ENERGY CONSUMPTION SAVINGS
Future UH Residential Hall
To determine the amount of energy saved from implementing green roofs on a future UH residential hall, we will assume that the new residential hall will be in the style of Cougar Place. According to UH Housing & Residential Life, Cougar Place has somewhere between 900-1000 rooms total. According to Energy Star, the average dormitory that has 600+ rooms uses around 311 kBtu/ft^2 annually (10). Through the simple conversion factor 1 kWh=3.142 kBtu, we can convert the 311 kBtu/ft^2 to 98.98 kWh/ft^2. The average college dorm is approximately 130 ft^2, so if we multiply 130 ft^2 by the amount of dorms in Cougar Place (we will use 950 because it is the mean of 900 and 1000), then we can determine that the square footage of all the rooms in Cougar Place comes out to 123,500 ft^2 (13). Finally, if we multiply 98.98 kWh/ft^2 by the total square footage of Cougar Place, 123,500 ft^2, then we can see that the total amount of kWh that Cougar Place uses up annually is about 12,224,030 kWh.
If we implemented a green roof onto Cougar Place, then we can see the potential energy savings that the future implementation of the green roof on the future residential hall can produce. According to a Canadian study, 10% of the total energy was saved when they implemented a green roof on a commercial building in Toronto, so we will use this approximation for our green roof (11). Because the green roof will save 10% total energy, we can multiply the amount of energy that Cougar Place uses up, 12,224,030 kWh, by 90% to determine the amount of energy that Cougar Place will use up if the green roof is added. The amount of energy that Cougar Place now uses up is only 11,001,627 kWh annually which is 1,222,403 kWh less than the amount of energy used before the green roof is factored in.
To determine the costs that are saved, all we need to know is how much expending a kWh costs in Texas. According to npr, 1 kWh in Texas costs 11.3 cents (12). If we multiply the difference between the energy used without the green roof and the energy used with a green roof by $0.113, we will be able to calculate the amount of money that UH will save annually with the implementation of the green roof on the future UH residential hall (based on all of the assumptions). The difference is equal to 1,222,403 kWh, so when we multiply this number by $0.113, we get that the amount of money saved annually by having a green roof installed comes out to $138,131.54 saved annually.
