Saving With Sliding Glass Doors
In my dining room I have an old, wide window in a brick veneer wall. I�d like to replace it with a sliding glass door. Does this make energy sense? If so, how do I make this improvement?�Mike M.
Your plan makes energy sense, but only if you select an efficient sliding glass door and install it properly. I made this improvement to my own kitchen last year.
The overall efficiency of an airtight sliding glass door can be better than an insulated partial wall with a large inefficient window above. My double horizontal slider window had double-pane glass, but the gap seal failed on one panel and all the weatherstripping was worn out, creating air leaks.
Most homes have a lot of reinforcing lumber framing around window openings, which is great for structural strength, but leads to inefficient thermal bridges and leaves little room for insulation.
I selected a super-high-efficiency sliding glass door from Thermal Industries Inc., with a steel-reinforced vinyl frame and triple-pane glass panels. Two of the panes have a low-emissivity coating and dense krypton inert gas between them, providing high insulation and cutting down on noise. Select a door that is ENERGY STAR-qualified and meets federal energy tax credit requirements.
Installing the doors
The manufacturer of the sliding glass doors sent along an expert to help me with my installation. Here are some tips he taught me.
Spend a few extra dollars and rent a large masonry saw to cut through the brick wall in one pass from outdoors. I bought a cheap masonry blade for my circular saw, and I had to make both outdoor and indoor cuts to get through the wall. This led to an uneven cut and an unbelievable amount of dust indoors.
With a brick veneer wall, the width of the brick and the total wall framing thickness will be about twice the width of the door frame. The installer recommended positioning the door out on the brick to create a more stable door base.
For the simplest installation, cut straight down from the existing window opening. You will have to build out the interior opening with studs to the same width as the brick, but this is still easier than resizing the entire opening. This will leave a gap between the new studs and the brick that must be insulated with low-expansion foam or fiberglass.
EFFICIENCY IDEA
A cool option from France
If you have clearance in your dining room for swinging doors, French patio doors are more efficient than sliding glass doors. Swinging doors close on compression weatherstripping, so they seal better over the long term than a seal on sliding glass doors. Also, when you open both swinging doors, they provide more ventilation.
