United States Environmental
Protection Agency
Office of Air and Radiation, Office of Radiation
and Indoor Air (6604J)
402-K92-003
August 1992
Table of
Contents
Overview
Introduction
How Radon Enters
Your House
Radon is a
Cancer-Causing Radioactive Gas
What Do Your
Radon Test Results Mean?
Why Hire a
Contractor ?
Why Use a
State-Certified and/or Privately Certified Radon Professional?
How to
Select a Contractor
-- Get Estimates
-- The Contract
What to Look
for in a Radon Reduction System
-- Installation and Operating
Costs
-- How a Radon Reduction System May Affect Your Home
Radon
Reduction Techniques
-- House
Foundation Types
---- Basement and Slab-on-Grade Houses
----
Crawlspace Houses
-- Other Types of
Radon Reduction Methods
Does Your
Contractor's Work Meet RPP Requirements?
Living in a
House with a Radon Reduction System
-- Maintaining Your Radon
Reduction System
-- Remodeling Your Home After Radon Levels Have Been
Lowered
Buying or
Selling a Home?
Do You Have a
Well?: Radon in Water
-- What Do the Results of Your Water Test
Mean?
-- How is Radon Removed from Water?
Installation
and Operating Cost Table
How to Order
This Guide
Reduce Radon Levels In Your
Home
Radon is the second leading cause of lung
cancer. The Surgeon General and the EPA recommend testing for radon and
reducing radon in homes that have high levels. Fix your home if your
radon level is confirmed to be 4 picoCuries per liter (pCi/L) or higher.
Radon levels less than 4 pCi/L still pose a risk, and in many cases may
be reduced. If you smoke and your home has high radon levels, your risk
of lung cancer is especially high.
Select A State Certified
And/Or RPP Contractor
Choose a radon contractor to fix
your home who is state certified and/or listed for radon reduction
[mitigation] in EPA's National
Radon Proficiency Program (RPP). RPP-listed mitigation contractors are trained, must pass a comprehensive exam, and must agree to follow standards developed to ensure effective radon reduction. Call your state radon office for a list of qualified contractors in your area.
Radon Reduction Techniques
Work
Radon reduction systems work. Some
radon reduction systems can reduce radon levels in your home by up to
99%. The cost of fixing a home generally ranges from $500 to $2500. Your
costs may vary depending on the size and design of your home and which
radon reduction methods are needed. Thousands of people have reduced
radon levels in their homes.
Maintain Your Radon Reduction
System
Maintaining your radon reduction
system takes little effort and keeps the system working properly and
radon levels low.
| Consumer
Federation of America strongly urges consumers to have
elevated radon levels in their homes reduced. EPA's "Consumer's
Guide to Radon Reduction" will assist those individuals and offers
very good advice for selecting and working with a qualified radon
contractor. |
Return to the Table of Contents
Introduction
You have tested your home for
radon, but now what? This booklet is for people who have tested their
home for radon and confirmed that they have elevated radon levels -- 4
picoCuries per liter (pCi/L) or higher.
This booklet can help
you:
- Select a qualified contractor to reduce
the radon levels in your home
- Determine an appropriate radon reduction
method
- Maintain your radon reduction
system
If you want information on how to test your home for radon, call your state radon office and ask for a copy of A Citizen's Guide to
Radon.
How Radon
Enters Your House
Radon is a naturally occurring gas
produced by the breakdown of uranium in soil, rock, and water. Air
pressure inside your home is usually lower than pressure in the soil
around your home's foundation. Because of this difference in pressure,
your house acts like a vacuum, drawing radon in through foundation
cracks and other openings. Radon may also be present in well water and
can be released into the air in your home when water is used for
showering and other household uses. In most cases, radon entering the
home through water is a small risk compared with radon entering your
home from the soil. In a small number of homes, the building materials
can give off radon, although building materials rarely cause radon
problems by themselves.
Radon is a
Cancer-causing, Radioactive Gas
Radon is estimated to cause many
thousands of lung cancer deaths each year. In fact, the Surgeon General
has warned that radon is the second leading cause of lung cancer in the
United States. Only smoking causes more lung cancer deaths. If you smoke
and your home has high radon levels, your risk of lung cancer is
especially high.
What Do Your
Radon Test Results Mean?
The amount of radon in the air is
measured in "picoCuries of radon per liter of air," or "pCi/L."
Sometimes test results are expressed in Working Levels, "WL," rather
than picoCuries per liter of air. A level of 0.02 WL is usually equal to
about 4 pCi/L in a typical home.
Any radon exposure has some risk
of causing lung cancer. The lower the radon level in your home, the
lower your family's risk of lung cancer. The U.S. Congress has set a
long-term goal that indoor radon levels be no more than outdoor levels;
about 0.4 pCi/L of radon is normally found in the outside air. EPA
recommends fixing your home if the results of one long-term test or the
average of two short-term tests taken in the lowest lived in level of
the home show radon levels of 4 pCi/L (or 0.02 WL) or higher. A
short-term test remains in your home for two days to 90 days, whereas a
long-term test remains in your home for more than 90 days. With today's
technology, radon levels in most homes can be reduced to 2 pCi/L or
below.
Have You
Confirmed Your Radon Test?
If your first short-term test
result is 4 pCi/L or higher (or 0.02 WL or more), EPA recommends that
you take a second test to be sure. For a better understanding of your
year-round average radon level, take a long-term test. If you need
results quickly, take a second short-term test and average it with the
first. The higher your initial short-term test result, the more certain
you can be that you should take a short-term rather than a long-term
follow-up test. If your first short-term test result is several times
the action level -- for example, about 10 pCi/L or higher -- you should
take a second short-term test immediately.
Why use a
tester or a test kit that meets EPA requirements?
Whether you use a short- or
long-term test, use a device and a testing company that is state
certified and/or is listed in
EPA's Radon Proficiency Program (RPP). If you want to use a do-it-yourself
test kit, use one that displays the phrase "Meets EPA Requirements." EPA's RPP Program is designed to help assure that consumers get reliable radon measurement and mitigation services. If you want to hire a professional to take the measurement contact your state radon office for a current list of state certified and/or RPP listed companies and individuals. Listed RMP Program participants must follow quality assurance and EPA measurement procedures and have demonstrated the ability to take reliable measurements with specific devices. Your state may also have additional requirements for professional radon testers.
Return to the Table of Contents
Why Hire a
Contractor?
EPA recommends that you have a
qualified contractor fix your home because lowering high radon levels
requires specific technical knowledge and special skills. Without the
proper equipment or technical knowledge, you could actually increase
your radon level or create other potential hazards. But, if you decide
to do the work yourself, get information on appropriate training courses
and copies of EPA's technical guidance documents from your state radon
office.
Why Use A
State-Certified And/Or RPP Contractor?
EPA recommends that you use a
contractor trained to fix radon problems. The radon mitigation
contractor portion of EPA's National Radon Proficiency Program (RPP)
requires contractors to take training courses and pass an exam before
being listed as proficient. EPA maintains a list of radon contractors
who meet RPP requirements. RPP mitigation contractors carry a current
RPP photo identification card and all RPP contractors are required to
follow EPA standards to make sure that their work meets minimum quality
standards. A number of states have their own contractor certification
programs which have additional requirements. Check with your state radon
office to see if the contractor you are considering is state certified
and/or RPP listed.
How To
Select A Contractor
Get Estimates
Choose a contractor to fix a radon
problem just as you would choose someone to do other home repairs. It is
wise to get more than one estimate, to ask for references, and to
contact some of those references to ask if they are satisfied with the
contractors' work. Also, ask your county or state consumer protection
office for information about the contractors.
Use this check-list when
evaluating and comparing contractors and ask the following
questions:
| Yes |
No |
| |
|
Will the
contractor provide references or photographs, as well as test
results of 'before' and 'after' radon levels of past radon
reduction work?
|
| |
|
Can the
contractor explain what the work will involve, how long it will
take to complete, and exactly how the radon reduction system will
work?
|
| |
|
Does the
contractor charge a fee for any diagnostic tests? Although many
contractors give free estimates, they may charge for diagnostic
tests -- these tests help determine what radon reduction system
should be used, but are not always necessary (see "Radon Reduction
Techniques" below for more on diagnostic tests).
|
| |
|
Did the
contractor inspect your home's structure before giving you an
estimate?
|
| |
|
Did the
contractor review the quality of your radon measurement results
and determine if EPA testing procedures were followed? [An RPP
requirement]
|
Compare the contractors' proposed
costs and consider what you will get for your money. Take into account
the following: a system that is less expensive to install may have
higher operating and maintenance costs than a system that is more
expensive to install; the best system for your house may be the more
expensive option; and the quality of the building material will affect
how long the system lasts.
Do the contractors' proposals
and estimates include:
| Yes |
No |
| |
|
Proof of
liability insurance and being bonded and
licensed?
|
| |
|
Proof of state
certification and/or RPP Listing?
|
| |
|
Diagnostic
testing prior to design and installation of a radon reduction
system?
|
| |
|
Installation of
a warning device to caution you if the radon reduction system is
not working correctly? [An RPP Requirement]
|
| |
|
Testing after
installation to make sure the radon reduction system works well?
[An RPP requirement]
|
| |
|
A guarantee to
reduce radon levels to 4 pCi/L or below, and if so, for how
long?
|
The Contract
Ask the contractor to prepare a
contract before any work starts. Carefully read the contract before you
sign it. Make sure everything in the contract matches the original
proposal. The contract should describe exactly what work will be done
prior to and during the installation of the system, what the system
consists of, and how the system will operate. Carefully consider
optional additions to your contract which may add to the initial cost of
the system, but may be worth the extra expense. Typical options might
include a guarantee that the contractor will adjust or modify the system
to reach the promised radon level, or an extended warranty and/or a
service plan.
Important information that should
appear in the contract includes:
- The total cost of the job, including all
taxes and permit fees; how much, if any, is required for a deposit;
and when payment is due in full.
- The time needed to complete the
work.
- An agreement by the contractor to obtain
necessary licenses and follow required building codes.
- A statement that the contractor carries
liability insurance and is bonded and insured to protect you in case
of injury to persons, or damage to property, while the work is
done.
- A guarantee that the contractor will be
responsible for damage and clean-up after the job.
- Details of warranties, guarantees, or
other optional features, including the acceptable resulting radon
level.
- A declaration stating whether any
warranties or guarantees are transferable if you sell your
home.
- A description of what the contractor
expects the homeowner to do (e.g., make the work area accessible)
before work begins.
What to
Look for in a Radon Reduction System
In selecting a radon reduction
method for your home, you and your contractor should consider several
things, including: how high your initial radon level is, the costs of
installation and system operation, your house size and your foundation
type.
Installation and Operating
Costs
For most homes, radon reduction
measures are no more expensive than having a new hot water heater
installed or having the house painted. The cost of a contractor fixing
a home generally ranges from $500 to $2500, depending on the
characteristics of the house and choice of radon reduction
methods.
Most types of radon reduction
systems cause some loss of heated or air conditioned air, which could
increase your utility bills. How much your utility bills will be
affected depends on the climate you live in, what kind of reduction
system you select, and how your house is built. Systems that use fans
are more effective in reducing radon levels; however, they will
increase your electric bill. The table below lists the installation
and average operating costs for different radon reduction systems and
describes the best use of each method.
How a Radon Reduction System
May Affect Your Home
In order to minimize the effect
of installing a radon reduction system in your house, ask your
contractor before any work starts how the system can be made to blend
with its surroundings. For instance: radon vent pipes may be encased
with materials that match the exterior of your house, or the pipes may
be routed up through closets.
Return to the Table of Contents
Radon
Reduction Techniques
There are several methods that a
contractor can use to lower radon levels in your home. Some techniques
prevent radon from entering your home while others reduce radon levels
after it has entered. EPA generally recommends methods which prevent the
entry of radon. Soil suction, for example, prevents radon from entering
your home by drawing the radon from below the house and venting it
through a pipe, or pipes, to the air above the house where it is quickly
diluted.
Any information that you may have
about the construction of your house could help your contractor choose
the best system. Your contractor will perform a visual inspection of
your house and design a system that considers specific features of your
house. If this inspection fails to provide enough information, the
contractor will need to perform diagnostic tests to help develop the
best radon reduction system for your home. For instance, your contractor
can use a "smoke gun" to find the source and direction of air movement.
A contractor can learn air flow sources and directions by watching a
small amount of smoke that he or she shot into holes, drains, sumps, or
along cracks. The sources of air flow show possible radon
routes.
Another type of diagnostic test is
a "soil communication test." This test uses a vacuum cleaner and a smoke
gun to determine how easily air can move from one point to another under
the foundation. By inserting a vacuum cleaner hose in one small hole and
using a smoke gun in a second small hole, a contractor can see if the
smoke is pulled down into the second hole by the force of the vacuum
cleaner's suction. Watching the smoke during a soil communication test
helps a contractor decide if certain radon reduction systems would work
well in your house.
Whether diagnostic tests are
needed is decided by details specific to your house, such as the
foundation design, what kind of material is under your house, and by the
contractor's experience with similar houses and similar radon test
results.
House
Foundation Types
Your house type will affect the
kind of radon reduction system that will work best. Houses are generally
categorized according to their foundation design. For example: basement,
slab-on-grade (concrete poured at ground level), or crawlspace (a
shallow unfinished space under the first floor). Some houses have more
than one foundation design feature. For instance, it is common to have a
basement under part of the house and to have a slab-on-grade or
crawlspace under the rest of the house. In these situations a
combination of radon reduction techniques may be needed to reduce radon
levels to below 4 pCi/L.
Radon reduction systems can be
grouped by house foundation design. Find your type of foundation design
above and read about which radon reduction systems may be best for your
house.
Basement and Slab-on-Grade
Houses
In houses that have a basement
or a slab-on-grade foundation, radon is usually reduced by one of four
types of soil suction: subslab suction, drain tile suction, sump hole
suction, or block wall suction.
Active Subslab suction (also
called subslab depressurization) is the most common and usually the
most reliable radon reduction method. Suction pipes are inserted
through the floor slab into the crushed rock or soil underneath. They
also may be inserted below the concrete slab from outside the house.
The number and location of suction pipes that are needed depends on
how easily air can move in the crushed rock or soil under the slab,
and on the strength of the radon source. A contractor usually gets
this information from visual inspection, from diagnostic tests, and/or
from experience. Acting like a vacuum cleaner, a fan connected to the
pipes draws the radon gas from below the house and then releases it
into the outdoor air. Passive subslab suction is the same as active
subslab suction except it relies on air currents instead of a fan to
draw radon up from below the house. Passive subslab suction is
generally not as effective in reducing high radon levels as active
subslab suction.
Some houses have drain tiles to
direct water away from the foundation of the house. Suction on these
drain tiles is often effective in reducing radon levels if the drain
tiles form a complete loop around the foundation.
One variation of subslab and
drain tile suction is sump hole suction. Often, when a house with a
basement has a sump pump to remove unwanted water, the sump can be
capped so that it can continue to drain water and serve as the
location for a radon suction pipe.
Block wall suction can be used
in basement houses with hollow block foundation walls. This method
removes radon from the hollow spaces within the basement's concrete
block wall. It is often used together with subslab suction.
Crawlspace
Houses
In houses with crawlspaces,
radon levels can sometimes be lowered by ventilating the crawlspace
passively (without the use of a fan) or actively (with the use of a
fan). Crawlspace ventilation lowers indoor radon levels both by
reducing the home's suction on the soil and by diluting the radon
beneath the house. Natural ventilation in a crawlspace is achieved by
opening vents, or installing additional vents. Active ventilation uses
a fan to blow air through the crawlspace instead of relying on natural
air circulation. In colder climates, for either natural or active
crawlspace ventilation, water pipes in the crawlspace need to be
insulated against the cold.
Another effective method to
reduce radon levels in crawl space houses involves covering the earth
floor with a heavy plastic sheet. A vent pipe and fan are used to draw
the radon from under the sheet and vent it to the outdoors. This form
of soil suction is called sub membrane depressurization.
Other
Types of Radon Reduction Methods
Other radon reduction techniques
that can be used in any type of house include: sealing, house
pressurization, natural ventilation, and heat recovery ventilation.
Most of these methods are considered to be either temporary measures,
or only partial solutions to be used in combination with other
measures.
Sealing cracks and other
openings in the foundation is a basic part of most approaches to radon
reduction. Sealing does two things, it limits the flow of radon into
your home and it reduces the loss of conditioned air, thereby making
other radon reduction techniques more effective and cost-efficient.
EPA does not recommend the use of sealing alone to reduce radon
because, by itself, sealing has not been shown to lower radon levels
significantly or consistently. It is difficult to identify and
permanently seal the places where radon is entering. Normal settling
of your house opens new entry routes and reopens old ones.
House pressurization uses a fan
to blow air into the basement or living area from either upstairs or
outdoors. It attempts to create enough pressure at the lowest level
indoors (in a basement for example) to prevent radon from entering
into the house. The effectiveness of this technique is limited by
house construction, climate, other appliances in the house, and
occupant lifestyle. In order to maintain enough pressure to keep radon
out, the doors and windows at the lowest level must not be left
opened, except for normal entry and exit.
Some natural ventilation occurs
in all houses. By opening windows, doors, and vents on the lower
floors you increase the ventilation in your house. This increase in
ventilation mixes radon with outside air and can result in reduced
radon levels. In addition, ventilating your house can help to lower
indoor radon levels by reducing the vacuum effect. Natural ventilation
in any type of house, (aside from ventilation of a crawlspace), should
normally be regarded as a temporary radon reduction approach because
of the following disadvantages: loss of conditioned air and related
discomfort, greatly increased costs of conditioning additional outside
air, and security concerns.
A heat recovery ventilator
(HRV), also called an air-to-air heat exchanger, can be installed to
increase ventilation. An HRV will increase house ventilation while
using the heated or cooled air being exhausted to warm or cool the
incoming air. HRVs can be designed to ventilate all or part of your
home, although they are more effective in reducing radon levels when
used to ventilate only the basement. If properly balanced and
maintained, they ensure a constant degree of ventilation throughout
the year. HRVs also can improve air quality in houses that have other
indoor pollutants. There could be significant increase in the heating
and cooling costs with an HRV, but not as great as ventilation without
heat recovery (see "Installation and Operating Cost Table"
below).
Return to the Table of Contents
Does Your
Contractor's Work Meet RPP Requirements?
There are certain basic
requirements that all radon reduction systems should meet. RPP
Mitigation Service Providers (formerly known as RCP Contractors) must
meet the following performance standards (for a complete list of RPP
standards call your state office). Some states have similar
requirements:
- Radon reduction systems must be clearly
labeled. This will avoid accidental changes to the system which could
disrupt its function.
- The exhaust pipes of soil suction systems
must vent 10 feet or more above the ground, and away from windows,
doors, or other openings that could allow the radon to reenter the
house.
- The exhaust fan must be located in an
unlivable area. For instance, it should be in an un-occupied attic of
the house or outside - not in a basement!
- If installing an exhaust fan outside, the
contractor must install a fan that meets local building codes for
exterior use.
- All active radon reduction systems require
electrical connections that must be installed according to local
electrical codes.
- A warning device must be installed to
alert you if the system stops working properly. Examples of system
failure warning devices are: a liquid gauge, a sound alarm, a light
indicator, and a dial (needle display) gauge.
- A warning device must be placed where it
can be seen or heard easily. If your monitor shows that the system is
not working properly, call a contractor to have it checked.
- RPP contractors must make sure a follow-up
radon test is done within 30 days of system installation, but no
sooner than 24 hours after your system is in operation with the fan
on, if it has one. To test the system's initial effectiveness, a 2-7
day measurement is recommended. Test conditions: windows and doors
must be closed 12 hours before and during the test, except for normal
entry/exit.
- RPP contractors must recommend that you
get an independent follow-up radon measurement. Having an independent
tester perform the test, or conducting the measurement yourself, will
eliminate any potential conflict of interest.
Your RPP contractor should also
check that your radon reduction system's warning device works. Make sure
your contractor completely explains your radon reduction system,
demonstrates how it operates, and explains how to maintain it. Ask for
written operating and maintenance instructions and copies of any
warranties.
Return to the Table of Contents
Living in
a House with a Radon Reduction System
Maintaining Your Radon
Reduction System
Similar to a furnace or chimney,
radon reduction systems need some occasional maintenance. You should
look at your warning device on a regular basis to make sure the system
is working correctly. Fans may last for five years or more (although
manufacturer warranties tend not to exceed three years) and may then
need to be repaired or replaced. Replacing a fan will cost around $250
including parts and labor. By testing at least every two years, you will
confirm that your radon level is staying low and that your fan is still
performing well.
Remember, the fan should NEVER be
turned off; it must run continuously for the system to work
correctly.
The filter in an HRV requires
periodic cleaning and should be changed twice a year. Replacement
filters for an HRV are easily changed and are priced between $5 and $15.
Ask your contractor where filters can be purchased. Also, the vent that
brings fresh air in from the outside needs to be inspected for leaves
and debris. The ventilator should be checked annually by a heating,
ventilating, and air-conditioning professional to make sure the air flow
remains properly balanced. HRVs used for radon control should run all
the time.
Remodeling Your Home After
Radon Levels Have Been Lowered
If you decide to make major
structural changes to your home after you have had a radon reduction
system installed (such as converting an unfinished basement area into
living space), ask your radon contractor whether these changes could
void any warranties. After you remodel, retest in the lowest lived-in
area to make sure the construction did not reduce the effectiveness of
the radon reduction system. If you are adding a new foundation for an
addition to your house, address the radon problem during
construction.
Return to the Table of Contents
Buying
or Selling a Home?
If you are buying or selling a
home and need to make decisions about radon, consult EPA's Home Buyer's
and Seller's Guide to Radon. If you are selling a home that has a radon
reduction system, inform potential buyers and supply them with
information about your system's operation and maintenance.
If you are buying a new house,
consider that it is almost always less expensive to build
radon-resistant features into new construction than it is to fix an
existing house that has high radon levels. Ask your builder if he or she
uses radon-resistant construction features. Your builder can refer to
EPA guidance about radon and new construction, or your builder can work
with a state certified and/or RCP contractor to design and install the
proper radon reduction system. To obtain EPA's technical documents
contact your state radon office.
All homes should be tested for
radon and high radon levels should be reduced.
Return to the Table of Contents
Do You
Have a Well?: Radon in Water
Well owners with elevated indoor
radon levels should test their well water for radon. Radon in your water
supply can increase your indoor radon level, although, in most cases,
radon entering the home through water will be a small source of risk
compared with radon entering from the soil. EPA estimates that indoor
radon levels will increase by about 1 pCi/L for every 10,000 pCi/L of
radon in water. You can find publications and documents developed by
EPA's Office of Ground Water and Drinking Water relating to radon in
drinking water and the radon in drinking water rule at
http://www.epa.gov/safewater/radon.html.
What do the results of your
water test mean?
Estimate how much the radon in
your water is elevating your indoor radon level by subtracting 1 pCi/L
from your indoor air radon level for every 10,000 pCi/L of radon that
was found in your water. (For example: if you have 30,000 pCi/L of
radon in your water, then 3 pCi/L of your indoor measurement may have
come from radon in water.) If most of the radon is not coming from
your water, fix your house first and then retest your indoor air to
make sure that the source of elevated radon was not your private well.
If a large contribution of the radon in your house is from your water,
you may want to consider installing a special water treatment system
to remove radon. EPA recommends installing a water treatment system
only when there is a proven radon problem in your water
supply.
How is radon removed from
water?
Radon can be removed from water
by using one of two methods: aeration treatment or granular activated
carbon (GAC) treatment. Aeration treatment involves spraying water or
mixing it with air, and then venting the air from the water before
use. GAC treatment filters water through carbon. Radon attaches to the
carbon and leaves the water free of radon. The carbon may need special
handling in its disposal if it is used at a high radon level or if it
has been used for a long time. In either treatment, it is important to
treat the water where it enters your home (point-of-entry device) so
that all the water will be treated. Point-of-use devices, such as
those installed on a tap or under the sink, will only treat a small
portion of your water and are not effective in reducing radon in your
water. It is important to maintain home water treatment units properly
because failure to do so can lead to other water contamination
problems. Some homeowners opt for a service contract from the
installer to provide for carbon replacement and general system
maintenance.
Return to the Table of Contents
Refer to the Installation and
Operating Cost Table for more information on water treatment
systems.
| INSTALLATION AND
OPERATING COST TABLE |
| Technique |
Typical
Radon Reduction |
Typical
Range of Insulation Costs
(Contractor) |
Typical
Operating
Cost Range for Fan
Electricity &
Heated/
Cooled Air Loss
(Annual) |
Comments |
Subslab
Suction
(Subslab Depressurization) |
80-99% |
$800-$2,500 |
$75-$175 |
Works best if
air can move easily in material under slab. |
| Passive
Subslab Suction |
30-70% |
$550-$2,250 |
There may be
some energy penalties |
May be more
effective in cold climates; not as effective as active subslab
suction. |
| Draintile
Suction |
90-99% |
$800-$1,700 |
$75-$175 |
Works best if
draintiles form complete loop around house. |
| Blockwall
Suction |
50-99% |
$1,500-$3,000 |
$150-$300 |
Only in houses
with hollow blockwalls; requires sealing of major
openings. |
| Sump Hole
Suction |
90-99% |
$800-$2,500 |
$100-$225 |
Works best if
air moves easily to sump under slab; or if draintiles form
complete loop. |
| Submembrane
Depressurization in a crawl space |
80-99% |
$1,000-$2,500 |
$70-$175 |
Less heat loss
than natural ventilation in cold winter climates. |
| Natural
Ventilation in a crawl space |
0-50% |
none
($200-$500 if additional vents installed) |
There may
be some energy penalties. |
Costs
variable |
| Sealing of
Radon Entry Routes |
0-50% |
$100-$2,000 |
None |
Normally used
with other techniques; proper materials & installation
required |
| House
(Basement) Pressurization |
50-99% |
$500-$1,500 |
$150-$500 |
Works best with
tight basement isolated from outdoors & upper
floors. |
| Natural
Ventilation |
Variable |
None
($200-$500 if additional vents installed) |
$100-$700 |
Significant
heated/cooled air loss; operating costs depend on utility rates
& amount of ventilation. |
| Heat Recovery
Ventilation |
25-50% if
used for full house;
25-75% if used for basement |
$1,200-$2,500 |
$75-$500
for continuous operation |
Limited use;
best in tight house; for full house, use with levels no higher
than 8 pCi/L; no higher than 16 pCi/L for use in basement; less
conditioned air loss than natural ventilation. |
| Water
Systems: Aeration |
95-99% |
$3,000-$4,500 |
$40-$90 |
More efficient
than GAC; requires annual cleaning to maintain effectiveness &
to prevent contamination; carefully vent system. |
| Water
Systems: Activated Carbon (GAC) |
85-99% |
$1,000-$2,000 |
None |
Less efficient
for higher levels than aeration; use for moderate levels (around
5,000 pCi/L or less); radon by-products can build on carbon may
need radiation shield around tank & care in
disposal. |
| * NOTE: The fan
electricity and house heating/cooling loss cost range is based on
certain assumptions regarding climate, your house size, and the
cost of electricity and fuel. Your costs may vary. Numbers based
upon 1991 data. |
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Created: March 17, 1997, Last Modified: July
18, 2000
http://www.epa.gov/iaq/radon/pubs/consguid.html
