HAC 165-350 ASSIGNMENT #7 DOE mandated efficiency increases Information: The DOE is scheduled to increase the minimum AFUE (efficiency) of gas furnaces form the current 78%, to 92% in 2021. It seems reasonable that the federally mandated minimum SEER (efficiency) for air conditioners will also be raised by a similar percentage, which will bring it from 13 SEER to 15 SEER. What effect will this have on a homes heating and air conditioning costs? Assigned Problem: Assume the following: The sample town has a population of 6000. According to federal guidelines, there are 2.5 people per household. That means there are (6000/2.5) 2,400 homes in the town. If we mandate that all homes in the town are 1800 square feet (and why not.were making up the town), then by using the Rule Of Thumb that air conditioning sizes are 600 square feet per ton, and heating sizes are 40 BTU per square foot..we end up with each house having a 3 ton air conditioner (1800 sq.ft./600 sq.ft. per ton) and a heating need of 72,000 BTUH furnace (1800 sq.ft X 40 BTU per sq.ft.). So, the base system for each house at current minimum standards is 3 tons AC at 13 SEER, and a 93,300 btu 78% efficient furnace. NOTE _ we got 93,300 btu because I need 72,000 btu to heat the house at design conditions and 78% efficientso thats 72,000 btu OUTPUT. How much comes into the furnace? We can set this up as a ratio like this: 72,000 btu output = X BTU input Then we solve for Xso 72,000X 100 = 7,200,000, then 78% use. 100% use divide that by 78 and that equals 92,300 So the input of a 72,000 BTU output 78% efficient furnace is 92,300 BTU. By the way, what you just did above is called cross multiplication and can be done on just about anything. OK, so now the DOE comes along and says that ALL furnaces installed after 2021 will need to be 92% efficient. Thats an increase of 18%. How did we figure that? Well, use cross multiplication again: 78% efficiency = 92% efficiency Solving for X.92 times 100 is 9200, 100(this years base percentage) X then divide that by 78 gives us 118 (rounded up), or an 18% increase. So if the furnaces increased by 18% in efficiency, you can bet that they wont leave air conditioning alone, but that will also increase by 18%. So, if the current minimum SEER is 13, then if thats increased by 18% we would end up with 15 SEER (15.34 to be exact, but go ahead and round down). OKheres the questions: Given the prior formulas you have worked with for estimating annula heating and air conditioning costs, What will the home owner experience in annual heating fuel bills with the more efficient furnace? What will the home owner experience in annual air conditioning costs with the more efficient air conditioner? How much money totally will they save in heating and air conditioning annual fuel consumption (yes, I just made you figure out the annual coast for the less efficient equipment by asking this)? Since the mandated upgrade to more efficient equipment is NOT voluntary, and will be required if when the old equipment fails, there really isnt a payback issue herethis is not a voluntary decision. So, what could you suggest the federal government offer to the homeowner to make it hurt less financially to install better equipment to be in compliance with the new efficiency guideline? Or, if youre not feeling benevolent, what could the federal government do to panelize the homeowner for not installing the better equipment?