If your dryer takes a long time to dry, but you still feel heat, you probably have a clogged dryer exhaust duct. The first thing to check is the hose on the back of the dryer. It should be as short as possible and not kinked. If it is kinked, try to straighten it. The best vent hose to use is the rigid kind, not the super flimsy and flexible kind.
You can find vent hose like this at Home Depot. Be careful installing it because it will crimp. Here is a link to it: Dryer vent hose
If you clean the vent and it still takes a long time to dry, you may have bigger problems. You may need a professional to come out and clean it. I often find birds nest or just a lot of lint is blocking the air making it really hard for the dryer to run properly. I recommend my friend Joel at West Houston Dryer Vent Cleaning. He does a good job. You also might need me to clean the inside of the dryer before or after he cleans the vent. Lint filled dryers can cause fires! For appliance service, or to clean out your dryer in the Katy area, please contact Steve Slaton Appliance Repair.