Apartment Window Condensation Complaints — Humidity or a Bad Window
January brings the calls: water pooling on the sills, frost on the glass, ice along the bottom of the sash and mildew on the drywall below the window.
Reply within one business day. Or call / text 763-204-2099.
Apartment window condensation complaints come from one of two things: indoor humidity meeting cold glass, or a window that has failed at the glass, the frame or the seal around it. JMB Builders walks the complaining units, notes where the water or frost forms on each window, sorts humidity problems from window problems, and quotes replacement only where it fixes the complaint. Twin Cities metro to St. Cloud. Priced per opening; photos or a free in-home estimate.
- Where frost forms, noted window by window
- Replacement quoted only where it helps
- Priced per opening
Where the water forms tells you what is wrong. A light fog across the room side of the glass is humidity. Frost or ice along the bottom edge of the glass and on the frame means a cold frame or glass edge plus humidity, and old aluminum frames and worn sash are the usual cause. Fog between the panes is a failed seal, not humidity. Water at the trim corners or wet drywall below can be an air or water leak around the frame rather than condensation.
Apartments run humid. More people per square foot, showers, cooking, laundry dried indoors, plants, bath fans that are off or not vented, and blinds pulled tight against the glass all add up. New windows do not fix that, and we say so when it is the answer. Ventilation questions go to your maintenance staff or a licensed mechanical contractor.
When the window is the problem, replacement changes the result: warmer frames, warm-edge spacers, low-E glass and a frame sealed with foam and sealant all the way around. Document as you go. A photo of each complaining window with the unit number and date becomes the scope, and it shows which stacks and sides of the building are worst.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-204-2099.
What you supply
- Your complaint log with unit numbers and dates
- Access to the complaining units, ideally on a cold morning
- What your maintenance staff knows about bath fans and ventilation
- Your decision on which windows to replace and when
What JMB supplies
- A walkthrough of the complaining units with photos labeled by unit and window
- Notes sorting each window: humidity, cold frame, failed seal or leak
- A line-item quote only for the windows that need replacing
- In-person measure of each of those openings and one order
- Install with foam, backer rod and sealant around every frame
- Photos of each finished window in your job folder
How it is priced: per opening
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- How many windows actually need replacing, not the whole building by default
- Frame material and glass package, including triple-pane
- Insert in the old frame or full-frame removal
- Water-stained or rotted stools, sills and jambs under the windows
- Drywall or plaster damage below the window, quoted as its own line
- Upper-floor exterior access
Send your complaint list and a close photo of the wet or frosted spot on each window, labeled by unit.
How long it takes
The walkthrough takes a few hours for a handful of units. Replacement typically runs one to two working days per unit once windows arrive; lead time depends on the brand and is written on the quote.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Fog on the room-side glass
Usually humidity. Ventilation, fans and air movement come first. New windows with warmer glass reduce it but will not stop it in a very humid unit.
Frost on the frame and glass edge
A cold frame or glass edge, common on old aluminum and worn sash. Replacement with a warmer frame and warm-edge spacer is the usual fix.
Fog between the panes
The sealed glass unit has failed. The glass can be replaced in a sound frame, or the window replaced if the frame is also worn.
Water at the trim or wall
Often air or water getting in around the frame. The casing comes off and the gap is sealed, or the window is reinstalled with proper flashing.
Apartment Window Condensation Complaints — Humidity or a Bad Window: questions, answered
Why is there frost on the inside of apartment windows?
Warm, moist room air meets glass or a frame that is below freezing on the room side. Old aluminum frames and the bottom edge of old glass get coldest, so frost forms there first. Lowering humidity helps; a warmer frame and glass edge fixes the window side.
Will new windows stop condensation in an apartment?
They stop it where the window was the cause: cold aluminum frames, single-pane glass or failed seals. In a unit with very high humidity, even new windows can fog on the coldest mornings. We sort the two on the walkthrough and quote replacement only where it helps.
A tenant complains the windows sweat. Is the window bad?
Not always. Look where the water is: fog across the whole room-side pane points to humidity, frost on the frame points to a cold window, and fog between the panes is a failed seal. A photo of the window on a cold morning usually tells which one it is.
Can condensation damage apartment window sills and walls?
Yes. Water that runs off the glass every morning soaks the stool and the drywall or plaster below, and mildew and rot follow. When we replace a window we price any rotted stool, sill or jamb, and wall repair is quoted as its own line.
How should a property manager document window condensation complaints?
Photograph each window on a cold morning with the unit number, room and date. Note whether the water is on the glass, the frame, between the panes or on the wall. That list lets a contractor price only the windows that need work and shows which sides of the building are worst.
Should we replace every window or only the units that complain?
If the complaints come from one side or one stack, start there and phase the rest. If the windows are the same age and type everywhere, the other units are usually close behind. The line-item quote lists every opening so you can choose either way.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and the builders we work with. Counts come straight from our job log; no customer names.
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Read morePage reviewed October 9, 2026 · JMB Builders LLC, MN license BC809005 · All apartment buildings pages
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