Many HVAC Contractors

Many HVAC Contractors are looking for ways to expand and grow your business. It makes sense to consider a service that have good long term potential, a service that compliments your existing services, a service that is not difficult to enter and a service that offers good profitability. The indoor air quality market in general and air duct cleaning in particular is just such a service.

Operatives

Operatives to carefully remove filters one by one from canopy and place into tank, taking care not to over stack filters. Note: filters can be easily damaged especially Vokes filters.
6  Operatives to let filters in tank soak for a minimum of 10 minutes.
7  After 10 minutes, operatives to remove filters one at a time from solution. Whilst also holding filters over the tank, clean the edges of the filters using a ‘Greenie’.
8  Operatives to place filters into the spray tank and repeat process until spray tank is full.
9  Operatives to spray filters using high pressure jet sprayer in a methodical way (as instructed by supervisor) ensuring that all parts of the facing side of the filter have been sprayed.
10  Operatives to repeat this procedure until completed on each side of filters and then to repeat operation for reverse side of filters.
11  On completion, operatives to place filters carefully in drainage area and allow excess water to drain out.

On completion of cleaning

 On completion of cleaning, operatives to switch off machine and remove plug and RCD from the power socket and recoil machine cable/ lead. Operatives to check cable for any damage while recoiling cable/ lead.
13  Operatives to clean machine and check that pads or discs are not damaged or broken.
14  On completion of cleaning, operatives to dispose of all waste chemicals and materials on site and remove all cleaning equipment, chemicals and signage to company vehicle.
15  Operatives are not to leave the site until authorised by Supervisor.
This Method Statement to be used only to underpin a Full Site Specific Method Statement
Ceiling Cleaning – Stainless Steel – Painted –  False & Clipped Tiles
Applicable to both stainless steel ceilings and painted/false ceilings
1  Operatives to check all PPE, cleaning equipment and chemicals required for the task. Refer to COSHH assessments supplied for chemicals being used. Operatives to set out all ‘Caution/Warning’ signage required and cordon off cleaning area prior to work commencing.

help keep visible

help keep visible mildew from returning. But when mold spores get into the air conditioning system, they can settle in the air conditioning ductwork along with dust and other contaminants. Air conditioning duct systems, especially in Florida's humid climate, can be virtual incubators for microbial pollutants such as mold and bacteria. With the alternating high and low humidity conditions which regularly occur in air conditioning ducts during air conditioner operation, molds will grow, spread, produce spores and distribute the spores throughout a house. Mold contamination in air conditioning ducts poses a serious problem. Inhibiting Mold Growth in Air Conditioning Ducts To effectively prevent conditions that lead to air condition ductwork contamination, two considerations must be made: 1. Keep the ducts free from dirt and spores. 2. Check and repair any leaks in ducts that might introduce dirt and moisture.

WHAT TO DO WITH THE RESULTS

WHAT TO DO WITH THE RESULTS If the test indicates the leakage is greater than acceptable, the ducts should be sealed, repaired, or renovated (replaced). The threshold is set by the October 2005 Title 24 Building Code, which requires duct leakage to be reduced by 15% of the pre-work leakage found. In every case the closer to zero leakage attained, the better your duct system will perform. Sealing Duct sealing involves following established procedures and applying approved materials to seal air leaks. Locations where sealing is typically performed include the supply and return plenums (which are connected to the furnace cabinet), starting collars (where ducts are connected to the plenums), fittings in the duct runs (Ys, where ducts branch off, and elbows), splices within the duct run, and terminations where the ducts connect to the supply registers. The most important leakage areas are in the supply and return plenums, because these areas are closest to the air handler and under the highest pressures when the system is operating.

To evaluate acoustic pollution

To evaluate acoustic pollution, the sound power emitted by a sound source must be measured. This must be done in such a way that any kind of noise source, regardless of where it will later be used, can be quantified. One of the most accurate methods for measuring the sound power of small and medium sound sources is described in standard EN ISO 3741:1999 “Acoustics. Determination of sound power levels of noise source using sound pressure. Precision methods for reverberation rooms”. Eurovent chose this measurement method for the certification programme for air conditioners.
In 1994, the heat pump laboratory of CEIS (Centro de Ensayos, Innovación y Servicios, S.L.) was selected by Eurovent as an independent laboratory to perform the above measurements. The actual sound power measurements are carried out by the external laboratory UPLA at the Polytechnic University of Madrid.

Discussions

Discussions. It also made clear that heat pumps are really beginning to break through market and other barriers and that all markets are showing signs of growth. China and Europe are good examples of significantly growing markets. “Heat pumps are where the action is” certainly applies to China with its booming construction sector and HVAC industry. Of course, the success of the conference was also the result of thorough preparation, the excellent location and the participation of over 300 people who came from all over the world.
The status of heat pumps can best be characterised by the diversity in technology, markets and developments. Examples are gas heat pumps, combined heat pumps and thermal storage, advances in CO2 technology for water heating, diversity in system design, and the broadly applied and expanding ground-coupled heat pump markets. New competing technologies are emerging, such as micro-CHP and fuel cells in residences and light commercial applications. There is no single solution available and this provides excellent opportunities for countries to collaborate and learn from each other.

A utility

A utility’s view The Swedish utility Vattenfall operates in the most mature heat pump market (heating mainly) in Europe. That is not a coincidence. The company is one of the energy suppliers that continued stimulating the use of heat pumps after the deregulation in 1996. The key to their heat pump success was that they marketed heat pumps within their solar energy programme.
Electricity offered by Vattenfall in 1999 was mainly from nuclear and hydropower, increasing the environmental benefits resulting from use of the heat pumps. In the initial part of the 20-year period they have worked with heat pumps, Vattenfall was involved in equipment testing and (re)designing. Later they focussed on retaining customers

Thermoroad

Thermoroad – Applied Peltier technology Netherlands - Road asphalt may find another use in the near future. By applying Peltier elements in the road surface and underground, small-scale electricity can be generated. Highway tests in the Netherlands are being conducted to prove the technical concept. In summer, the high temperature in the asphalt layer and the low temperature of the groundwater create a voltage potential, which produces electricity in the Peltier elements. In winter, the system works the other way around. Five U-shape copper prefab elements containing cables, groundwater pipes and other hardware have been installed across the road. The Peltier elements are mounted on the copper elements. A top layer of 6 mm highconductivity, water-resistant asphalt protects the energy system. The system produces 20 kWh of electricity per m2 of road annually, as the result of an expected temperature differential of 2 to 10°C. Source: Techniek 28 June 2002 (in Dutch) Micro CHP emerging Japan - Honda Motor Co. has released information saying that it has entered the final stage of development of a compact, home-use cogeneration unit, scheduled to go on sale from March 2003. The unit’s compact design (640 mm x 380 mm x 940 mm) was achieved using an efficient layout, combining the world’s smallest natural gas engine, developed especially for this use, with a compact, lightweight power generation system employing the company’s sine wave inverter technology to ensure electrical output on a par with commercial power sources. The driver is a 4-stroke, water-cooled, single-cylinder engine. A 3-way catalyst and oxygen feedback control is employed to reduce NOx emissions. The unit has a thermal output of more than 3 kW and an electrical output of 1 kW, achieving an overall efficiency of 85%. Source: Honda Press Information Energy-efficient distillation Netherlands - A Dutch consortium of research institutes, contractors and chemical process industry has been formed to develop highly energy efficient distillation columns within the next 4 years. Traditional distillation column designs are tall and high. By integrating the upper half of the column in the lower part, the size can be reduced substantially and energy savings of 60-90% could be possible compared to traditional designs. When compared to mechanical vapour recompression columns, energy savings of up to 50% can be achieved. The so-called Heat-Integrated Distillation Column (HIDiC) is also equipped with mechanical vapour recompression technology. Top vapour from the outer section is compressed and fed to the inner high-pressure section of the column; se

General Information.

General Information. • References to Specific Items—Reference in these specifications to any article, device, product, material, fixture, form or type construction by name, make, or catalog number shall not be construed as limiting competition or an endorsement of a manufacturer. These references are only intended to establish minimum standards of quality. • Codes—The QCN member is responsible for compliance with locally adopted public codes or regulations affecting work under these specifications. Where local codes or regulations require greater standards than those required in this section, local codes govern. Where local codes or regulations permit lower standards than those required by these specifications, the standards contained herein govern. TVA does not assume any responsibility for determining, interpreting, or enforcing compliance with local codes and regulations. In addition, TVA does not interpret or determine local codes and regulations. • Materials and Appliances—Unless otherwise stipulated, the QCN member must furnish all labor, equipment, tools, materials, and services necessary for the execution and completion of all work. All equipment and materials shall be new and of the quality specified in these standards.

Packaged Terminal Heat Pumps

Packaged Terminal Heat Pumps (PTHP), Self-Contained Through-The-Wall Heat Pumps (SCTTWHP), Free Delivery Split Heat Pumps (FDSHP), and Window Heat Pump Systems (WHP). The following subsections do not apply to the above-named systems: Equipment Requirements, item 1; Condensate Piping, item 3; Indoor Thermostat, and Auxiliary Electric Heaters. The minimum air flow requirement of 400 cubic feet per minute per 12,000 Btuh in Duct System Design, Modification, and Installation section, item 1, shall not apply. All other sections of these standards remain applicable unless otherwise noted. 1. Free-delivery split heat pumps, self-contained through-the-wall heat pumps, packaged terminal heat pumps, and window heat pump systems are designed to deliver conditioned air to the space without the use of ductwork. Self-contained through-the-wall heat pumps and packaged terminal heat pumps are designed to be installed through an exterior wall. Window heat pump systems are designed primarily for use in window installations. Free-delivery split heat pumps are split-type, free delivery heat pumps that may consist of one or more indoor units. The indoor units are designed to be attached to an indoor wall or ceiling. 2. The auxiliary electric heater for these types of heat pumps shall be provided by the heat pump manufacturer within the unit cabinet or fan coil section as part of the heat pump and shall be controlled by the unit's indoor thermostat. 3. These types of heat pumps shall be installed and supported in accordance with the manufacturer's instructions, subject to local building codes and standards. The installing QCN member shall be responsible for the complete installation of these systems, including the wall/window case. 4. Where ductwork is used, the duct design and installation shall be as recommended under Duct System Design, Modification, and Installation section. The only exception is where the heat pump manufacturer provides specific duct application and installation criteria for their equipment. In all cases, the duct design and installation shall be such that the system provides the amount of air flow across the indoor coil recommended in the manufacturer's specifications.

Wet or Damp Existing Insulation

Wet or Damp Existing Insulation—Adequate attic ventilation shall be provided when the existing insulation is found to be wet or damp, and the insulation shall be allowed to dry prior to installing additional attic insulation. If the insulation fails to dry after a reasonable period of time, it shall be replaced. • Customer Responsibilities—The customer shall be responsible for seeing that preparation work such as repairing the ceiling, roof leaks, pipe leaks, vent leaks, removing objects stored in the attic, etc., is completed if failure to do so would adversely affect the installation of additional insulation. • Blocking Materials—Blocking materials shall be installed in accordance with the following requirements: − Mineral fiber batts shall not be placed on the narrow edge. − Sheet metal used as firestopping or blocking material shall be secured in place using nails, tacks, staples, or screws. − Gypsum board/sheetrock or wood shall be secured in place using nails or screws. When using these materials as blocking, the clearances to both the insulation and the blocking shall be maintained. − Blocking materials shall be installed so that their height is above that of any surrounding loosefill insulation material. • Clothes Dryer Vents —Clothes dryers shall be vented to the outside. • Plumbing and Other Pipes, etc.—Cracks and gaps around ceiling penetrations, such as plumbing, exhaust fans, etc., should be sealed prior to installing ceiling insulation. • Recessed Light Fixtures—Insulation shall not be installed within 3 inches of the sides of a recessed incandescent or fluorescent light fixture (including its wiring compartment and ballast), and insulation shall not be installed over the top of such fixtures. The 3-inch air space shall be provided by utilizing acceptable blocking material

Be custom-fitted

Be custom-fitted to each prime window opening to match the size and shape of the existing window opening  − Be installed in a vertical position only; sloped installations shall not be permitted − Be mounted on the interior side of the prime window opening to achieve an isolated air space between the two glazing materials of 3/4 inch minimum to 4 inches maximum − Be permanently attached to the prime window opening and provide a weather tight seal establishing an air tightness greater than that of the existing exterior prime window over which it is installed  Clearance must be allowed for prime window light operation, removal, and cleaning. Where the design of the prime window precludes mounting the storm window to cover the entire window opening, the installation must be accepted in advance by TVA and the customer.  When subframing materials are used for mounting interior applied, thermoplastic storm windows, subframes shall be permanently attached to the prime window opening or mounting surface with mechanical fasteners positioned on approximately 12-inch centers to provide a secure installation for the storm window assembly.  Subframes shall be effectively sealed to the prime window opening by a continuous bead of approved caulk. The sealant shall provide a permanent seal between the storm window assembly and the surrounding prime window opening.   Thermoplastic hook-and-loop mounting systems, such as Velcro, or equivalent, are not permitted.
Section 2C   01/16/2007
 15
 A thermoplastic insert panel may be attached to its framing members by use of magnetic strips if the following conditions are met:  − The magnetic holding force of the magnetic strip shall be a minimum of 6-1/2 pounds per linear foot with a maximum of 10 percent variance at zero air gap around the window perimete

Determine system heating capacity

Determine system heating capacity.  System inspection should never be conducted within 48 hours of completion of soaker hose operation, and should not be conducted within one week of completion of soaker hose operation if the DXGS system is installed during the heating season.  Consult with the Quality Heat Pump Contractor to determine appropriate inspection time during heating season.  For heating capacity tests, the return air temperature should be between 65 degrees F. and 70 degrees F. (Major)
3)  3) Measure the compressor run current while in the heat mode.  The expected current readings should fall within the ranges as specified by the manufacturer. (Major)
4) The air flow shall be between 400 and 450 CFM per ton of capacity. (Major)
a) Determine heating capacity by using the following formula: Btuh = TD x 1.1 x CFM TD =  temperature difference between supply air and return air 1.1 = air properties constant CFM =  Cubic feet per minute air calculated, from funnel, temperature rise, or return air method
b) Verify that system capacity is + 10% of the equipment manufacturer's rating at the test conditions.
Section 2E   01/16/2007
 13
Note:  If the heating capacity is low, this may be due to an unadjusted heating valve.  The Quality Heat Pump Contractor can adjust the heat valve before re-calculating the heating capacity.
5) Determine system cooling capacity. For cooling capacity tests, the return air temperature should be between 75 degrees F. and 80 degrees F. (Major)
6) Measure the compressor run current while in the heat mode.  The expected current readings should fall within the ranges as specified by the manufacturer. (Major)
7) The air flow shall be between 400 and 450 CFM per ton of capacity. (Major)

Providing quality

Providing quality workmanship performed in a workman-like manner in compliance with all specifications listed in the program guidelines • Submitting a detailed invoice of the heat pump installation, which separates costs for the heat pump, ductwork, weatherization, extended warranty, programmable thermostat(s), electrical upgrades, and/or other applicable and acceptable costs • Practicing good business ethics and ensuring customer satisfaction to best of their ability, including leaving the premises in a “broom clean” condition after the installation • Honoring all service and warranty commitments made to customers Customer Responsibilities. Customers participating in the energy right Heat Pump Plan are responsible for: • Providing a copy of a deed or other evidence of ownership of the dwelling to meet a condition of financing eligibility under the program • Entering into an agreement with a member of the QCN for the installation of a heat pump • Notifying the distributor to arrange for the loan closing or inspection • Ensuring that the heat pump is installed to the customer’s satisfaction • Signing the Work Completion Form after the work is completed to the customer’s satisfaction

Charge procedure

Charge procedure 1.- De-pressurise the units. 2.- Drain the refrigerant. 3.- Clean out with dry nitrogen. 4.- Solder the tubes, with a dry nitrogen flow inside the tubes. 5.- Use low melting-point rods with a minimum silver content of 5% for soldering. 6.- Fill with 2 kg R-22 refrigerant to detect leaks. 7.- Empty out the refrigerant. 8.- Clean out with dry nitrogen. 9.- Create a vacuum down to 200 microns. 10.- Put in the refrigerant, using scales or a calibrated cylinder. The charge accuracy should be of 30 grams. The outdoor unit is fitted with pressure and temperature points on the connection outlets, for checking of over-heating and sub-cooling. Check that these values are around 5°C. Insulation of tubes The interconnection cooling tubing must be insulated. The insulation requires specific characteristics: it must be

the calculations

the calculations can be either the test points given in this method or test points given in EN 14511.  
The maximum heating capacity, Pmax, at the different climates is calculated from the heating capacity data obtained in the test. It is not possible to choose the size of the required heat load for the building, but is given by the model for each bin level based on the capacity of the heat pump. To meet the lower heat load requirements at the different bin levels, the heat pump is assumed to work in part load condition. The heat pump does not have to be tested in part load operation; instead the model uses a degradation factor, Cd, to calculate the COP when working in part load condition. Cd can either be obtained from tests or a default value, Cd=0.15, can be used.  
For fixed capacity units the default is COPmin= 0.89*COP at power output Phpmin=0.5*Php. For staged capacity units the default is COPmin= 0.975*COP at power output Phpmin=0.5*Php.  For variable capacity units the default is COPmin= COP at power output Phpmin=0.4*Php.
It is optional to choose whether the heat pump operates with night set back or not. The bin assumes constant night temperatures during night set back to +1°C, +6°C and 0°C for each climate respectively

Sammanfattning

Sammanfattning I denna rapport redovisas de delar av projektet ”Beräkningsmetoder för årsvärmefaktor för värmepumpsystem för jämförelse, systemval och dimensionering” som SP Sveriges tekniska forskningsinstitut svarat för. Projektet har genomförts av SP och KTH. KTH:s del av projektet redovisas i en separat rapportdel. I en inledande del av projektet har förberedelser för ett IEA samarbete, samt gemensam övergripande projektplanering tillsammans med industriparterna utförts. IEA-projektet har godkänts att starta av styrelsen för IEA Heat Pump Programme, och ett första inledande möte har hållits. SP har koordinerat samt sammanställt resultat av fältmätningar. Väl genomförda fältmätningar är en förutsättning för validering av olika beräkningsalgoritmer. Sammanställningen visar att det finns ett flertal utförda fältmätningar i Sverige under de senaste 20 åren, men få har gjorts med SPF som fokus, utan ofta har mätningarna gjorts med syfte att studera en viss teknikförändring, eller andra faktorer. Det har inte under de senaste 10 åren utförts någon stor mätning på värmepumpar liknande de välkända Fraunhofermätningarna eller FAVA-studien i Schweiz. Den enda studie som syftat till att mäta SPF är den som SP utfört. Detta kan ses som en brist i ett land där värmepumpar har ett så stort genomslag för uppvärmningen av bostäder

Human occupants

Human occupants of the building contribute sensible heat according to their activity. From Reference 1, 200 Btu/hr per person is estimated for light activity.  For two people in the building, this gives a heat gain of
                              q = 2 (200) = 400 Btu/hr
Adding all the heat gains from conduction and internal sources gives
                             Total sensible load Qs  =   35274 Btu/hr
Human occupants also contribute to the latent heat gain in the building.  For light activity people produce a latent gain of about 180 Btu/hr per person so this heat is                               q = 2 (180) = 360 Btu/hr
The assumed infiltration of 20 cubic foot per minute of outside air brings latent heat into the building which is given by equation 9 as

This procedure

This procedure is followed: •Check if air is correctly distributed to all the occupied rooms of the building. •Inspectthe air filtration equipment. •Inspectthe refrigeration coils. •Check central heatequipmentand refrigeration (including humidity regulators).
Inspection of the ducts is done through existing openings,such as access doors,or grid openings, inspection panels etc.
Visual inspection is done first:If mould or any ‘unusual’material is detected,samples are gathered for further analysis.Inspection openings mustbe closed before proceeding with cleaning.
b) Ductopenings Regardless of building type and insulation material used with the duct,openings should be made to ensurethe bestair tightness when cleaning operations arefinished.
c) Ductcleaning methods Several methods are used to clean insulated ducts.The most common ones, also considered the mosteffective,are briefly described in this handbook: •Contactvacuum method •Air sweep method •Mechanical brush method

FCC COMPLIANCE

FCC COMPLIANCE
This equipment has been tested and found to comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference when the equipment is operated in a commercial environment. The
equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case
the user will be required to correct the interference at his own expense.
Shielded interconnect cables must be employed with this equipment to insure compliance with the
pertinent RF emission limits governing this device.
Changes or modifications not expressly approved by Adam Equipment could void the user's authority
to operate the equipment

The heating, ventilation

The heating, ventilation, and air-conditioning (HVAC) system is arguably the most complex
system installed in a house and is responsible for a substantial component of the total house
energy use. A right-sized HVAC system will provide the desired comfort and will run efficiently.
Right-sizing of an HVAC system is the selection of equipment and the design of the air
distribution system to meet the accurate predicted heating and cooling loads of the house. Rightsizing
the HVAC system begins with an accurate understanding of the heating and cooling loads
on a space; however, a full HVAC design involves more than just the load estimate calculation;
the load calculation is the first step of the iterative HVAC design procedure. This strategy
guideline discusses the information needed to design the air distribution system to deliver the
proper amount of conditioned air to a space. Heating and cooling loads are dependent upon the
building location, sighting, and the construction of the house, whereas the equipment selection
and the air distribution design are dependent upon the loads and each other.

Documents to be Submitted

Documents to be Submitted
The following documents are to be submitted to GL for approval. To facilitate a smooth and efficient approval
process they should be submitted electronically via GLOBE. In specific cases and following prior
agreement with GL they can also be submitted in paper form in triplicate. GL reserve its right to ask for
supplementary copies, if deemed necessary:
 ventilation and air condition scheme – accommodation and service spaces
 ventilation system machinery spaces and technical spaces
 ventilation system cargo holds
 details of fire closures and weather tight closures
 details of duct penetrations
 approval information (flexible ducts, fire dampers, duct penetrations)
 principal electrical supply, control and monitoring
 emergency stops of fans

International standards

International standards
For design and construction of ventilation systems the following international standards are recommended
as guidance. The last edition of each standard should be applied.
 ISO 7547, Shipbuilding – Air-conditioning and ventilation of accommodation spaces on board ships
– Design conditions and basis of calculations
 ISO 8861, Shipbuilding – Engine room ventilation in diesel-engined ships – Design requirements
and basis of calculations
 ISO 8862, Air-conditioning and ventilation of machinery control rooms on board ships – Design conditions
and basis of calculations
 ISO 8864, Shipbuilding – Air conditioning and ventilation of wheelhouse on board ships – Design
conditions and basis of calculations
 ISO 9785, Ships and marine technology – Ventilation of cargo spaces where vehicles with internal
combustion are driven
 ISO 9943, Shipbuilding – Ventilation and air-treatment of galleys and pantries with cooking appliances

If duct cleaning

If duct cleaning is determined to be the best option:
1. Hire a duct cleaning contractor who is a member in good standing of the National Air Duct
Cleaning Association. Duct cleaning companies must meet strict requirements to become NADCA
members. Among those requirements, all NADCA Members must have certified Air System Cleaning
Specialists (ASCS) on staff, who have taken and passed the NADCA Certification Examination.
2. PROTECT building occupants during and after duct cleaning:
• Place a filter over supply and return grills to capture dust when HVAC system is placed back into
service after cleaning.
• Perform duct cleaning during hours when the building is unoccupied, such as nights and
weekends.
• Use containment barriers and proper ventilation equipment, such as “negative‐air” machines
equipped with high‐efficiency filters.
• Avoid the use of biocides and sealants. Even EPA‐registered biocides may pose health risks,
including eye, nose, and skin irritation.
• No biocides are currently EPA‐registered for use on fiberglass duct board or fiberglass‐lined
ducts. Both the EPA and NADCA recommend replacing wet or moldy fiberglass duct material.

PREVENTION

PREVENTION of duct contamination is KEY to avoiding problems
Follow these recommendations to avoid the need for costly duct cleaning:
• Perform routine preventive maintenance of HVAC systems, by complying with manufacturer
schedules for changing HVAC filters and cleaning coils and other components.
• During building renovation, seal ductwork to prevent construction dust and debris from entering
the HVAC system.
• New ductwork frequently contains oil and debris. Before new ductwork is connected to the air
handling system, it should be inspected for cleanliness and cleaned if necessary.
• Maintain good housekeeping in occupied spaces.
• Ensure that air intakes are located away from contaminant sources.
• Consider routine inspections of ductwork. The National Air Duct Cleaning Association (NADCA)’s
standard, “Assessment, Cleaning and Restoration of HVAC Systems – ACR 2006,” recommends that
HVAC systems be visually inspected for cleanliness at regular intervals, depending on the building
use. For healthcare facilities, the standard recommends annual inspections of air handling units, as
well as supply and return ductwork

component. BEFORE hiring a duct cleaning contractor, make sure you can answer “YES” to all of these questions:

When is duct cleaning appropriate?
Although the value of regular duct cleaning remains
questionable, the U.S. Environmental Protection
Agency (EPA) and indoor air specialists agree that
duct cleaning (or, in some cases, duct replacement) is
appropriate in the following circumstances:
• Permanent or persistent water damage in ducts
• Slime or microbial growth observed in ducts
• Debris build‐up in ducts that restricts airflow
• Dust discharging from supply diffusers
• Offensive odors originating in ductwork or HVAC
component.
BEFORE hiring a duct cleaning contractor,
make sure you can answer “YES” to all of
these questions:
9 Are there known or observed
contaminants in the ductwork?
9 Have you confirmed the type and
quantity of contaminants based on
testing or observation?
9 Are the contaminants (or their by‐
products) capable of entering occupied
spaces?
9 Have you identified and controlled the
source of the contaminant?
9 Will the duct cleaning effectively
remove, inactivate, or neutralize the
contaminant?
9 Have you considered other options,
such as removal of affected ductwork?
9 Is duct cleaning the only (or most
effective) solution?
In all cases, duct cleaning should be undertaken only after the source of the contaminant has been
identified and controlled. Otherwise, the problem will not go away. For instance, the water source

Latest Findings

Latest Findings
Despite more than two decades of research, there is still not enough evidence to draw solid conclusions
about duct cleaning’s benefits on indoor air quality, occupants’ health, HVAC system performance, or
energy savings, according to a 2010 review of scientific studies on duct cleaning.1 The review did find
clear evidence that ductwork can be contaminated with dust and can act as a reservoir for microbial
growth under normal operating conditions. Yet, even when duct cleaning was extremely efficient at
removing contaminants within ducts, the
effectiveness of reducing indoor air pollutants was
highly variable, and in many cases, post‐cleaning
levels of contaminants were higher than pre‐
cleaning levels.

Introduction

Introduction
In recent years, ventilation duct cleaning has grown into a huge industry, in response to surging public
concern about indoor air pollution. The industry claims that cleaning ductwork can improve indoor air
quality, control molds and other allergens, enhance heating, ventilating, and air‐ conditioning (HVAC)
system performance, and reduce energy costs. Yet there is little scientific evidence to support these
claims, and poor duct cleaning practices can actually cause or increase air quality complaints. This fact
sheet provides guidance on when duct cleaning may be appropriate, how to protect building occupants
during duct cleaning, and how to prevent the conditions that drive facility managers to undertake this
costly procedure.