Furnace Filter Whistle

I like the idea of this product, but don't see how it can work with the design of my air filters. I have several cats, and am never sure when is the right time to change my furnace air filter. So, I ordered this product, thinking it would give me a better idea of when to do that. The filter I currently have installed, and a couple of others I have on reserve, all have wire honeycombed throughout the filter, and I cannot attach the whistle. I don't buy the cheapest filters, more like the mid-range-priced ones, so maybe the cheaper ones don't have the wire in them and so would allow me to attach the Air Filter Furnace Whistle. I'll report back after I have checked out other kinds of filters.

I stopped using it as it may come apart and fall inside of my air handler.It seems not to snap or lock enough for me.The sound was not loud enough for me.

My furnace filters have a sort of chicken-wire mesh built into them. I suppose I could have snipped that with a wire cutter and then pushed this through, but I thought meh, why bother. They should make the part that pushes through the filter only as big as is needed to let the whistle work.

I guess it might be fine under some circumstances, but i didnt hear it whistle for many months and when i finally gave up on it and changed the filter it was FILTHY. Cant depend on it.

Bought three and have given two away. No whistling yet but all were put into new filters. Product came quickly and was recommended in utility saving brochure. We'll see.

I installed this as per the instructions, and waited for over two months. No whistle. I inspected the filter, found it very dirty, and concluded this item doesn't work -- at least, if it does, it should have worked a lot sooner! Also, what if the darn thing goes off in the night??

This item was too small to fit my filter so I passed it on to a friend and he seems to be quite happy with it.

i put it on my filter and it never did anything. possible i installed it wrong