Humidifier supplied by hot water

[David C. Mull, CMI]

During a recent inspection I found a whole house humidifier supply connected to the hot water. Is an acceptable method? Should consideration be given to the additional use of hot water and fuel cost associated with it?

[Paul Tos]

Concern would be for bacteria.

excerpt

http://www.safety-council.org/info/home/hotwater.html

Bacteria
In 2000, the Walkerton disaster had sent a wake-up call about the safety of Canada’s drinking water. While standards for domestic hot water must consider scald prevention, they must also address the broad spectrum of public health and safety issues. To minimize bacteria contamination, water must be stored at 60 C or higher.
For example, temperatures under 50 C may increase the risk of Legionnaires’ disease, a form of pneumonia, due to bacterial growth in the tank. That disease is caused by Legionella bacteria, which live in water. Temperature is a critical factor for Legionella to grow. The risk of colonization in hot water tanks is significant between 40 and 50 C.
Legionella bacteria most often enter the lungs due to aspiration. (Aspiration means choking such that secretions in the mouth bypass the choking reflexes and enter the lung.) Drinking contaminated water is not a major cause of Legionnaire’s disease.
The Centers for Disease Control and Prevention estimates 8,000 to 18,000 Americans contract the disease annually. Five to 30 percent of the cases are fatal. While Canada has no national statistics, Hydro-Québec says about 100 people a year are hospitalized in that province for pneumonia caused by contaminated residential water heaters

excerpt

http://customer.honeywell.com/WaterC...me/Problem.htm

How common is Legionella bacteria in my hot water tank?
“In Quebec, a study of 211 homes (178 electric water heaters, 33 oil or gas water heaters) found Legionella contamination in 40% of electric water heaters. No water heaters using fossil fuels were contaminated. The authors concluded that, because of design variables, use of an electric water heater was the most significant factor leading to Legionella contamination in hot water in the home.” (2

[Roy D. Cooke, Sr]

Good info thanks Paul.

Roy Cooke

[Roy D. Cooke, Sr]

Originally Posted by dmull1

During a recent inspection I found a whole house humidifier supply connected to the hot water. Is an acceptable method? Should consideration be given to the additional use of hot water and fuel cost associated with it?

I am not too concerned with the fuel cost . humidifiers do not do much in the summer so the heat only goes to the building .
I am not a lover of Humidifiers as they are a great place for bacteria to grow . Many of the tests I have seen recommend they be removed ,( and I agree ) ( I write them up as recommending removal and explain why ).
Most homes in our area do not need more moisture.
Roy Cooke

[mthomas2]

Honeywell says either hot or cold water can be used, see pp 2 here:

http://electronicaircleaners.com/dat...stallation.pdf

I don't have most of the references on this PC, but when I researched this a few years back I was surprised to discover that some manufactuers recommend attachment to the hot water line.

[phinsperger]

If it is not a flow though humidifier I would also not be very concerned. As Roy said the heat in the winter when the humidfier is on is simply deducted from the heat required fron the furnace. I would suspect this is very very small amount anyway.

If its a flow though design then I would change it to the cold supply for energy consevation reasons.

Using preheated water in a humidifier may reduce scaling to a small degree and thus reduce maintenance but I would not rely on it or tell the homeowner this as they may intrepret that too mean "maitenace free"