Home design

Windows serve several very different roles in a house: a view of the exterior, allowing sunlight to enter, can provide fresh air, and block the flow of heat. The relative importance of these functions varies according to climate and location of the windows of the house. For example, residents of Minnesota will most likely be interested in passive solar heat gain and therefore want windows that transmit a large amount of

solar heat, especially on the south side of the house. Florida residents, however, will probably be more concerned with blocking the solar heat gain (see Chapter 7 for more information on passive solar heating).
Next to the amount of insulation in the house and seal on the house, the selection of windows and doors have the greatest impact on energy use for heating and air conditioning. Fortunately, this is where some of the most significant advances have been made in building technology over the past decades. The best windows now have up to four times the insulation value of the best windows in the 1970s.

These improvements in performance energy window was made possible thanks to several major technical events, the most important of which was transparent, lowemissivity (Lowe) facing a window glass or plastic film suspended between the glass plates .

became more and more confusing and (in some cases) improved deceptive.As glass, window frames began with a greater share of the loss of heat, so that the old way of advertising the energy efficiency of a window – the value at the center of the window glass – was no longer an accurate representation of the energy efficiency of the entire window.
To address this problem and ensure a more coherent energy efficiency of windows, the National Fenestration Rating Council (NFRC) was formed in 1989. NFRC developed standards for measuring and reporting the energy efficiency of the windows of the unit, which is the Ufactor, or the number of BTUs of heat flowing through a square foot of window per hour for each difference in degreeFahrenheit temperature through the window (Btu/ft2 ° F · h). Unit values represent the energy efficiency of heat flow through both the glass and through the frames, and was informed industrystandard window dimensions.
In most of today’s windows, is showing NFRC labels Ufactor energy efficiency in a consistent manner, so that different products quickly compare with one another. Also included in these labels is information on solar heat gain, which tells how sunlight is transmitted through the information is useful to glass.This passive solar heating designs as it is concerned about the air cargo conditioning. NFRC Certified window publishes a directory of products, which lists the energy efficiency of thousands of windows on the market.