The whole house vacuum system has up to 100 feet of small pipe (duct work) that is approximately 1 and a half inches or smaller. The many turns and elbows to go to all the outlets(plug in hose adapter in wall), can be easily blocked or clogged. Especially avoid sucking up (vacuuming up) items 1 and a half to 2 inches long, (short lollipop sticks, bobby pins, toothpicks, etc.), as they will get stuck in the turns(elbows) and all the fuzz begins attaching to it and eventually blocks it completely. It is very difficult to unclog the hair and debris. You may have to cut into the PVC pipe and undo the mess(clog) and then repair/replace the piping. I suggest that at any accesible elbow that a y piece be put beside it inline. Just plug the open part of the Y and it is now an awesome access point to unclog future problems. Open up the end of the Y and vacuum or fish out the blockage, and you can be back to full power in no time. A professional carpet cleaning would be a good idea,, since your vacuum was probably working inefficiently for a long time(months) before it was clogged enough to notice. A powerful steam cleaning and deodorizing will put you in good shape, now that you have a lot of suction again to keep your carpet clean again. Don’t forget how important it is to keep the Dryer vent (duct work) pipes clean also. It can be a fire hazard and waste of energy if the dryer does not have maximum flow out these vents(pipes). Whole house air duct cleaning can cost several hundred dollars, but it is definitely worth it. Every 5 years or so the dust builds up that gets past your filter, until lots of dust blows into your rooms each time the fan blows(cycles). A professional cleaning can have you breathing much cleaner/healthier air in no time.