[Stephen Israel] Living in a historic home can be an incredibly rewarding experience, but also an incredibly trying one. It seems there is always some new challenge rising up out of the woodwork, especially when it comes to original wood windows. Some professionals will say the only way to improve the efficiency of your windows is to replace them, no matter if you want to preserve craftsmanship that’s lasted decades if not centuries. Today’s guest, Sam Pardue of Indow Windows, was faced with just that problem and he ended up creating a solution that is now being applied to windows across the country. As part of Preservation Month, we want to bring you up close and personal with a technological innovator and his invention. Step right up to the glass on this week’s PreserveCast.

From Preservation Maryland Studios in the historic podcast district of Baltimore, this is PreserveCast.

[Nick Redding] This is Nick Redding. You’re listening to PreserveCast. Today, we’re joined by Sam Pardue who is a serial entrepreneur, who left the Intel mothership to form startup ventures in Portland, Oregon. Upon graduating from Carnegie Mellon’s MBA program in 1998, Sam first worked at the Intel Corporation as a marketing manager and after several years, he left Intel to co-found LensBaby, a celebrated Portland-based manufacturer of award-winning special effect SLR camera lenses. Then in August 2010, Sam stepped down to found Indow, a company that manufactures and markets Pardue’s patented award-winning invention: a thermal window insert that presses inside window frames to deliver double-pane performance at a much lower cost. He’s received numerous awards for this product and Indow has become an important piece of the preservation puzzle when it comes to saving historic windows and we are so pleased to have Sam join us today by telephone from the West Coast. Thanks so much for joining us today, Sam.

[Sam Pardue] It is so great to be here online with you from sunny Portland, Oregon. We actually have a sunny day today.

[NR] Is it really sunny? Wow, that’s interesting. It’s actually sunny in Baltimore right now, too, so I guess we’re doing pretty well. So let’s see here. I mean you start with Intel, then you have your MBA from Carnegie Mellon, then you work on SLR camera lenses, and now you are a celebrated hero of historic preservation. How on earth do you go from Intel to historic preservation?

[SP] That is a great question. I sometimes refer to myself as an accidental historic preservationist. I came up with the idea for the Indow Window insert because at the time I was living in a 1906 Portland craftsman house and as an environmentally-minded person and as someone who wanted to be comfortable in his home, I thought I should do something about this leaky windows. And so I started thinking about replacements. But fortunately, I saw the light before I took that terrible step, because really I’d started looking more closely at the windows I was thinking about replacing and I thought how beautiful they were with the rippling glass, and the incredible craftsmanship, and the woodwork. And I later learned about that wood was old growth timber from the forests around the Portland area and I decided I just couldn’t rip out those windows and replace them. No matter how good of a replacement window, I would lose the character of the home. So I founded Indow because I was looking for a solution to my own historic windows in my own house.

[NR] And so I mean I guess like a lot of great inventions, it comes about because you have a problem. And so, you have this problem, and that’s one thing to say, “Well, I solved it by creating something.” But then, you turn into a real legitimate business. And how long have you been running it as a business? Do you have any stats to give us a sense for people listening to this, like, “How many Indows have you sold? How many windows is this in now? Going from this problem at Sam’s House to now, legitimate business that’s tackling this issue?”

[SP] That is a great question. Currently, at Indow, we have 35 employees working with us, plus other contractors so it’s become a nice little operation. We’re selling everywhere in the United States and in Canada so we’ve expanded to have a national footprint. This has taken a lot of hard work, going from an inspiration from what seems like a really simple idea to a business. It’s often more difficult than it looks like. In the case of Indow, we had to develop a whole laser-measuring system to laser-measure each one of these window inserts, because it turns out, old homes have very out of square windows, and we need our product to fit perfectly so that it looks great, and so that it performs great. So, in order to actually make this concept into a business, we had to develop an end-to-end IT system with a laser-measuring component. It flows right into our custom-manufacturing process.

[NR] And so, the laser piece, that’s a whole other piece of technology associated with that. Is it based on anything or was it custom-made just for this application?

[SP] Well, the lasers are off-the-shelf lasers that we buy and if a homeowner is outside of a dealer territory, we’ll actually mail the homeowner the laser measuring device so they can get really good accurate measurements of their window frames. But what is proprietary, what we need basically developed was the whole measuring system where you measure your windows, you input that data into a personalized web portal, and then our software detects if you made a measurement error so there’s also never a measurement error with our product. And then, the data flows into our cloud-based IT system and then, it goes into our manufacturing process so that we can make window-inserts that are perfectly-fitting, 4′ x 6′ shaped trapezoids, parallelograms. When a customer gets them, all they have to do to install them is just press them into the window frames and that’s what makes them really magical and really nice for historic building. Basically, our product installs without any kind of mounting bracket and virtually no modification at all to the existing window frames.

[NR] Right, which is a big deal, because a lot of people, they’e concerned that, “Well, if I keep this wood window, it’s so leaky and it’s always cold,” and they kind of make the decision from that direction and this is a great way for the preservation community to push back on that because sometimes it’s hard to answer that question about, “Well, how do you keep it from being so drafty?” Maybe you could explain a little bit [about] the thermal window itself. How does this thing work? If someone hasn’t seen this before what exactly are we talking about? What does it do?

[SP] So, first to describe what it is, if you can imagine a sheet of plexiglass that is custom-cut to be the exact shape of the inside of your window frame, and then we edge it with our patented compression suite. So that’s what we came up with to solve the problem of how to insulate the windows in my house, was this sheet of plexiglass or acrylic, really. It’s acrylic glazing that’s edged with the compression suite. We laser-measure the window frame to get the exact shape, then we make the insert a little bit bigger so that you install just by pressing in place and as you press it into place, that, too, then compresses and that creates the spring force that holds the things in-place. Once it’s in there, it blocks all the drafts. It keeps hot air out. It prevents noise from penetrating the building, so it brings a tremendous sense of quiet and calm to the interior space, and it does all this without modifying the window frames.

And another nice benefit of the product is that it prevents warm, moist interior air from reaching the original windows and condensing on the windows. So our product prevents condensation or dramatically reduces condensation almost all of the time. And that’s an important variable. And preventing mold, preventing condensation can be helpful to help those windows last longer. So I like to refer to our product as an antidote to the temptation of window replacement. People look at windows and they have some misconceptions that there’s nothing that can be done except for replacement. There’s actually great alternatives to replacement and Indow will give you all the comfort and energy efficiency of the high end replacement window but you do not have to modify your beautiful original windows at all.

[NR] And that’s different from a lot of – I mean, I know that the preservation community has seen indoor or interior storms before. But a lot of them do trap moisture. I mean, you see that from time to time. But you’re describing something very different there, where this does not have a moisture issue, I guess.

[SP] Well, what makes our product unique is the tight seal that goes all the way around the edge and the way that we make the insert to be the exact shape of the outer square window frame. These two things, because we make our inserts so tight-fitting and so perfectly fitting inside those window frames, that’s what prevents the warm moisture from having the chance to reach the cold window surface and condense.

So we have found this again and again. I was recently at a Window Preservation Alliance, their national meeting in Greensboro, North Carolina. I had the pleasure to join that wonderful group of people. They’re all dedicated window preservationists. I was staying at a historic Airbnb, in a nice historic house in Greensboro. And I took a shower, and I came out, and the windows were coated with condensation, and the exterior storm windows were also coated with condensation. There was some mold growing on them, and I just knew that if my window inserts were in those windows, there would not be any condensation at all. Exterior storm windows can be a very important part of the preservation equation for preventing exterior weather from hitting the windows. Our product does a fantastic job of delivering comfort, and quiet, and energy efficiency, and preventing warm moisture from reaching those windows.

[NR] Well, and you brought up the Window Preservation Alliance, which is interesting because as a preservationist, I find your product pretty cool and has a lot of value too. But I’m curious what the broad response has been. But it sounds like if you’re being invited to speak to the Window Preservation Alliance, unless they’re inviting you for a debate, they must be excited about what you guys are doing, and I guess it kind of works in line with their whole mission and ethos as well.

[SP] Well, I would say I was not… I’m a member. We’re members of the Window Preservation Alliance. We find that people that are working to repair windows instead of replace them are our allies

[NR] Right.

[SP] – in the effort to give people great options besides window replacement. A lot of people think just because the pulley cord is broken or just because their window is painted shut, that it’s broken and they need to replace it. That is not true. Often, those windows have lasted more than a century! That’s how good the quality of them is, and they can be repaired, and they should be repaired. Because if you take care of them, they will last another century, whereas the average replacement window will last maybe fifteen, seventeen years. The dirty secret of the window replacement industry is that half of all replacement windows are sold to replace replacement windows because they’ve broken. They don’t have a good life span. They just can’t match the quality of the original windows that are already there.

So we’ve found a great reception in the historic preservation community because historic preservationists know that there’s a lot of people who have been told through all the aggressive marketing campaigns by the replacement window industry that they should replace their windows, that that’s the right response. It’s kind of where I started before I founded this company. Fortunately, I sought a different path. But what Indow does is it gives people and it gives historic preservationists a great alternative to window replacement that looks really good, that performs really well, and that will deliver all the benefits of replacement windows without the tragic damage to the historic structure.

And because we have such a light touch, I believe that our product has the lightest touch, both aesthetically and structurally, of any window installation solution. I think that’s why it appeals, is that it’s completely reversible. You take the product out, there’s your original windows in perfect condition, that have not been modified. There’s no frame, there’s no mounting bracket, so it satisfies that reversibility test. The product basically disappears when it’s installed because of the very low-profile design. So what you see are the beautiful original windows. You don’t see our product at all.

[NR] Yeah. Just from every different perspective, it’s a fantastic addition to the preservation toolbox. Well, why don’t we take a quick break right here? And then when we come back, we can talk a little bit more about what’s next for Indow, what’s in development, how people can get these if they’re interested in getting one of these, and different applications of this. And we’ll do all of that when we come back right here on PreserveCast.

And now, it’s time for a Preservation Explanation

[Stephen Israel] Nick and Sam are talking via the telephone, something that in this day and age may almost seem like an outdated piece of technology. With how frequently we use it, the convenience of instant communication kind of feels like it belongs with a roof over your head and food on the table as part of basic human comforts. The same could not be said this same day in May 1844.

It was 174 years ago this Thursday, on May 24th, 1844 when Samuel Morse sent the first long-distance telegraph message. Standing in the basement of the U.S. Capital Building in Washington D.C., which at the time housed the Supreme Court, Morse transmitted the first long-distance message, thirty-eight miles to his partner Alfred Vail who sat in the Mount Clare Station stop of the B&O Railroad in Baltimore City. The message, a quote from the bible, was suggested by Annie Ellsworth, the daughter of the U.S. patent commissioner, “What hath God wrought?”

While English investors, William Cooke and Charles Wheatstone had, in fact, submitted an earlier patent for an electrical telegraph in 1837, their system was significantly more expensive and, at least according to Morse, was an attempt on their part to steal his idea. It wasn’t long after 1844 that Morse’s cheaper method overtook the multiple wire system of Cooke and Wheatstone.

The case of Cooke and Wheatstone’s alternative telegraph is not the only muddy water surrounding Morse’s most famous invention. Both parties’ inventions were built in no small part on the work of Joseph Henry, an esteemed American Scientist and the first-ever secretary of the Smithsonian Institute. Indeed, the language of rhythmic communication, once synonymous with the telegraph and still known to this day as Morse Code, was actually very much a joint effort between Morse and his aforementioned partner, Alfred Vail.

Still, I feel it’s kind of hard to blame Morse for how vehemently he fought to be remembered as the father of telegraphic communication. Originally, a celebrated artist, his life’s work changed mid-way through to become seeking a way to speed up human communication in 1825 will he was on a commission to paint the portrait of Lafayette in Washington D.C. Having left his wife at their home in New Haven, Connecticut, he had no idea she was ill until he received a letter from his father that arrived via a messenger on horseback. A day later, the message arrived that she was dead. Even though he left immediately, by the time he returned home, she had already been buried. Morris dedicated himself after this experience to improving long-distance communication.

In the end, his work changed the lives of every person on the planet. Starting with that fateful message from the from the capital to Baltimore, Morris pioneered a practical means by which humans could communicate faster than any one individual could travel. The first of its kind unless of course you count cemiform or putting a candle in the window. Speaking of windows, I’ve got to let you get back to Nick and Sam on PreserveCast.

PreserveCast isn’t just for Mondays anymore. Find all of our episodes at anytime. And we’re on social media to continue the conversation @PreserveCast. If you have a question or want to suggest a topic, drop us a line at

[NR] This is Nick Redding. You’re listening to PreserveCast. We’re joined today by Sam Pardue who is the CEO of Indow. We’ve been talking about all things interior storm windows and how this product is another tool that preservationists have to deploy to help protect and save historic wood windows. Before we took our break, we heard about how Sam got into the business and how a problem prompted him to design this piece, and how it actually works, and the compression technology, and laser measurements. You know, PreserveCast is all about the intersection of preservation and technology and that’s all we’ve been hearing about so far. I’m curious, people listening to this might be thinking, “Are there any other things you can use an Indow for?” Do people put them in doorways? Are there massive Indows that you can put in a church if you have a big window? I mean have you had other interesting applications or use of the technology anywhere?

[SP] Great question. We actually do not do doors because our product is so hard to see. It’s almost invisible. It seems like it might create kind of an issue for egress. Whereas, in the window, it’s very easy to pop out.

[NR] Well, I guess that answers the question about visible it is. I guess.

[SP] Right. We do, though, do very large windows and we also do beautiful custom geometries, we call them, or arched windows, batwings. We’ve done a beautiful project at Bowdoin College and just many, many projects around the country where we’ve created these window inserts to go in the inside of beautifully shaped arched, and half-round, and I-windows. So we can do that kind of thing very, very handily.

[NR] And does the laser system work sort of the same in terms of measuring those sorts of things or do you have to do that by hand?

[SP] Well, actually, those are usually done by hand. Great question, very intuitive. We sometimes will get some validating measurements of key dimensions, but we may actually for those kind of windows, use a tracing technique in a very old-fashioned kind of approach to handcrafting the window inserts. The laser measurements’ really important for the rectangular-esque windows, but we do have other measuring techniques for those very kind of ornate shaped windows. We are doing large windows. In fact, if the window is very, very large, we can subdivide it with a custom mullion bracket, which will subdivide the very large opening into multiple pains which can make them easier to handle. We’re also doing some big projects. We’ve done some interesting commercial spaces, and university spaces, government spaces; and we’re excited to do more and more in museums and things like that. We’ve been working on those types of projects as well.

[NR] Any big famous historic buildings that people might be familiar with or a project you might be particularly proud of in terms of what you got to work on?

[SP] In terms of famous buildings that we’ve done that are historic, we’ve done a Frank Lloyd House up in Chicago and it was actually done for Frank Lloyd Wright’s Restoration Architects. We did a case study house in California, which it is one of the homes that were done right after the war to showcase mid-century modern manufacturing techniques. That house is kind of interesting because they used what we call our museum grade inserts, which filter out 98 percent of the UV coming through the windows. That’s a great way to preserve the interiors.

Other examples of historic structures include the Homewood Museum at John Hopkins University put them in. They also use the museum grade product because in order to preserve all the beautiful interior items that they have, which are all historic objects, they were closing the shutters all the time and that was actually not replicating the actual usage pattern of the residents of that structure when it was used as a residence back around the time of the Revolutionary War. In order to allow the visitors to experience the structure in a way that was more consistent with how the residents had used it, we decided to put Indow Window inserts onto the inside of those windows providing all the insulation values, but also filtering out the UV so that they could preserve all the precious artifacts in the interior of the museum. So, we loved that project. There were a number of arched windows involved in that one as well. And that one is right there in the Maryland area.

[NR] Yeah, and you also mentioned the UV component, which is fantastic particularly for museum applications but there’s also – you haven’t brought it up – but there is a sound component too. You can do some sound blocking with these as well I guess, right?

[SP] It’s actually incredibly important and noise is one of the motivations for people to replace their windows, but you do not have to replace your windows in order to deal with noise. Our standard product will reduce the amount of noise coming through an operable single-pane window by about 50 percent and we actually have an acoustic grade option, which will block 70 percent of the noise coming through a single-pane window. This far outperforms replacement windows at noise reduction. So if you want to deal with your noise problem in a historically-sensitive way, our product is fantastic. This is really important for Main Street organizations where people are developing commercial districts. They’ve got beautiful single-pane windows but sometimes it’s too noisy to actually do a conference a call in such a scenario. That’s where we can come in and really solve that problem without messing with the windows.

[NR] Yeah, which is a whole different issue but, obviously, another thing that you can kind of solve and a lot of historic communities are pretty dense and a lot going on around them. So that’s another exciting thing. In terms of development, next thing, you’ve described yourself as a serial entrepreneur so you’re always inventing and creating new things. Is there anything on the horizon that you can share about anything with Indow? Is the goal just to keep growing or new product lines? What can we expect from Indow in the coming years?

[SP] Well, we expect to continue being innovative. We already have seven different grades in our product line which can do everything from filter out noise to filter out UV or block heat. We have a heat blocking insert, which is nice for homes who have really hot exposures to the sun. You know, and while we are working on some new products, we can’t really talk about products we haven’t released yet but I can say that one of the major strategic focuses of the company moving forward is to deepen our relationships and our engagements with the historic preservation community across the United States. And in fact, what we’re doing with Preservation Maryland I think is really innovative. We have a program where we’re sharing to let people know about the Indow Window product and we’re able to provide financial support to Preservation Maryland through these efforts. So the more we can grow our business, the more we can support the historic preservation community. And we’re really trying to work with Preservation Maryland to really kind of create a wonderful synergy in the historic preservation ecosystem while we’re working together to prevent people from replacing their windows by giving them great options and great alternatives.

What we could do with the historic preservation community is equip people with presentations that help them inform homeowners and building owners that there are great alternatives to replacement. And we can work with the historic preservation community to raise awareness around this because I think it’s such a key part of the preservation struggle, and it’s such a hot-button issue, and it’s something that we’ve heard from the historic preservation community that they really value help, and that’s where we can work together.

[NR] So if people want to learn more about this, they want to see the product, they want to learn about how to buy it, they’re living here in Maryland or they’re in California for that matter, where would you send them? How do they get to learn more?

[SP] Best place to go is our website,, that’s I-N-D-O-W-W-I-N-D-O-W-S dot com. And there we have videos. We have tons of case studies including a number of historic preservation case studies that tell about stories about how people encountered challenges in their life with their windows and how we worked with them to help them solve the problems that they were facing. Getting an estimate is really easy and free, so just get in touch with us. We’d be happy to help you guys check it out.

[NR] So before we let you go – and this is been a lot of fun to hear about this and particularly the process behind developing it and all the technology that goes on involved in it. We ask this of everyone; it’s normally is the most difficult question. A lot of our folks stumble over this and try not to answer it. But be that as it may, what is your favorite historic building or place, Sam Pardue?

[SP] Fort Astoria. Out here in Oregon at the end of the Oregon Trail… Well, before the Oregon Trail existed, there was a great expedition out here that was organized by Jacob Astor. He wanted to create this global spanning fur empire, and Astoria, Oregon, right there at the mouth of the Columbia River where it empties out into the Pacific Ocean was where he wanted to base this empire. It’s a fascinating story. The story of the people that came out, the impact it had on U.S. history here in the Pacific Northwest, it just really resonates. Portland Center Stage put on a wonderful theatrical production of a book that was written about this adventure. And so just having the place, the fort to see and to imagine what life was like for those people really connects me to the heritage that we have here in the Great Northwest.

[NR] I think that’s a fantastic answer. That might be our first – no, we got Fort McHenry. Maybe that’s our second fort, but fantastic answer and fantastic interview. Thank you so much for joining us today. Although you weren’t able to share any of the top secret information about new products, maybe when you have a new product we can have you back and talk about what’s new in the world of interior storms and Indow. And as you said, if people want to find out more, they just go to, and they can get all the information there and figure out how to take advantage of this fantastic technology. Sam, thanks so much for joining us today on PreserveCast.

[SP] Oh my gosh, it’s been a great pleasure, and thank you guys for al the work you’re doing sharing the importance and the centrality of historic preservation in our lives.


You don’t need to open a history book to find us. PreserveCast is available online from iTunes, the Google Play Store, and wherever else you download your podcasts, as well as on our website, where you can find a complete archive of all our previous episodes plus photo galleries and additional content. We’re also on Facebook and Twitter @PreserveCast.

This podcast was developed under a grant from the National Center for Preservation Technology and Training, a unit of the National Park Service, and in partnership with the Anacostia Trails Heritage Area. Its contents are the sole responsibility of Preservation Maryland and do not necessarily represent the official position or policies of the National Park Service or the National Center for Preservation Technology and Training.

Our website is made possible by the Historic Preservation Education Foundation. This week’s episode was produced and engineered by me, Stephen Israel. Our executive producer is Aaron Marcavitch. Our theme music is performed by the band, Pretty Gritty. And most importantly, thank you for listening and preserving!

Show Notes

Preservation Maryland and Indow have entered a cooperative partnership to help save Maryland’s historic windows! When you request a quote and purchase Indow window inserts using this link, you’ll help support Preservation Maryland, too.