I heard that there are heat pumps in Germany that have the ability to add moisture to dry indoor air in winter. In Northern climates interior air tends to be far too dry, uncomfortable for skin etc. Has anybody heard of any Heat Pump makes and models that have that function? Thanks!

  • 2
    Add-on humidifiers have been an option for most heating devices for a long time.
    – crip659
    May 17 at 19:53
  • Heat Pump is very brought therm. It mostly describes HVAC compressor running in reverse mode to heat the home in winter.. That is a close high pressure loop, with not water involved. A air humidifier uses heat to evaporate water.
    – asinine
    May 17 at 21:13
  • 1
    That's true for air in every country, because of the way humidity works. Colder air is physically incapable of holding as much water as warmer air. That makes humidity complicated, and is why we state humidity in %age rather than as milligrams/litre (which would be an absolute measurement). Air with 5 mg/l of water in it is 100% RH at 32F, but only 30% RH at 68F. That's true in Germany and here. It sounds like you are noting differences in products. May 17 at 21:25
  • 1
    @Ruskes The humidifier I have is just a tank holding water, a net like rotating cloth, and a fan. No heat required.
    – crip659
    May 17 at 21:37

2 Answers 2


I think you're mistaken. A heat pump can't add water to the air. Probably someone described their HVAC system that includes a humidifier as a heat pump, not knowing any better.

  • I recall in that conversation that the heat pump in question had a water tray that needed to be filled up once in a while.
    – absonoklue
    May 17 at 20:07
  • @absonoklue That is the complete explanation of what a humidifier is. Air is blown over water. Most of the rest is just icing on a cake.
    – crip659
    May 17 at 20:24
  • I wish I could recall who I spoke with, but they described it as a heat pump with "Feuchtigkeits Anpassung", which translates somewhat as "humidity adaptation"
    – absonoklue
    May 17 at 21:29
  • There ARE heat-pump retrofits to "traditional" forced-air HVAC systems. Those might include humidifiers.
    – keshlam
    May 17 at 21:59
  • you can also use an ERV instead of an HRV. May 18 at 0:45

A heat pump itself can't humidify the air, just as a gas or oil fired furnace cannot humidify the air. But a humidifier can be added to any of these systems, and if the manufacturer provides it with the system it might be marketed as a "heat pump that adds moisture to the air". Any good HVAC contractor should be able to help you, or just google "whole house humidifier" to see what's available.

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