In America, if a note is sent in appreciation, it is often written on a Thank You card.  

These are fold-out cards (similar to Birthday Cards or Christmas Cards, but maybe half the size.) They typically have a decorated front side preprinted with "Thank You" (or some variation), and a totally blank inside, in which the writer pens a short note. They are often sold in a pack of 10, 12, 20 or so, with little envelopes. Here's what they look like:

http://www.google.com/search?q=thank+you+card+images&amp;client=safari&amp;hl=en&amp;source=lnms&amp;tbm=isch&amp;sa=X&amp;ei=ZAYlVfeZENGzoQSqq4C4CA&amp;ved=0CAYQ_AUoAQ&amp;biw=320&amp;bih=356

Is there any word for "small hand written note/letter" in English?
Will enclosing my porches during the winter help keep my house warmer? There is a lot of wind hitting the house, and I'm afraid that is causing a drop in temperature.
