Already Warmer in my house

I put up plastic finally over all the windows in my house and it's already feeling warmer in here not only that but our heating system is a central heating system meaning that once the thermostat is set the heat kicks itself on and off based on the set temperature and we haven't heard the heating system kick itself on as much so that tells us that heat is being kept inside. I'm happy that so far I have been able to turn the thermostat down and still keep it warm in here I used to have to crank my thermostat to nearly 80 to get some kind of warmth but now I can keep it at around 70 during the day and at night since we are sleeping and we don't need the extra heat we turn it down to about 65. I'm glad the plastic is seeming to work I haven't gotten an updated bill yet but I think that I will see some kinds of savings this winter based on the fact that I don't have to crank the heat up. Here's to hoping.