Learn · Siding & Windows

Siding & Windows, in plain English.

Siding types, window ratings, drafts, rot and curb appeal.

The lingo.

Argon fill
An inert gas between panes that insulates better than air. Double-pane with Low-E and argon is the usual replacement window.
Double-hung
A window with two sashes that slide up and down. Casement windows crank outward and seal tighter; sliders move sideways; picture windows do not open.
Egress window
A window big enough to escape through, required in bedrooms and finished basements. Minimum opening sizes are set by code.
Engineered wood
Wood strand siding treated with resins and wax (LP SmartSide is the common brand). Looks like wood, costs less than fiber cement, and needs paint maintained.
Fiber cement
Siding made from cement, sand and cellulose (Hardie is the best-known brand). Fire resistant, holds paint for years, and heavier and more expensive to install than vinyl.
Flashing
Metal or membrane at windows, doors and trim that directs water out over the siding below. Window leaks are almost always flashing problems.
House wrap (WRB)
The weather-resistive barrier under siding that sheds water that gets past the siding while letting vapor out. Missing or badly lapped wrap is why walls rot behind siding that looks fine.
Insert vs. full-frame replacement
An insert fits inside the existing frame and is cheaper; a full-frame replacement removes everything to the rough opening, fixes rot and re-flashes. Rotted frames need full-frame.
J-channel
The trim piece vinyl siding tucks into around windows and doors.
Low-E
A microscopic metallic coating on glass that reflects heat while letting light through. Standard on quality windows.
Rot
Wood softened by moisture and fungus, usually found at window sills, trim bottoms and under failed flashing. Every siding estimate should state how rot found during the job is priced.
SHGC
Solar heat gain coefficient, how much of the sun's heat a window lets in. Lower is better in hot climates; higher is sometimes wanted on south-facing windows up north.
Soffit and fascia
The underside of the roof overhang and the board at its edge; usually wrapped in aluminum or vinyl as part of a siding job.
U-factor
How much heat a window loses; lower is better. Look for 0.30 or lower in cold climates. Found on the NFRC label on every new window.
Vinyl siding
The most common siding: low cost, no painting, decades of life. Quality varies by thickness; it must be hung loose to expand and contract, which is why it is nailed, not screwed tight.

Guides.

Reading list.

Articles from around the internet that our Pros trust. They open on the source's site.

  • Update or replace windows · U.S. Department of Energy

    When repair beats replacement, how to read ratings and what to look for in a new window.

  • Weatherize your home · U.S. Department of Energy

    Air sealing, insulation and moisture control, the work that makes new siding and windows pay off.

From the Pros.

Written by the people who do this work every day, in your area.

The first posts from Siding & Windows Pros are on their way.

Questions from homeowners.

Ask the Pros

No questions yet for Siding & Windows. Yours would be the first, and a Pro will answer it.