Air leaks occurring in a door frame is a pretty common problem for any house owner.
This is caused by your house shifting because the moisture changes in the soil.
And when your house shifts, your door also shifts and creates holes that allow air to leak in.
Having air leak into your home can cause a lot of discomfort, as well as can overcharge your heating or cooling bill.
The most common way to solve this problem is to add some kind of sealant, like foam, between the frame of the house and the frame of the door.
You can do this by removing the interior casing of the door, which is the wood trim between the wall and the door frame.
Another type of air leaking that usually occurs is between the door frame and the door.
Fixing this problem is not hard, all you need is weatherstripping.
Keep in mind that, at some point in time, the weatherstripping will suffer such damage so it won't be effective anymore, so don't wonder why you experience air leaking even though you have weatherstripping installed.
So don't be cheap when installing the weatherstripping.
Consider it an investment for the future.
The most common and easiest to install weatherstripping consists of a rubber bean attached to a strip of metal.
All you have to do is easily push the rubber portion against the door and the door frame at the same time.
After that you have to attach the metal part with the screws provided in the package.
Do that properly and you will be covered against any future air leaks.
All in all, fixing air leaks around your doors is doable without any professional help.
Just make sure you respect the instructions and you can get the job done all by yourself.