The present invention relates to a microcapsular powder having a latent heat storage material as a capsule core and a capsule wall constructed of from 10% to 100% by weight of one or more C.sub.1-C.sub.24-alkyl esters of acrylic and/or methacrylic acid (monomers I), from 0% to 80% by weight of a water-insoluble or substantially water-insoluble bi- or polyfunctional monomer (monomers II), and from 0% to 90% by weight of other monomers (monomer III) all based on the total weight of the monomers, having an average particle size in the range of 150-400 .mu.m and having 80% by weight of particles .gtoreq.90 .mu.m in diameter, to a process for its production and to its use in bindered building materials, textiles and dumped beds.