Another reason to reject the claims that ventilation alone will allow hot granite countertops to be sold is the long term efficiency of the ventilation systems.
Here is a study, Post Mitigation Radon Concentrations in Minnesota Homes,
by Dr. Daniel Steck, one of the Radon scientists leading the granite testing effort.
A total of 150 homes were chosen from past clients of six professional Radon mitigators and the Radon levels rechecked after from six months to seven years. The study found that the mitigation dropped the levels from an average of 10.3 down to .8 pCi/L.
Potential causes loss of mitigating ventilation are blockages, fan failures, someone turning the unit off, and leakage. A previous study in 2005 by Dr. Steck found some homes that did not do well after mitigation efforts, with an average of 2.9 pCi/L and 28% exceeding the EPA action level of 4 pCi/L. But 12 of those homes were professionally mitigated and had lower Radon levels, averaged at 1.7 pCi/L with only 8% exceeding the action level.
In the recent study we are discussing, 3% of the 129 homes returning measurements had average Radon levels over the EPA action level of 4 pCi/L and 6% had at least one measurement above 4 pCi/L. Homes with 3 pCi/L were about 6% and 9% of the homes were at 2 pCi/L.
Dr. Steck also addressed the costs of mitigation per life saved. Keeping in mind that these are sub slab depressurization systems so the only air exchange is that seeping through the floor, not air being sucked out of the interior of the home. Despite that, installation costs can be as much as $1,800 for a home, $110 for each test to ensure the system is working (once per year, is that safe enough?), heating costs between $70 and $500 per year, six replacement fans in the 70 year life span, and electricity costs all can add up to one percent of the EPA’s value of a statistical life ( $6,900,000.00) or $69,000.00 for each life saved. Far less than a fraction of the medical care needed for a single cancer case.
Now, if we use the common estimates of air infiltration in homes (.35 ACH) we find that up to one third of your yearly heat and cooling costs are wasted.
Looking back at the Colorado study where they used an open window (10″ gap), this would allow 40 cubic feet of air exchange per minute. Imagine the cost to heat and cool a home with that amount of leakage on top of the usual waste from normal air exchange.
No matter how you look at this, the Radon mitigation costs to remove any Radon from a granite countertop would be much more than anyone would imagine, some where between $69,000 and $13,230 for the life of the home. In this day of concern over the planet, carbon foot prints, and energy costs, it just makes little sense to add more heat loss so one can have a granite countertop.
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