The best windows for your home are the ones that keep the summer sun out of the rooms you use, open and close without a fight, and hold up to Central Texas weather with very little upkeep. For most houses in this part of Texas that means vinyl frames with insulated, low-E glass chosen for the direction each wall faces, installed carefully. Brand names and sales pitches matter much less than those few things.
Here is how to judge any window you are shown, using the information printed on the window itself.
Find the NFRC label
Most new windows carry a sticker from the National Fenestration Rating Council. It lists several performance numbers measured in a standard way, so you can compare one manufacturer to another without relying on marketing language. Ask to see the label, or the ratings for the exact configuration you are being quoted. A window with no ratings to show is hard to evaluate.
Four numbers on that label are worth understanding.
Solar heat gain coefficient
This number, usually written as SHGC, tells you how much of the sun’s heat passes through the window. It runs from zero to one, and lower means less heat gets in. In a climate with a long cooling season and plenty of 100-degree days, this is often the most important number on the sticker. It matters most on west-facing walls, which take direct sun during the hottest part of the day, and on large panes like picture windows and patio doors.
U-factor
U-factor measures how easily heat moves through the whole window by conduction, the way warmth passes through a pan. Lower is better. In cold northern states this is the headline number. Here it still matters, both for keeping cooled air inside in August and for the occasional hard freeze, but it usually ranks behind solar heat gain for Austin homes.
Visible transmittance
This tells you how much daylight comes through. Higher means brighter rooms. Some coatings that block a lot of heat also dim the view slightly, so check this number if you like a bright house. Good modern glass can keep heat out while still letting plenty of light in.
Air leakage
Some labels list air leakage, which shows how much air sneaks through the window assembly itself. Lower is better. A tight window helps with comfort and does a better job of keeping out cedar pollen in winter and dust from nearby construction.
Condensation resistance
Some labels also include a condensation resistance rating on a scale up to 100. Higher numbers mean the window resists moisture forming on the inside surface. In Austin this matters on the handful of cold, damp mornings each winter, and more so in bathrooms and kitchens where indoor humidity runs high.
How the numbers work together
No single rating tells the whole story, and the numbers trade off against each other. A coating tuned for very low solar heat gain may let in a bit less daylight. A window with excellent insulation but high solar gain would suit a cold climate better than ours. When you compare two quotes, line up the same numbers for the same style and size so you are comparing like with like. If a salesperson only wants to talk about one rating, ask about the others.
Look for ENERGY STAR on the right configuration
ENERGY STAR sets performance criteria by climate zone. A window that qualifies for one region may not qualify for another, so the label should match where you live. Our windows are available in ENERGY STAR qualifying configurations, and we can tell you which glass options meet the criteria for your home.
It is also worth calling your electric provider before you buy. Austin Energy serves the City of Austin, and Pedernales Electric Cooperative, Oncor and others serve surrounding areas. Utilities sometimes offer efficiency programs, and the details change, so ask what is current.
Choose glass by the direction each wall faces
You do not have to put the same glass in every opening. A north-facing window gets little direct sun and may be fine with a standard low-E package, while a west wall that bakes every afternoon can justify a coating with a lower solar heat gain. Talk this through with your installer. A company that asks which rooms get hot and which way they face is paying attention to how you live in the house.
Why vinyl frames suit this climate
The frame holds the glass, so it has its own effect on comfort and upkeep. Vinyl does not conduct heat the way metal does, so the frame stays closer to room temperature on a hot day. It does not rot or need painting, and termites have no interest in it. The color runs through the material instead of sitting on top as paint, so there is no peeling to scrape later.
Quality varies between vinyl products, so look at how the corners are joined, how solid the sash feels when you open and close it, and how smoothly the locks engage. A good showroom sample or a demo window at your kitchen table will tell you a lot. You can see the range of styles we install on our vinyl windows page.
Pick a style that suits the opening
The best window for a living room view is a different style from the best window over a kitchen sink. Picture windows give the most glass and seal tightly because they do not open. Casements and awnings crank open and suit hard-to-reach spots. Double-hung and single-hung windows fit most traditional homes. Sliders work well in wide, short openings. Match the style to the job, then apply the same glass rules above.
Remember that installation counts as much as the product
A top-rated window installed poorly will leak air and water. Around Austin, expansive clay soils make some houses shift a little over the seasons, and an opening that has moved can be slightly out of square. Installers need to check for that, shim and level the new unit, insulate the gap around it and seal it properly on the outside. Ask how a company handles these steps and who does the work. Professional installation is part of what you are buying.
Think about upkeep and warranty
A window you can clean in a few minutes and never paint is a window you will be happy with in the long run. Tilt-in sashes on hung windows make the outside of upper-floor glass easy to reach. Ask about screens too, since a good screen keeps bugs out on spring evenings when you want the windows open. Check that screens pop out easily, because you will want to rinse the pollen off them every year or two.
Finally, read the written warranty for whatever you buy. We offer double lifetime warranty options; ask us what the terms cover for the specific product you choose.
See your options at home
We bring samples to your house, look at how each wall faces the sun, and recommend glass and styles that fit the way you use each room. Call (512) 524-9455 or book a free in-home estimate with The Window Source of Austin.