8 Saved Help Save & Exit Subm Check my work If you insulate your office for $18,000, you will save $1,800 a year in heating expenses. These savings will last forever a. what is the NPV of the investment when the cost of capital is 4%? 10%? Cost of Capital 4% 10% NPV b. What is the IRR of the investment? (Enter your answer as a whole percent.) ces IRR c. What is the payback period on this investment? Payback period years