I'm not sure this is helpful as I'm not familiar with that particular device. But in general, anything that helps remind a homeowner to change the filter in a meaningfull way would be good. We all tend to forget the maintenance required for the things we own inluding our bodies.
Some Thermostat systems have such a device built in such as the Honeywell Perfect Climate control system.
How that unit works is it keeps track of the actual time the blower is on and therefore the filter is used.
This is in contrast to the time honored tradition of marking the date of a filter change on the furnace and changing it at a certain time interval. The problem with the traditional method is that it does not keep track of actual use and doesnt compensate for vactions or hot or cold spells.
The device appears to use pressure drop. Pressure drop could be another way, but though the concept is problaby the best engineering wise, there could be a number if areas where the detailed implementatin of the concept causes problems. My beleif is that a well desinged pressure drop system is expensive and may not get you much more than an "ON time" indicator.
How much is the unit?
I'd also want to understand the installation issues in
detail.
Maybe someone else is familiar with the details
[Edited by hoffa on 03-09-2005 at 01:22 PM]