Abstract: A clean air filter may be used to set an air filter change threshold value for an air filter monitor installed in an HVAC system. The air filter change threshold value may be used to determine a status of an air filter (e.g., clean or dirty).

Abstract: An air filter assembly has a fan, pre-filter, a main filter, and a control circuit which generates various signals to the user as to when the pre-filter and the main filter should be replaced. The control circuit detects when the pre-filter should be replaced from two conditions: a first pre-filter replacement condition based decreased air flow, and a second pre-filter replacement condition based on cumulative operating time. The control circuit detects when the main filter should be replaced based on a formula containing a number of the occurrences of the first pre-filter replacement condition and a number of occurrences of the second pre-filter replacement condition. The control circuit also detects a main filter replacement condition based on cumulative operating time of main filter. The main filter can have a fuse that is blown when the main filter should be replaced.

Abstract: A system for a vehicle includes a regeneration module and a disconnection indication module. The regeneration module indicates when a regeneration of a particulate filter is complete. The disconnection indication module receives a pressure difference across the particulate filter measured using delta pressure sensor. The delta pressure sensor generates the pressure difference based on first and second pressures upstream and downstream of the particulate filter applied to the delta pressure sensor using upstream and downstream pressure lines, respectively. In response to an indication that the regeneration of the particulate filter is complete, the disconnection indication module selectively indicates that the downstream pressure line is disconnected based on a comparison of the pressure difference and a predetermined pressure.

Abstract: A method for purifying polluted air having particle phase pollutants and gaseous phase pollutants is provided. The method comprising: separately purifying and treating particle phase and gaseous phase pollutants present in the air; providing a dust cleaning apparatus, a catalytic filter core and a valve for controlling an airflow path within an air purification apparatus; controlling the airflow path for the air to bypass the catalytic filter core in a way that: if the amount of particle phase pollutants is above a predetermined value, the valve is moved to the open position to enable the air to bypass the catalyst filtering core; if the amount of particle phase pollutants is less than a predetermined value, the valve is moved to the closed position to force the air to pass through the catalyst filtering core.

Abstract: An air elutriation device for an air conveying household appliance includes a housing with an air elutriation zone delimited by a filter element, a detection element in a storage space for the filter element, and a cover sheet on the filter element. The detection element can be actuated via the filter element by the cover sheet.

Abstract: An HVAC system has an electrically powered air cleaner, a fan configured to selectively move air through the air cleaner, and a controller having an interface for receiving a selection of a clean air cycle. The controller is configured to control a clean air delivery rate (CADR) of the HVAC system for a clean air cycle duration in response to a receipt of a selection of the clean air cycle. A method of controlling air cleaning includes displaying a first clean air cycle that is configured to control a clean air delivery rate for a first clean air cycle duration wherein the first clean air cycle is associated with a first air flow related setting and a first air cleaner power level setting, selecting the first clean air cycle, and overriding at least one of a previous air flow related setting and a previous air cleaner power level setting.

Abstract: A method and a system for controlling dust particle emissions from an electrostatic precipitator (1), which has a first and a second bus-section (16, 20), are provided. Dust particle emissions are controlled by observing that a rapping event of the first bus-section (16) is about to be initiated, verifying, before allowing the rapping event of the first bus-section (16) to be initiated, that the second bus-section (20) is ready to receive the dust particles to be released during the rapping event of the first bus-section (16), and then initiating, after verification, the rapping event of the first bus-section (16).

Abstract: A self-alarming air cleaner is disclosed. The air cleaner includes an air filter element (1), a light emitting element (2) and a light sensor (3). The light emitting element (2) and the light sensor (3) are both faced to the air filter element (1). The light emitted from the light emitting element (2) is reflected by the air filter element (1) or permeated to the air filter element (1), then forms an area of light attenuation where the light sensor (3) is located. The light emitting element (2) and the light sensor (3) connect with a circuit which has an alarming device. When much dust is accumulated on the air filter element (1), the intensity of the light reaching the light sensor (3) is weakened and the alarming device (4) can give an alarm automatically.

Abstract: A powered air cleaning system has a flow path extending through the system from an inlet to an outlet. A motor-driven fan is located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow. An ejector port ejects particulate debris laden air from the stratified rotating flow in the system. At least one de-swirl component located within the rotating flow aerodynamically redirects clean air from the innermost orbits of the stratified rotating flow toward the outlet to provide a positive airflow pressure out of the outlet. The system has a variable speed fan motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system. The controller receives a signal that is a function of airflow requirements of a device supplied with clean air by the system.

Abstract: A method for purifying polluted air having particle phase pollutants and gaseous phase pollutants is provided. The method comprising: separately purifying and treating particle phase and gaseous phase pollutants present in the air; providing a dust cleaning apparatus, a catalytic filter core and a valve for controlling an airflow path within an air purification apparatus; controlling the airflow path for the air to bypass the catalytic filter core in a way that: if the amount of particle phase pollutants is above a predetermined value, the valve is moved to the open position to enable the air to bypass the catalyst filtering core; if the amount of particle phase pollutants is less than a predetermined value, the valve is moved to the closed position to force the air to pass through the catalyst filtering core.

Abstract: A filter system for an explosion-proof enclosure is described herein. The filter system can include a pre-filter assembly located outside the explosion-proof enclosure. The pre-filter assembly can include a pre-filter material configured to control air passing therethrough. The filter system can also include a filter assembly coupled to the pre-filter assembly. The filter assembly can further control the air received from the pre-filter assembly and passing therethrough into the explosion-proof enclosure.

Abstract: A system and a method are disclosed for changing a filter provided in an air purifier at an optimum time by measuring the rotational speed of a motor that operates the filter. The system for determining an air purifier filter change time includes: a motor speed measurement unit; a time counting unit; a speed determination unit; a time comparison unit; and a filter change time determination unit.

Abstract: An air sanitization system including a reactive oxygen species generator, a variable speed fan, a pathogen sensor and a controller. The reactive oxygen species generator generates reactive oxygen species from an oxygen-containing gas and discharges the reactive oxygen species to a conditioned space. The variable speed fan directs the oxygen-containing gas to the reactive oxygen species generator at a controlled speed. The pathogen sensor senses a level of airborne pathogens in the conditioned space and generates a signal indicative of the level of pathogens sensed. The controller receives the signal from the pathogen sensor and varies the speed of the variable speed fan in response to the signal to decrease a speed of the variable speed fan in response to an increase in the level of airborne pathogens sensed by the pathogen sensor.

Abstract: Herein are disclosed devices and methods that can be used to provide an indication of the need to change a filter in a small forced air handling unit, based on the actual operating time (runtime) of the unit. The methods rely on the use of at least one vibration sensor that is placed in contact with a surface of an exterior component of the air handling unit and that can determine whether the unit is operating by sensing vibrations of the surface caused by operation of the unit.

Abstract: An inline water trap including a filter component and a panel connector configured to interface with a patient gas monitor. In one embodiment the inline water trap indicates to the patient gas monitor that it is in place and that the patient gas monitor may begin intaking and analyzing the filtered patient sample. The inline water trap receives a patient sample and filters water and contaminants from the sample before allowing the remaining gas portion of the sample to pass through to the patient gas monitor, thereby protecting the patient gas monitor from damage. One embodiment of the inline water trap additionally contains an RFID tag to indicate to the patient gas monitor that the correct type of inline water trap is engaged.

Abstract: An indicator device for a filter includes a filter replacement indicator that is actuatable by thermal expansion. The indicator device can be included in a filter. Also, a vacuum cleaner including a filter having the indicator device.

Abstract: The invention is directed to a device that removes humidity/moisture from a container or enclosed area. The device includes a plastic housing having a cavity chamber. A silica desiccant is in the cavity chamber. A color indicator indicates if the silica desiccant is active. A polyester screen/filter is heat welded to the raised circles on the bottom inside of the cavity chamber of the plastic housing. The polyester screen/filter ensures that the silica desiccant stays inside the housing even when the device is reactivated in a microwave or oven. A cover with a number of holes may be placed over the screen/filter and the screen/filter may be welded to the cover. The cover and housing may be made out of food safe polypropylene.

Abstract: An apparatus (10) for purifying polluted air consisting of particle phase pollutants and gaseous phase pollutants, the apparatus (10) comprising: a dust level sensor (23) to measure the amount of particle phase pollutants in the polluted air; a dust removal component (14) to remove the particle phase pollutants from the polluted air; a catalyst filtering core (17) to decompose the gaseous phase pollutants by chemical reaction; a valve (22) for selectively controlling a path of air flow within the apparatus (10) and is movable between an open position and closed position, the valve (22) being positioned downstream from the dust removal component (14); wherein if the amount of particle phase pollutants measured by the dust level sensor (23) is above a predetermined value, the valve (22) is moved to the open position to enable the air to bypass the catalyst filtering core (17); and if the amount of particle phase pollutants measured by the dust level sensor (23) is less than a predetermined value, the valve (22)

Abstract: A powered air cleaning system has a flow path extending through the system from an inlet to an outlet. A motor-driven fan is located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow. An ejector port ejects particulate debris laden air from the stratified rotating flow in the system. At least one de-swirl component located within the rotating flow aerodynamically redirects clean air from the innermost orbits of the stratified rotating flow toward the outlet to provide a positive airflow pressure out of the outlet. The system has a variable speed fan motor and an integrated controller for adjusting the speed of the motor and thereby the flow rate of clean air through the outlet of the system. The controller receives a signal that is a function of airflow requirements of a device supplied with clean air by the system.

Abstract: An air filter assembly has a fan, pre-filter, a main filter, and a control circuit which generates various signals to the user as to when the pre-filter and the main filter should be replaced. The control circuit detects when the pre-filter should be replaced from two conditions: a first pre-filter replacement condition based decreased air flow, and a second pre-filter replacement condition based on cumulative operating time. The control circuit detects when the main filter should be replaced based on a formula containing a number of the occurrences of the first pre-filter replacement condition and a number of occurrences of the second pre-filter replacement condition. The control circuit also detects a main filter replacement condition based on cumulative operating time of main filter. The main filter can have a fuse that is blown when the main filter should be replaced.

Abstract: Methods, systems, and products for monitoring an air filter. Methods involve determining a difference between a baseline pressure differential and a current pressure differential, the differential pressure between pressure at an upstream side of the filter and pressure at a downstream side of the filter. The baseline pressure differential may be set automatically or by a user. Reaching or exceeding a predetermined threshold triggers an indication of a clogged condition. The method also includes monitoring the air filter condition intermittently. The filter monitor may operate for extended periods in a sleep state and intermittently power up to a wake state to measure the current pressure differential and compare the current pressure differential with a baseline pressure differential.

Abstract: A particle trap for a remote plasma source includes a body structure having an inlet for coupling to a chamber of a remote plasma source and an outlet for coupling to a process chamber inlet. The particle trap for a remote plasma source also includes a gas channel formed in the body structure and in fluid communication with the body structure inlet and the body structure outlet. The gas channel can define a path through the body structure that causes particles in a gas passing from a first portion of the channel to strike a wall that defines a second portion of the gas channel at an angle relative to a surface of the wall. A coolant member can be in thermal communication with the gas channel.

Abstract: A vacuum clean-out system including a separator chamber and associated collection chamber for removing liquid material and debris from a vacuum output and providing a vacuum return line free of contaminants. A vacuum exhaust line is coupled to a cyclonic separator chamber that induces a circular rotation within the incoming vacuum stream, causing the liquid and debris to impinge the chamber's surfaces and fall to the bottom thereof while the “clean” vacuum is drawn upwards into a return line. The collection chamber is maintained at the same negative pressure as the separator chamber so that the accumulating liquid and debris easily drains into the collection chamber. A sensor associated with the collection chamber may be used to determine when the collection chamber is full and needs to be discharged. At that point, the separator chamber is isolated from the collection chamber, the collection chamber is vented and the accumulated material is discharged and/or analyzed.

Abstract: A method is provided for indicating the useful service life of a gas filtration and purification system comprising steps of embedding two or more mass-responsive electronic sensors (e.g., surface acoustic wave devices) in a sorbent bed of a filtration cartridge, wherein the mass-responsive electronic sensors are coated with a non-conductive absorptive organic polymer; passing a gas containing a volatile chemical of interest through the filtration cartridge and in contact with the two mass-responsive electronic sensors; and measuring a difference in an electronic property between the two mass-responsive electronic sensors. In such a manner, the two mass-responsive electronic sensors act as internal references with respect to each other, thereby eliminating variations in temperature, interferents, pressure, and the like.

Abstract: An instrument gas conditioning system is provided. The system includes filtering, and optionally drying, a gas stream to obtain a filtered, and optionally dried, gas stream. The filtered, and optionally dried, gas stream is heated in a heater and then regulated through a regulator. The filtered, heated, regulated, and, optionally dried, gas stream may be used as instrumentation gas.

Abstract: In one aspect of the invention a smart air filter monitoring system for a cabinet for electronic devices is provided that includes: an air filter positioned in an air flow so that substantially all the air flows through the filter, the air flow being defined by the cabinet; a light emitting device on a first side of the air filter; at least two light sensors mounted near the air filter, each light sensor directed to the air filter to receive light emitted from the light emitting device after the emitted light has passed through the air filter, the light sensors adapted to generate electrical signals from the emitted light striking the light sensor; an electrical circuit, the electrical circuit generating a signal for indicating that the filter needs to be serviced when the electrical circuit determines that electrical signals received from a combination of the sensors indicates that the filter needs to be serviced.

Abstract: Herein are disclosed devices and methods that can be used to provide an indication of the need to change a filter in a small forced air handling unit, based on the actual operating time (runtime) of the unit. The methods rely on the use of at least one vibration sensor that is placed in contact with a surface of an exterior component of the air handling unit and that can determine whether the unit is operating by sensing vibrations of the surface caused by operation of the unit.

Abstract: A gas chromatography inlet liner comprises a glass tube formed by a glass wall, the glass wall having pore channels formed therein, and an indicator present in the pore channels in at least part of the inlet liner. The indicator may be any element, compound, dopant, or mixture additive that modifies color or transparency of the inlet liner.

Abstract: A variable speed fan device includes a housing, a motor, a fan blade, a controller, and a first plurality of discrete light sources. The motor is maintained by the housing and the fan blade is connected to the motor. The controller is electronically coupled to the motor and manages an operational status of the variable speed fan device. The light sources are adapted to emit light from the display panel along a discontinuous perimeter at the exterior face. In an activated state, the light emitted by each light source is visually perceptible an exterior face of the display panel. The controller is programmed to individually activate and deactivate the light sources in a predetermined pattern creating a perception of movement of light about the discontinuous perimeter at the exterior face of the display panel corresponding with an operational status of the variable speed fan device.

Abstract: The invention relates to a filtration system and method for carrying out a process for the filtration of fluids, comprising at least one filtration device with at least one filtration element comprising readable data and a check and/or test apparatus to which the filtration device may be connected, by means of data and testing means lines. The check and/or testing device is connected to a process controller, by data exchange means, for regulation and control of the filtration process and the process controller is connected to a filtration databank, by means of data exchange means, which comprises data sets for at least one filter element and/or for each filtration device and/or for the filtration process. The invention further relates to a computer program product for carrying out a filtration process on fluids whereby program components may be called up from a program memory which support the carrying out of the filtration process.

Abstract: A method is provided for indicating the useful service life of a gas filtration and purification system comprising steps of embedding two or more mass-responsive electronic sensors (e.g., surface acoustic wave devices) in a sorbent bed of a filtration cartridge, wherein the mass-responsive electronic sensors are coated with a non-conductive absorptive organic polymer; passing a gas containing a volatile chemical of interest through the filtration cartridge and in contact with the two mass-responsive electronic sensors; and measuring a difference in an electronic property between the two mass-responsive electronic sensors. In such a manner, the two mass-responsive electronic sensors act as internal references with respect to each other, thereby eliminating variations in temperature, interferents, pressure, and the like.

Abstract: A thermal management system includes an airflow sensor that measures airflow in an air path inside an enclosure to be cooled, wherein the air path includes a filter and a fan. A controller is responsive to the airflow sensor for monitoring the rate of airflow inside the enclosure and determining the condition of the filter. In one embodiment, the airflow sensor is an active type sensor, such as a thermistor, disposed on circuit boards. In further embodiments, the airflow sensor is disposed proximate a tube through the filter.

Abstract: A control system and associated methods for an air treatment system. In one aspect, the present invention provides a control system and method for controlling blower speed as a function of separately determined smoke and dust concentrations. In one embodiment, the control system and method provides a variable delayed between changes in motor speed to address undesirable rapid changes between speeds. In another aspect, the present invention provides a system and method for calibrating a sensor to provide more uniform operation over time. In yet another aspect, the present invention provide a system and method for calibrating motor speed to provide more consistent and uniform motor speed over time. The present invention also provides a system and method for tracking filter life by as a function of time, motor speed and/or a sensed variable, such as particulate concentration in the environment.

Abstract: A particle trap for a remote plasma source includes a body structure having an inlet for coupling to a chamber of a remote plasma source and an outlet for coupling to a process chamber inlet. The particle trap for a remote plasma source also includes a gas channel formed in the body structure and in fluid communication with the body structure inlet and the body structure outlet. The gas channel can define a path through the body structure that causes particles in a gas passing from a first portion of the channel to strike a wall that defines a second portion of the gas channel at an angle relative to a surface of the wall. A coolant member can be in thermal communication with the gas channel.

Abstract: An air cleaner is provided according to an embodiment of the invention. The air cleaner includes a high voltage power supply configured to provide a high voltage to a collector cell and a shut-down circuit coupled to the high voltage power supply. The shut-down circuit is configured to monitor an electrical current supplied to the collector cell, remove electrical power to the collector cell if the electrical current exceeds a predetermined cell current threshold for a predetermined time period, and generate an indication if the electrical power is removed from the collector cell.

Abstract: The present invention relates to a method and a device for providing a zone (2) of clean air at an operation area (3) by means of an air treatment device (1) with a lighting device (25).

Abstract: An apparatus and method for testing the integrity of a filter under humid conditions is provided. The apparatus includes an injection assembly which is located on a first side of the filter and a detection assembly which is spaced from the injection assembly and located on a second side of the filter. The injection assembly injects a mixture of an air stream and a hydrophilic test chemical vapor of a known concentration through the filter. The injection assembly includes a sealed vaporizer which generates the mixture of the air stream and the hydrophilic test chemical vapor. The vaporizer includes a contact bed having an inert packing media for vaporizing the hydrophilic test chemical. The detection assembly detects a concentration peak of the hydrophilic test chemical vapor exiting the filter. The detection assembly includes a chemical sampling member, a chemical enriching member and a chemical detector.

Abstract: An air filter apparatus with a self-contained detachable programmable clogging indicator for use in forced air HVAC systems, air heaters, internal combustion engines, vacuum cleaners, medical devices, biomedical devices, inert atmosphere glove boxes, scientific equipment, etc. . . . and method of use is disclosed. The self contained detachable clogging indicator consists of downstream rotating vane anemometer to measure the air flowing through the filter as a means to accurately estimate the degree of filter clogging. A detachable user interface allows manipulation of the operating parameters and threshold limits and provides a means to alert the user of filter replacement. The filter media is inserted into the filter housing and may be a specialty or commercially available filter.

Abstract: Data of a barometric pressure that a barometric pressure sensor outputs, and data of an air volume that an air-volume sensor outputs are input into a system control circuit. The system control circuit is provided with a table storing portion. In the table storing portion, a control table is stored. The control table is formed of a plus supplied-voltage value to fan power set by a barometric pressure value and an air-volume value, and a warning instruction. In a case that the warning instruction is selected based on the barometric pressure value and the air-volume value, the system control circuit turns on a warning-use LED so as to inform a user that a filter is clogged.

Abstract: A method is provided for indicating the useful service life of a gas filtration and purification system comprising steps of embedding two or more mass-responsive electronic sensors (e.g., surface acoustic wave devices) in a sorbent bed of a filtration cartridge, wherein the mass-responsive electronic sensors are coated with a non-conductive absorptive organic polymer; passing a gas containing a volatile chemical of interest through the filtration cartridge and in contact with the two mass-responsive electronic sensors; and measuring a difference in an electronic property between the two mass-responsive electronic sensors. In such a manner, the two mass-responsive electronic sensors act as internal references with respect to each other, thereby eliminating variations in temperature, interferents, pressure, and the like.

Abstract: Provided is an air purifier, comprising: a body having an air inlet and an air outlet, a blower, an electric control box, an electrostatic absorption device and a carbon dioxide sensor. The air purifier effectively removes dust particles and bacteria in the air, measures and controls the carbon dioxide content in the air, displays the content of carbon dioxide to users and helps to protect human health.

Abstract: An air filter cartridge is mounted in an air purification device of a commercial vehicle. The air filter cartridge includes an identification device, the information of which can be recorded by a recording device. The method detects the characteristics of an air filter cartridge for use with the air purification device.

Abstract: A method of detecting leaks in the filter bags of a baghouse filter chamber that includes determining when the filter bags have been cleaned and, during a post-cleaning period after the cleaning of the filter bags, determining whether the opacity level of the exhaust of the baghouse filter chamber exceeds a predefined opacity limit. The determining whether the opacity level of the exhaust of the baghouse filter chamber exceeds a predefined opacity limit may include monitoring the opacity level of the exhaust of the baghouse filter chamber with an opacity sensor during the post-cleaning period and comparing the opacity readings during the post-cleaning period with the value of the predefined opacity limit.

Abstract: An air cleaner is provided according to an embodiment of the invention. The air cleaner includes a power supply, an electrostatic precipitator cell, and a door. The door closes the electrostatic precipitator cell inside the air cleaner. The air cleaner further includes a door switch that is actuated by the door when the door is substantially closed. The air cleaner further includes a cell presence switch. The electrostatic precipitator cell actuates the cell presence switch when the electrostatic precipitator cell is at least partially inserted into the air cleaner. The cell presence switch and the door switch enable electrical power to be supplied from the power source to one or more air cleaner components when the electrostatic precipitator cell is at least partially inserted into the air cleaner and when the door is substantially closed.

Abstract: The present invention relates to a method for separating off odor substances from gases, comprising gas with at least one filter comprising a porous metal-organic framework material, the framework material comprising at least one, at least bidentate, organic compound which is bound by coordination to at least one metal ion.

Abstract: An apparatus and corresponding method for automatically changing out a filter cartridge in a continuous air monitor. The apparatus includes: a first container sized to hold filter cartridge replacements; a second container sized to hold used filter cartridges; a transport insert connectively attached to the first and second containers; a shuttle block, sized to hold the filter cartridges that is located within the transport insert; a transport driver mechanism means used to supply a motive force to move the shuttle block within the transport insert; and, a control means for operating the transport driver mechanism.

Abstract: The invention provides a system and method comprising an apparatus for removing contaminants from a gas in a semiconductor processing device, which can include a filter unit having at least two parallel filter stages located therein. The filter stages are designed to remove a least a portion of the contaminants present in the gas flowing through them. The apparatus can also include a flow controller for distributing the gas flow among the filter stages. In one embodiment, the controller may consist of a diffuser plate. The invention also provides a sampling tube orifice for gas flow control in a system or method of the invention. In another embodiment, an apparatus for removing contaminants from a gas in a clean room comprises a filter unit having at least two parallel filter stages, which are used to remove a portion of the contaminants in the gas as it passes through the apparatus.

Abstract: An intense field dielectric air filtration system associated with an air conditioning unit includes a microprocessor based control system which may be connected to the thermostat of the air conditioning unit to energize the air filtration system in response to a call for heat or cooling signal at the thermostat or startup of the fan motor for the air conditioning unit. The control system includes a power supply for the air filtration system together with voltage and current monitoring circuits for detecting a fault condition. Filtration system on/off and timing function reset switches are connected to the microprocessor and visual displays, including a multicolored LED bargraph display, are controlled by the microprocessor to indicate voltage potential applied to the air filtration system, a fault condition or a test mode.

Abstract: A fuel processor and a fuel cell system which have a desulfurizer with multiple sensors, and a method of measuring an adsorbent state in of an adsorbent the desulfurizer The desulfurizer determines the saturation state of the adsorbent using a signal difference between at least two sensors installed adjacent to an inlet and an outlet of the desulfurizer. The desulfurizer provides an accurate determination of the saturation of the adsorbent, and can be used to determine when the adsorbent should be changed. Two desulfurizers can be alternatively used to allow for a consistent fuel flow.

Abstract: A method and system for detecting and predicting air filter condition for an air handling system operates by determining a system resistance to air flow. The system resistance is utilized to determine a detection statistic indicative of current filter condition and to predict remaining life of the air filter. The system resistance is determined using models that approximate the expected operation of the air handling system. The approximation is then compared to actual values to obtain a difference. Once the difference between the approximated value exceeds a threshold value, an alarm is initiated that is indicative of system resistance. The remaining air filter life is then determined by using historically gathered data, or by using a known degradation rate of the air filter. Once the remaining life of the air filter is estimated, replacement can be scheduled that would coincide with other maintenance.