Hand warmers are used in cold environmental conditions to warm hands. Disposable air ac-tivated hand warmers and reusable hand warmers which generate heat by crystallization are present in the market. In the present study utilizing heat of wetting of silica gel and zeolites in warming hands was tested in a system simulated to warm hands by inserting warmer packages in knitted wool gloves. Sodium acetate solution was also tested as a reusable hand warmer by melting and recrystallization. While the commercial warmers released heat slowly for long period, dry silica gel and dry zeolite 4A released heat fast. Around 25% water and inert dilu-tion materials should be used to limit the temperature rise in silica gel and zeolite 4A within reasonable limits.