The use of latent heat to greenhouse heating in winter days is an important issue. The storage of the excess heat in greenhouses for sunny days in cold season is necessary with the increasingly up of the fossil fuel cost. In this research, we used two identical greenhouses. One, uses a latent heat system for heating, constructed and installed in the CRTEn (Research and Technologies Centre of Energy) in Tunisia. This heating system consists of a new solar air heater collector using a packed bed of spherical capsules with phase change materials. The solar air heater was inserted inside a greenhouse planted with tomato plants and operated during the winter season. The nighttime recovered heat of this system attained 30% of the total requirements of heating. (C) 2013 Elsevier Ltd. All rights reserved.