Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
călĕfactĭo, ōnis, f. [calefacio], a warming, heating (post-Aug.): balnei publici, Dig. 50, 4, 18, § 4.
In plur.: calefactiones thermarum, Dig. 50, 4, 1, § 2.