It takes only seconds to dry, then you just trim off the excess. For immediate results you might want to think about purchasing small awnings for your windows. It will create more shade over your windows making it cooler inside as well. They will shade your windows and home, causing less need for air-conditioning in the warmer months, and blocking harsh winds in the cooler months, and they will beautify your home as well. Little things really make a difference, and if you are planning to stay in your home for many years, plan on the long term too.
Every little bit helps.
Many of them offer free or very low cost energy audits. An energy expert will come to your home and test for drafts or other leaks. This will use the sun's energy to your advantage. We have a house about the same size. When it gets warmer, we use box fans to push air thru the house.