Editing Humidifier (section)

===Humidification calculation===
[[File:Ceiling vent.jpg|thumb|Ventilation determines most of the [[air changes per hour]] in a space without windows.]]

: Humidity per hour: X = ''[[Air changes per hour]] (ACPH) * M³ * [[density of air]] * humidity ratio''
:: Humidity per day: X * 24

* The [[air changes per hour]] (ACPH) ranges wildly based on:
** [[Ventilation (architecture)|Ventilation]]: Values may be obtained from the HVAC maintainer that routinely (typically every third year or so) tests the ventilation of the residence.
** Insulation leakage: Measured with a [[Blower door#Airflow at a specified building pressure|standard blower door test]].
* Cubic meters: The volume of the room, excluding the [[bathroom]] that should be kept closed since it ventilates humidity.
* [[Density of air]]: Typically 1.2 for dry air.
* Humidity
** Current relative humidity: 20%
** Humidity needed to reach 55%: 35%
*** Humidity ratio for 35%: 0.0051

For example, a typical modern apartment of {{convert|50|m2|sqft|abbr=on}} with closed windows (wood isolation) may consume {{convert|36.72|L/d|U.S.gal/d|abbr=off}} to raise the relative humidity from 20% to 55%: 24 * 1,53 L/h (2*1×125×1.2×0.0051):
* Air changes per hour
** Ventilation: 2
** Insulation leakage: 1 (a few windows)
* Cubic meters: 125 m<sup>3</sup> (50 m<sup>2</sup> * 2.5 m height)
* [[Density of air]]: Typically 1.2 for dry air.
* Humidity
** Current relative humidity: 20%
** Humidity needed to reach 55%: 35%
*** Humidity ratio for 35%: 0.0051