7. You decide to add insulation to your attic and walls and figure out it will cost you $2,000 but there is a government program that will reimburse you 30% of the cost. Later on, you want to figure out how effective the insulation is so you pull up the natural gas bill in Jan 2008 before the insulation and Jan 2009 after the insulation. You found you used 150 therms (a therm is 100,000 BTU of natural gas) to heat your home in Jan 2008 and 75 therms in Jan 2009. You think, that's great, a 50% drop. But then you remember that class you took at GWU where you learned about heating degree days. You go to the NOAA website and discover that Jan 2008 was 1,000 HDD and Jan 2009 was 800 HDD. a. Calculate the correct percentage reduction in your home energy bill with the insulation. b. Assuming $2/therm, and a total winter heating consumption of 1000 therms (before insulation). Calculate how much you saved with the insulation in one year using your percent reduction calculated in part "a". c. With the initial cost of $2000 and a government subsidy of 30%, what is your simple