04 May 2014
Last week, we discussed how to use curtains to trap and release the heat that comes into your house. The “window dance” sounds complicated, but it’s based on a simple principle: Trap the heat when it’s cold, keep the heat out when it’s hot.The next section describes how we perform the window dance during the seasons. All of the windows have a curtain, sheer drapes and a quilted cloth panel that either hangs on hooks screwed into the frame or is on a tension bar that slides easily into the frame. By opening and closing the curtains and putting up and taking down the panels, we can regulate the temperature so that warm rooms don’t become hot (and kick on the air conditioner), and cool rooms don’t become cold (and turn on the furnace).
Eventually, however, the weather will win, but delaying the start of the furnace / AC season will help keep your energy costs down. More so, at least, than the people who let their ACs run throughout the summer, and their furnaces throughout the winter.
The window dance changes with the season and the time of day. It will be a rare day when you don’t open or close something. Here at Fortress Peschel, this job is usually done by Second Son (SS). I go over any changes in the routine with SS as the weather changes. We can break down the dance by season.
In winter, you want as much light and heat as possible from your solar gain while losing as little heat as you can manage.
1. An hour or so after sunrise (depending on how cold and cloudy it is outside) open all the layers on the morning-sun side of the house to catch every bit of sun. The windows themselves will stay closed and the sheers don’t move. Even if it is heavily overcast, open the draperies. There is still heat from the sun.
2. As the sun goes around the house, open drapes to follow it. At sunset, close the layers beginning on the side of the house away from the sun. When you open up for the day, the drapes are tied back to the sides of the window, the shades are up, valances and sheers don’t move. The window quilts are taken down, rolled up on their dowel, and stood up alongside and behind the drapes.
3. When you close up shop at sundown, hang the quilt, spreading it out to cover the frame; close the shade so it hangs well below the sill; the sheers remain unchanged; the drapes cover the window completely and all the layers below. Make sure that the drapes touch the wall at the sides: you will lose more heat at the sides (because nothing blocks this) than you will dead center where you have 4 separate layers of dead air, not counting the three layer drapes.
For a better seal, apply Velcro to the edge of the drapes and to the wall and press the Velcro strips together permanently.
The only real change in winter comes on very warm days when you can open a window to air out the house and hopefully let in warm air. Obviously, only open the windows long enough to change the air and not drop the interior temperature too much.
The goal in the first half of spring is to keep your heat. The goal in the second half is to cool the house as much as you can before the blaze of summer.
1. As before, open window treatments to follow the sun and close up at night. Now is also the time to open the windows to air out the fug of winter. This is a careful balancing act: fresh air versus temperature change. Keep an eye on the thermostat as each day progresses. Try to trap enough heat to keep the furnace from coming on and no more.
2. You want to start the summer with a cold house. As spring progresses, you will find yourself leaving the windows open all the time. The window shades now become important during the day to block the heat. Open the drapes, open the shades, take down and roll up the quilts, open the windows, pull the white shades down to the top of the screened opening. The big white shade will reflect the heat of the sun while still allowing air movement in and out.
3. At night, depending on your area, you may not close the drapes or windows at all: leaving them open all night to further maintain your house temperature. Set the shades to whatever opening you have your screens at and leave the quilts rolled up and out of the way. You cannot block the screens with layers and layers of drapes and expect to get any air exchange. You will get all the noise and some of the light pollution and none of the cooling fresh air you desire.
Now we keep the sun outside.
1. Start the morning with all the layers in place. Do not open up any layers at all until after the window no longer receives direct sun.
2. Follow the sun around the house, opening layers only when the window is out of direct sun. Depending on how cool it is at night (and how safe your area is) you may have the windows open all night (except for the shade pulled down to the top of the screen and no more) and then close them up in the morning.
3. Reopen in the late afternoon / early evening as the temperature permits. Never raise that light-reflective white shade when the window is in direct sun! You may find that certain windows will not be opened up at all: they always get solar gain, either directly or from reflected heat.
For example, we have two bedroom windows facing the north. They only receive direct sun in very late afternoon. However, because of the bright white house next door, these windows are always hot hot HOT since they receive a full dose of reflected sunshine from dawn to dusk. Nice in the winter but bad in the summer. The layers remained untouched day and night.
We also have a large picture window that acts as a heat trap: both the quilt and the shade stay in place all summer long.
Doing all this keeps the heat outside so the air conditioner has to run much less. The difficulty with keeping the drapes closed is you may need to turn on electric lights as your house is dark. You have to decide: pay for electricity for your lights or raise the temperature of your house with the solar gain. I go back and forth on this one.
Now we want to air out the house from the summer and trap every bit of heat for the coming winter.
1. As soon as the sun kisses a window, open up every layer. Warm days mean open windows with warm air. Watch your inside temperatures: do not let the house cool off anymore. If your windows are open and the temperature is dropping, close the glass! Heat up the house during the day and as soon as the sun goes down tightly close every layer to trap the warmth.
2. You won’t be leaving windows open at night anymore. You will lose too much heat. Open those windows during the day only to catch warmer air. For us, this means opening up at the hottest part of the day, usually mid-afternoon and only for two hours. Closing the windows at 3 p.m. lets the house catch solar gain for a few more hours before sunset. The warmer the house is going into the winter, the longer it will take to need the furnace.
Next Week: Using Trees for Long-Term Shading