17 Sep The Axiom House is a flatpack prefab net-zero “game-changing concept home”
Being an architect can be so frustrating; the established ways are so entrenched, residential building technology is so primitive, it’s all done by hand in the field where the biggest innovation in thirty years was the nail gun replacing the hammer. Meanwhile in the architects offices there are tools that we never dreamed of thirty years ago- computers instead of drafting boards, 3D renderings that spring our of our drawings like magic, and perhaps most importantly of all, the Internet that changes how architects can market what they do.
That’s why the Axiom House, being developed in Kansas City by Acre Designs, is so interesting. Jennifer Dickson is an architect; Andrew Dickson is an industrial designer; together they are trying to turn a house into an industrial product that can be delivered anywhere in a shipping container, for a price that is competitive with conventional construction. They are not thinking like designers, but like a tech startup:
Acre is the very definition of a technology company. We apply scientific knowledge from the fields of architecture, engineering, environmental design, and material and construction science in the most practical way imaginable. We’ve used these practices to create homes that take half the time to build, use a fraction of the resources, and have as little as half the lifetime cost of traditional homes.
The house itself is a flexible 1800 square feet, designed to adapt to its occupants’ life cycles. It’s described as Net Zero energy, producing as much energy as it consumes; it achieves this by being built to near passive house standards so that very little energy is required to operate it in the first place. As they note,
Our homes are 90% more efficient than standard construction to begin with, and we make up the difference with a small solar panel (PV) array. We start with an efficient floor plan and a tight building envelope to prevent air from getting in or out. We use high-efficiency doors, windows, and appliances, take advantage of natural (passive) heating from the sun, and utilize unique heating and cooling solutions.
The heating and cooling system is indeed unique; I had to ask for an explanation. In the early days of Passive Houses, many had what are called Earth Tubes, or big pipes buried in the ground that were used as ducts to pre-cool or pre-warm air to the ground temperature, which is about 55°F in Kansas City. But earth tubes proved hugely problematic, delivering condensation, mold, radon and other wonderful things as well as air. Instead, the Axiom house has what they call Passive Geothermal, (PGX) a riff on what others have called brine loops or glycol ground loops. There is a grid of pipes buried in the ground which deliver water at near 55°F to a heat exchanger built into theHeat Recovery Ventilator (HRV) that is required in a house that is so tight. So one gets all the benefits of an earth tube, preheating or precooling the air, without the problems and at a lot lower cost than a fancy ground source heat pump. They appear to work well; in an article by Martin Holladay in Green Building Advisor, a passive house builder called them “amazingly effective.” However Martin, always the skeptic, writes:
Of course, just because a ground loop works, doesn’t mean the system is cost-effective. Many energy experts have speculated that the pump needed to circulate the glycol solution uses almost as much energy as the system collects. The results of one monitoring study indicate that these experts may be right; data gathered in Vermont suggest that the simple payback period for this type of system may be as much as 4,400 years.
They are also delivering the tempered water to the radiant floor, and and addition to this system, the house also has a mini-split air source heat pump. Given the near- passive house amount of insulation, tight construction and careful siting, I suspect it won’t get a lot of use.
The structure is a flatpack of SIPs, or structural insulated panels. These are a sandwich panel of plywood or OSB board and expanded polystyrene insulation, 10″ thick for the roof and 8″ for the walls. They claim that that it can be built at prices competitive with other houses in Kansas City, running now at $110 to $135 per square foot. How do they do it?
It’s not any one thing, but a combination of strategies, that allows us to achieve this. A few examples:
By offering fixed plans, we can build hours of engineering and design into the base cost of the home. Just like with your car or phone, focused product developmenthelps us deliver a refined, high-performance home that can be repeated again and again. Starting with a right-sized, efficient floor plan has a domino effect: reducing up-front costs, energy demands and system sizes throughout the house. With a lighter load, we can eliminate ductwork, wiring, plumbing runs, and the expensive labor associated with these. With streamlined, repeatable construction, we shave months of labor costs out of each job.
Jennifer Dickson tells Metropolis:
We see no reason why architect-designed, highly efficient housing should not be attainable at a reasonable price point. To do that, we are treating this more like a car than a house. With cars, the design effort goes in at the front end, and at the purchase end, the customers do not get a custom product, but they get access to high-end finishes and their choice of features. We think we can leverage buying power by providing a set of well-designed packages.
Having used these same arguments for a decade when I was working in prefab, I am a bit skeptical that they can do that. I found again and again that designs are rarely repeatable, everyone wants to customize, and that customers don’t care about right-sizing, they care about price per square foot. And it’s just so hard to compete with conventional construction, the guy in a pickup with a magnetic sign and a nail gun.
But it is so exciting to see architects and designers trying to innovate in the design of homes and the way that their services and the product are delivered. I am really rooting for them and hope it works.