U-factor
The rate of heat loss through the whole unit, frame included. Lower is better. The best units sit around 0.15, and the Travis County ceiling under the 2015 IECC is 0.40.
Energy-Efficient Window Installation in Austin, Specified for Climate Zone 2
Austin Quality Windows offers energy-efficient window installation in Austin, TX as Travis County's specialist in glass specified by the numbers, specializing in low-E insulated glass units, argon-filled double and triple glazing, and frames with a low U-factor across the whole unit. We offer low solar gain coatings for west walls and thermally improved spacers at the glass edge.
- Free in-home measure
- Elevations you approve
- Installed to manufacturer instructions
- One written price
About our energy-efficient window installation
Our team provides an elevation-by-elevation glass schedule for every window, delivering rooms that stay comfortable through an Austin afternoon for both residential and commercial projects. We read the NFRC label on each unit before it is ordered, our own crew measures and installs every opening, and we flash it to the manufacturer's written instructions so the seal around the frame matches the rating on the glass.
From the solar heat gain coefficient printed on the label to the air sealing around the finished frame, our team handles every detail. Serving Austin, West Lake Hills, Sunset Valley and Barton Creek, we specify the glass for the way your house actually faces the sun.
Why Austin Quality Windows
How We Work
No handoffs between a salesperson, a measurer and a subcontracted crew. The crew that measures your openings installs the windows.
Measured on siteEvery opening measured in the wall it sits in, by the crew that will install it
Elevations firstYou approve the drawings, sizes, glass and finish before anything is ordered
Flashed to specSill pans, flashing and sealant to the manufacturer's written instructions
Water testedOpenings checked for leaks before the interior trim goes back on
The Five Numbers on an NFRC Label
The National Fenestration Rating Council is a nonprofit set up by the industry in 1989 that runs the rating and labeling program for windows, doors and skylights. Its label is the real spec sheet for an energy-efficient window, and we read it with you before anything is ordered. Five ratings matter.
Solar heat gain coefficient
The share of incident solar heat that passes through the glass. Lower keeps more sun outside, and it is the number that matters most on an Austin west wall.
Visible transmittance
The share of visible light that passes through. Higher means a brighter room, so the goal is a coating that cuts solar heat without turning the view gray.
Air leakage
Measured in cubic feet per minute per linear foot of crack between sash and frame. A lower figure means fewer drafts and less humid air pulled indoors.
Condensation resistance
A scale of 1 to 100, where a higher score resists condensation better. It matters on a humid morning after the air conditioning has chilled the glass overnight.
What Climate Zone 2 Asks of the Glass
Travis County is in Climate Zone 2. The state energy-code floor for houses is still the energy chapter of the 2015 IRC, and under the 2015 IECC prescriptive table the limits are a fenestration U-factor of 0.40 and a glazed fenestration SHGC of 0.25. SPEER's compliance guide says that table covers additions, alterations and replacement windows, not only new houses, and that up to 15 square feet of glazed fenestration is exempt.
Some towns go further. West Lake Hills and Lakeway have adopted the 2021 IRC and IECC, and West Lake Hills keeps the Climate Zone 2 window U-factor at 0.40 in its own amendment. Volente enforces the 2018 editions. We check the edition your town enforces at quote time.
The ratings have to come from NFRC. A unit with no label is assigned a default U-factor and SHGC, and those defaults are not where you want a whole-house order to land at inspection.
ENERGY STAR sets its own window criteria on a map of four United States climate zones, and in the hot southern zones those criteria are driven mainly by solar heat gain. It is a useful benchmark when comparing products, and we show you where a unit sits against it. It describes the product, not the company installing it.
Low-E Coatings, Gas Fill and the Glass Edge
A low-E coating reduces the emission of radiant infrared energy, keeping heat on the side of the glass where it started while letting visible light through. In Austin that mostly means keeping summer heat outside the room.
- Pyrolytic coatings. Fluorinated tin dioxide deposited at high temperature, usually at the float glass plant as the glass is made. Durable enough to handle.
- Sputtered coatings. Thin silver layers with antireflection layers, deposited in a vacuum chamber five to ten or more layers deep. Silver is environmentally unstable, so these coatings must be sealed inside an insulated glass unit.
- Argon. Conducts heat at about 67 percent the rate of air, which is why it is the standard fill.
- Krypton. About half the conductivity of argon, used mainly in thin double units and high-performance triple units.
- The gap. Most sealed units reach their best insulating value with a space of about 16 to 19 mm between panes; a wider gap lets convection carry heat across.
- Spacers. Metal spacers conduct heat at the edge of the glass, so we specify thermally improved spacers of structural foam or aluminum with a thermal barrier.
Triple glazing adds weight and thickness that some frames cannot carry, so we put the labels for a double and a triple unit side by side for your openings and let the ratings decide.
West-Sun Walls, Reflectivity and the Rules That Limit It
Austin's highs pass 90 degrees Fahrenheit on about 123 days a year and 100 degrees on about 29. A west elevation takes that heat late in the day, at a low sun angle, straight through the glass. That is where the SHGC on the label earns its place: we often specify a lower-gain coating on west and south walls than on the north side, and keep visible transmittance as high as the coating allows so the room does not go dim.
Reflectivity is the catch. Low-E glass reflects, and highly reflective low-E windows can concentrate sunlight onto nearby siding and parked cars. Several places we serve limit it outright.
- West Lake Hills bans glass at 20 percent reflectivity or more, and the inspector may ask for a sample first.
- Steiner Ranch lists reflective glass among the facade materials its design manual rules out.
- Barton Creek does not allow mirrored glass, and window specifications go to the committee first.
- City of Austin historic properties are asked to use glass or film without noticeable tint, coloration or reflectivity.
We choose coatings that hit the performance target and the local rule at the same time, and we carry samples to the committee when one is asked for.
Installation Decides Whether the Rating Holds
An NFRC rating describes the unit, not the gap around it. A unit with an excellent air leakage figure still leaks if the space between frame and framing is left open, so the installation is where the label either holds or does not.
- Measured by the installer. We measure every opening ourselves, so the unit fits without oversized gaps.
- Flashed and drained. A sloped sill pan and shingle-lapped flashing to ASTM E2112 and the manufacturer's written instructions.
- Sealed at the perimeter. The gap between frame and framing is insulated and sealed with materials the manufacturer approves.
- Tested. We water-test each opening before the interior trim goes back.
- Label kept. The NFRC label stays on the glass until you and the inspector have seen it.
On a historic house in Austin, the Historic Design Standards suggest retrofitting insulated low-E glass where it is appropriate, and allow historic windows on non-street-facing walls to be replaced for energy efficiency once other upgrades are made or in the same project. We work inside those conditions rather than around them.
What Drives the Price of Energy-Efficient Windows
We do not publish a figure, because performance glass is specified wall by wall and the specification is what moves the price. These are the drivers.
- The glass package. Dual or triple pane, pyrolytic or sputtered low-E, argon or krypton, laminated glass for sound or security, and tempered glass where safety glazing is required.
- How many glass types. One coating everywhere, or a lower-gain coating on west and south walls and another elsewhere.
- Frame material. Vinyl, fiberglass, aluminum-clad wood, thermally broken aluminum or steel, since the frame counts in the whole-unit U-factor.
- Size and count. Unit sizes, oversize and custom shapes, and operable against fixed.
- Installation type. An insert into a sound frame, or full-frame removal with a new sill pan and flashing.
- Structure and access. Header work on an enlarged opening, second-storey or hillside access, and a lift for heavy triple units.
- Approvals. A reflectivity sample, HOA review, a permit or historic review.
The real number comes from the free in-home measure, where we note each opening's orientation, propose the glass for it and put price, labels and scope in writing.
The process
From First Measure to Finished Openings
Four steps, and nothing is ordered until you have signed off on the drawings and the price.
Free in-home measure
We measure every opening, check the framing and the header, and talk through glass, frame material and how each window should operate.
Elevations and a written price
You get drawings of every unit for your approval and for any HOA or historic review, with one written price.
Ordered to your sizes
Units are ordered to the approved sizes and glass package, and checked against the drawings when they arrive.
Installed and water tested
Old units out, openings flashed, new units set, sealed and water tested, then trim and cleanup.
More of What We Install
Service area
Where We Install
- window installation in Rollingwood
- Barton Creek windows and glass doors
- window installation in West Lake Hills
- Tarrytown windows and glass doors
- window installation in Lost Creek
- window installation in Volente
- Sunset Valley windows and glass doors
- window installation in The Hills
- window installation in Lakeway
- Steiner Ranch
Questions
Energy-Efficient Window Installation: Common Questions
What U-factor and SHGC should I look for in Austin?
At minimum, the Travis County Climate Zone 2 limits: a 0.40 U-factor and a 0.25 SHGC under the 2015 IECC table. On west and south walls we usually go lower on SHGC, and we show you each label before ordering.
Is triple pane worth it in Austin?
Sometimes, mostly for sound or a very large opening. It adds weight and thickness, so we compare a double and a triple unit's labels for your openings and choose on the ratings.
Will low-E glass make my rooms darker?
Not if visible transmittance is part of the spec. We pick a coating that lowers solar heat gain while keeping as much daylight as it can, and you see the visible transmittance figure on the label first.
How much will new windows lower my electric bill?
We do not quote a savings figure, because it depends on your house, its orientation and how you run the air conditioning. What we give you is the U-factor, SHGC and air leakage of every unit, in writing.
Does my HOA or town restrict low-E glass?
Some restrict how reflective it can be. West Lake Hills bans glass at 20 percent reflectivity or more, Steiner Ranch and Barton Creek do not allow reflective or mirrored glass. We pick coatings that meet the rule.
Do you install ENERGY STAR windows?
We can specify units that meet the ENERGY STAR criteria for your climate zone and show you the label. ENERGY STAR describes the product; it is not a rating of the installer.
How long from order to install?
It depends on the manufacturer and the glass, and custom coatings can take longer. Your install date is written into the quote.
Can I upgrade the glass and keep my frames?
Where the frames are sound, an insert unit with new low-E glass can go inside them. Where frames leak or have rotted, full-frame replacement is the only way the rating holds, and we tell you which at the measure.
Is the installation under warranty?
Yes. Every installation carries a written warranty, which we explain when you receive the quote.
Free in-home measure
Talk to us about energy-efficient window installation
Free in-home measure across Austin and the west side. We call you back to set a time.
Calls only, we do not receive text messages.