Window Blankets - Having your windows and enjoying them too
by Cynthia Rush
      (copyright 2008 Cynthia Rush)
Your windows let in sunlight and give your home a feeling of openness and being connected to the world around you. Unfortunately, they also let in cold or heat, depending on the season. They can account for more than 50 percent of your house's heat loss (or gain), depending on the size, quantity and quality of your windows.
This website will show you how to create Window Blankets, which can control the amount of heat lost (or gained) by your windows during extreme temperatures. Anybody can do it, and after using them for a year or two, depending on how much of the time you cover your windows with them, you will have saved more in energy costs than you spent on the materials to make them.


Here I am, putting the Window Blankets in place.

Along the way, I'll tell you a little about my own experiences with homes with extreme heat loss and gain, and what I learned about heat control.

At age 27, at a celebration dinner for my completion of my college degree (a B.A. in English from Antioch College), my father kiddingly suggested that I build a solar house in his woods. Being an English major, I had taken only one architecture course, but I knew he could afford it (financially) and I had a wealth of the required enthusiasm and energy. I began reading up on how solar energy worked. Eventually we hired someone to teach me how to build -- a guy who abruptly quit. After that I took over, reading workbooks late into the night on how to design and build trusses (roof framing), while mastering, by day, the art of smacking a nail, not my thumb, with this tool called a hammer. With the help of a big, energetic hired worker, the 1000 sq. ft. 3-story house was completed in 1981 when I was 28. A UPI story about the accomplishment ran in many newspapers across the country. I lived in the house for seven years before marrying and moving away, never to live full time in the house again.

There were successes and failures in the design of that house. My father likes to quote Somebody-Or-Other who says: Build your first house for your enemy; Build your second house for your friend; Build your third house for yourself. I didn't have the energy to build three houses, so we were stuck with my mistakes.

The best part about the Solar House, as we refer to it, is the thick, heavily insulated walls. We framed our own windows and built double-walls packed with 10" of insulation. When you step inside that house, the front door goes thunk, and the temperature remains fairly steady, even when the electric baseboard heaters are set at a low setting.



This 1980 photo shows me standing inside a nest of the trusses I designed and built for the solar house constructed in my parents' woods.

This is the UPI photo of me and my bassethound in 1981 in front of the solar house I built in my parents' woods.
The worst part about the Solar House was that there were too many cooks for that stew. I had planned to build a small shading roof to go over the wall of south facing windows which lined the living and dining area, but my parents, who had been so supportive of my independence, now were so protective they didn't want me to climb a ten-foot ladder, or to spend the $500 in materials required. The window roofs never happened, and boy did I cook! You can't imagine how hot a solar house can be during an Ohio summer until you've tried to fend off heat from uncovered, south-facing windows!
Years passed after I moved away, and we all experienced life changes. I divorced and remarried. My parents, still living independently, moved into their 80s. My father had a stroke and survived, but now my parents needed me to be closer, to provide support some of the time. So my husband and I purchased a house in a nearby town, one surrounded by woods, viewed from the new house's many windows.

The house we purchased north of Dayton with north-facing windows.

What distinguished the windows of the second house from those of the first was that the windows faced north, rather than south. And of course, the walls were the normal thickness of 3 1/2" rather than 10".

This house was built in the 1990s by a contractor (translation: cheaply). Most appealing was its location, just a half mile north of downtown Dayton, surrounded by the woods of a nature preserve, so although we don't own it, the woods will always be there.

Soon it became apparent that installing vertical blinds was the absolute minimum necessity -- even though most of the windows faced north. On a typical Ohio day, the clouds parted, revealing brilliant sunlight, reflected off the many tree leaves. Suddenly it felt scorchy inside! In time, it became obvious that installing glare film would also help cut down the UV gain.

The winter problems were quite different from the summer ones. At night, one bedroom froze while another cooked. Built on the side of a hill, the main living area is actually the upstairs. Downstairs is a lower level we use like a basement, but since a huge crawl space with 14' ceilings lies beneath it, in truth our "basement" is the first floor, and we actually live in the attic. As a result, the furnace pushes heat up through two stories before it reaches us. The thermostat doesn't always figure out, quickly enough, that where we are is too cold or too hot, especially in rooms where the space below it is gets chilly. In a regular house, you just don't realize how important your basement is.
If it felt like I was living in a greenhouse during my years in the Solar House, this was a replay of those experiences, except that, at the Solar House I had a wood stove which, along with those thickly insulated walls, helped keep the house toasty when the winter nights turned really cold.

Recently, in our Dayton home, the power went out on a night when the temperatures plunged to 12 degrees! The wind howled outside. The wind was so strong, the house almost leaned! With all those windows, we should have been freezing, but twelve hours later when the repair crews located the fallen wires that had robbed us of all furnace activity, our living room was still 58 degrees. We credit our window blankets with helping us cut our energy consumption probably by one third or more.

At right, you can see me tucking in one of the windows at night, with a window blanket in our bathroom. You may decide a bathroom window is where you would like to have your first window blanket -- which you'll learn how to build, yourself, elsewhere on this site.

Materials for Building Your Window Blankets
by Cynthia Rush


Materials Needed for creating Window Blankets:


- Reflectix insulation (foil-faced bubble pack)

- Contact paper (various brands on market)

- Duct tape

- Good scissors and/or utility knife

- Tape measure

- Velcro

Here (right and below) is Reflectix. It comes in several widths, including 16", 24" and 48". Reflectix is like foil-faced bubble pack. Available at lumber yards like Lowe's and Home Depot, you can buy a roll for $25 or $50, depending on the width.


Measuring and cutting to create your Window Blankets

The first decision you must make is choosing where to have your first Window Blanket. Like that house I built, expect to make some mistakes.

A bathroom is a good choice, because the privacy is appreciated. You can create a covering for just the lower half of the window, so daylight still comes in the upper half.

It's pretty simple, but there are a few words of wisdom I'll offer to help you avoid the pitfalls.


1. Measure the window. Plan to make the Window Blanket slightly wider than the window.

2. Lay out your material -- either on the floor, or a table, depending on where you plan to cut it. The scissors will work well enough for cutting the Reflectix. Sometimes the Velcro can gum up your scissors -- that's when you may decide to switch over to the box cutter knife.


3. Here is the only tricky part about the entire process: Plan on which side will face the room, and which side will face the glass. Put the side that will face the glass facing down against the contact paper, which you will cut to be about 2 1/2" larger than the Reflectix, as shown below. (There is no difference in the Reflectix, but at some later date, you may make a complicated design where it matters which side is which.)


Contact paper is sticky, and can become unwieldy. Cut it as I have shown. The first side of the Reflectix (we'll call this the "glass-side") that you cover should have contact paper coming completely around the edges, with a margin of about 2 1/2". The second side can just be the same size as the Reflectix.

(See photos below.) My "technique" for doing this so the contact paper doesn't tangle too much is to cut it, then stick that 2 1/2" margin onto the Reflectix on one edge, and then flip the whole thing over and keep peeling the contact paper as I go. Then I go back and fold the other edge of contact paper down over the end.

Soon, you are going to stick Velcro onto the "glass-side" of the contact paper. If you don't wrap the contact paper all the way over and beyond the edges of the Reflectix, after several times of ripping the Velcro on and off, the contact paper will begin to fall apart.

(This is why you started by doing a simple little project like a bathroom window, so you can get the hang of it while only wasting a small amount of materials.)

As you can see here (above), after wrapping the "glass-side" with an over-sized piece(s) of contact paper, I then covered the top-side with a piece of contact paper just the same size as the Reflectix, lapping it over the 2 1/2" margin framing the Reflectix. The Velcro will be stuck onto the face-down ("glass-side") side.
Obviously, many factors go into the decision of whether to use one layer or two layers of Reflectix. Nothing is free, and we don't want to waste materials, but then again we don't want to skimp, if the added layer is really going to help. Here is the reasoning I use when making this decision:

Where am I going to store the Window Blanket when it is not in use? A flimsy little one-layer Window Blanket may be easier to move around than a bulkier, stiffer one. Then again, if I'm going to have to lean it against a wall, the stiffer thickness will stop the corners from becoming folded or bent.

Consider whether the window or surface where you are putting the Window Blanket is flat, or if you're having to 'hump' the Window Blanket over a window air conditioner or a ledge used for raising or lowering the window.

Duct tape may be used to piece together pieces of Reflectix. I'm afraid I have not investigated different brands -- sometimes the glue on the duct tape 'burns' the Reflectix. But really, I've had mine now for a couple years or more, and wear, generally, is not a problem.

Next comes the topic of Velcro.
Tricks for applying Velcro to your Window Blanket

Velcro, as packaged here, costs around $25 at Meijer's or Lowe's. This is a 15 foot roll.

Initially, I thought it might be a good idea to have a solid line of Velcro around the edges of all my Window Blankets. Several thoughts made me reconsider.

- If you use too much Velcro, there is much more 'ripping' on and off, which tends to wear down the contact paper.

- Is there any advantage? The main purpose of a Window Blanket is not to reduce air infiltration. A storm window will do that. Mainly, the window blankets are decreasing the radiant heat loss (picture micro-waves, like a microwave cooker). It's nice to have a moderately tightly sealed edge, but it's not imperative.


So, I decided to economize, and use just patches of Velcro about 1 1/2" - 2 1/2" long.

I am providing two sets of illustrations on this topic.

Below is a photo of Velcro attached to the metal window track itself. Think carefully before placing Velcro onto the metal window track. Will the window still move up and down easily? Or, will the Velcro get ripped off when you try to open the window?

The Window Blanket should be just a little bit too large for the box-like cavity where the metal window parts are. See photo at right to see where I've put the (inner) Window Blanket.



Now, back to the topic of how-to stick the Velcro onto the window, whether you're putting it on the metal frame of the window, or putting it onto wooden screen molding, as pictured at right.

My method goes like this:

- Apply the scratchy side of the Velcro to the wall or the window frame. (see upper photo at right)

- Then, take the soft, fuzzy pieces of Velcro that go with your scratchy ones, and stick them together. (see next photo down, at right)

- Now, hold your Window Blanket in place and remove the backing from one or two of the Velcro patches. Press the gluey side from the two patches onto your Window Blanket.

- With your Window Blanket holding itself up against the window, your hands are free to go all the way around the edges, peeling the backing off the rest of them.




When Two Window Blankets are better than just one...

I now have Window Blankets all over my house. If I'm going to sit in a room for any length of time on a sunny day, I take down the Window Blankets and store them, but, (in winter) if we're having a cloudy, Ohio day, I may leave most of them in the windows. On excessively hot days in summer, I also leave most of the Window Blankets in place. Only on moderate days do I get lazy about how much heat is allowed in or out of my windows.

Gradually, as I fill up our house with Window Blankets, I am beginning to feel it's best to have two layers: one Window Blanket up against the glass, and one covering over the frame.


If you want to install a Window Blanket covering over the frame, certain things must be considered:

- You do not want to damage the window frame (if there is one), because when you move out, the next buyer or tenant may not want your Window Blankets.

- You cannot affix Velcro to plaster, so, if there is no window frame (made of lumber) -- if the window is frameless, as the one pictured directly above (with the Velcro strips), then you must install some sort of wood for the Velcro to attach to.

    Below, I am measuring the width of the window. Here the window has a half-window sized Window Blanket that sits in the window cavity. By having a half-sized Window Blanket, I can leave the bottom half in, and still get some daylight, on a day that is cold and bright.
 
       
How to Install Window Blankets Covering the Window Frame

In the following instructions, I assume you have some basic knowledge of carpentry. If in doubt, ask for help. This really is not very complicated for a person who is just a little bit "handy."
Materials needed for mounting Window Blankets to cover the window frame (rather than up against the glass):

- hammer

- small finish nails (1" tacks - not pictured)

- screen molding

- chisel and scrap board (for cutting screen molding without a saw)

You can buy screen molding and finish nails at the same lumber yard where you bought the Velcro and the Reflectix.

Be careful to buy little tiny, tiny finish nails that will not split the screen molding, but, they must be a minimum of 1" to go through the half inch drywall, if your house is modern construction and you're going directly onto the wall. If you're nailing straight onto a wooden window frame (using the screen molding as a way of protecting the window frame), you could possibly use a smaller tack/nail.


- Measure and mark the length you need for the screen molding strips. (I'm sorry I can't give you more detail than that, because it all depends on whether you already have a window frame, which you are trying to protect, or if you're just tacking these strips up right onto drywall.)

- Eliminate the hassle of sawing the screen molding by chopping into them with a chisel. It's very simple (see photo at right). If you hold your chisel as I'm holding mine (we're looking at the flat side of the chisel here -- the bevelled side is turned toward the edge of the cut), your result will be a perfectly bevelled cut. (see below)



I do not attempt anything fancy like mitered corners when I am putting up screen molding for Window Blankets. If the space I'm trying to fill is three feet wide and four feet high, I measure, then cut the top and bottom pieces to be three feet wide. I nail the top piece into place. Then I measure downward, leaving a half inch or so for the bottom piece of molding. I install the bottom piece last. My top and bottom pieces are the full width of the project, and the two vertical strips are slightly less than four feet, in the above example.

To make it easier to nail a long piece of screen molding into place, I pre-nail (as pictured right -- this is looking down at the table surface where I was working). I gently hammer my tacks into the strip of wood at around 12 inch intervals, and then I can hold it up into place and hammer the first couple nails without help.

Keep in mind, that if you are nailing around a frameless window (as is pictured several photos above, in my Velcro illustration), the screen mold needs to be absolutely no closer than 3/4" from the inner edge of the window (notice, mine are about an inch out from the window). This is because there is nothing but drywall if you get too close to the edge surface -- you want to hit the framing lumber that surrounds the window!
You might ask which windows I would not covered with Window Blankets. There really aren't any. Our house is so much warmer when we cover the patio door at night.  
 
The whole point is to be able to save money so you can enjoy the good things in life, and and protect the planet from humans like us who are "cooking" the environment!