Chandra, Subrato. Standards for Clean Air Florida Homes.
This report was prepared as an account of work sponsored by
an agency of the United States government. Neither the United
States government nor any agency thereof, nor any of their
employees, makes any warranty, express or implied, or assumes
any legal liability or responsibility for the accuracy, completeness,
or usefulness of any information, apparatus, product, or process
disclosed, or represents that its use would not infringe privately
owned rights. Reference herein to any specific commercial
product, process, or service by trade name, trademark, manufacturer,
or otherwise does not necessarily constitute or imply its
endorsement, recommendation, or favoring by the United States
government or any agency thereof. The views and opinions of
authors expressed herein do not necessarily state or reflect
those of the United States government or any agency thereof.
for Clean Air Florida Homes
These standards should result in a house with excellent indoor
air quality where allergy or asthma sufferers can breathe
easier. However, the indoor air quality is also highly dependent
on occupant lifestyle and household management practices e.g.
changing air filters and maintaining the heating, cooling,
dehumidifying and ventilating equipment per manufacturer instructions,
maintaining sanitary conditions inside the house and related
factors. Therefore FSEC/UCF gives no assurances, or will be
held liable, regarding the actual indoor air quality that
will result. Likewise, no assurance can be given that a person
will feel better living in such a house.
standards are designed for new, slab on grade homes built
in Florida. Changes to the standards may be necessary for
other house construction types.
These standards are not meant to be exclusionary. The home
builder may submit alternative materials or design details
which will result in equivalent performance. These standards
complement all building codes and do not supersede any codes.
and Rain control
Finished floor level at least 12" above the 100 yr.
Bottom of slab at least 8" above the top of backfilled
dirt which is graded for proper drainage.
Garage floor and driveway properly sloped to drain out.
Garage floor must be at least 3 inches lower than the living
Roof pitch at least 3 in 12.
All roof valleys and penetrations properly flashed and all
flashing details shown on drawings.
All windows must be carefully installed and sealed to avoid
rain and moisture intrusion. Submit details to FSEC for
Walls must be designed to dry to the inside. Complete wall
section drawings including details must be submitted which
clearly show intended air barriers, vapor retarders, and
have central vacuum cleaner installed. Preferably the kind
with electrical power to the brush/vacuum wand. The central
vac must be ducted to the outside. The unit should be in
an unconditioned space.
have space for HVAC and dehumidification equipment inside
the conditioned space. Recommended dimension is 4 ft. x
8 ft. x 8 ft. high for each air handler. Insulate all walls
around air handler closet for noise control. Air handler
not allowed in the garage.
Laundry rooms if inside conditioned spaces must have an
operable window to the exterior or alternate means to provide
direct make-up air to the dryer.
Air handlers are not allowed in attics (unless unvented
attic with roof line insulation).
Provide a well defined area inside the garage near the entry
door to the house where shoes, umbrellas and outerwear can
be conveniently removed and hung. This will reduce tracking
of dirt and pollen inside the house.
be clearly defined separation and barrier from garage to
Plan for all the exhaust and intake vents so that they
are not in each others way:
The fresh air intake(s) should not be over driveways
or locations where exhaust fumes from cars or dirt or
pollen can easily enter. The intake must be at least
10 ft. away from any other exhaust points and at least
6 ft. above ground level.
The dryer vent must exhaust to outside through the wall
(no vertical dryer vents through the roof). Also the
vent must be at least 10 ft. away from any air conditioning
condensers or the inlet for the fresh air supply to
Bathroom and kitchen vents must exhaust to outside
The central vacuum should exhaust to outside, not in
All bathrooms must have operable windows.
The inside door to the garage must have spring loaded hinges
or equivalent so that it cannot stay in the open position
for extended periods of time.
Dehumidification / Ventilation System
Must have central dehumidification system with separate
RH controller so that RH can be controlled year round to
stay below 55% independent of temperature
Must have central ventilation system providing positive
or neutral (rather than negative) pressure ventilation distributing
ventilation air to at least 3 different points in the house
24 hrs/day. The ventilation rate should be at least 30 cfm
for the master bedroom and an additional 15 cfm for each
additional bedroom. Must have visible indication of system
status and failure.
The air intake vent must have a damper which can be closed
during episodes of bad outdoor air (e.g. road work, forest
The central house filter must have an ASHRAE dust spot efficiency
of 35% or better.
ventilation air filter must have an ASHRAE dust spot efficiency
of 35% or better.
filters must be certified by the manufacturer to be usable
for low pressure residential air handling systems.
All filter housings must be airtight so that there is no
air bypass around the filter.
Air filtration equipment must not produce any ozone.
and Air Sealing
Blown dry insulation which may enter the house by air movement
is NOT allowed.
Sill sealant between bottom plates and foundation.
Tub drains and other floor drain areas sealed to prevent
radon and other soil gas entry.
Careful detailing at wall corners, band joists, and garage
areas to assure air tightness and uniform insulation coverage.
Air and water seal between wall and door/window assembly.
Vapor retarders, if applied, should be on the exterior side
of the wall/ceiling assembly.
Minimum of R-30 insulation on all surfaces that is mated
to the attic.
Eave detailed to allow insulation over top plate and good
ventilation from soffit vents.
All top plate penetrations sealed. Care should be taken
to preclude any air movement to or from the attic space
and the conditioned space. This would include non-uniform
framing details, varying ceiling heights, electrical boxes,
All dropped ceiling areas and tray ceilings to be uniformly
insulated. If insulation follows the bottom chord of the
truss and not the top surface of the ceiling, then a mechanical
support system must be used to hold the insulation in place.
(Paper is not a support system.)
All kneewall areas to have insulation tightly held in place
Batted insulation in ceiling areas must be detailed carefully
to prevent air convection around insulation.
Minimum of R-19 insulation on all surfaces between the “conditioned
attic” space and the exterior.
The thermal and air barriers must be continuous as it transitions
from the wall assembly to the attic assembly
and Combustion appliances
Any fireplace used must be direct vent, sealed combustion
type preferably on an exterior wall. No wood burning fireplace.
All combustion appliances should be sealed combustion devices
or located in spaces with provisions for outside air so
that the spaces cannot go to severe negative pressures (i.e.
the house has any combustion appliances install a continuous
reading line powered (with battery backup) CO sensor.
Ductwork and Air Handler:
meet current state duct sealing code requirements.
Air tight supply and return ducts. Duct leakage (including
air handler) to outside not to exceed 30cfm25 per 1000 sq.
ft. of house.
All bedrooms to have individual jump ducts or return ducts
or transfer grills so that positive pressures in bedrooms
do not exceed +2.5 Pa when interior doors are closed. This
criteria is achieved by using at least 50 square inches
of free return or transfer grill area per 100 cfm of supply
air. The free area at a door undercut can be counted in
the return area calculations.
The air handler closet when closed must maintain a slight
positive or neutral pressure with respect to the attic and
neutral with respect to rest of the house.
All return air stream surfaces must be metal or other reasonably
tough surface which is easy to clean by duct cleaning methods.
fiberglass duct work and register boots must be made of
coated or lined fiberglass duct board. Also seal fiberglass
cut lines on the inside to prevent loose fiberglass from
entering the air stream.
Duct collar to register boots and all duct joints and seams
sealed with mesh and mastic. No tapes or ties as primary
Register boot to ceiling drywall sealed with mastic or caulked
with acrylic water based caulk.
Building cavities may not be used as part of the forced
air distribution system for heating, cooling or ventilation.
Condensate drain trap with adequate design for cleanout
and verified trap performance.
Air handler to have smooth insulation on surfaces contacting
the air stream.
condensate drain pan must have a good slope to assure good
drainage. It should be installed such that air in the drainage
line is at a positive pressure relative to the ambient.
Size the air conditioner correctly per industry accepted
manual J procedure. Calculations must be provided upon request.
Air handler return air flow at design conditions must meet
manufacturer specified air flow over the cooling coil.
Thermostat and other HVAC system controls must NOT operate
the blower for a few minutes after the compressor shuts
off in the cooling mode. OK to do it in the heating mode.
recessed can lights must be IC rated and airtight (unless
unvented attic with roofline insulation)
All bathrooms must have exhausts vented to outside with
30 or 60 min crank timers. The timers should work just the
exhaust fan. The lights should be separately controlled.
must have direct vent to outside with the hood capturing
fumes from all burners. For kitchen exhausts with a exhaust
flow >200 cfm, provide fresh make up air.
Install a line powered (not battery powered) CO sensor with
a continuous readout.
low VOC caulks and adhesives and sealers
Use Zero VOC interior paint
All wood cabinets preferred, particle board ok if coated
on all sides.
pine or plywood for flooring on second floor (rather than
OSB) and stairs.
No OSB to be used for built in areas
Minimize carpets, all carpets must be 100% Nylon and have
CRI green label, low pile preferred
Carpet pad not to be "rebond". Use synthetic fibre
or virgin urethane with no glues.
or other wood type flooring to be carefully screened to
have low VOC emissions (including low VOC during installation)
vinyl wall paper any where on an exterior wall surface.
Avoid siting the house on the down wind side of large empty
fields of grasses, weeds or near large stands of oak trees.
Minimize pollen producing trees near the house. Avoid Oaks,
Cypress, Cedar and Elm trees.
Avoid large amounts of flowering and pollinating plants
inside or outside the house.
addition to manuals provided by equipment manufacturers,
the home builder must provide a comprehensive home owners
manual listing all recommended cleaning and maintenance
required for a long lasting home with excellent indoor air
more information regarding the technical aspects of the standard
Subrato Chandra, Ph.D.
Florida Solar Energy Center
1679 Clearlake Rd
Cocoa, Fl 32922
Phone: 321-638-1412 Fax:321-638-1439