Ferroelectric nanopowders of 10% KF-doped BaTiO3, which show very large dielectric constant at room temperature, were synthesized by a sol-gel method. We embedded the powder into PNIPAm hydrogels, which have a discontinuous volumetric phase transition at TC～34℃. The dielectric constant of the gels in water was measured at 40 MHz in a temperature range between 23 and 43℃. The gel shows a dielectric anomaly at TC and the gel,s dielectric constant increases up to 28% after the post-embedment, in comparison with that of the distilled water. The results indicate that the nanopowders are useful for heating the gel using radio frequency radiation.