Pushed by digital systems development and the pressure to reduce costs, in the last 40 years health monitoring (Hm) capabilities evolved from simple Built In Tests to system health prognostics, causing the development of new maintenance and operation concepts and new business models. Hm functions allow business growth by maximizing availability, optimizing the logistics, improving productivity and reducing maintenance costs and nowadays they have assumed a central role in aviation business. This role has to be captured by Hm system providers in order to fully exploit the opportunities provided by the market. To define Hm requirements is a very complex task as it necessitates considering many complex interrelated aspects such as costs reduction, concept of operations and business models. Nevertheless very little guidance exists about Hm requirements capture and this gap represents one of the main blockers to the diffusion of Hm systems. This work will then try defining a structured way to produce good Hm high level requirements. House of Quality (HoQ) has been identified as a structured but flexible methodology, which allows taking into account all the complexity of Hm and integrating business, maintenance and operational aspects. The research guideline for the design of the Hm HoQ matrices is based on the understanding of the economic value created by Hm and on the results of the total life asset cost analysis. The use of the proposed method has been demonstrated and validated through case studies where the high level Hm requirements for a metering valve and a landing gear monitoring system have been investigated. The results obtained in this phase proved that the methodology is credible as it confirmed some of the conclusions previously obtained by using traditional approaches; in addition to this new aspects are brought into consideration, making the requirements definition process more complete.