Implied warranties are promises or guarantees implicitly made by a seller of goods or services—even when they are not included in a contract for the goods or services. Such promises are sometimes said to be "made by operation of law."

For example, the implied warranty of habitability in residential construction focuses on the state of the completed structure. In contrast, the implied warranty of good workmanship in residential construction focuses on the builder’s conduct. These two implied warranties parallel one another, and they may overlap.

For example, a builder’s inferior workmanship could compromise the structure and cause the home to be unsafe. But a builder’s failure to perform good workmanship is actionable even when the outcome does not impair habitability. Similarly, a home could be well-constructed and yet unfit for human habitation if, for example, a builder constructed a home with good workmanship, but on a toxic waste site.

Thus, the implied warranty of habitability is more limited in scope, and protects the purchaser only from those defects that undermine the very basis of the bargain. It requires the builder to provide a house that is safe, sanitary, and otherwise fit for human habitation. In other words, this implied warranty only protects purchasers from conditions that are so defective that the property is unsuitable for its intended use as a home.

As compared to the warranty of good workmanship, the warranty of habitability represents a form of strict liability, because the adequacy of the completed structure governs liability—not the manner of performance by the builder.

The warranty of habitability generally may not be disclaimed. And the warranty of habitability extends only to latent defects—it does not include defects that are known by or expressly disclosed to the buyer—even if they are substantial.

Laws regarding the implied warranty of habitability vary from state to state and are often located in a state's statutes.

In Pennsylvania (PA), the implied warranty of habitability is a legal doctrine that ensures a new home is safe, sanitary, and fit for human habitation. This warranty is automatically included in the sale of a new home and cannot typically be disclaimed by the builder. It protects the purchaser from latent defects that make the property unsuitable for living, but it does not cover defects that are known to or expressly disclosed to the buyer. The warranty of habitability is a form of strict liability, focusing on the condition of the completed structure rather than the builder's construction process. On the other hand, the implied warranty of good workmanship requires builders to perform their work in a skillful manner. This warranty is actionable even if the poor workmanship does not affect the home's habitability. Both warranties may overlap, as poor workmanship could lead to a breach of the warranty of habitability if it results in the home being unsafe or unsanitary. Pennsylvania's laws on these warranties are derived from state statutes and case law, and they provide important protections for homebuyers against construction defects.