Replaces radon-laden indoor air with outdoor air. High reductions result because natural ventilation both reduces the flow of soil gas into the house, by neutralizing the pressure difference between indoor and out, and dilutes any radon in the indoor air with outdoor air. Reductions can be greater in tight houses. Rather than relying on natural air movement, forced air fans can be used to provide a controlled amount of forced ventilation. The cost for electricity to operate on of the larger units with two 200-cfm fans is about $30 per year. There are two basic sources of excess water. EPA;s experience suggests that you should install two or three fans rated at twice the air moving capacity calculated to be needed for the desired increased ventilation. The additional cost of electricity for forced-air systems will vary depending upon the size of the fans, the number of fans used, and the amount of use. Use of natural ventilation in cold weather will increase your heating costs substantially.
As with natural ventilation, if you were to increase the air exchange rate to eight times its normal level in your basement while maintaining comfortable temperatures there, your annual house heating bill could be as much as three times greater than normal. A crawl space not connected to a basement can be ventilated (as discussed in the section on natural ventilation), or the earthen floor can either be covered with a gas-proof liner (with passive vents to the outside) or covered with concrete. This project aims to stop the water before it enters your crawl space or basement. To simplify the necessary ducting runs to different parts of the house, the heat recovery ventilator unit, consisting of the core and fans, can be located in an inconspicuous part of the house-such as an unfinished basement or utility room. A device called a “heat recovery ventilator” (sometimes referred to as an “air-to-air Heat exchanger”) uses the heat in the air being exhausted to warm the incoming air. In technical terms, this is called o.1 ach (air changes per hour).
Newer houses, which are generally “tighter” may have air exchange rates as low as 0.1 ach (one-tenth that of the average house). The rate in older houses on the other hand, may be more than twice the average (2.0 ach). In the average American house, outside air equal in volume to the inside air infiltrates about once every hour. Reductions will vary throughout the house, depending on ducting configurations. If you normally have an air conditioner running in hot weather, your cooling costs will be similarly greater. If you normally run an air conditioner in hot weather, your cooling costs will be similarly greater. The actual cost will largely depend upon the amount and location of piping and the fan location. A single window fan can have electricity costs as low as $20 per year, while a central furnace fan may cost $275 a year to operate. In many homes, blowing air in through an existing central furnace is quite practical.
Alternatively, fans could blow air into the house through protected intakes through the sides of the house, or could be mounted in windows. Air should be blow into the house and allowed to exit through windows or vents on adjacent or opposite sides. Water travels freely through the pipe, which empties a safe distance from the house. Without correct drainage unwanted water or waste can sit and buildup and cause numerous probelms. If the septic tank overflows, the French drain catches the raw effluent and allows the anaerobic bacteria do their job in breaking down the solid waste particles. Using a perforated pipe allows small amounts of water to soak into the ground, but carries larger quantities of water away more quickly to help with flash flooding. Covering or sealing small areas (and ventilating covered air spaces as necessary) often costs under $100. Use of forced ventilation throughout cold weather will substantially increase your heating costs. On entering the trench the water will have to run to a suitable drain-off point, and in most cases this is a soakaway or watercourse. It would be best to have professionals build your soakaway for you.