Ms$.$ Hugger, after taking the EGEE $102$ class, added more insulation to her attic $(500$ sq$.$ ft$)$ at the cost of $1,236$ dollars. After the addition, she noticed that her heat loss from the entire house went down from $43$ million BTUs to $27$ million BTUs. She heats her home with natural gas at a cost of $$14\mathrm{.}4$ per MCF$.$ What is her pay back period? Answer to two decimal places without a unit. Remember that payback period is the time it takes to recover the extra cost of insulation through savings because of that extra insulation.