Ferroaluminophosphate (FAPO₄-5)/MgSO₄ composites were prepared as a series of new materials with low charging temperatures and improved volumetric heat storage capacities. A microporous zeolithic compound FAPO₄-5 was used as an adsorbent of water vapor and a matrix of MgSO₄ salt particles. Composites with various MgSO₄ contents (5-40 wt%) were then prepared using a wet impregnation method. The MgSO₄ salt particles were impregnated into the micropores and textural pores of FAPO₄-5 without the crystal structure of the host material, confirmed by XRD patterns. Although nitrogen adsorption isotherms of the composites showed approximately a half of FAPO₄-5 pore was blocked by MgSO₄, the water uptake of the composites reached the sum of those from FAPO₄-5 and MgSO₄. The dehydration temperature of MgSO₄ in the FAPO₄-5 matrix decreased with its decreasing content due to the easier dehydration of FAPO₄-5. The heat storage recovery of the 25 wt% loaded sample at 80°C was 85.5% while that of MgSO₄ was 52.2%. The swelling and agglomeration of the composites containing 25 wt% and less salt were suppressed by the micro and textural pores of FAPO₄-5. The composite at 25 wt% of MgSO₄ loading exhibited a total volumetric heat storage capacity of 174 kW h m⁻³ based on the volume in the hydrated state.