Helps furnaces function properly:
gas and wood heating appliances need combustion air to operate. Furnaces
need a minimum of 5 cu ft. of space for every 1,000 BTU/HR they produce. That
means that for a 100,000 BTU furnace-- it needs to be located in a space that
has a minimum volume (with the doors closed) of 5,000 cubic feet, or it is
considered to be in confined space and needs an outside air source.
Unfortunately, not all houses are built correctly with this in mind. I've
seen large furnaces in 800 cubic foot rooms. If your furnace is in a small room
it may not function without the addition of an outside air source.
about the air you breathe:
Indoor air pollution is the #1 public health hazard.
(Environmental Protection Agency)
50% of all illnesses are either caused or aggravated
by polluted indoor air. (American College Of Allergists)
Children, the elderly, and those suffering with
breathing problems or allergies are especially sensitive to indoor air
pollutants. (Dept. Of Consumer Affairs)
Plusaire« supplies fresh
air to a house, correcting indoor air quality, excessive condensation and negative air pressure. Tight houses could display any or
all of these symptoms causing health problems for
the occupants. A US Plusaire« whole
house ventilator will provide warmed fresh air at the rate your house is
exhausting or using it in the most cost effective manner.
Expressed simply, US
Plusaire« supplies warmed fresh air to your house at a rate equal to
or greater than the rate at which your house is using it.
Mechanical ventilation is when a fan
is used to draw air into the house. Passive ventilation is the same
as opening a window. Air is free to enter as its required. US
uses both methods to bring air into the house.
Firstly air is mechanically drawn
into the house by the furnace fan during the heat cycle, this is the time when
more oxygen is burnt and exhausted up the chimney than at any other time. Air is
also mechanically exhausted by the various fans such as in the bathroom, clothes
dryer, central vacuum, and kitchen causing outside air to be drawn into the
house through US Plusaire«.
Without an entry point for the replacement air it would
have to find it's way in through holes in the house structure, or depressurize
Secondly, when the furnace fan is
off, fresh air is drawn into the house through US Plusaire« by the combusting appliances such as a wood stove or fire
place. The air that is being combusted must be replaced and US
Plusaire« does this in the most economical way.
Remember for every cubic foot of air that
leaves a house a cubic foot must be brought in to replace it. The diagram shows
the method of installation and the air flows.
Other problems that can be
corrected with US
Fireplaces, wood stoves and inserts sometimes
experience back drafting. This is generally blamed on the wind or the chimney
not being high enough. To really solve
the problem first it has to be correctly defined.
Smoke or fumes come out of the heater when
the door is opened, or the fire is difficult to light because of cold air coming
down the chimney. In most cases it's because the house is at a lower pressure
than outside and the air is being sucked backwards down the chimney. The problem
can be worse when it's windy so generally the wind gets the blame. There is a
name for this phenomena, it is called Stack Effect.
Stack Effect is occurring because the
house is acting as a better chimney than the chimney. All of the air within the
house is warmer and more buoyant than the air outside and therefore wants to
rise. If there is an opening in the uppermost part of the house then the warm
air will find it and leak outwards. This creates a powerful draw in the lower
part of the home pulling cold air in through the easiest opening; the chimney.
The areas that leak in the upper most parts of the house are the attic access
hatch, ceiling light fixtures, and poorly fitting windows. Each of these areas
can be reworked to stop the air leaks. By doing this it will not only reduce the
Stack Effect but your heating bills will also be reduced. What cannot be changed
are the various exhaust fans that blow air out of the house. These can create a
Stack Effect which can only be corrected by adding air to the house to balance
the air that is being blown out. The cure to Stack Effect is therefore a
combination of adding adequate ventilation air and sealing the leaks in the
upper most areas of the house. Sealing air leaks only in the basement can
aggravate the situation.
Remember for every cubic foot of air that
leaves a house, a cubic foot of air must be brought in to replace it.
handle the ventilation and combustion air, the other measures can be easily
corrected by the homeowner.
The Consumer Federation of America cites
that indoor air pollution is responsible for up to 50% of all illness. Estimated
cost in medical bills and lost work time amount to over $100 billion annually.
Medical Association has stated
that with the reduction of fresh air entering a home, increased levels of Radon gasand
other know carcinogens have been detected. The pollutants are know to cause
serious health problems.
Indoor air quality, or lack of it, can be
identified by the three
"B's" of ventilation.
The first "B"
Consider all of the people and pets
breathing in air and out
dioxide. Each breath reduces
the amount of oxygen that is available within the house. If the house is tight
then the oxygen content will lessen and air quality will deteriorate.
The second "B"
is blowing. Take
into consideration all the fans within the house, bathroom, kitchen, clothes
dryer, central vacuum, power vented furnace or water heater each of these blows
air out, not one is designed to bring air in to balance itself. Too much air
being blown out of a house can lead to depressurization. Smoke escaping from a
stove is one indication that
your house is being depressurized. Few people realize that they have a down
draft problem but freely admit to having that nice woodsy aroma. That nice
woodsy aroma turns to a nasty creosote smell in the early hours of the morning.
The third "B"
and concerns all of the
appliances that heat or involve the combustion process. These appliances include
a furnace, water heater, fireplace,woodstove, cooker, toaster
and toaster oven. When these appliances are working they simply burn up the
oxygen again reducing the amount available for breathing. If you leave a fireplace burning, in the early hours of the morning,
when the fire is nearly out and the furnace comes on, there is enough draw up
the furnace flue to reverse the flow in the
fireplacechimney, thereby creating a downdraft and
the nasty smell associated with it. This can also work in reverse where furnace
fumes can be drawn out of a flue by a briskly burning fire, these fumes are
dangerous and could lead to carbon
If your house is closed up and does not
have adequate ventilation, when morning comes you can actually smell the residue
from the wood fire or the previous days activities, couple these with the
household chemicals and the off gassing from furniture and carpets and you can
see that you are living in a soup of low pressure polluted air. The easy answer
is to open a window in each room however this solution is not always practical
since the air coming in will be cold and your heating bills will go up very
quickly. Obviously you need fresh air but in a controlled fashion and at the
lowest possible cost. What is required is a ventilation system that is able to
supply warmed fresh air, be able to compensate for negative air pressures,
supply combustion air at a place and time when needed and be cheaper to run than
opening a window. Fortunately the US Plusaire«
system was designed to do
Carbon monoxide (CO) is called the silent
killer or the silent threat. This is because it is colorless, odorless, and
silent. It is formed as a by-product of combustion of carbon based fuels such as
natural gas, propane (LPG), coal, coke, furnace oil, kerosene and wood. Carbon
monoxide is absorbed by breathing and is 245 times more absorbent to the body
than oxygen. Symptoms of poisoning can be misdiagnosed as flu since they are
Dizziness and blurred
Nausea and vomiting
Confusion, weakness of
Insomnia and constantly
Cherry colored skin
High concentrations of 4000 parts per
million can kill in minutes but lesser amounts can produce any or all of the
above symptoms. A level of nine parts per million is reckoned to be the maximum
safe level over 24 hours which is very little so you can see just how deadly it
is. It is highly recommended that CO detectors be installed in your home at
places recommended by the manufacturer. These detectors can be purchased for
around $30, a small price to pay for protection.
The appliances that can generate CO within
your house are the furnace, boiler, water heater, un-vented fuel burning heaters
and solid fuel burning appliances. The three main problems are improper
installation, chimney or vent blocked by bricks or birds nests etc. and
inadequate ventilation, providing insufficient air to properly fuel the
Improper installation can be easily
checked by referring to the manufacturers installation instructions and by
having your heating system checked yearly by a qualified professional. A flue
system should be checked by a professional at the beginning and end of each
burning season and cleaned accordingly. A flue that is in poor condition will be
easily spotted and the appropriate action taken prior to disaster.
Supplying adequate combustion air is very
simple. A window opened in the room of the appliance is a good, cheap method but
not too practical since it will allow cold air in unless you close it when the
appliance goes off. A better solution is a US
sized for the house. It will supply not only adequate combustion air but
also ventilation air to compensate for any of the exhaust fans that tend to
depressurize the house.
Radon is an odorless invisible gas that is
produced naturally by the decay of the element of uranium. On average about six
atoms of Radon emerge from every square inch of soil per second. In the air
Radon is diluted to about 2 Pico curies per liter of air which is not dangerous
but in concentrations it has been found to cause lung cancer.
Radon gas can enter a house through a soil
floor or through any crack or hole in or around the basement.
Since prevention is better than cure it
would be wise to prevent any Radon from concentrating within the house. This can
be done in two ways:
First, by sealing up any crack or hole in
the basement wall and covering any earth floor with plastic sheeting. There are
companies that specialize in Radon protection sealing.
The second is to increase the ventilation
in the house so that concentrations cannot build up. All houses should have a
complete air change every three to four hours. This level of air change has been
found to be the most economical balancing air quality with heating costs.
Supplying adequate air is very
simple. A window opened in each room is a good, cheap method but not too
practical since it will allow cold air to enter. A better solution is a US
Plusaire« correctly sized
for the house. It will supply not only adequate ventilation air but also
combustion air to compensate for any of the combusting appliances that burn up
the oxygen in the house.
In the mid 1970's new houses were constructed
and were advertised as being energy efficient. This trend has grown to the
present. Now the houses are so energy efficient that some people boast of $300
yearly fuel bills. Building an energy efficient home really meant using better
built windows and doors and sealing up the structure to stop the outside air
from leaking in and the inside air from leaking out.
Unfortunately what was not apparent was
that the older houses had air leaks which supplied combustion and ventilation
air. What was starting to happen was that the energy efficient houses were
becoming tighter and indoor air quality was deteriorating as a result. The
tighter the house the worse the condition. Combustion and ventilation air is not
able to infiltrate into the house and combustion devices are being starved of
air. There is no replacement air for the exhaust fans to blow out which causes
the house to depressurize. Depressurizing a house can lead to a new set of
problems including carbon
monoxide poisoning. The
problem is not confined to new houses.
Anyone who has renovated with a few tubes
of caulking, new windows, doors or siding, has changed the air infiltration
rate. In every case the cost of heating would be less, but, tightening up the
structure, without considering the need for combustion or ventilation air, can
Symptoms of a too tight house are
condensation on the windows, smoke escaping from the fireplace or wood stove,
mold or mildew growing in corners or cupboards, residual smoking or cooking
odors and a general stale smell especially in the mornings. Another common sign
is a high humidity level that cannot be corrected.
While these symptoms are unpleasant and
undesirable, symptomatic health problems can be far moreserious. Constant headaches,
dizziness, sleepiness, watery eyes, coughing, breathing difficulties and in some cases
death can be attributed to houses with poor air. Most susceptible are the very
young and the elderly. Asthma sufferers and people with allergies are especially
susceptible to poor quality air.
Since the tightness of the house is
causing the health problems then it follows that if the house is made less tight
then related health problems will also cease. The common thread linking all of
these symptoms together is the lack of ventilation, and this can be verified
quite easily by following some simple steps. Begin by opening a window about
1", on each floor. Leave the windows open for 24 hours or until the house
symptoms are gone and then close the upper most window each day until the
symptoms reappear. This test requires very little effort and will only cost some
heat. Measure the amount of opening that is left and that is the amount of
opening that must be provided in the outside wall. This test will verify that
you have a lack of ventilation air.
The simplest form of adding ventilation
and combustion air is to keep the windows open but since the air coming in would
be freezing cold it is not too practical. What is required is a device that
brings in outside air, warms it, delivers it around the house and is as cheap to
operate as opening a window. A US Plusaire«
correctly sized for the house
is such a device.