26 Apr 2014
The window dance is what we here at Fortress Peschel call the daily routine of opening and closing draperies and windows. This is far more important than it seems. The window dance allows us to control solar gain and heat loss throughout the year. The idea is to match the needs of the house to the weather via manipulation of windows and drapes: to catch warmth and light in the winter; to repel heat and trap cool air in the summer; and air out the house as much as possible whatever the season. You expend your energy to prevent writing big checks to the power company for their energy.All windows should be considered to be holes in the wall. Insulating properties of windows are measured in U-values. Insulation everywhere else (walls, ceilings, floors, etc.) are measured in R-values. The U-value is a reciprocal of an R-value. Windows (and only windows) are measured as U-values because this hides the horribleness of their R-value. It lets you think that a U-value of a double-pane glass window is twice that of a single pane glass window. And it is! And that you have greatly increased your energy efficiency. Which you have not! What you don’t see is that you have gone from an R-value of 1 to an R-value of 2. A standard exterior wall should be 15 or 20 or more. But we have to have light and air and views. Otherwise you might as well live in a cave. So we compensate for the miserable R-values of our windows with window treatments and their correct usage.
One, Two, Three
There are three parts to the window dance. The first is the window treatments themselves. More layers mean more trapped, dead air. Close all your drapes one night. Turn on all the interior lights. Walk around your house outside. Every bit of light leaking out is the same as lost heat. The goal is to not have any light peeking past the drapes. The second part of the dance is opening and closing drapes, shades, quilts, and windows as the time of day and season demand. Once the treatments are made and installed, they don’t change but they do move.
The dance itself changes every day, sometimes multiple times a day. The more careful and observant you are in doing the dance, the more energy you save and the more comfortable your house becomes. The third phase of the window dance takes the longest. This is the planting of deciduous trees placed to provide shade in the summer and allow heat and light in during the winter. A tree grown from a sapling will take 10 to 15 years to start working for you. Work out the solar orientation of your house, choose the right trees, and plant them today.
Dress Your Windows For Success
Every window should be dressed in multiple layers. Working from the glass out into the room should be: a window quilt which fits the frame from side to side and hangs down lower than the sill; a room darkening WHITE window shade that covers the window frame completely from side to side; sheer lace or net curtains; heavy drapes consisting of a muslin (or Roc-lan room darkening) lining, a flannel interlining, the fashion fabric; and a valance or pelmet. The valance is hung over the top of the drapes to slow down heat loss at the top of the window and is made of the lining fabric, interlining of quilt batting, and the fashion fabric. The stiffer batting helps the valance hold its shape better. You can cut down on heat loss more with a pelmet or cornice. This is a 4-sided plywood box (front, side, side, and top) mounted to the wall above the window. The draperies, their hardware, and everything else fit under the pelmet. It is covered with padding and the fashion fabric to coordinate with the drapes. The solid top of the pelmet prevents a chimney effect of air moving up behind the drapes from the floor to the ceiling. Drapes should hang as close to the floor as your animals, children, and cleaning practices will allow. Again the idea is to slow down the movement of air (and hence heat) from the room to the window and then outside.
I made my own window quilts from old sheets (Goodwill has plenty) and leftover quilt batting. I always use white or cream sheets as this layer shows to the street. Each quilt is three layers: a front and a back of plain fabric with a core of quilt batting. They hang in the window frame off of a wooden dowel that hangs from a pair of cup hooks; one in each corner of the frame. While you are learning to sew (or getting someone else to make them) use towels safety pinned over the dowel. This won’t be as insulating but it will make an insulating layer. The dowel needs to fit easily in and out of the window but the quilt should be wider than the glass by several inches and long enough to hang over the sill by a few inches. The overhang will give a better seal to the window when all the other layers are in place.
The window shades were purchased from a local dealer —- the most expensive part of the set-up —- and even though we do most things ourselves it was absolutely worth it to get someone else to install good shades that will last for years. Do not buy those cheapie do it your selfshades at Wal-mart. The spring rollers wear out quickly and then you have to replace the shades. If you can afford them, by all means buy the honeycomb shades; the more honeycombed the better. They insulate far better than plain old shades and cost way more too. The local dealer should measure for and install the shades.
A word on shades: vertical blinds belong only in office parks. They do not insulate, room darken, or allow you to open windows while repelling the sun. Horizontal blinds are marginally better but are difficult to keep clean and don’t provide a solid barrier to heat loss. Heavy grass cloth roll-up shades take up a lot of room. Insulated roman shades are nice (and expensive!) and take up a lot of room when stacked up. They work well when you can’t have all the other layers of fabric as in a bathroom or kitchen. Wooden plantation shutters are useless. Have the dealer install the shades to completely cover the frame of the window from side to side with enough shade to hang down well past the bottom sill. Get white shades, preferably room darkening as they are a little heavier. A clutch cord will make the shade mechanism last for years and it keeps you from touching — and having to clean! — the shades.
Next come the sheers. I have made my own sheers for years and it is a pretty easy sewing job. Any basic sew your own window treatments book gives the directions. They are inexpensive to buy and easy to find. The purpose of the sheers is to add another layer of dead air. More importantly, they screen you from the neighbors. A big part of the window dance is having all the layers open during the day most of the year. Your sheers don’t move: they are a compromise between privacy and light. That layer of netting makes it that much harder to see inside to your big-screen TV while still allowing in sun and air. Choose whatever patterns you like in white or cream. These hang from a rod pocket style curtain rod hung above the window frame and several inches to each side on the wall. Your sheers should be two or three inches shorter than your drapes.
Next comes the drapes. These will be large and heavy and need very sturdy rods for support. They are so heavy that wider windows may need Kirsch traverse rods to support the weight and make them easy to operate. Do your research to see what kind of rods you need and if you can install them yourself. I had my 16 foot Kirsch traverse rod installed professionally although I made the pinch-pleated drapes myself. Other drapes are hung on heavy duty standard curtain rods with center supports. The important thing to remember with drapes is its stack back. This means where does all that fabric go when the drapes are open? The stack back should be outside the edge of the frame and on the wall so when the drapes are open, all the glass is exposed to light the room. This means that the rods must be mounted on the wall several inches away from the outer edge of the window frame and several inches higher as well.
As with the sheers, there are plenty of books on how to sew these drapes, including how to make pinch-pleated drapes. Tab tops and ring tops will lose heat so don’t get or make that style. If you must do this, you will have to use a pelmet to block the heat loss and then you won’t see the tab tops. Rod pockets work fine for windows that are less than four feet wide. Pinch-pleats must have a traverse rod. Drapes should have three layers: a lining facing the street made of muslin, old sheets from Goodwill or, if you really need the room darkening and can afford the cash and weight, Roc-lon blackout lining. Because the other layers of window treatment show to the street first (quilt, shade, sheers) this one really won’t be visible but white or cream are standard. The interlining is flannel. Quilt batting gets very heavy very fast and has to be quilted in place. It also makes the drapes hugely bulky and awkward to handle. Old flannel sheets can work for this layer. The layer facing the room is the fashion fabric and this is whatever you want. It should be heavy enough to conceal the interlining; that is, don’t put lace over flannel. Heavier fabrics will block more air and heat than thinner ones. The drapes should come close to the floor. How close? Draperies that puddle beautifully on the floor don’t open and close easily which you will need to do every day. They catch every bit of dirt on the floor. Your animals and children will step on them and lay on them and try to pull them off the rods. Bad cats may use them as a litter box. Keep them at two inches above the floor and the drapes will open and close easily without losing too much heat up behind them. The hardest part of sewing drapes yourself is dealing with huge sheets of fabric. My biggest set of drapes are made up of two panels each seven feet high and 16 feet wide.
The final layer is the valance or pelmet. This layer hides all the drapery hardware and slows down the chimney effect. This is when cold air is sucked up from behind the drapes at floor level, moves upward, and exits out through the top at the ceiling. Leaky windows will make this air movement worse. A valance is three layers of fabric again: lining, interlining, and fashion fabric. A valance should have an interlining of quilt batting as opposed to flannel: it stiffens the valance so it hangs better and traps more heat. A pelmet is a four sided box of plywood mounted to the wall over all the drapery hardware. It has a top, front, and two sides and is covered with padding and the fashion fabric. A pelmet completely stops any chimney effect as it is closed off at the top. Mount your valance or pelmet high enough up so that all the window glass is seen when the drapes are open. Setting your stack back off on the walls and your valance up high makes your windows look larger, and gives all the light you paid for. If you use roman shades, a pelmet may hide the stack back better when the shades are open.
All the window treatments in the world will not fix broken or leaky windows. If you have old style single pane glass windows, especially if they are true divided lights (small panes of glass in a wooden grid) you need storm windows. Get the permanently installed kind with operable screens. Replace any broken panes and make sure each pane is set snugly with glazier’s points and good putty. The library is full of books with instructions for this. If you have to reglaze a lot of windows, work your way through them and then go back and redo the first ten or so with your newly improved skills. Reglazing can make an amazing difference. In a previous house, I had 20 or so windows with true divided lights and old storm windows. Some of the panes were broken and all were loose in their frames. A local handyman replaced every broken pane, scraped out and reputtied every single window, added glaziers points (there were none), and tightened and trued up the storm windows. It was an amazing difference; no drafts, no leaks, less noise infiltration, and no rattling at night in the wind.
Based on personal experience, if you can possibly save old solid-oak windows you should do so. Good storm windows will go a long way to improving the dreadful energy efficiency of single-pane glass. Replacement double pane glass windows vary wildly in quality and price and they don’t seem to be made to last the lifetime of a house as old fashioned windows are. When the seal fails on your replacement double pane glass windows you have the equivalent of single-pane glass. Rehab those old windows and get good storms. Otherwise, resign yourself to the fact that replacement windows will eventually have to be replaced themselves.
Next Week: Performing the Dance