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How It Works


Please read all instructions on the heat pack before use.


To activate heat pack:

  1. Flex metal disc back and forth inside heat pack to activate solution.
  2. Feel heat pack reach therapeutic temperature within 15 seconds.
  3. Apply heat pack on desired area. Use fabric pouch if provided to attach heat pack securely and target the heat therapy.

Top tips for activation:

Place on a flat surface or at least make sure there is liquid surrounding the metal disc.

  • Place two index fingers under the dome of the metal disc and press the top with your thumb to click it.
  • Don’t bend the disc – you are trying to click it inside-out, not snap it in half.
  • If nothing happens, try clicking the disk again!

To reset heat pack:

  1. Heat water until boiling in a pan or rice cooker.
  2. Place the heat pack in the Boiling Bag or on a cloth in the boiling water. Keep boiling until ALL CRYSTALS dissolve, around 5 minutes if the water is boiling hot and bubbling.
  3. Let the heat pack cool to room temperature before using. If it crystallises on cooling, then boil it again.

 If you are having difficulty resetting your heat pack, please have a look at our FAQ for more ideas there.

More Information about Kwikheat Warmers


How Heat Packs Generate Heat (quick version)

  • The liquid inside is a very concentrated salt solution
  • It’s safe to eat but doesn’t taste very nice
  • Tiny little crystals form in the holes in the metal disc
  • When you click the disc, these crystals are pushed into the liquid
  • The crystals make all the salt molecules in the liquid join together, releasing heat energy
  • Melting the crystals in boiling water turns them into liquid again and puts the energy back into the heatpack, ready for use

How Heat Packs Generate Heat (more sciencey version)

  • Water is a liquid above 0oC and becomes a solid (ice) below 0oC
  • The salt solution used in heat packs is a liquid above 54oC and crystalises to become a solid below 54oC
  • However, the solution is very stable as a liquid and can be ‘supercooled’ easily as a liquid so that it remains a liquid at room temperature (around 25oC), just like in a Kwikheat Warmer ready to be used
  • Tiny crystals of solid salt form in microscopic cracks on the surface of the metal disc inside the heat pack
  • When the disk is flexed these crystals are pushed out into the liquid
  • The crystals act as ‘nucleation centres’, causing all the surrounding salt molecules in liquid form to join the crystal lattice until everything has solidified
  • The process of crystalisation releases heat, raising the temperature of the salt to 54oC a.k.a its boiling point
  • Placing the heat pack in boiling water melts the salt crystals into liquid form again – as long as all the crystals have dissolved, the liquid will be stable again