This investigation deals with the thermal performance of two passive solar components. An attached sunspace with horizontal heat storage and another one with vertical thermal storage were designed in order to optimize the use of solar gain, its storage and distribution in an industrialized component. These sunspaces have been tested under real conditions, comparing their thermal performance with two commonly used components in residential buildings in Spain: a window and a double window making up an attached sunspace. Different series of experimental measurements were made in two test-cells exposed to outdoor conditions in Pamplona (Northern Spain). As a result, nine scenarios during winter 2011 and six ones during summer 2012 have been carried out, comparing all the prototypes two by two with different use modes. Resu**lts show that a sunspace with heat storage takes advantage of the solar energy and improves the indoor thermal performance of the adjacent room during winter in a better way than a window or a simple sunspace, and that it has also a better performance in summer. The best results in winter and summer were obtained when an appropriate use of the component is performed, in concordance with outdoor conditions; some thermal control actions for the good performance of these components are suggested. (C) 2014 Elsevier B.V. All rights reserved.