If you are about to set up a service call because your clothing dryer does not heat. Wait just one minute! There are two questions you need to ask:

• Does my dryer heat at all?
• Is there no heat?

If your dryer does not heat at all, go ahead and set up that service call to have a technician to come repair your dryer. If your heats but is just slow to dry, don't set up that service call just yet. The reality is that you have an airflow problem, hence, a ventialtion issue.

When is the last time you changed your dryer filter?

Check the filter first. If you have not been changing the filter it may be possible that you will need someone to come and take your dryer apart and clean out the lint that is inside the dryer. However, before jumping to that conclusion. Check the vent behind the dryer.

Is the vent hose packed with lint?

If so, clean it out and test the dryer. If there is still an issue you may need the vent cleaned inside the wall. Last of all, I would have a technician come out to clean the inside of the dryer and  check the themostats (it is rare that these go bad by improper cycling, it is more common for them to stop functioning all together and then there would be no heat.)