FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Discussion Forum

Discussion Forum

Condensation on Inside of Storm Windows. Help!

MBerger | Posted in General Discussion on December 30, 2009 04:31am

Finally I get to post to Breaktime about something other than the forum technology… I live in a 1950s house that was originally built as a small summer lake cabin and then over the years was added on to by someone who I suspect was an intoxicated summer vacationer who didn’t own a square, not a builder. Every winter when I wake up in the morning nearly every storm window is frosted over on the inside. These are old storm windows and probably leak a lot of air. I suspect this is not good. But how not good is it? Do I just need new windows or is there a bigger problem with moisture going on? Thanks! Matt

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. Honeymoon | Dec 30, 2009 04:40pm | #1

    Matt, the warm moist air from iside of your house is condensing on the cold surface of those storm windows. That is what happens when warm moist air hits a cold surface. Think cold bottle of beer in the summer.

    Perhaps the air inside this structure is too humid. I would say around 40 to 45% at this time of year? Cold Northeast? Do you know what the humidity is inside the home? Perhaps you have a dirt crawlspace or basement?

    Obviously, there is conditioned air ( the air inside the home that you paid to heat or cool) reaching the storm windows, so that of itself is not the best scenario.

    On any count, if you have windows with the old triple track storms it's time for and upgrade most likely. I remember when we were kids we would scratch drawings into the frost!

    Glad you could catch a break from the chaos this place has become.

    Eric

    1. MBerger | Dec 30, 2009 04:50pm | #2

      thanks for the quick reply. I live in connecticut and it is very cold and dry out right now. And I do have a basement, though its more like a slab foundation with earth on one side because we live on the side of a hill.

      I'll have to check the inside humidity. But now that you mention it , I suspect I know one potential cause. We run a woodstove during the day and it gets really dry so my wife runs a vaporizer. When the fire goes out over night the vaporizer doesn't and it must fill the house with excess moisture. One other thought: I put new windows in the basement and added insulation to some of the walls down there so all the moisture from the basement is probably going right up stairs...

      1. cussnu2 | Dec 30, 2009 05:02pm | #3

        You could probably add an interior storm window of plexiglass and solve the air leak problems as well as vastly improve the efficiency of those windows without replacing them. Pretty easy plans can be found on line.

      2. Honeymoon | Dec 30, 2009 06:18pm | #5

        MBerger wrote:"I live in connecticut and it is very cold and dry out right now. And I do have a basement, though its more like a slab foundation with earth on one side because we live on the side of a hill."

        Matt, if you have exposed earth in your basement you need to cover it as well as you can with poly. Probably no vapor barrier under the slab either.

        I'm not exactly sure what your specific concern is with all of this........the frost?.........crappy windows?

      3. User avater
        Luka | Dec 31, 2009 11:28am | #17

        Matt,

        You need to replace the weatherstripping on the windows.

        For now, just get some of that "rope caulk", and press it into the crack all around the window sashes. Peel it off in the spring, and make sure you replace all the weatherstripping in the spring or summer.

        Or, alternatively, get some of the clear stretch plastic "inner storms" that someone else mentioned. (You still need to replace the weatherstripping in the spring or summer.)

        As for the humidifier...

        Stop using that.

        If the concern is dry air because of the woodstove...

        Make the woodstove, itself, cure the problem.

        Put a pan of water on top of it.

        When the fire goes out, the pot of water doesn't go on adding the amount of moisture to the air, that the humidifier does...

        They make cast iron "pots" just for this purpose.

  2. mike_maines | Dec 30, 2009 05:43pm | #4

    Matt, do you have and use exhaust fans in the kitchen and bathroom(s)? A huge amount of moisture is generated while you're taking a shower and it's best to get rid of it at the source.

  3. calvin | Dec 30, 2009 06:24pm | #6

    Matt, as has already been stated-the fact the storms show frost means moist air is between the interior glass and the storm. Higher than "normal" interior humidity levels or not, there's air leakage from the prime sash. Seal that up and you might still be able to be comfortable inside with no frost on the storms.

    My only reason to answer was to get this in the post thinking you might read this sooner than the Matt Berger/Ed Pirnik thread.

    new

    Submitted by calvin on Wed, 12/30/2009 - 18:14.

    If you can send me a link to a particular post with missing images I can track them down.

    http://forums.finehomebuilding.com/node/128903

    Here you go Matt. This was a few yr old thread that had some pretty nice photo's included as both imbedded and linked. That I started it has me really concerned about it's past and potential future. I asked you folks early on about it and didn't get any kind of reply-generic or specific. So there you have it. Any answer?

    thanks

    1. Clewless1 | Dec 30, 2009 07:23pm | #8

      No one said anything specific about the moisture between the sash and the storm. But, by the same token, he didn't tell us where the storm window was ... inside or out.

      1. MBerger | Dec 30, 2009 07:52pm | #12

        storms are on the outside.

        1. calvin | Dec 30, 2009 09:41pm | #14

          Matt,

          You had an initial picture in the Gallery that I think I remember showing a flashing/siding/moisture issue. Was there one of these windows in that area? (assuming my memory is somewhere close......)

          1. MBerger | Dec 31, 2009 09:39am | #16

            picture from this morning...

        2. Clewless1 | Dec 31, 2009 09:06am | #15

          If so, your windows are pretty leaky. Does this only happen on one side/area of the house? If everywhere, your house is overpressurized (e.g. w/ an imbalance of a heating system fan).

  4. User avater
    BillHartmann | Dec 30, 2009 06:48pm | #7

    This does not necessarily mean that the moisture level is too high in the house.

    What it means is that air (moisture) is moving through windows faster than it can move out past the storms.

    Storm windows are suppose to have weep holes at the bottom. This will be one or two 1/8 to 1/4" holes or notches.

    Often this will get caulked and painted over.

    The other thing is that the weatherstripping on the windows might need fixing.

    If the interior humidity was too high you would be having condensation on the inside of the windows.

    1. Clewless1 | Dec 30, 2009 07:25pm | #9

      You're assuming the storms
      You're assuming the storms are on the outside ... may or may not be the case.

  5. Clewless1 | Dec 30, 2009 07:30pm | #10

    Looks like some clarification needed. Where are the storms ... on the outside of the window or the inside?

    If storms on the outside, this means a leaky window. Frost would normally form on the inner most pane of glass on a cold day.

    But you are beginning to see the issue w/ your vaprizer running ... that can easily cause condensation ... but I still agree w/ Bill H. - high humidity would mean condensation/frost on the inner most pane of glass. Frost between means a lot of air leakage around the window and not [relatively speaking] around the storm ... assuming storm on the exterior. Always good idea to assess moisture generation and the ways you are getting rid of moisture ... do you have exhaust fans in bath and kitchen that positively connect to the outside (not just dump in the attic)?

    1. calvin | Dec 30, 2009 07:40pm | #11

      And I suppose you can ask him if this is his first winter there.

  6. DanH | Dec 30, 2009 09:17pm | #13

    What you describe is reasonably normal, and, while not "good", is not a serious problem. You want to make sure that the weep holes at the bottom of the storms are open so any condensation can drain out (vs causing rot), but if that's taken care of, and the condensation isn't extraordinarily bad, it's nothing to lose sleep over.

    The simplest fix is to buy the 3M heat-shrink plastic film you apply over the inside of your windows with double-stick tape. It takes a little time to install, but it's reasonably cheap and will both solve the condensation problem and make the place more comfortable.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Simple and Discreet Countertop Power

A new code-compliant, spill-safe outlet from Legrand offers a sleek solution for a kitchen island plug.

Featured Video

SawStop's Portable Tablesaw is Bigger and Better Than Before

The 10-in. Jobsite Saw PRO has a wider table, a new dust-control port, and a more versatile fence, along with the same reliable safety mechanism included in all SawStop tablesaws.

Related Stories

  • Fire-Resistant Landscaping and Home Design Details
  • A New Approach to Foundations
  • A Closer Look at Smart Water-Leak Detection Systems
  • Guest Suite With a Garden House

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Fine Homebuilding Magazine

  • Issue 332 - July 2025
    • Custom Built-ins With Job-Site Tools
    • Fight House Fires Through Design
    • Making the Move to Multifamily
  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data