Double Hung Window Styles: Types, Grids and How They Work

A double hung window has two sashes, the moving frames that hold the glass, and both of them slide up and down. One feature explains most of what people like about them. Open the top sash and hot air leaves. Open the bottom and cool air comes in. On a modern unit both sashes also tilt inward. You can clean the outside glass from inside the house.

The styles come down to 3 choices: the frame material, the grid pattern, and how many sit together in one opening.

We fit ProVia double hung windows across the St. Louis area, mostly as replacements for the original windows in older homes.

If you are ready to price new ones, start with our double hung window replacement page, which shows the ProVia lines we install.

What Makes a Window Double Hung?

A woman with a cup of coffee standing beside a row of double hung windows, with a small grid of panes in the top sash of the window behind her

The whole window is two sashes, each on its own track, held in place by a balance hidden inside the side of the frame. Everything else is a detail of that.

Sash. The frame that holds the glass. You get an upper one and a lower one.
Meeting rail. The bar across the middle where the two sashes meet. The lock sits here.
Balance. A spring system in the side channels that holds the sash where you leave it. Old wood windows used weights on cords instead. When a window will not stay up, the balance is what failed.
Tilt latches. Small tabs on the top rail of each sash. Slide them and the sash swings inward for cleaning.
Jamb. The frame around the whole window.

ProVia uses a constant force balance in its double hung line. The balance is the part that keeps a sash moving smoothly and stops it dropping when you let go.

How Can You Tell It From a Single Hung Window?

Turn the lock and push the top sash. If it moves, the window is double hung. If it will not budge, it is single hung.

You cannot tell them apart from the street, which is why people get this wrong. A single hung window has a top sash that is fixed in place, and only the bottom one opens. The push test is the one check that always works. I would push the top sash on every window in the house before calling anyone. It takes about 1 minute and it shows you what you own.

Look at the top corners of the upper sash as well. 2 small latches there mean the top sash tilts, and that only happens on a double hung. The full comparison, including cost, is in our single hung vs double hung guide.

What Do the Numbers Like 2 Over 2 Mean?

A living room wall of tall double hung windows, each sash divided into small panes by grids, with a row of shorter windows above them

The first number is how many panes are in the top sash. The second is how many are in the bottom sash. So 6 over 6 has six panes in each sash, and 6 over 1 has six small panes above one big one.

The dividers between the panes are called grids, or muntins. Each pattern points to a style of house:

1 over 1. No grids. Each sash is one pane. Plain, modern and the easiest to clean.
2 over 2. Two tall panes in each sash. A Victorian look.
6 over 6. 6 panes in each sash. Colonial and Georgian houses.
6 over 1, 4 over 1 or 3 over 1. Small panes on top, one big pane below. Common on Craftsman bungalows.
Cottage style. The top sash is shorter than the bottom one.

You will see many of these on older St. Louis brick homes and bungalows. A new window can copy any of them. On ProVia units the grids can sit between the panes of glass, so there is nothing to collect dust and the glass wipes flat.

What Are the Main Types?

You choose by frame material, by grid pattern, and by how many windows sit side by side.

Material comes first, because it decides how the window looks and how much care it needs. ProVia makes 4 double hung lines, and we fit all of them:

Endure. Vinyl, and our most popular line.
Aeris. A pre-finished wood interior with a vinyl exterior, for rooms where you want the look of wood.
Aspect. Built around energy savings.
EcoLite. The economy line.

Grouping is the other choice. A double hung can stand alone. It can sit in a pair, or in a group of three that share one frame. It can also flank a large fixed picture window in the middle. That last arrangement is common on front walls and in great rooms. The center pane gives you the view, and the two sides give you the airflow.

Double Hung or Casement: Which Is Better?

Neither one wins everywhere. Double hung suits tall walls, upper floors and rooms that need a window air conditioner. Casement usually seals tighter and opens all the way. Our guide to the types of casement windows covers the casement side.

	Double hung	Casement
How it opens	Slides up and down	Swings out on a crank
How much opens	About half the window at a time	The whole window
Cleaning from inside	Both sashes tilt in on modern units	Swings open, so the outside glass is in reach
Window air conditioner	Fits in the bottom sash	Does not fit
Air seal	Good, with a seam in the middle	Usually tighter, since it presses shut against the frame
What to watch	A worn balance lets the sash drop	Swings out over a walkway or porch

Where Do They Fall Short?

Only half the window opens at any moment, because one sash always covers the other half. If you want the biggest possible opening, a casement gives more.

Double hungs also have more moving parts than a fixed window. On an old one, the middle seam and the side tracks are where air gets past. A worn balance makes a sash drop or rattle. None of this is a reason to avoid them, but it is why the balance and the seals matter more than the brand name on the frame. If I were comparing two quotes, the balance and the seals would come first and the brand name last.

Do You Need a Permit to Replace Windows in St. Louis?

Inside a City of St. Louis historic district, yes. Outside those districts, the city’s Cultural Resources Office does not review the work.

The city’s own permit FAQ lists window replacement among the exterior work that district standards cover. Each district has its own standards, and the city says most permits are approved within 5 working days. Whether your street is in a district is something that office can tell you. Its main line is 314-657-3865.

The permit rule covers the city itself. Homes in the county and the suburbs follow their own city or county building rules. Call your city hall before you order.

When Is It Time to Replace One?

Replace a double hung when the sash will not stay up, the glass has fogged between the panes, or the frame has gone soft.

The sash drops or will not stay open. The balance has failed.
Fog or water between the panes. The sealed glass unit has failed, and it will not clear up.
Soft or rotted wood at the sill. Water has been getting in for a while.
A draft at the middle seam or the side tracks, even when it is locked. The seals have worn out.
A sash painted or swollen shut. Common on old wood windows.

Our guide to the signs it is time to replace your windows goes through the rest, including what a failing window costs you on the energy bill.

What Should You Ask Before You Buy?

Ask for the numbers on the label, not the brand name. Rated windows carry an NFRC label with two numbers. The U-factor is how much heat gets through the window. The solar heat gain coefficient is how much heat from the sun gets through. A lower U-factor keeps more heat in during a cold St. Louis winter. A lower solar heat gain keeps more sun heat out during a hot summer.

What is the frame made of? Vinyl, fiberglass, wood or clad wood price and age differently.
What glass is in it? Ask about a low-e coating and gas fill, and whether it is double or triple pane.
Do both sashes tilt? Modern units do, but ask, because older double hung units do not tilt at all.
What is the U-factor and the solar heat gain number? Two quotes with different numbers are not the same window.
What does the warranty cover, and who installs it? A good window installed badly still leaks.

When This Is Not Our Job

Repairing or restoring the windows you have. We supply and install new windows. We do not repair old ones or restore old wood sashes.
Anything commercial. ProVia windows are made for homes, and residential work is all we take on.

If all you need is a stuck sash freed or a balance replaced, this guide is not for you and we are not the right call.

Common Questions

Double hung means the window has two sashes and both of them move. “Hung” is an old word for a sash that is held up on a balance. So double hung means the top and the bottom are both hung, and both slide.

Turn the lock on the middle rail, then push the bottom sash up or pull the top sash down. A balance inside the frame holds it where you stop. To clean, slide the tilt latches and swing the sash inward. With children or pets in the house, open the top sash and leave the bottom shut, so the opening is out of reach.

The top sash. On a single hung window it is fixed and only the bottom opens. On a double hung, both open. Single hung usually costs a little less, because it has fewer moving parts. Double hung gives you two ways to ventilate and, on modern units, two sashes that tilt in for cleaning.

No. Double hung describes how the window opens. Double pane describes the glass, which is two layers with a sealed gap between them. A double hung can have single, double or triple pane glass, and most new ones come with double or triple.

Two panes in the top sash over two panes in the bottom sash. The first number is the top sash and the second is the bottom. A 2 over 2 window has two tall panes in each sash, a pattern often seen on Victorian houses.

Yes. Raise the bottom sash, set the unit on the sill and close the sash down onto it. Most window air conditioners are made for this. A casement window cannot hold one, because it opens outward on a crank.

The best one is the one whose numbers and build suit your house, not the one with the biggest name. Compare the frame material, the glass package, the U-factor and solar heat gain on the label, whether both sashes tilt, and the warranty. For most homes we fit, that means the ProVia Endure. If you want a wood interior, it means the Aeris.

The wall decides. Double hung fits tall openings and upper floors, holds an air conditioner and tilts in for cleaning. Casement opens the whole window and usually seals tighter, but it swings out into the yard, a porch or a walkway. A lot of houses use both.

Getting a Price

What these windows cost at your house depends on the size, the frame, the glass and the opening. That number comes from measuring, not from a web page. Ask for an on-site estimate. We measure every opening at that visit. Call 314-277-5952, or start with the estimate page.

The windows are ProVia. To confirm we are a Platinum dealer, search for us on the ProVia dealer locator. Our workmanship carries a 10 year guarantee. Finished work is in our photo gallery.