A survey has been conducted as part of the European project SOLABS (unglazed coloured solar absorbers for building facades) to provide the design team with a set of formal design guidelines. Targeted mainly at European architects of the three climatic regions but also at engineers, façade manufacturers and building owners, the questionnaire was structured into three parts. First, the architectural integration quality of ten existing installations was rated by the respondents, to help understand their preferences and associated rationale. From these results, basic solar integration guidelines are derived and proposed. Then the formal aspects characterizing unglazed collector design were defined, and the possible options for their further development proposed to be appreciated. This covers issues from shape, size and jointing mode through colour and finishing. Variations between respondents are described and explanations proposed. Finally the questionnaire seeks to evaluate the general approach taken by architects to implement solar installation within façades, in particular whether they should be emphasised or not.