As with any home maintenance work, especially when dealing with appliances, there are safety concerns to consider. When cleaning a furnace, there are a few things you should pay particular attention to.
First, you should always turn the power off before you begin cleaning the furnace -- before you even touch the furnace to open the front panel. Though you won't actually be altering any of the electrical wiring, you are still dealing with the internal workings of your furnace, which may entail having to move some of the wiring to get to your filter [source: Standley].
When you are cleaning the filter (or wiping down any other part of the furnace), be sure not to drip water everywhere. Furthermore, if you choose to rinse down your filter, make certain it is completely dry before reinstalling -- water and electricity don't mix.
When vacuuming or washing the filter, you will most likely encounter a lot of dirt, dust and grime. So, you might want to consider wearing a dust mask.
Lastly, always take care to return everything to its proper place. Make sure you reinstall everything properly, leaving the correct amount of space between the filter, vents or any other equipment within the furnace [source: Hayner]. An improperly configured furnace won't work right, and the consequences can be bad.
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