 OK, for this problem, 3.15. We do more or less the same thing as the last house, except this house is in Anchorage, Alaska, where HDD happens to be 11,000 degree days. OK? Now, we have to calculate here heat loss through windows, through walls, and through roof to calculate the total heat loss from the house, the same way that we have done before. Heat loss through windows, we need the area of the windows first. So area of windows equal to each window is 4 feet by 6 feet. So this is 24 square feet. So we have six of them. So the total area is 144 square feet. So heat loss equal to 144 feet square times HDD's 11,000 degree days times 24 hours in a day and divided by r value. r value happens to be 1. So 1 feet square degrees Fahrenheit hour over BTU. So if we cancel out some of these, we will get BTU's heat loss. This is in a year, OK? So we would get this one to be approximately 38 million, 38 million 16,000 BTUs. This is per season or per year, OK? Now, second thing that we have to do is walls. Here, we have to calculate the area and also the r value. r value, because it is a composite wall consisting of four layers. It has wood siding, which has an r value of 0.81 and 2 inches of polyurethane. And 2 times 6.25, so that is 12.5 r value. And we have a third layer of four inches of fiberglass. Four inches times 3.7. That's equal to 14.8. And then we also have half inch of drywall. And we know that the drywall r value is straight away point is 4.5. So now, the total r value of this wall happens to be 28.56, OK? Now, we have to calculate the area of the walls. Area of the walls, we can calculate. Let me draw a little picture here and show you if we have. So let's say this is the area. And we have, and this side is about 70. This side is 50. And we will have another 50 this side and another 70 this side. So total times this height is 8 feet. So the total area would be 2 times 120. 120 is 70 plus 50 times 2, because twice these values times 8 feet is the height. So we get about 1,920 feet squared. Of course, this also has some windows, about six windows, as we originally looked at. But at this point, we will take this as 1920 and subtracting windows from this. Windows is 144 feet squared. So 1,920 minus 144 would give us 17,76 feet squared, OK? So now, we have to calculate the area of. Now, if we calculate the area of 1776 feet squared times 11,000 times, this is degrees Fahrenheit days, times 24 hours per day divided by we have 28.56. So the heat loss in here comes out to be 16,416,806 BTUs per year. OK, now we have to calculate roof. Roof happens to be 1.1 times the area of the walls. Area of the walls was 1920 feet squared. Again, we have to take this without the windows. Actual area of the walls times 1.1, that happens to be 21,2112 feet squared. So heat loss, 2112 feet squared times 11,000 times 24 divided by R value of this is 30 degrees Fahrenheit feet squared hour over BTU. So this comes out to be 18,585,600 BTUs per year. So the total heat loss now would be addition of all these three together. So that is, first, we have how much? If we look at, we have 38,016,000. So 38,016,000 plus 16,416,806 plus 18,585,600. So that is equal to, so 73,019,000 BTUs. So that is the total heat loss from the house.