The radon issue is a negotiation between buyer and seller. Reasons are because first the seller has lived in the house with no concern about it or any bad health. Does not usually see why they need to provide this for the next family. The EPA admits that there has never been a documentable incidence of anyone getting cancer from a household basement. They also don't really know what proper levels really are. This number(4.0) was selected arbitrarily. They have difficulty converting hours worked in a mine to hours spent in a residential basement. Most radon deaths involve mine workers. If you have ever smoked there is an unquantifiable and untested possibility that radon may then be more harmful. But people who smoke have already chosen to put their lungs at risk so why would a seller have to protect them from radon ?Some sellers just don't have the money to install this either. Buyers can be frightened away from getting a house they love if they have not really researched radon. In truth they put their children at more risk every time they let them play in the sun or ride in the car. Radon ,by the way, is everywhere like air. Some houses may be way off the charts (over 20) . A buyer should test in all seasons before deciding to mitigate. This is impossible for a real estate transaction. The buyer should be aware that it is best that they choose the system. Roof exhaust systems are effective but will cost them about $700 a year in increased utility costs. It will also need about $500 in routine maintenance every 4 years or so. Also in cold areas like New England it should be shut off in winter because the exhaust pipe on the roof blocks up with ice. Ironically winter is when radon is highest. They are better off choosing their own system and installing it themselves if radon keeps them awake at night. They might ask for the seller to give them some money back at closing for this. That may be appropriate in a buyers market, or if the house is in bad condition overall. Also if they overbid , didn't get closing costs. But if its a sellers market, or the seller has already spent a lot of money on the condition of the house and its nice, or is paying buyers closing costs, the buyer might be wise to consider installing it when they are the homeowner and leave it out of the transaction. I have seen many a good deal turn bitter over this issue, even if a resolution is found.

Yes radon fans break like any other motor device. You should have access to it for replacement in the future. The installer put the fan outside the building which is good, HOWEVER the pipe then proceeds into the house which is not good. If the pipe develops a leak, it would be pumping radon into the house. The correct installation location is in the attic, with the pipe terminating at the roof, or the fan can be installed outside along the wall with the pipe running upwards on the wall. The exterior installation is contraindicated in cold climates, due to total freeze up of the condensate in the system. Attic installation is the best option. See #6 here http://www.indoor-air-health-advisor.com/install-radon-mitigation.html Also, http://www.thisoldhouse.com/toh/video/0,,20046344,00.html

If you live in an area it freezes, the second option is contraindicated. The condensate in the system will freeze inside the pipe and block it. It takes up as much room as a 3" or 4" pipe if exposed, or a small wall bumpout (vertical bulkhead) to hide it. It does not take up much space in the interior, and if you need an active system, the fan is installed in the attic. In retrofits, where a system is installed in an older home, it is often run through a closet, out of sight. Any active system should have vibrations mitigated to stop noise transfer in the house. Passive system does not have this problem.

R408.3 Unvented crawl space. Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where: 1. Exposed earth is covered with a continuous Class I vapor retarder. Joints of the vapor retarder shall overlap by 6 inches (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall or insulation; and 2. One of the following is provided for the under-floor space: 2.1. Continuously operated mechanical exhaust ventilation at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7m2) of crawlspace floor area, including an air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1103.2.1 of this code; 2.2. Conditioned air supply sized to deliver at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7 m2) of under-floor area, including a return air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2 of this code; 2.3. Plenum in existing structures complying with Section M1601.5, if under-floor space is used as a plenum. http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_sec008.htm