I have an electric furnace. 1 year old. I noticed the air is not very warm. It is running my electric bill sky high. I change the filter every 2 months. This morning it is 9 degrees and I am cold. The air seems like it should be warmer. I also have a 1 year old thermostat. I covered my windows with plastic on the inside so it should be warmer. Thank you for any suggestions.