose that my wife once again complained that the dryer was not working properly. That was when she deduced that the vent line into the attic must be clogged.
The following day I made my way up to the roof with the idea that I could pop off the vent cover and do my cleaning from the roof. This turned out not to be an option as the vent was one single unit. Next option meant a trip into the cramped crawl spaces of the attic. In the attic I found the dryer vent line hiding behind several large ducts for the central air system. Getting to the vent line was a challenge. Planning ahead, I took a small piece of plywood up to lie across the rafters so I would have a place to stand and work from.
The dryer vent line did not go straight up to the roof. Instead, it made 45 degree jog with a three-foot section that then angled into the exhaust vent on the roof. The angled section was easily removed once the aluminum tape was taken off the joints. I peered down the vent line towards the dryer. There was lint but not enough to cause the problem; however, when I looked into the three-foot section that was at a 45-degree angle, the lint build up was extreme. Even the roof exhaust vent had severe build up. Had it not been for all the moisture coming out of the dryer, the lint could have easily caught fire from spontaneous combustion.
Now that the cause of the problem had been found, how to clean the vent lines? The angled fittings and the short length of tubing were easily accessible by hand with a small brush. The problem was the ten-foot section of vent tubing going from the attic down to the dryer. I was about to bring my Shop Vac up to attic when I realized, I don’t need the vacuum; I just need the hose. The flexible Shop Vac hose was ideal. The ribs on the hose would act like course brush bristles, and the extension tubes could be used to add length to get all the way to the bottom of the vent. Perfect! And so it was, but I did need the vacuum to suck out all the lint at the dryer end of the vent once the cleaning was completed.
Reassembling the vent ducts was simple enough. The first load of laundry dried in record time without having to be run a second or third time. My wife was excited about how much time she would now save doing laundry. Me, I’m thinking of all the money I’ll now be saving on my electric bill. It was three hours of my time well spent.