The Thermal Envelope - Our new curtains

Next to food, climate control is usually the next largest area of energy consumption.  This includes heating and air conditioning.  These are the things that keep us comfortable in our homes, workplaces, shopping mall, gym etc.

• At our home we have a programmable thermostat. 68 degrees morning & evening, 66 day, 62 night time.
  
• We have double pane windows. 
• We have added draft stoppers behind all the switches and outlets. 
• We have weather stripping around our doors and have raised the threshold on both door to eliminate air gaps under the doors. 
• We have latex spray foam insulation around all the places that plumbing passes thought the walls. 
• We had a heating expert tighten up all the joints in the ducts and insulate. 
• We also had diverters added to the ducting so that we can adjust how much heat going to different parts of the house. 
• We keep an additional draft stop under the door in winter.
• Our only air conditioning in the summer is the fireplace chimney and our windows.

We would recommend all of these easy steps to any home owner.  Once you have done all of these things, what next?

We have insulation in the floor but no where else.  We have some moisture and pest issues we have to deal with before we can insulate the walls and ceiling.  This is rather sad since an insinuated wall has an R-Value of about 4.  This is about equal to the R-value of our double pane window.   Normally windows are the weak point in a buildings envelope even with double or triple pane windows.  I couldn’t tackle the walls or ceiling even though that would be the best move so I put my efforts into improving our windows further.  Good window coverings can raise the R-value of a window by 3 or 4.  That doubles the R value of a good window.  Warm Windows insulated shade system claims that their curtains have and R-value of 7 when done correctly.

The good news is that the insulating shade will help not only stop the loss of heat in the winter, but will also reduce the gain of unwanted heat in the summer.  The bad news is that our windows probably have a higher R-value than our walls now.

I didn’t want to go with Warm Windows for two reasons.  One, its expensive which isn’t such a bad thing if you are a novice DIYer or can get it at JoAnns at 40% off.  Mostly I wanted to use "green" materials and launch out on my own.  I designed and sewed some roman shades with magnets around the edge to seal the curtain to the wall.  Warm Windows work on the same principal but I created my own assembly method with my own materials purchased from the hardware store.  This was important to me since I wanted to use primarily second hand materials.    Here are picture of a few of the shade I have created for our home thus far.  

I started working on this during the summer so I started with the south facing windows and it made a noticeable difference in how hot the house got during the day.  The office window is cover by a nice sheet.  Would you have guessed it?  The insulation is provided by an old mattress pad.  The wood came from our scrap pile and the lining material was a remnant from the fabric store.  The cord lock, rings and screw eyes and magnets were purchased new. 

Now that the weather has turned cold, I have moved on to doing the north facing windows.  Here is our kitchen window.   Its made from an old drapery, and old drapery lining.  I oopsed and made it a little to narrow so I added pieces into the sides.  The pieces came from a used bed skirt.  The insulation is made from another mattress pad. 

I don’t have any instrumentation to measure the R-value of the curtains I have made.   I can tell you that I placed a thermometer in the window and the temperature behind the curtain is about 10 degrees lower than the temperature in the room by morning and the glass is noticeably colder to the touch than the glass of the windows that had not been covered.

I have a few more windows I would like to do but for the mean time, I have covered over some of them with insulating plastic which actually does a very good job.  Im also hatching a plan to add thermal shutters to our large SW facing living room window.  It has a fearsome gain in the summer and is among the coldest rooms in the winter.