The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California

First Aid For The Ailing Houses

The second type of attic fan is primarily to ventilate and cool the living space of the house. This type may be mounted in the same manner as the other, but without air-intake louvers into the attic. In use, this type of fan pulls air through the house and through a central ceiling vent or open hatch. The air enters through lower-level windows and is exhausted from the gable opening.

If the attic is already supplied by a number of louvers, it may be simpler to place the attic fan in a suction chamber than to close all of the openings. This chamber is simply a large box built over the vent or hatch in the ceiling. The fan is mounted in one side of the box and forces hot air from below into the attic area, from whence it escapes through the existing louvers. The louver area should be figured by the same formula used for kitchen exhaust-fan intakes (see section on Kitchen Fans).

For one room, a fan can be obtained to be placed at the lower part of a window, other windows being closed, to give a full flow of air without drafts. Some fans are combined with filters to clean the air of dust and pollens, and are so made that outside noises are excluded. They are especially satisfactory for city use.

With a sloping roof, ventilating dormers can be set in opposite sides; in one usual form to be had ready-made at a lumber yard, these have something of the appearance of an eyebrow and a half-opened eye.

Shed roofs may be satisfactorily ventilated with under-the-eave louvers installed at each end of every between-rafter space. Flat roofs usually require such under-the-eave louvers, and a mechanical vent at the center of the roof. Louvers are generally most efficient if they provide 1 square foot of opening for every 300 square feet of attic floor space. When louvers are installed, they should be protected against insects by nailing a piece of window screening to the inside of each louver frame. If this is not done, hornets, bees, wasps, and other insects may use the attic space for a nesting area.

In a flat roof, air is confined in the spaces between the roof, the beams, and the ceilings below. While the rooms beneath may be chilly during the winter, the effect is more serious on a hot summer day and evening because of the heat that will be passed through and retained. Filling these spaces with rock wool or something similar by the blowing method previously described will greatly check the passage of heat.