Before we get into why you’d want to own a duplex as part of your investment portfolio, you have to know what a duplex is. Simply put, a duplex is a property that has two units either side-by-side or on top of one another with two separate entrances. This means that when you build a duplex, you build two individual properties set for two separate families to live in. Building a duplex is one investment strategy that has proven time and time again to be one of the most rewarding real estate investment strategies available. This is especially true for first-time real estate investors to get ahead with instant equity and even for experienced investors looking to add and grow their property portfolio.