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Innovative materials like Eco-Panels are gaining attention in the pursuit of sustainable and energy-efficient construction. These prefabricated wall systems—a new take on structural insulated panels, or SIPs—combine framing and insulation into a single step, and the manufacturer says they promise superior insulation and structural integrity, as well as an alternative to traditional building methods. To assess their real-world application, we embarked on a project using Eco-Panels for a pump house in Texas. While the project didn’t have all of the details and complexity of building a house, it provided insights into the panel’s advantages and challenges in a low-risk project. Here’s what we learned.
Discovering Eco-Panels
During research for an article on cost-effective, high-performance residential construction, I interviewed Rob Howard, founder of Howard Building Science in North Carolina. Howard, known for his commitment to sustainable building practices, introduced me to Eco-Panels—a prefabricated wall system he had successfully implemented in his projects.
Intrigued by Eco-Panels’ potential, I contacted Charles Leahy, the company’s founder, based in Mocksville, North Carolina. Leahy invited me to visit the manufacturing facility to gain firsthand insight into the production process and the panels’ unique features.
The Eco-Panels facility operates on a modest scale, resembling a high-end cabinet shop more than a large manufacturing plant. During the visit, Leahy highlighted key distinctions between Eco-Panels and traditional SIPs:
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9 Comments
Glad to see they're still making panels, not so keen to see there are still some (seemingly) easy areas for improvement. I toured the factory probably 8-9 years ago and spoke with Charles; they're less than an hour from me.
They have a franchised manufacturing facility in Tennessee too, but I haven't been there. I do wonder if the equipment and processes are the same in both facilities, or if there are any differences in quality, etc., between the two.
I do not know, but it's a good question.
Hello Chris - I encourage you to read my response to Fernando's article. "Context" is not something that he apparently appreciates, and so I have tried to add context in my response to him below. He is quick to cast disparaging remarks, that is clear, in a quest to find fault - but the faults that he found would not be expected to be seen by the typical client. Leaving panels sitting out in weather near humid Houston for close to two months didn't help either. Note, our manufacturing operation in Tennessee is an AMAZING group of people that follow the same process that we do. We both work very hard to ensure the best quality that we can provide and their booming business is clearly evidence of the good and hard work they are doing. Traditional builders like Fernando are often our harshest critics - I mean, who likes change, right? So we're used to harsh criticism from builders - it's just a shame he left out critical context that would have put his article in a different perspective if it had been included. We do see lots of trolling on Green Building Advisor - that's really why we are not active in the forum.
“[Deleted]”
Hello Fernando - this is Charles Leahy, president of Eco-Panels. First off, I would like to thank you for your business! I was however surprised to see your article without notice to us and your revealing bits of information - including potential quality issues - that you had not shared with our company as the building was being assembled - but I understand the whole social media thing and a desire to create a story. As you may recall, our team had been significantly interested in being involved with your panel set in the Houston area because you had mentioned you might be documenting it, yet our attempts to reach out and be involved and see photos were rebuffed by you. If the panels had not been left out in the Houston weather for a month or two prior to assembly you might have had a better experience. We never heard from you that the panels fit tight over the base plate - this can happen for at least three different reasons. First, when we fabricate the panels we are using untreated 2x4 lumber to create the "void" at the bottom of our 4.5" thick wall panels - and when we are typically shipping panels to a jobsite that has only JUST attached their base plate to the floor platform just prior to panel arrival, there is no "tightness of fit" issue like your team experienced. If however the foundation with plates was "ready" almost two months before the panels were set, then those plates would have swollen from weather. This absolutely will happen and could have been the cause. While we had asked you for photos of the jobsite prior to our delivery of panels - and even after the delivery of panels - we did not receive them - so who knows? Second - if your team used a pressure treated piece of lumber as the base plate - that is always swollen compared to untreated 2x lumber - then that would have been a reason for the tightness and absolutely it would have been needed to be trimmed - we even talk about this in our Assembly Manual which we had sent you prior to assembly. Again photos might show evidence of what happened. Third possible reason - the fact that the plywood skins of our panels sat out in humid Houston area weather for well over one month and possibly close to two months virtually guarantees that the plywood interior skin that you had requested (and is NOT typical of the panels we shipped) swelled at the edges - including the bottom of the panel - and this would cause an inconveniently tight fit. Note our Assembly Manual and other documents SPECIFICALLY ADVISE to NOT receive panels before they are ready to be used because we know things like the swelling of plywood - or swelling of untreated base plates - or damage on a jobsite - can happen. I do wish this had gone more according to our recommended and normal course of business - I think better cooperation and communication with your team would have prevented those issues being a concern. Regarding the 1.5" gap - where did that occur? As we shared photos of the structure set up in our factory prior to shipment, we saw no large gap (some of those photos are attached). As with every structure - we assemble it and check dimensions prior to it shipping out the door - we would have seen a gap that large and it would not have passed our quality check. Of course if dimensions are not accurate on a jobsite (and they rarely are), then that is a darn good reason for the gap - but our panel system does have a way of dealing with that. I assume that they were able to work through it. I am glad that you seem to have liked the electrical layout - at least you did not complain about it - as you know you pretty much left it up to us to figure out the details after you gave us a high level specification.
Regarding the siding chosen - we love the LP Smartside Product - but as their installation guidelines show, gaps are most commonly covered by their trim - that is by design of their product. Regarding the AC plywood - I do remembering cautioning your team about undo expectations even before we build panels - but it seems you have forgotten that conversation. 99% of our clients do not even try to achieve a finished interior skin when they order our wall panels - we like it that way because we are better able to meet client expectations which we already try to take very seriously. And while you mention "drywall" as a siding in your article - that is definitely NOT a siding that we offer - though we do love the Huber ZIP System sheathing that you mention - it is our most popular exterior siding option by far.
As already mentioned I have provided in this response photos of the panels assembled in our factory for a quality check of your pump house that we took prior to shipping the panels to you in Houston in December. I think your unit was actually assembled by your team some time in February - two months later. I can appreciate your team's assembly of our panels because the finished product in your photo looks great! They are clearly a good team and do good work and can clearly overcome obstacles without reaching out to the manufacturer (though our extreme preference is that if people are having any problems they reach out to us and COMMUNICATE). Please note that our Assembly Manual - even the one written in Spanish that we sent you - does advise to reach out to us if someone is having any issues.
And we have documented 50 and even 60 degree temperature differences from passively cooled structures (see video proof in our website video gallery) when viewing outside surface temps and interior temps of structures made with our panels. I have never observed this degree of behavior (20 deg is typical) of stud framed structures and I look forward to your collecting data this summer in the Houston area. We know in some parts of the country the crews work until around noon in the summer and then it is too hot in the house under construction and they go home (they do start very early) - this would not be the case when using our panels (and has been proven).
As a former (award winning) writer myself I would suggest that when writing a story context matters. When you don't share additional critical details - such as the panels weathering prior to assembly, such as lack of investigation of that base plate, such as the fact that the configuration of panels that you chose - and were cautioned by us regarding their final assembled finish - and that happened to be some kind of impression-forming experience that is then somehow relatable to the average reader that would not even be using that siding - I think that warrants an air of further clarification on your side AT THE START of the article. We work with amazing clients every year that are building their own homes complete for between $100 and $150/sqft (and of course others building homes for more expensive than that) and we could not be more proud of that. To try and cast doubt about our product without sufficient and critical context and call into question our quality when you provided us a very difficult working experience I believe is not fair.
Charls, I wrote to you about the discrepancies, and I do not believe that some time in the weather would have shrunk the panels two inches or created a 3-inch misalignment between stacked panels. Nonetheless, I believe you read with too much sensitivity, especially for a writer. My book was just reviewed in JLC. I appreciate the review very much, but not all of it was positive. If I made a factual error, I will gladly correct it. But the issues were created at the factory, not on-site. I do not dislike Eco-Panel; it's a brilliant product that would benefit from improved manufacturing tolerances. I was very complimentary of the energy performance.
I did ask Charles about the discrepancies and included the reply in my article. On a positive note, we have started having hot days- up to 90 degrees - here in Houston, and, as predicted, the interior is remarkably cool. I set a thermometer inside to track the temperature differences between the exterior and interior, especially as the days become more humid.
I’ve done several homes using Eco-panels and coming back on GBA after Charles told me about this article. Long time fan of Fernando’s articles but I disagree with some of the observations being familiar with Eco-panel’s product in relation so other SIPs. I have built with three other SIP companies and Eco-panels was the best of the four.
Surely the 1.5” discrepancy had more to do with site conditions because walls are preassembled in the factory. Maybe more detail could clarify that problem.
The sill plate issues are common to all SIPS. Typical polystyrene SIPS can be more easily forced on top of swollen sills. Maybe due to lesser grades OSB but also because the bond to insulation is not as strong as with Eco-panels. I have never experienced delamination with Eco-panels unlike with polystyrene panels. We always pre-rip our sills 1/8” if pressure treated and may take some off kiln dried lumber if expected to get wet before panel erection. This issue is made clear in their assembly manual.
We have never attempted an interior finish integrated into our SIPS and I’m sure the issues of doing so were made clear. No SIP company appreciates panels sitting outside of conditioned space for long periods before installation. This is especially true for wet and humid climates.
Exterior finish should not be taken lightly and requires extreme attention of detail to properly weatherize.
The cam locks are nice but it’s never bothered us when one doesn’t seem to work. They are more of an assembly assistance than necessity. Shimming out fascias is another thing common to all SIPs. Run a string and fill it in.
Comparing time and labor to conventional framing is difficult with the many variables. Experienced crews and access being equal, dry-in is usually faster with SIPs. It is time and labor intensive to make conventional framing match the level of energy performance of polyurethane panels. Panels are much easier to air-seal and do not require exterior insulation for high effective R. All homes we built with Eco-panels met Passive Haus levels of airtightness and one was 2X tighter than minimum. Our Eco-panels always tested higher than other brand SIPS and much higher than more conventional framing.
Thicker walls use a surprising amount of floor area. Eco-panels have the highest amount of R per inch thickness of wall. It’s hard to calculate the value of lost floor area to gain equivalent energy performance.
Maybe the author is new to SIPs or expectations for speed and labor savings were too high. All building systems have their own unique drawbacks and advantages and builders are an opinionated bunch. I commend the author for trying and publicizing newer systems but didn’t agree with how some of the problems with the project were attributed to the company when it sounds like planning and site conditions played a part. In the realm of high performance panels, I have yet to find anything better than Eco-panels.
Brian, I appreciate your thoughtful and detailed reply—and your kind words about my articles.
I’m not sure where we actually disagree. You confirm that the 1.5–2" misalignments can happen and that pre-ripping the sills is necessary. That’s what we ran into. These are realities of the product, not unfair criticisms.
Charles reacted to what he felt was a disparaging article. I didn’t write one. I praised the concept and highlighted the strengths—especially energy performance. But I also noted shortcomings, as any builder would want to know before using a system like this.
Our program was explicit: we wanted to explore whether the factory-applied plywood interior could serve as the finished wall. That’s where the misalignments became a real issue. We dealt with the exterior issues using wide battens. Inside, that wasn’t an option.
I agree that all SIPs require care at the sill. But some systems—especially CNC-cut ones—don’t show the same degree of dimensional variation. Eco-panels aren’t made in a shop environment, and it shows. That’s not a dealbreaker, but it’s something to factor in.
Again, I think the concept is smart, and I never knocked the performance. But builders need to hear the full story—good and bad. That’s what I tried to give.
Fernando
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