Is your house too hot in the summer or too cold in the winter? Do you suffer with drafty of windows? Most of us can probably answer yes, and if that is the case then the solution is simple. Add storm windows. The truth about replacement windows is that they are expensive and the payback takes decades whereas storm windows are a lower cost option that help you realize the benefits, both financial and comfort, more quickly than a replacement window could dream of.
Storm windows not only save you money on your heating bill, but they also cut down on noise, protect the prime window (in the case of an exterior storm), eliminate drafts, and a whole lot more.
There are a lot of options when it comes to choosing the right storm window for your house. Do you need exterior or interior storms? Wood or aluminum or vinyl? Press-fit or magnetic frames? Can you make modifications to the frame or does it have to be preserved? There are so many options and manufacturers I thought it would be helpful to give you a guide to storm windows so you can acquaint yourself with the different designs, manufacturers, and options you really have.
Why Do You Need Storm Windows?
While noise and thermal improvement may be issues for certain folks, the biggest advantage is by far their ability to stop air infiltration.
According to a 1999 University of California Berkley study:
“Walls, infiltration, and roofs are the biggest contributors to heating loads in the old, uninsulated buildings.” – Source: Simulation Research
According to the study, infiltration accounts for approximately 28% of heat loss in older buildings and a major place in which that occurs is around ill-fitting doors and windows.
Another important study by The Center for Resource Conservation in Boulder, Colorado in 2011 showed that:
“It is possible to improve the overall energy performance of existing window systems by well over four fold through repairs, weatherization and installing storm windows with insulated frames.”
How Much Could Storm Windows Save You?
This depends on a lot of variables that can’t be determined without a personalized inspection of your house. Questions like climate, HVAC equipment, local power costs, issues with your individual house all make the calculations difficult, but the savings can be significant and the payback is quicker than most other home improvements.
Here’s the proof: Keith Haberern, a professional engineer in New Jersey, performed an energy audit study related to historic windows called “Old Wood Window Replacement Window Energy Analysis” in which he was trying to determine if replacement windows or storm windows would provide better performance and financial savings.
His findings were astonishing!
“The payback period for the new windows is 40.5 years. The payback period for the storm window is 4.5 years.” – Source: Window Preservation Standards Collaborative
Ultimately, the savings are greater in the more extreme climates. Especially heating climates like New England and the northern tier states in the US.
The savings are still there for warmer climates too. Whether the storm is helping to keep the air conditioning in or freezing temps out, they are helping to seal up your house more than most other options available. And they do it with minimal alteration to the original structure.
A typical un-restored, un-weatherstripped double-hung wood window could have an average CFM (cubic feet per minute) of about 0.5. Which means that every 2 minutes, your window leaks about 1 CFM of air.
Compare that same window with the addition of a storm window and you get 0.05 CFM. That means that instead of 2 minutes to lose 1 CFM ,it takes a full 20 minutes. That is a 90% decrease in infiltration!
The other area where you’ll find significant savings with storm windows is in stopping conduction of heat through glass. Glass is a terrible insulator. Duh! It’s not designed to insulate, it’s designed to let in light.
Double-paned windows try to resolve this conduction problem by putting a small airspace between the panes of glass. Sometimes that space is filled with argon of some other gas to improve performance even more.
Storms take the air space to the extreme! The air space between the panes of glass on a storm and the main window is much larger than in any double-paned sash which greatly increases its insulating ability.
What Material is Best?
There is no best material when it comes to storm windows. Come on, you knew I was going to say that right? It depends on the application and your needs. A commercial hotel vs a small bungalow certainly don’t have the same needs, and the same applies to a cabin in Maine vs a Floridian beach house. Different climates and applications need different storm windows.
Here is a quick run down of some of the more popular materials that storm windows are made of and their benefits and drawbacks
Aluminum has been a popular material for the frames of storm windows since the mid 20th century. Most commercially available storm window options (especially for exterior application) are made using aluminum so you’ll have a lot of options to choose from in this material.
- Excellent strength and rigidity
- Factory painted for longevity in a variety of colors
- Wide variety of operability options
- Not historically accurate
- Frames provide poor thermal insulation
A classic material for storm windows that’s been used as long as there have been windows to protect. Wood has endured for centuries and is readily available anywhere you live.
- Strong frames
- Historically accurate
- Readily available material
- DIY friendly option
- Frames provide excellent thermal insulation
- Susceptible to rot and insect damage
- Heavy and difficult to handle
- Very few design options for operability
The newest kid on the block and most common on interior storm windows vinyl is popping up everywhere due to its great availability and relatively low expensive.
- Great flexibility
- Good thermal performance
- Must be install on interior
- Low strength and rigidity
Exterior Storm Windows
The standard storm window for hundred of years was a wood frame with one or two pieces of glass putty glazed in place and hung from storm/screen hangers installed on the window casings. This very simple design is a classic and still very effective. In the mid 20th century manufacturers began looking to aluminum which was lighter and stronger than wood and so the triple track storm window was born.
These storm windows were extremely popular for years because, unlike their wood predecessors they could be opened and closed without climbing up on a ladder. The fact that the first versions were poorly made and very leaky didn’t seem to matter compared to the convenience they provided.
Fast forward a couple decades and the aluminum storm window has really come of age. Though not a historically appropriate option they are very effective. I’ll go through some of the benefits and drawbacks of exterior storms below.
- Protects the Prime Window – Adding a layer of protection to your window is always a great idea. It’s cheaper to maintain a wood storm window than the prime window and aluminum storm windows really need little to no maintenance other than cleaning, so exterior storms really shine here.
- DIY friendly – While aluminum storms are not DIY friendly, wood storms are very simple to make yourself if you are handy. I’ve included a video in this post showing you a simple design and process to make a storm window yourself.
- Huge Variety – Compared to interior storm windows there are more options for exterior storms. With more manufacturers and more styles you have a better chance of finding exactly the style and price you want.
- Operability – There are operable interior storm windows, but there is greater flexibility in exterior storm window options. Some manufacturers have options where you can swap out glass panels for screens in the warmer months without having to completely remove your storms.
- Professional Install – For aluminum storm windows you will usually need a professional to measure and install them. Once they are installed this isn’t an issue, but the initial expense and trouble is an issue sometimes.
- Appearance & Approval – Installing an exterior storm window means having to get approval from a historic district if you are in one. They may only approve certain types of storm windows or none at all. Be sure you check what the rules are in your area before you end up with a bunch of paid for storm windows you aren’t allowed to install.
Exterior Storm Window Manufacturers
Below is a list of some of the most popular makers of exterior storm windows and a little bit about their products. This is just a small sampling of some of the larger manufacturers since there are literally hundreds of quality makers out there.
- MonRay – MonRay has been making storm window since 1947 and they make have made a ton of them. Made from premium aluminum frames these storms have a range of operability options and have been installed on residential projects as well as huge commercial projects around the country.
- Allied – Allied makes interior storm window too, but they are best know for their exterior aluminum storm windows. Again, lots of style, operability, and color options to fit your needs.
- Larson – Larson makes windows, doors, and storm windows. Similar to the above options they manufacturer aluminum storms and also have a new ComfortSeal interior option.
- QuantaPanel – QuantaPanel makes interior and exterior aluminum storm windows with operability and changeable screen and glass panels available in over 250 colors.
If you are a DIYer like me then I have a tutorial and woodworking plans for you to make your own DIY wood storm windows with a few basic shop tools.
Interior Storm Windows
While storm window shave traditionally been installed on the exterior of a window there is a growing segment of the market that prefers interior storm windows. You might be asking, “Is it really a storm window if it is on the inside?” The short answer is yes!
Storm windows typically served two purposes. 1) To protect the prime window against the weather 2) To improve the energy performance of the prime window. It’s this second purpose where interior storm windows really shine. They can be very effective at improving the efficiency of old windows without compromising the exterior aesthetics.
Some of the key benefits and drawbacks of interior storm windows are below.
- Ease of Installation – No more climbing up on a ladder and precariously installing your storms. Interior storm windows can be safely installed from indoors. Plus most of these windows require only minimal mounting hardware since they are not subject to the exterior elements and some like Indow have zero hardware and just press-fit into place which makes installation about as easy as it can be!
- Better Air Sealing – Exterior storm windows need some venting to perform well and not have moisture issues (or rot if you’re using wood storms). Interior storms don’t have this issue and generally have extremely tight seals compared to exterior storm windows.
- Lower Prices – Less complicated installation coupled with a storm that doesn’t have to be as tough as an exterior version usually equates to a lower price point for interior storms compared to exterior storm windows.
- Historic District Compliance – No need to get approval from a historic district for interior storm windows since they are treated much the same as other interior window covering likes drapes and blinds. Unlike exterior storms, interior storms of any style are permitted for historically significant properties.
- Lack of Protection – Sadly interior storms do nothing to protect the prime window from the wear and tear that mother nature subjects it too.
- Moisture Issues – Some interior storms can cause moisture build-up between the storm and the prime window. The cause is based on a lot of potential issues like high indoor humidity, leaky prime windows, improper installation, HVAC design, etc. It doesn’t happen to all interior storms but it is a potential side effect that needs to be considered depending on your windows and weather.
Interior Storm Window Manufacturers
Below is a list of some of the most popular makers of interior storm windows and a little bit about their products.
- Indow – Indow makes a compression fit storm window that requires absolutely no mounting hardware! Check out the video below to see how easy the installation process is. They are a vinyl frame around acrylic glazing with a silicone compression tube. They have a lot of different grades to choose from like Acoustic, Shade, Sleep Panel, etc. that allow you to customize according to your needs, but they do not have an operable option. Disclosure: Indow is a sponsor of this post, but the opinions expressed are my own.
- InnerGlass – Innerglass makes an interior storm with a vinyl frame around your choice of glass (tempered, low-e, standard, etc.). It has a compression fit technology and requires minimal mounting of hardware. They do have operable interior storm windows to work with double-hung windows and slider options which are an added convenience.
- Allied – Allied manufactures aluminum interior and exterior storm windows. They have several options when it comes to operable or non-operable storms, different glass options up to 3/16″ thick and different colors of the aluminum frames. Installation of these effective storms requires a bit of skill and is not in the DIY category in my opinion.
- Magnetite – Rather than using a compression tube magnetite windows have a magnetic frame that is installed onto the window casing and then the storm window is held in place by the magnets on the perimeter. Magnetite is acrylic glazing in various grades like Indow to focus on Sound, UV-blocking, Privacy, etc.
Again if you don;’t want to go the route of purchasing interior storm windows I have a tutorial and plan for making your own interior storm window which is slightly different and a little bit easier than the exterior storm windows I mentioned earlier. You can find that DIY Interior Storm Windows tutorial right here.
Maybe one of these options is right for you or maybe it’s another type of storm window, but the main thing is to realize the comfort and savings that storm windows can provide. You’ll not only retain the original historic windows, but you’ll get your investment back in years rather than decades like replacement windows.
What kind of storms do you have? What do you like or dislike about them? I’d love to hear your thoughts in the comments below.
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
8 thoughts on “Guide to Storm Windows”
I know storm windows are more about energy efficiency than actually weathering storms, but I haven’t been able to find any information about the actual impact resistance of exterior storm windows. Are certain styles/brands/materials more impact resistant than others?
Hi! I love reading your blog, I have a ranch home that is built in 1952 with single-pane wood windows with aluminum storm windows on the exteriors that can change between a screen or Plexiglas. What do you recommend for restoring this type, the aluminum storm windows are pretty worn out and the wood is painted shut in many places and have years of layered paint. Restore the wood portion and then replace the aluminum storm windows? Or restore both?
It’s good that you point out that storm windows can help you lower your heating costs. I want to spend less money on heating and cooling my home, so I’m considering buying some storm windows. I’m going to look for a good company in my area that can install some storm windows for me.
My biggest concern is getting the correct measurements. I am not at all builder savvy. Also, I have casement windows. I dont mind taking the crank off but wondering how much space I a need to fit the window in.
Is there any DIY interior storm options?
I’ve been meaning to email you for some time on your input on my situation, but since you just published this article and asked for input, I’d like to share my story.
I am in the process of getting storm windows for my home. I own a beautiful stone tudor in the Birmingham, AL with over 44 original windows in good condition. I am determined to install storm windows for many of the reasons that you describe in your various posts on the subject, but there are so many barriers to actually accomplishing this that even I, someone dedicated to the mission, am tempted to just give up and let my windows be destroyed by neglect.
The ideal storm window for me would be:
-Exterior storm windows, because I would like to protect my existing windows.
-One with the correct glass for the southern US climate, which according to the studies I have read would be low SHGC low-e glass.
-Aesthetically pleasing – I do not want the frame of the storm window to be larger than the frame of my existing windows. The color should match my existing windows. Ideally they would be unnoticeable or look historically appropriate.
I think that sounds like a very simple set of requirements, but let me discuss what I have installed so far on my home in order to illustrate the issues:
– 3 Larson Performance windows.
– I have contacted all of the recommended aluminum storm window companies online. Many of them would not sell directly to me, and no contractors in my area deal regularly with installing storm windows or have relationships with the companies. Quantapanel and Allied to appear to have the closest aluminum storm windows to what I’m looking for, but they are much more expensive than what is advertised in pro-storm window articles and in the ROI studies, which I find frustrating. There aren’t enough drawings, pictures, reviews of different models online for me to feel like I really know what I’m buying and how it would look. If I can find a product that I am completely happy with I still may go back to either company.
– The three windows I wanted to protect are above a slate porch that needed some work, so I was in a little bit of a hurry. I wanted something relatively permanent installed while the porch was being fixed so that it would not get walked on again. It is on the north-side of the house (so I did not mind that the glass is high-SHGC), and I discovered that of all of the dual-track storm windows, the Larson performance series has the smallest borders. They do not come in the correct color, so I had to sand and paint the windows before having them installed.
– They look relatively nice, but the frames are still larger than the frames of my original windows, they do not have the correct glass for our climate, and painting an aluminum storm window yields to a number of compromises (painting moving parts, longevity of paint over aluminum). I do not think this is a reasonable scalable option for my entire home.
– 1 homemade wood storm window. Not seeing a reasonable aluminum option where I wouldn’t have to make serious compromises, I decided to pursue wood storm windows, and ran into the following problems:
– I am unable to locate a local craftsman who is willing to make them. It appears that the few companies online who make them will not sell a finished product, and none will use the correct glass (a few will use regular low-e). If I am going to have to do a significant amount of the work my self, I figured I’d just make my own.
– I called all the glass companies in town, none of them have the correct glass. I used regular low-e glass, but the local glass company who would sell me low-e glass ended up charging me close to what the Larson performance windows cost. So even making my own wood storm window ended up being more expensive than the aluminum option.
– I could not locate a readily available good hardwood as described in your previous articles, so I used cedar.
– Glazing the window was frustrating and time consuming, and I broke a corner of the glass with a glazing point.
– Overall, the window looks perfect. It is beautiful, it matches the storm windows that were on the house originally in a few pictures that we found in the historic archive, and it does not obstruct the view. But… it took a ton of time to make and does not have the correct glass for our climate.
-3 “Deadlite” storm windows. I thought this could be an “invisible” option – large panes of glass surrounded by a small aluminum border (which I still had to paint). It was the cheapest and potentially least labor-intensive option, but I could not use low-e glass for larger panes since the decreased structural support necessitated thicker glass. Since I could not find low-SHGC low-e glass anyway, I decided that I would use regular glass and apply solar film for our west-facing windows. The deadlites looked nearly invisible without the solar film (aside from just being one large pane of glass when looking at the reflection), but with the solar film they look like giant mirrors from the outside when the sun shines on them.
I have a very irregular schedule, and restoring windows/making wood storm windows has so many steps with subsequent long wait times that it may take me months from start-to finish if I can’t just devote a large chunk of time to it over a few consecutive days. Additionally, I don’t have a large indoor workshop, so unless the weather is nice enough outside to let things dry, I can only work on a few things at a time. Realistically it would take me years before I could produce wood storm windows for all of my house.
The thing that frustrates me most about my situation is that I feel its just a microcosm of the state of skilled trades in the US – craftsmen don’t exist. We live in a rip-out-and-replace culture. I can’t find anyone locally willing to take on even a large chuck of my project, or ANY restorative/maintenance project in my house for that matter – I have to do it all.
Back on topic, after seeing how appropriate the wood storm window is, I think this is the route that I need to go. I will suck it up and use regular low-e glass, and I’d like to streamline the process in terms of steps with subsequent wait times. I would like to eliminate or at least reduce glazing, and I hate glazier’s points. I am thinking that I should make some form of “combination” wood storm window, but there are not many plan for them online, and the only ideas I can come up with/have seen online all include glazing the upper pane in place. A few basement windows that I have restored have the glass mounted in a groove, which would eliminate the need for glazier’s points and may cut-down drying time.
Do you have any advice regarding combination wood storm windows or mounting glass in a groove as opposed to a rabbet?
Spencerworks makes a hybrid wood storm window. The frame is wood and has a concealed modern storm window. Hung just like traditional wood storms. I’m seriously considering them for my house to replace the mix of old and new aluminum ones. It would certainly make working on the old windows a lot easier.
How about stained glass and leaded glass windows? We have both on our house and there were no storm windows on the property when we bought it…. Are there special considerations with this fancy glass? The leaded glass is in the top sashes of double hungs and some is in french casements. The stained glass is in a fixed transom and sidelites at the front door. Thank you!