Numerical simulations were performed at Aberdeen University to evaluate and optimize the transient performance of a newly proposed hybrid solar housing development in Monymusk, Scotland. The development is for sheltered dwelling units built as row houses and embodying several unique features, including a traditional exterior that is indistinguishable from the local vernacular, a new solar roof collector system to provide both heating and ventilation, and the ability to automatically 'switch' between a range of heating and/or ventilation modes as required. An important outcome of this research is a new prototype solar roof collector system which mimics the external appearance and function of conventional roofing and serves as a solar energy conversion device. The thermal performance of two representative dwelling units, one facing N/S and the other facing E/W, was examined in accordance with architectural plans, expected occupancy and usage, and meterological conditions for the location. The results from a series of detailed transient simulations suggest that with careful construction, good thermal insulation, moderate thermal mass and properly controlled ventilation, the proposed roof collector system is able to meet the space and water heating requirements at this high latitude almost entirely, reducing the annual heating bill, with full price electricity, to less than £50 per dwelling unit at 1993 prices.