The answer is that both metrics may tell you something, but neither will give you the whole picture and they are both much less meaningful for short term holds because they can return astronomical and radically different numbers the shorter the term is. The IRR and NPV both tell you something about the value of the investment over time. The npv is the difference between the amount you would be willing to pay today vs the amount you come to based on the anticipated future cash flows discounted back at a certain discount rate, and the IRR is the derived discount rate that you would put in the present value formula so that when you discount the future cash flow it would equal your purchase price.
Michael has great videos on both below
If this project is less than a year, it would be better to focus on the equity multiple and think more about the risk for either return on capital.
Having said that, all of our models provide IRR calculations as well as equity multiple calculations, but very few have npv.
Below are some of our single-family home models to check out: