The water collected by a dehumidifier is often compared to distilled water, but they are not the same due to differences in their purification processes and resulting purity levels. Distilled water is created under controlled, sterile conditions, while dehumidifier water is merely condensed moisture collected from the air, which introduces various contaminants. Understanding this distinction is necessary for determining the safe and appropriate use of each water type.
Understanding Distilled Water
Distilled water is a highly purified form of water produced through vaporization and condensation. This method involves boiling water until it turns into steam, which leaves behind virtually all non-volatile impurities, such as minerals, salts, heavy metals, and most non-volatile organic compounds.
The steam is then collected and cooled, condensing back into liquid water. This process reliably removes over 99.9% of contaminants, resulting in water with extremely low Total Dissolved Solids (TDS). The high heat involved in boiling also sterilizes the water, eliminating bacteria, viruses, and other microorganisms. This combination of demineralization and sterilization establishes distilled water as the baseline for high-purity applications.
The Nature of Dehumidifier Condensate
A dehumidifier operates by drawing humid air over chilled coils, cooling the air below its dew point. This action causes water vapor to condense into liquid water, similar to condensation forming on a cold glass. The collected water, known as condensate, is initially pure because evaporation leaves minerals behind; however, it rapidly becomes contaminated during the collection process.
The primary source of contamination is the air itself, which contains various airborne particulates captured along with the moisture. These include dust, pollen, mold spores, and bacteria. Furthermore, the internal components of the machine are not sterile, and the standing water in the collection tank provides an ideal environment for microbial growth. Trace amounts of metals, such as copper, aluminum, or lead, can also leach into the water as the condensate flows over the dehumidifier’s metal cooling coils.
Purity Comparison and Safety Concerns
While both types of water are low in mineral content, the key difference lies in the presence of biological and chemical contaminants. Distilled water is demineralized and sterilized by the high-temperature process, while dehumidifier condensate is only demineralized and collected at room temperature, making it non-sterile. This results in a significant difference in biological purity, as the dehumidifier water can contain viable microorganisms.
The concentration of Total Dissolved Solids (TDS) in dehumidifier water is usually low, often below 20 parts per million (ppm), comparable to distilled water. However, the TDS measurement only accounts for dissolved inorganic substances, failing to register biological contaminants or trace metals leached from the machine. Using dehumidifier water for ingestion or in sensitive devices poses serious safety concerns because of these unmeasured contaminants. Ingestion risks introducing pathogens, and using the water in medical equipment like CPAP machines can aerosolize bacteria and mold spores, introducing them directly into the lungs.
Appropriate Applications for Each Water Type
The distinct purity profiles of the two water types dictate their appropriate uses. Distilled water is the standard choice for applications requiring both low mineral content and high biological purity. This includes use in CPAP machines, laboratory experiments, steam irons to prevent mineral buildup, and automotive batteries. Due to its controlled purity, it is the only safe option for mixing baby formula.
Dehumidifier condensate is suitable only for limited, non-sensitive applications where the presence of bacteria or trace metals is inconsequential. It can be safely used for non-potable purposes such as flushing toilets, mopping non-wooden floors, or washing outdoor tools. While it is low in minerals, it should never be used for drinking, cooking, or watering edible plants due to the risk of transferring contaminants.