A few conversations we’ve had from the Ice Box Challenge.
The Ice Box Challenge at the Cincinnati Homearama has been an incredible experience. We set up two small structures in the sweltering sun: one built to standard building code, and one built to rigorous Passive House standards. Inside each, we placed a large block of ice.
The results have been a powerful, visual conversation starter.
While many Homearama guests initially come to admire the beautiful finishes and luxury options in the show homes, our little boxes have consistently drawn them in. It’s been a fantastic opportunity to shift the focus from the surface level to the “bones” of a home—and have wonderful conversations about building for a more sustainable and comfortable future.
We’ve chatted with curious homeowners, developers, realtors, and subcontractors alike. Here are the most common questions we’ve been asked while standing beside the rapidly melting ice in the code-minimum box and the impressively solid block in the Passive House box.
Q: Can a house be too airtight?
This is the most frequent question, and it’s a great one. The simple answer is: People need to breathe, but buildings do not.
In fact, a leaky building is an inefficient one. Modern building code requires new homes to have an airtightness of no more than 3.0 Air Changes per Hour (3.0 ACH50). This means that when the house is depressurized (like on a windy day), all the air you just paid to heat or cool can leak out and be replaced by outside air three times every hour. In the winter, you could be losing all your heat every 20 minutes!
A Passive House, by contrast, targets an incredibly airtight 0.6 ACH50. That’s five times more airtight than a standard new home. This means the energy you use for thermal comfort stays inside, dramatically lowering your utility bills.
But what about fresh air for people? And what about moisture? An airtight home is always paired with a continuous, balanced ventilation system. This system, called an Energy Recovery Ventilator (ERV), constantly supplies fresh, filtered air while exhausting stale, moist air. In the process, it transfers the heat from the outgoing air to the incoming air, so you get fresh air without the energy penalty.
And building assemblies (your walls, roof, etc.) are designed to dry out if they ever get wet. Airtightness is the key to controlling heat, air, and moisture.
Q: What type of insulation do we use?
Passive House is a performance-based standard, not a prescriptive one. This means it doesn’t mandate specific materials—it mandates a specific result. This gives us the flexibility to choose the best insulation and structural system for each unique project.
At Trilobite Design, we often prioritize sustainable and high-performance options. Some of our favorites include:
- Mineral Wool & Cellulose: Great for their sustainable properties, vapor permeability, and fire resistance.
- Spray Foam & Polyisocyanurate: Used strategically, these are powerful insulators that create an exceptional air seal.
In the Cincinnati region, we typically target an insulation value of R-40 in the walls and R-65 in the roof to meet the rigorous performance targets of a Passive House.
Q: Is there a “Passive House look”?
Absolutely not! Because it’s all about performance, Passive House principles can be applied to nearly any architectural style, from traditional to ultra-modern.
Think of it as the high-performance chassis and engine of a car—the beautiful bodywork on top can be anything you want. We focus on what’s inside the walls, roof, and foundation. The wall assemblies we design can be clad in virtually any material—brick, stone, wood, or modern metal panels. You can have the aesthetic you love with the performance you deserve.
Q: How much does it cost?
This is the million-dollar question (ha!), and while the honest answer is always “it depends on the project,” we can provide a solid baseline. Based on our recent projects, building to a Passive House standard typically carries a 5% to 10% upfront cost premium compared to a basic, code-minimum home.
Where does that investment go?
- Better Components: Higher-performance windows and doors, more insulation, and specialized air-sealing materials.
- Skilled Labor: It requires more attention to detail from the construction team.
- Expert Design: We invest time upfront in detailed energy modeling and planning to ensure the home performs as designed.
The crucial part is the return on that investment. That upfront premium translates directly into long-term dividends:
- Drastically Lower Energy Bills: Often a 70-90% reduction in heating and cooling costs.
- Superior Indoor Air Quality: Continuous filtered, fresh air reduces allergens, dust, and pollutants.
- Unmatched Thermal Comfort: No drafts, no cold spots. Just a quiet, comfortable, and healthy living space.
On-site energy generation, like solar panels, can be an additional investment, but those systems come with their own clear payback benefits as well.
Do these conversations spark your curiosity?
Whether you’re planning a new build, a major renovation, or are just interested in making your next home healthier and more efficient, we’d love to chat.