The purpose of this paper is to present a methodology for the design and predictive control of thermal zones with bifacial semi-transparent photovoltaic (STPV) windows, motorized venetian blinds (MVB), and hydronic radiant floor heating (HRFH). Solar gains and daylight are controlled by the blind tilt angle, ß, of the motorized venetian blinds, for passive heating and natural daylighting in the zone. Near-optimal temperature setpoint strategies control the room temperature with hydronic radiant floor heating, which promotes preheating overnight, before the morning peak demand period of the grid in Quebec (6-9 AM), and in the afternoon, before the evening peak period of 4-8 PM. We can increase the energy flexibility in the building electricity demand profile with a predictive control model of window and blind transmittance and zone setpoint profile, based on a one-day ahead prediction for different design days in the heating season. An explicit finite difference thermal network model is used to predict heating loads and the building temperature profile associated with the thermal response of the zone. The energy flexibility in the demand profile is quantified by a building energy flexibility index (BEFI) [2]. The concrete slab thickness of the hydronic heating system will be analyzed parametrically to further improve the energy flexibility and efficiency of the thermal zone. Four different slab thicknesses of concrete are considered, including 5, 8, 10, and 12 cm (1.97, 3.15, 3.94, 4.72 in), while three different window-to-wall ratios (%) are considered. A 10 cm (3.94 in) thick slab and 32% WWR produces a BEFI = 100% for both morning and peak periods, for a cold and clear February day, in Montreal; completely displacing the heating demand for the peak periods. There are several pre-determined design variables for this zone, including the building orientation and the coverage ratio of the STPV (%). Simulations are based on a typical zone at a test facility on Concordia’s Loyola campus, which will be validated experimentally in the future.