Shades, Curtains, and Drapes

Hi, we're back in that sunny room, but the sun is going down. It's time to trap some warmth, lest it all be lost through the windows that have gathered the sun's rays all day. The windows have a low Emissivity coating, but that doesn't completely stop radiant energy escaping once evening sets in, and the room will get uncomfortably cool if we don't do something.

Forward the Roman shade. Credited to the old pre-Italian inhabitants of that sunny Mediterranean country, the Roman shade varies from other shades in its ability to be raised and lowered by means of cords and pulleys. Before there was glass, Roman shades were used in concert with shutters to keep out cold winds, barbarians and rain. Later, when windows became more elegant, with glass panes and movable sashes, shades were used to exclude light and drafts, and to ensure privacy in city homes. Today Roman shades are hot again because they enhance the energy performance of even the most expensive coated windows, and make sunny rooms more comfortable to be in at night.

Shades, as a class of window treatment, raise and lower from the top. Curtains, by contrast, slide left and right, often parting in the middle. Drapes, often synonymous with curtains, tend to be drawn apart with ties or loops rather than sliding on overhead rods. All window treatments help to make windows more comfortable and less revealing, but not all treatments perform equally in keeping a room warm.

Unless the window treatment is sealed against the window frame, or made to hang within an inch or so of the glass, the resulting space powers a convective current which circulates warm air continuously in the manner of a convective radiator. Energy is passed through the glass to the outside by conduction and some radiation. Curtains and drapes are difficult to install sufficiently close to the glass to defeat this convective effect. Roman shades are more adaptable to close-fitting installations. Roller shades also lend themselves to the kind of mounting that seals better and keeps more warmth in the room. We'll be back soon with some remarks on how to cover your windows with homemade shades and curtains, on a budget, without having to hire a fairy godmother and pay those rates.