Single Hung vs Double Hung Windows: What a Portland Installer Tells Homeowners

Single hung vs double hung windows comes down to one moving part. On a single hung window only the bottom sash slides up. On a double hung window the top sash slides down too, and both sashes usually tilt in so you can clean the outside glass from inside the house. For most Portland and Vancouver homes, single hung is the better value and seals a little tighter. Double hung earns its place upstairs, in kids' rooms, and on any window you cannot reach from the outside.

Not sure which one your house needs? Ask for a free written estimate and you get one written price with the exact Milgard series for each window.

That is the short answer. The longer one is more useful. The choice also decides which Milgard product lines you can even pick from, whether a bedroom window meets the escape rule, and whether a second-floor window needs a safety stop. Those are the parts most comparisons skip, and they are the parts that cause problems after the install.

Single Hung vs Double Hung at a Glance

The Fact Most Comparisons Skip: Milgard Makes One Double Hung

Read a national article on this topic and you will get a tidy list of pros and cons. What it will not tell you is that the brand on your quote limits the answer. Milgard, the brand we install, builds a single hung window in six product lines and a double hung in exactly one.

• Single hung: V250 Style Line, V300 Trinsic, V400 Tuscany, V450, C700 fiberglass, and A250 aluminum.
• Double hung: V400 Tuscany, a vinyl window. That is the whole list.
• No fiberglass double hung. The C700 fiberglass line comes as a slider, single hung, picture, awning, casement, and radius window, but not a double hung.

So the two decisions are tied together. If you want double hung, you are choosing Tuscany vinyl. If you have your heart set on fiberglass (here is how vinyl and fiberglass windows compare in Portland), your hung windows will be C700 single hung, and the upstairs windows where tilt cleaning matters may be better as casements. A good quote spells this out by series. A vague quote that just says "vinyl double hung" leaves room for a substitution.

The hardware is not identical across the line either. Trinsic, Tuscany and C700 use Milgard's SmartTouch lock. Style Line uses a Positive Action Lock that locks in one motion. The V450 has an interlock at the meeting rail, where the two sashes meet, to cut air leaks. These are small things you feel every day you open the window, so it is worth handling a sample before you sign.

Bedroom Egress: The Rule That Picks Some Windows for You

Every sleeping room needs an emergency escape opening, and in a lot of houses that opening is a window. Under the Oregon residential code the window has to give at least 5.7 square feet of clear opening (5.0 on a ground-level floor), at least 24 inches of clear height and 20 inches of clear width, with the sill no higher than 44 inches off the floor. Portland's own window permit page repeats the same numbers. Washington builds on the same model code, and its amendments keep those numbers.

Here is why that matters for a hung window. Single or double, a hung window only ever opens about half its height, because one sash slides past the other. So to get 24 inches of clear height, the whole window has to be close to twice that tall, plus the frame. Milgard's own size chart for the Tuscany double hung lists the smallest egress sizes as 3052 and 2664, which in window shorthand is about 3 feet wide by 5 feet 2 inches tall, or 2 feet 6 inches wide by 6 feet 4 inches tall. That is a big window for a small bedroom.

This is where a casement window often wins. A casement cranks open on a hinge, so nearly the whole window becomes the opening. A shorter casement can pass the same escape rule that would force a tall hung window. If your bedroom wall does not have the height for a tall hung window, ask about a casement before anyone talks about cutting the opening bigger.

Oregon and Washington Treat Replacement Windows Differently

This one catches people on the Washington side. Oregon's code has a replacement-window exemption: when you replace an existing window, the new one does not have to meet the full egress size and sill height, as long as it is the manufacturer's largest standard size that fits the existing frame or rough opening, and it is the same operating style or a style with an equal or larger opening. So in an older Portland house with small bedroom windows, you can usually replace like for like without cutting the wall.

Washington did not adopt that section. The state's amendments to the residential code list the replacement-window section for escape openings as "not adopted." In Vancouver, Camas and the rest of Clark County, a bedroom window being replaced is not covered by that exemption, so the size and style of the new window matter more. Swapping a casement for a hung window in a Vancouver bedroom, for example, can shrink the clear opening. Whoever quotes your job should check every bedroom window against the rule for your side of the river before ordering.

Second-Floor Windows and Kids: The 24-Inch Sill Rule

The code has a second rule most homeowners have never heard of. When a window sill sits less than 24 inches above the floor inside, and the opening is more than 72 inches above the ground outside, the window needs fall protection. In plain terms: a low window on a second floor. The window either has to stop a 4-inch ball from passing through, or carry a fall prevention device or a window opening control device that meets the ASTM F2090 standard.

A window opening control device is a small stop built into the frame. It holds the sash at under 4 inches open, the adult can release it for an escape, and it resets itself when the window closes. Milgard offers it as a factory option on Tuscany single and double hung, Trinsic single hung, and Style Line single hung. It is not listed for the C700, V450 or A250 hung windows. If you have a low upstairs sill, that alone can decide the series.

This is also the best everyday case for double hung. Children's hospital safety guides tell parents to open double hung windows from the top and keep the bottom sash closed. Fresh air comes in, and the opening sits up where a child cannot reach it. A single hung window can only open at the bottom, right at the height a kid climbs to.

Air Sealing Through a Wet Northwest Winter

Single hung windows have a real edge on air sealing, and the reason is simple: half as many moving parts. The top sash is fixed, so there is only one set of sliding seals to wear, loosen, and let in a draft over the years. On a window you rarely open, that is the smart pick.

Two honest caveats. First, any new window is far tighter than a 1950s original, single or double. Both types have to meet the same standards to be sold, and the difference shows up more after years of use than on a rating sheet. Second, you can check it yourself: the NFRC label has an optional air leakage number, lower is better, and a window rated above 0.3 cannot carry the ENERGY STAR label.

The number that matters more for your heating bill is the U-factor. Portland requires replacement windows in houses to be U-0.30 or better. For how glass, gas fill and Low-E coatings get there, see our guide to energy efficient windows for Portland homes.

Cleaning: Which Windows Can You Actually Reach?

This is the reason double hung became the most common style in the country. Both sashes tilt in, so you can wash the outside glass from inside the room. On the Tuscany double hung, Milgard says the sashes tilt inward so the window is very easy to clean. Most single hung windows do not tilt, and Milgard says as much. Some single hung models tilt the bottom sash only, which still leaves the fixed top pane to be cleaned from outside.

On the ground floor that hardly matters, since a hose and a squeegee reach it fine. On a second story over a steep yard, a deck, or a driveway, it is the whole decision. Picture where you would put a ladder. If there is no good answer, that window should be a double hung or a casement.

Does Opening the Top Sash Really Cool the House?

Window brands love this one: open the top and bottom of a double hung, warm air leaves at the top and cool air comes in at the bottom. The physics is real. The U.S. Department of Energy describes cool air entering low and warm air rising and leaving through upper windows. But The Spruce, which used to cover this topic, called the effect within a single window fairly minor, and we agree. The bigger win is opening windows on two floors, low downstairs and high upstairs, so the whole house pulls air through. On a summer evening in Portland, that works with any mix of window types.

Older Portland Houses, Historic Districts and Permits

Portland is an old-house city. Census data shows about 1 in 4 Portland housing units (25.9 percent) were built before 1940, and about 45 percent before 1960. In Vancouver it is under 4 percent before 1940. That gap is part of why window questions in Portland sound so different: tall old window openings, small bedroom windows that would not pass today's escape rule, and historic district rules.

• Permits in Portland: Portland Permitting and Development says replacing a window with no change to the header and no smaller clear opening does not need a permit. Widening a window or adding a new one does.
• Historic districts: in places like Irvington, Laurelhurst and Ladd's Addition, Portland's zoning code only exempts certain replacements from historic resource review, and they have to fit the existing opening exactly with the glass set back at least 2 inches from the siding. Vinyl windows on a contributing house are not on the exempt list. Fiberglass is allowed in some cases, such as on non-contributing houses.
• Vancouver: the city's Permit Center can confirm what your project needs, at (360) 487-7833.

If your house sits in a historic district, sort this out before choosing between single and double hung, because the material rule may narrow your choices first. Ask whoever quotes it to check the address first.

Casement vs Double Hung: The Third Option

Plenty of homeowners who start with single hung vs double hung end up with some casements. A casement cranks out on a side hinge, locks against its seals when closed, and opens almost the full window. That makes it a strong fit over a kitchen sink where you cannot reach up to lift a sash, in a bedroom where a hung window would have to be very tall to pass the escape rule, and anywhere you want fiberglass with full opening, since the C700 comes as a casement. The trade-off is the sash that swings out, which can be in the way next to a walkway or deck.

Which One Goes Where: Room by Room

• Living room and dining room on the ground floor: single hung. You reach the outside glass easily, it seals tight, and it gives you the most choices of series.
• Upstairs bedrooms, especially kids' rooms: double hung Tuscany, so you can vent from the top. If the sill is under 24 inches, add the opening control device.
• Small bedroom that must meet egress: price a casement next to the tall hung window. It often fits the wall better.
• Second-story windows over a deck, slope or driveway: double hung or casement, so nobody has to clean from a ladder.
• Whole-house fiberglass: C700 single hung downstairs, C700 casements where you need tilt-free cleaning or a bigger opening.
• Rentals and windows you rarely open: single hung. Fewer moving parts, fewer service calls.

Mixing styles in one house is normal, chosen opening by opening. Our Portland window replacement page explains how we install and how to get a free written estimate.

Five Questions to Ask Before You Sign

• Which exact Milgard series is each window? A good quote names it per opening, like V300 Trinsic single hung or V400 Tuscany double hung.
• Which windows are single hung, which are double hung, and why?
• Do any bedroom windows need to meet the escape size, and will the new ones pass on my side of the river?
• Do any upstairs windows have a sill under 24 inches, and is an opening control device included?
• Is this an insert into the old frame or a full-frame install, and what does the warranty cover?

Gorilla Works is a Milgard factory-certified installer, and our window work is backed by a limited lifetime warranty covering both the Milgard product and our factory-certified installation. Through our sister company, Exteriors Design, our crews have also installed commercial windows on mid-rise buildings and skyscrapers, and we bring the same flashing standard to your house.

Curious how the choice affects the bill? Our guide to window replacement cost in Portland explains every factor that moves the price, without a sales pitch.

Frequently Asked Questions

Can I replace a single hung window with a double hung in the same opening?

Usually yes. Both are hung windows of the same shape, so a double hung can go into the opening a single hung came out of. With Milgard that means a V400 Tuscany. On a bedroom window, check that the clear opening of the new window is not smaller than the old one.

Are double hung windows more expensive than single hung?

Generally yes, because there is a second operating sash, more balances and more seals. With Milgard there is a second factor: double hung only comes in the Tuscany line, while single hung starts in lower-cost lines like Style Line. A written estimate per opening shows the real difference for your house.

Can a single hung window be a bedroom egress window?

Yes, if it is big enough. It has to give 5.7 square feet of clear opening (5.0 at ground level), 24 inches clear height and 20 inches clear width, with the sill no higher than 44 inches. Since a hung window opens about half its height, that takes a tall window.

Do single hung windows tilt in for cleaning?

Most do not. Some models tilt the bottom sash, but the fixed top pane is always cleaned from the outside. If outside cleaning is hard, choose double hung or casement for that opening.

Does Milgard make a fiberglass double hung window?

Not today. Milgard's C700 fiberglass series comes as a slider, single hung, picture, awning, casement and radius window. Milgard's only double hung is the V400 Tuscany in vinyl.

Gorilla Works proudly serves Portland, Gresham, Beaverton, Hillsboro, Tigard, Lake Oswego, Happy Valley, Milwaukie, Troutdale, Vancouver WA, and Camas WA. Call (971) 343-4964 or request a window estimate.