Stopping air flow (to a point so as not to make it too tight) is the best way to help your utility bill.

Make sure that air flows freely and that each has an operable damper to prevent back flow of outside air and to keep small animals from entering your home.Inspect and clean all weep holes for water drainage (windows).On a seasonal basis:Every six months, inspect and service either your heating or air conditioning system, depending on the season.Twice a year, you should inspect and repair the following caulked areas, as necessary.

And #1 airflow.

However as I understand it, the fittings don't restrict flow as much as would be assumed by first glance and it's sort of calculated similar to air flow in duct work.... a 90 degree elbow fitting can be roughly accounted as the same as x ft of straight run in terms of how much pressure is lost.

My guess is it has something to do with the vent intself, maybe all the twists and turns are reducing air flow or it's a problem with the dryers themselves. 

Making sure homes are energy efficient, verifying a good pressure thermal boundary, proper air flow for a healthy home as well as CAZ saftey testing. 4.

They can also turn on the fan in bathroom and over the stove to increase air flow without opening a window.

I typically go with a split system to make sure there is good air flow throughout the new space and also get the most on your appraisal for the additional SF.

You could get vents and ductwork gather dust and have lower air flow. 

. $2,000 to replace a water heater... b/c the units were built with a gas hot water heater that was crammed under a tight stairway, don't really have enough airflow & now don't comply with code...