The most common type of radon remediation is "subslab suction," also called "active subslab depressurization" (ASD). It is the system recommended by the U.S. EPA and routinely installed by radon mitigation contractors or builders.
One or more suction pipes are installed through holes drilled in the floor slab and lead the radon-laden soil gas through a fan to the outdoors. Contractors normally guarantee that the indoor radon level will not exceed the EPA's "Action Level" of 4 pCi/L. Note that this is not a "safe" radon level.
According to the EPA (U.S. Environment Protection Agency) – "The average house costs about $1,200 for a contractor to fix, although this can range from about $800 to about $2,500, depending on the characteristics of the house and the method used."
The radon fans are guaranteed by manufacturers for 3 – 5 years. Their replacement cost, including installation, is usually $300 to $600.
Homeowners are aware that the fan must run continuously 24/7, year after year. The typical estimate of the electricity cost is $150 per year.
However, homeowners are not told about all the other operating costs which can be much higher – convective energy losses in heated and air-conditioned air. (Convection means the transfer of heat by the movement of heated gas.)
The subslab suction system draws not only the soil gas from underneath the slab but also air from the basement through any cracks and openings. To prevent back drafting of the furnace and hot water heater, building codes require one or two make-up fresh air openings in the basement. This allows outdoor air to be drawn in to replace the air sucked out by the radon ventilator.
In winter, the lost indoor air has been heated and in summer, air-conditioned. The energy used for heating or air-conditioning this lost air has been wasted.
The convective energy losses depend on the climate. Colder replacement air needs more energy to warm up. Typically, the heating loss is the largest part of the total operating cost, followed by electrical consumption of the fan, and the convective loss in air-conditioned air.
According to L. Moorman, Ph.D. ("Energy Losses and Operational Costs of Radon Mitigation Systems"), the total radon mitigation operating costs were found to vary from $225 per year in the warmest regions to $500 per year in the coldest regions when using heating by gas.
|Fan-Based Radon Mitigation|
|Installation Cost||EPA: $ 800 - 2,500||EPA: $ 1,200|
|Energy Losses, Electricity Cost||$ 225 - 500/year||$ 360/year|
|Operating Expenses over 10 years||$ 2,250 - 5,000||$ 3,600|
|Total Costs over 10 Years||$ 4,800|
In addition, homeowners will have to regularly replace the fan, which is usually guaranteed for up to 3 years (US EPA).
More information at How To Save $1,000's on Radon Mitigation
Seal all openings, cracks, and gaps:
Seal the concrete floor and walls with RadonSeal Deep-Penetrating Concrete Sealer which seals the pores inside the concrete.
This will seal the basement against the seepage or wicking of water, water vapor and excessive humidity causing molds, and radon gas. If done properly, you will not need to install a fan-based radon mitigation system – RadonSeal provides a Limited Money-Back Guaranteee!
If a Subslab Depressurization System is already installed, sealing the basement will reduce the convective energy losses by a half or more. But once the basement is finished, the openings and the concrete are not accessible, and the homeowner is destined to paying higher energy losses for years to come.
By reducing the flow of air from the basement to the fan, we can select a smaller fan, which will reduce the power consumption of the fan. In addition, it will reduce the annoying fan noise on balmy summer nights. And in turn, a smaller fan size will reduce the convective energy losses.