posted on
December 09, 2009 at 02:01AM
I've owned several over the years from different manufacturers and I've used them in vastly different operating environments ranging from damp basements where they run continuously to relatively dry spaces where they hardly turn on. I mention the different operating environments because in my experience, this has a lot to do with both the longevity and the preventative maintenance requirements.
Like any other mechanical device, dehumidifiers have an expected service life for their various components, and from an engineering standpoint, this is normally based upon a projected duty cycle (how often it's switched on versus how often it's switched off). In an "average" home--if there is such a thing--a dehumidifier will be on only part of the time and usually not year round, but if your specific environment requires more frequent operation, your product simply will not last as long as one that's placed elsewhere.
Complicating matters even more is the fact that humidity is already affected somewhat by the specific temperature settings of your home's thermostat, since air is capable of picking up more moisture as its temperature increases. Adding yet another variable is the outdoor air temperature, since the difference between indoor and outdoor temperature governs the duty cycle of your HVAC system, which can alter the level of humidity coming out of that system with some HVAC designs.
In essence, two dehumidifiers built to the exact same engineering standards but installed in different locations can have vastly different life expectancies based upon factors that may not be within the control of the operator. And, just like someone who is opening the fridge every five minutes (and causing the compressor to constantly kick in), frequent operation of a dehumidifier will make it wear out more quickly.
One thing that IS within your control is keeping the unit clean, since the efficiency of removing water from the air is directly proportional to how close the cooling coil surface temperature is to the air's dew point for that location. The dew point is dependent upon the room's temperature, but in general, the colder the coils get (and therefore the greater temperature difference between the coils and the ambient air), the more condensation will form on the coils. Dirt and dust on the coils acts as insulation and prevents the proper exchange of heat. This means that with lower efficiency, the dehumidifier will have to run longer to achieve the same humidity level, causing premature wear. Additionally, the excess heat COULD degrade other components such as rotating parts and electrical assemblies, resulting in their eventual failure. This is not so different from running a car with a broken cooling fan or water pump---the heat has to go somewhere or something will break.
The periodicity associated with cleaning the coils is dependent upon the environment---if your home is closed relatively tight with little traffic in and out, and if you have good HVAC filtration that keeps dust down, you may not have to do it very frequently. On the other hand, if you've got kids or pets coming in and out all day dragging in dust and dirt, you might have to do this more frequently.
In regard to manufacturers' recommended maintanence---I'm assuming this is brand and model specific, though having owned different types I can state that they're all pretty similar in basic design. I have no connections with Sears whatsoever other than as an occasional shopper, but I believe their dehumidifiers are as good as anything else out there. Just like any other brand there will occasionally be items that fail prematurely, but this is a product that's difficult to assign a projected lifespan to. My mother still has one that she's had since I was a little kid (and I'm 35 now), and I've had one fail after three years of heavy use. Just like a car, it's all about how you "drive" it.