through-wall fresh air inlets

TM
THROUGH-WALL FRESH AIR INLETS
THROUGH WALL
TM
The Through-Wall AIRLETTM is a make-up air inlet
for Indoor Air Quality ventilation
Make-up air is an essential element in a complete
central exhaust indoor air quality ventilation system,
particularly in structures that are well insulated and
tightly built.
The introduction of fresh air from the exterior provides
the make-up air to replace air being exhausted by an
exhaust fan.
As a result, indoor relative humidity levels are kept at acceptable levels and a healthy atmosphere is assured.
The AIRLET™ is satisfactory for climates with winter
design temperatures above 0 °F. Humidity and temperature-controlled AIRLETs™ are preferred in the lower
end of this range. Usually one make-up air inlet is
installed in each bedroom, plus one or more in the
main living areas.
AIRLET™ 100 or 200
Standard Self-Regulating Inlets
Standard self-regulating inlets allow a
constant amount of fresh air to enter.
A flow-regulating damper ensures
that the airflow is independent to
wind pressure. Available in round or
rectangular.
AIRLET™ 600
Humidity-Controlled Inlet
A unique make-up air inlet that
automatically adjusts incoming airflow
according to interior humidity levels.
Ventilation make-up air is modulated
according to the room’s needs.
AIRLET™ 700
Temperature-Controlled Inlet
Continuously regulates airflows in
response to the outdoor temperature.
AIRLET™ TL98
Manually Adjustable Inlets
Incorporates a variable control damper
and unique air-distribution grille.
American ALDES offers the most comprehensive line
of through-wall make-up air inlets available.
FEATURES
• American ALDES Quality
• Controlled airflow
• Draft-free fresh air
• Filter equipment
• Sound attenuating
• Aesthetic design
• Adjustable sleeves
• Solutions for every design challenge
• Tested and proven technology
• Meets Washington State IAQ Code
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* Through-Window AIRLETs™ are also available. See separate
brochure or contact factory for details
Through-Wall AIRLET™
The AIRLET™ TL98 manually adjustable fresh air inlet incorporates a
unique variable precision-control damper that is manually adjusted
using a discreet slide control accessible from behind the front cover.
The AIRLET™ TL98 includes an easily accessible permanent washable
filter, expandable wall sleeve, and exterior louver. The white color
blends well with any decor, and the AIRLET™ can be cleaned with a
damp cloth. Optional pollen filters and sound-absorbing wall sleeves
are also available.
The AIRLET™ 100 may be installed before or after the interior and
exterior surfaces have been applied to the dwelling. Two telescoping
sleeve combinations are available to accommodate different wall
thicknesses. Exterior and interior grilles are made of UV-resistant,
white plastic. The interior grille incorporates a flow-regulating damper
that deflects a thin ribbon of fresh air upwards, providing draft-free
fresh air that quickly mixes with warm ceiling air. A filter is provided
in the sleeve, and it may be easily accessed for cleaning by removing
the interior grille. There are no manual controls.
The round design of the AIRLET™ 200 permits easy installation after interior
and exterior surfaces have been applied to the dwelling. One standard
telescoping sleeve accommodates wall dimensions up to 9 inches thick.
Available with either a white epoxy painted exterior grille or a mill finish
aluminum exterior grille, the interior grille is made of UV-resistant white
plastic and extends 5/8 of an inch from the wall. The filter can be accessed
easily without tools, and there are no manual controls to reset.
The AIRLET™ 600 automatically adjusts the incoming airflow according
to interior humidity levels. Use with a continuously operating exhaust
system in tightly constructed dwellings. The AIRLET™ 600 provides a
controlled, dedicated pathway of fresh air. The discreet interior grille
housing sports an unobtrusive white design for a contemporary
look.
The AIRLET™ 700 is a temperature-responsive air inlet that automatically
adjusts the incoming airflow according to outside temperatures. The integral,
thermally powered actuator requires no external power to operate. The
pre-calibrated opening begins to close when the outside air temperature
drops below 50 °F, and it will completely close at 23 °F. A minimum airflow
setting can be set manually. The AIRLET™ 700 includes an easily accessible
permanent washable filter, expandable wall sleeve, and exterior louver.
AIRLET TL98
Filter
Damper
Slide Control
AIRLET 100
Damper
Filter
AIRLET 200
Damper Filter
AIRLET 600
Installation Diagram
AIRLET 700
Front
Cover
Thermostat
Filter
Condensation
Protection
(See individual specifications for performance and dimensional details)
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Q. WHY AIR INLETS? AREN’T HOMES NOW BEING BUILT TIGHTLY SO AS TO
REDUCE AIR INFILTRATION AND SAVE ENERGY?
A. Yes, homes are being built more tightly, but an immediate consequence of
this action is an increased level of indoor air pollutants: excessive humidity in the
winter causes condensation on windows and other cold surfaces; mold and mildew;
increased levels of carbon dioxide and formaldehyde from building products; and
other indoor pollutants from living activities. In the past, leaky buildings, combined
with the natural forces of wind and stack effect, permitted sufficient air change
to remove these pollutants through the leakage areas of the buildings. In mild
weather, windows can be opened to permit natural ventilation, but these natural
forces are not sufficient to ensure adequate air change on tightly built homes. In
addition, exfiltration of air through unintentional leakage areas, such as electrical
and plumbing penetrations, attic hatches, and sole plates, can result in hidden
moisture damage as humid indoor air encounters cold insulation and sheathing
in the exterior walls and attic. Thus, it is best to use continuous interior-vapor
retarders to protect the insulation and wall/ceiling components from moisture
damage, and to provide a dedicated ventilation system incorporating fresh-air
inlets to deliver fresh air into the home discreetly and without draft. Simply
adding air inlets is not the answer to indoor air pollution. By providing a low,
continuous exhaust rate, the minimum level of ventilation is assured, independent
of the natural forces of wind and temperature differences. Mechanical ventilation
on a tightly built home results in lower heating costs than a home with natural
ventilation that provides the same average ventilation rate. The natural system, if
adequate in milder weather, results in excessive ventilation during colder weather
and increased fuel costs.
Q. HOW DO SELF-REGULATING AIR INLETS OPERATE ? WHAT EFFECT DOES
BUILDING LEAKAGE HAVE?
A. These inlets are simply passive openings, fitted with airflow-regulating controls,
that permit air to enter the bedrooms and main living areas. The amount of air
that flows through the inlets depends on the indoor-outdoor pressure difference.
(See the AIRLET™ 100 and 200 specification sheets for performance charts).
The pressure difference in turn is determined by the exhaust rate of the fan(s)
ventilating the bathrooms and kitchen, and the total leakage area of the home,
including the areas of the inlets. During windy weather, all fixed openings will
permit more or less airflow, depending on the wind speed and direction. To be
effective, the exhaust fan must be capable of exhausting enough air, and the
house must be tight enough, so that a depressurization of 0.02 to 0.04 in. w.g. (5
to 10 Pascal) is achieved. AIRLETs™ 100 and 200 have about 5 in2 of equivalent
leakage area (ELA). In a home with 5 inlets, the air inlets provide about 25 in2 of
ELA. If the unintentional leakage area is large compared to this value, very little
fresh air will enter via the inlets.
Q. WHAT IS THE EFFECT OF WIND ON SELF-REGULATING INLETS?
A. Generally, as wind pressure increases so does airflow. AIRLETs™ 100 and 200
are provided with self-regulating dampers that close the inlet under increasing
pressure to limit the effect of wind-driven infiltration via the inlet. Some inlets
offer manual adjustments. Often occupants will close them during severe weather
and forget to re-open them later. Self-regulating inlets operate automatically,
eliminating the need for occupant adjustment.
Q. HOW DO HUMIDITY-CONTROLLED INLETS OPERATE?
A. The AIRLET™ 600 incorporates a unique relative humidity (RH) sensor composed
of nylon strips. Due to nylon's sensitivity to moisture, the strips expand and
contract with variations in the RH of the ambient air. The sensor is under tension
and is coupled to dampers in the opening of the inlet that modulate airflow as
the relative humidity varies. Incoming air is automatically regulated to maintain
an acceptable RH level in the space where the AIRLET™ 600 is located. Assuming a
tightly built structure, a room's RH level will rise when it is occupied. The AIRLET™
600 will gradually open, and additional air will be drawn in by the exhaust system.
This air, which is inherently drier than that of the interior (especially during colder
weather when IAQ problems are most severe), lowers the RH level as it mixes in
the room. (Note: AIRLET™ 600 is never completely closed. A minimum of 3 CFM is
always assured.) As the humidity level decreases, the inlet closes and the airflow
decreases. Because it varies airflow based on humidity levels, the AIRLET™ 600 is
recommended for use in colder climates. Excessively dry interior air, which may
result if standard, self-regulating inlets delivering constant levels of air are used,
is limited with its use.
Q. CAN WOOD STOVES OR FIREPLACES BE USED WITH INLETS AND CENTRAL
EXHAUST VENTILATION SYSTEMS?
A. Inlets have little, if any, effect on a wood stove or fireplace; however, the exhaust
fan with which they are intended to be used is a source of concern. An exhaust
fan will compete with a wood stove or fireplace for make-up air, and the result
may be the backdrafting of the appliance. Wood stoves and fireplaces (and their
exhaust flues) used under these conditions must be certified to operate safely in a
negative pressure environment. It is not sufficient to supply make-up combustion
air for the stove or fireplace with air ducted to a grille near the appliance. Naturally
drafted equipment must have airtight doors and combustion air supplied directly
into the combustion chamber from outdoors. AIRLETs™ are not intended to supply
combustion air to any appliance.
Q. HOW CAN COLD AIR BE DELIVERED INTO A ROOM WITHOUT DISCOMFORT?
A. By locating the inlet near the ceiling, and orienting the diffuser upwards, fresh
air is directed to mix with warmer air in the upper part of the room. By the time
it reaches the occupied zone, it is well mixed and draft is not perceptible.
Q. WHERE SHOULD INLETS BE PLACED?
A. Inlets should be located in bedrooms and main living areas such as living,
dining, and family rooms. They should not be used in bathrooms or kitchens.
(These rooms should be served by exhaust ventilation only. In this fashion, the
stalest air is exhausted from the home, with the freshest air in the bedrooms
and living areas where occupants spend the most time.) Within the room, they
should be installed high up on exterior walls, within 6-8 inches from the ceiling.
The following information applies only to AIRLETs™ 100 and 200: They may be
installed in a closet for aesthetic reasons, but this may result in cold clothing, if
the closet door is left closed. If used with a continuous exhaust system, they may
be installed just above perimeter baseboard heating convectors. (If the exhaust
is not continuous, however, this may cause excess heat loss.)
Q. I AM PLANNING A VENTILATION SYSTEM FOR A HOME LOCATED NEAR A
BUSY FREEWAY. WON’T THE AIR INLETS ALLOW FREEWAY NOISE TO ENTER
THE HOME?
A. American ALDES offers several solutions for reducing airborne noise through
the inlets. Acoustic versions of AIRLET™ models TL98,100, 500 & 700 are available.
Additionally, installing the inlet on an exterior wall with the siding spaced away
from the sheathing permits installation without the exterior weather cap. This also
reduces transmission of outdoor noise. The AIRLET™ 200 may also be installed in a
ceiling configuration with insulated flexible duct between the outdoor grille, in a
soffit area. Depending on the length of duct, varying degrees of noise attenuation
are possible.
Q. SHOULD INLETS BE USED WITH FORCED AIR HEATING SYSTEMS?
A. In general, make-up air inlets should not be used with forced-air heating systems
as a means of fresh air supply. Unless forced-air systems are installed with return
grilles in all major rooms, and the supply and return airflows are well balanced
in each room, positive pressure builds up in these rooms when the doors are
closed. This pressure will cause exfiltration through the inlets, resulting in possible
condensation in the inlet and on the weather cap in cold weather. Due to induced
exfiltration in this zone of the home, there may be induced infiltration in the main
living areas, possibly exacerbating such problems as backdrafting of fireplaces.
Forced-air heating systems also cause the relative humidity levels throughout a
structure to be essentially the same. In the AIRLET™ 600, this counteracts its unique
ability to respond to the need for increased ventilation in rooms with higher RH
levels and decreased airflow to rooms with low RH levels.
For make-up air IAQ ventilation solutions to be used in connection with forced-air
systems, please request MAK information from American ALDES.
4521 19th Street Court East, Suite 104
Bradenton, FL 34203 - USA
P: 941-351-3441 • F: 941.351.3442
www.americanaldes.com • info@americanaldes.com
© Copyright 2012 American ALDES Ventilation Corporation
Reproduction or distribution, in whole or in part, of this document, in any form or by any means, without the
express written consent of the President of American ALDES Ventilation Corporation, is strictly prohibited.
The information contained within this document is subject to change without prior written notice.
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