Caulking Is The Cheapest Form Of Energy Savings, And Very Efficient.

Caulking is the cheapest form of energy savings, and very efficient.

Caulking is not permanent.  Examining the caulking around your house should be something you do at least annually, if not semi annually.

Look at two photos from a bay window on the front of a house. 

Gaps existed all around the window where it attached to the house, and all around the framing underneath.

These gaps allow air to move freely. 

Even if the insulation inside the cavity under the window is well done, that air will influence the house.

So, is the air moving around inside the box and influencing the house?

Mighty Mo is definitive in his answer.  And the answer is YES.

The temperature outdoors was about 40F at the time of this image.

The floor looks very cold in this image and felt cold to the touch.

That, and the lousy windows, will influence that entire room dramatically.

And in every season!

My recommendation:  it's the little things that can make a big difference.  And caulking is a little thing!  But a very important one.  Get a good caulk that is made for the application you wish to take care of - AND OUTDOORS A GOOD CAULKING WOULD BE ONE THAT SAYS IT IS ELASTOMERIC - and go about making as attractive and sealing a bead of caulking can be.  Then sit back and for very little money create a huge energy saving that will last years.