Dryer vent covers have been used since dryers were first venting to the outside as a way to prevent water from entering the home and woodland creatures from taking up residence inside the ducting. You see depending on the time of year, that warm dryer metal tube makes a great place to make a new home. And with the added benefit of some nice fluffy lint as beading, what could be nicer.
The problem for us as humans is for efficiency and safety sake, we need our dryer ducts to function properly and the added restriction of nesting material simply is not a recipie for good airflow. So ever since the early days, there have been attempts and perfecting the perfect dryer vent cover that not only allows for good airflow, but also prevents access from the outside by creative animals.
Over the years we have used simple designs like sloped hoods or louvers to accomplish this and they have worked is some ways and failed in others. Generallly the sloped designs have resulted in backpressure to the dryer. So much so that according to most dryer manufactur installation guides, we need to take the vent cover type into consideration when calculating duct length.
As for the louvered vent covers, well they may limit the access by birds and such, but they tend to do a very poor job at allowing lint to be blown out of the system because of the louvers. And once the louvers begin to collect lint it is only a short time before the ducting literally gets blocked enough to begin to cause problems.
It is for this reason the only dryer vent cover I recommend in our very own pest proof cover. Made of steel, in the United States, powered coated and paintable. These offer the best of all worlds. Security from access by woodland creatures. No backpressure to the dryer because of the fully accessible door design. And great looks due to the use of supperior materials and design.
Look at the dryer vent cover on your own home and see how it is holding up to the job it was designed to do. Most likely, it is made of plastic and isn’t working too well due to exposure to the elements and the constant heating and cooling cycles of the task at hand. It may just be time to upgrade your vent cover to something a little more long term.