Condensation Inside Windows 2026
Many homeowners have concerns when they find condensation build up on the inside of their windows. The natural reaction is to assume that the window is somehow allowing the moisture or wetness to leak from the outside to the inside of the home. Typically, this is not the cause of the built up condensation. Let's take a closer look at the different scenarios.
Condensation In Windows Explained
Condensation is essentially moisture found in the air. It occurs when warmer moist air meets a cooler dry air. It's the same basic principal as taking a shower and having your mirror fog up. This is the same idea with your home windows, when warmer air meets the cool surface of the windows glass, it causes condensation to form. The condensation forms on your windows because the surface of window glass has the lowest temperature of anything found on your walls.
During the hot summer months, condensation can be found on the outside of the windows, while in the cold winter months, condensation will occur on the inside of the window glass. In general, these incidences of condensation are harmless (but often annoying). However, condensation found between the panes of glass (assuming a dual pane window) is a legitimate cause of concern.
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Condensation And Energy Efficient Home
The issue of condensation has become more prevalent with the advent of more energy efficient homes and products. Today's homes are much more energy efficient and thus better at trapping the warmer heat inside the home. The result is a greater incidence of interior condensation on the window surface. Older and less energy efficient windows let more heat escape from the house and therefore there was less moisture inside and less condensation.
Reducing Condensation In Your Home
So how do you reduce the amount of condensation in your home? The easy answer is to control the amount of humidity that exist within the home. If you notice condensation forming on the inside of your windows during the cold winter months, you can crack the window for several minutes and release some of the built-up moisture from inside the home.
Other solutions include running your exhaust fans a bit longer in the kitchen, laundry room, bathrooms, etc. Homeowners can also use a dehumidifier to reduce the moisture in the home and they may also consider opening their blinds or drapes, which will allow the air to better circulate against your windows.
When To Be Concerned
Condensation should only form on the inside of the inner pane or on the outside of the outer window pane. It should never be found between the two panes of glass. If you do find condensation between the glass panes, it is an indication that the airtight seal is broken and you will most likely need to replace one or both of the glass panes.
A cost savings approach is to call a local window glass repair company and get a price quote to replace the glass - tell them the type of window, the brand of window, and the size of the opening and most companies should be able to give you a price quote right over the phone. This will be a great starting point to deciding whether you need to replace the entire window unit or whether it is best to simply replace the glass pane.
Window Condensation Q And A
Window Condensation Questions 2026
| Window Issue | Reported Condition | Editor Takeaway |
|---|---|---|
| Interior Window Condensation | Recurring winter condensation on inside glass surfaces | Usually tied to elevated indoor humidity during colder months |
| Existing Vinyl Windows | Homeowner considering recaulking around the frames | Caulking may help with air leaks, but may not solve moisture-related condensation |
| Possible Failed Glass Seal | Condensation between double-pane glass would be a separate issue | Moisture between panes usually indicates insulated glass seal failure |
"I’ve been dealing with condensation on the inside of my windows every winter for the past three years. I’ve already taken several steps to improve the house, including air sealing, adding insulation, and replacing an old furnace, but the issue persists."
"At this point I’m wondering if the windows themselves are part of the problem. I have vinyl windows and are considering recaulking around them to see if that helps. If anyone has recommendations on the best caulk to use or tips on how to properly seal the windows, I’d really appreciate the advice. Hoping to finally solve this issue once and for all."
Homeowner — from 2026
Editor's Advice:
From what you’re describing, the condensation is probably related to indoor moisture levels rather than the windows themselves.
I’d suggest checking the humidity level inside the home during cold months. Activities like showers, cooking, etc. can add a lot of moisture to the air. Indoor humidity levels are best kept between 30% and 50%. Once it rises above that range, condensation on glass surfaces becomes much more common.
Having said that, the windows could still play a role, especially if they’re older single-panes, as those tend to get cold enough to attract condensation. But most vinyl windows are double-pane and insulated, so unless the seals inside the glass have failed, the windows themselves may not be the main issue.
If you get condensation between the panes of your double-pane glass, then you have a real problem.
Dane — Website Editor - from 2026
Paradigm Windows And Condensation
Hello Dane, I’m not sure if you can help me with my question but thought I would reach out. I recently purchased a house (sold as “to be built”), moved in October and the builder used Paradigm windows. I live in Vermont and now that it is below 32 degrees there is an unbelievable amount of condensation where the windows meet and the bottom window, and when it gets below 20 degrees I have ice on the inside of the windows. It’s even more so if I have my curtains drawn.
I was told that the condensation is because the slab is not fully cured but the humidity inside my home is 45% which I don’t think is all that high. Is this normal for a window to do this? Is this something I can expect every winter and if so what does it do to the window year after year? My slider has absolutely no condensation on it. I was told to simply wipe the windows which is extremely annoying and time consuming to do every morning for 10 windows.
Thank you for your thoughts.
Melissa - Homeowner - from 2022
[Website Editor Answers]
Melissa, I'm going to send you to a link on our site that deals with condensation. In terms of answers, I wish I had something more concrete for you. Make sure that the next windows you buy have a high CR or condensation resistance, which can certainly help.
Dane - Website Editor - from 2022
Windows Keep Fogging On The Outside
Bought a window from Home Depot a large window with two crank outs on each side It is in my living room which is where I have coffee in the morning watching my birds funny thing is I cannot see my birds the window keeps fogging up on the outside almost every morning please tell me what I can do with this I do not want this window I hate it the reason you have a window so you can see out it what can I do to make this stop I do not have bushes around my window I’m not gonna go out and clean it off every single morning I live in Michigan what is this going to do when it’s winter freeze up. Please help me before winter is here It was put in in July I am very unsatisfied with this window please get back with me. Not at all happy.
Amber - Homeowner - from 2021
[Site Editor's Answer]
Amber, here is a link sent a condensation article that hopefully helps you out. The link is to the above explanation.
Dane - Site Editor - from 2021
Window Condensation
Dane, I recently had some series 80 windows installed at my stepmothers house. We have a 3-4” strip of condensation periodically showing up on the lower Exterior of one window.This is on a 8-0 3-0 window. The strange thing is there is a 7-0 3-0 just 10 ft. away in the same line and the same roof overhang facing the same direction.
Any ideas?🤔 I can gather pictures if you need. 7 other windows installed and they don’t do this.
Thanks
Ken - Homeowner - from 2020
[Website Editor Answers]
Ken, I'd call up a local window company and ask for a bid for replacement windows. Then when he comes out, ask him to take a look. It doesn't cost you anything and while you're kind of duping the rep, who knows, you may have to get some windows down the line. He can probably tell you what the likely cause is.
Condensation on the outside of windows typically happens in the spring or fall when warm days turn to cool nights. Why it's occurring on one window and not the others...I can't say.
Dane - Website Editor - from 2020
Window Condensation Help
It is only October and I have moisture on the windows about an inch higb. Temp outside 55 temp inside 68! I have never heard of it happening like this unless the humidity is real high outside and the temp inside is real cold from running air! Also there are round knobs at each end of the window frame, not sure what they are for! My parents have regular Anderson windows that have a one piece flat sash that u can clean. These are two plastic pieces with drain holes that plug up and it takes forever to get dirt out of the split between the two groves ! Never saw a sash like this. Please help , just purchased house and can not afford to replace the new windows! I am wondering if they are installed correctly? Installer said moisture is normal!
Thank you much,
Lorelei - Homeowner - from 2015
[Site Editor's Response]
Lorelei My advise would be to hire someone local to come out and take a look at the locking mechanism and the windows in general, especially given the time of year and the weather changes that will happen over the next month. I did a quick search for Jax Bldg Supply and a store in Michigan comes up. Is this where you are located? If so, call them and see if they know which window you purchased and whether they can help with your issue(s). They may work with installers who you might want to pay for an initial hour to come take a look and see if there is a low cost solution to your condensation problems.
Dane - Site Editor - from 2015
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