Prefabricated or “Prefab” is a construction method in which both standardized and non-standardized building components are fabricated in a controlled factory environment then shipped to and assembled on site. Combine the prefab construction method with the Passive House standard and you have the most energy efficient building technology available today delivered in a fraction of the time required by traditional site-built construction.
In spring of 2016, RPA partnered with Ecocor to design and build the most energy efficient manufactured homes in North America. Together, Ecocor and RPA will produce fully prefabricated homes that are built to the rigorous Passive House standard.
Ecocor is a construction firm that designs, manufactures, delivers and assembles high performance buildings throughout North America. In the Ecocor factory, panelized walls, floors and other assemblies are fabricated in detail in a controlled environment ensuring the highest quality before they are trucked to and assembled on sites that have been evaluated and optimized for a Passive House building.
HOW TO GET A PREFAB PASSIVE HOUSE
Passive House prefabricated model homes designed by RPA are programed for manufacture in the Ecocor factory and range from a 323-square-foot cabin with one bedroom to a 2,685-square-foot home with three to four bedrooms. RPA will provide architectural services to clients who wish to modify or customize a model home for their particular tastes and requirements. RPA will also work with clients to design unique, custom Passive Homes for pre-fabrication by Ecocor.
Chris Corson, Ecocor
Getting a prefabricated Passive House includes 10 simple steps.
The cut parts are assembled on framing tables; air tight sheathing is applied and taped, the blanket cavity is installed, a state-of-the-art waterproof fleece is applied, and the ventilated rain screen is created.
RPA | ECOCOR PREFAB MODEL HOME MATRIX
|wdt_ID||Model||Type||Size||Details||Maine||New England||Mid-Atlantic||All Other States|
|1||Model A||Exterior 323 SF
Interior 218 SF
|2||Model C||Exterior 1051 SF
Interior 842 SF
|3||Model E||Exterior 1,333 SF
Interior 1,104 SF
|4||Model G||Exterior 1,431 SF
Interior 1,192 SF
|5||Model J||Exterior 2,219 SF
Interior 1,922 SF
|6||Model K||Exterior 2,230 SF
Interior 1,904 SF
|7||Model M||Exterior 2,685 SF
Interior 2,316 SF
|8||Model P||Exterior 1,632 SF
Interior 1,291 SF
|9||Model R||Exterior 1,753 SF
Interior 1,397 SF
|10||Model T||Exterior 1,850 SF
Interior 1,484 SF
FREQUENTLY ASKED QUESTIONS
Is Passive House more expensive than traditional construction?
The initial cost of a Passive House building is comparable to standard construction of a similar sized home. Industry estimates find that the construction of Passive Homes can be approximately 0% to 10% more expensive than typical construction. Given the high quality construction of a Passive House, monthly heating and cooling costs can be reduced by as much as 80% to 90%. The financial benefits are quickly realized by the homeowner with reduced cost of ownership.
How much does a prefabricated Passive House Cost?
The prefabricated RPA I Ecocor Model homes range in cost from $190sf to $275sf for the base models delivered anywhere in New England. For cost related to delivering a prefabricated Passive House to your region, go here.
What is the difference between a prefabricated Passive House compared to a Passive House built onsite?
Prefabricated or “Prefab” construction is a method in which both standardized and non-standardized building components are fabricated in a quality-controlled factory environment then shipped to and quickly assembled on site. RPA | Ecocor Prefabricated Passive Houses use patent pending wall components that are certified by the Passive House Institute to meet Passive House levels of airtightness. Prefabrication by Ecocor supports Passive House certification, lessens exposure to the outdoor elements during construction and speeds time to completion.
What about different climate zones?
RPA | Ecocor is currently servicing climate zones 5, 6, and 7 with plans to expand our offerings for other North American climates and conditions. For example, all RPA | Ecocor homes can be engineered for varying wind loads or seismic activity. We have found that clients in other climate zones where building costs are extremely expensive have found it economical to purchase one of our model homes instead of building on site.
How long does it take to get a RPA I Ecocor Model home?
Once you sign a contract and your model home is in the production schedule, it takes between 2 to 3 months for the Ecocor prefabrication facility in Searsmont, ME to manufacture, deliver, and assemble your model home, provided the site preparation is complete. The foundation can be installed concurrently with the fabrication of your new home, drastically reducing the total construction time Once the model home is set by Ecocor, your home is ready for mechanical, electrical, plumbing, interior and exterior finishes.
What about site selection and solar orientation?
Our model homes are designed to meet the Passive House standard using a raft slab foundation. An optimal site is relatively flat with good access to free solar energy from the sun. The south facing wall should be oriented within 20 degrees of solar south. We can meet the Passive House standard even if these requirements are not meant by adjusting the insulation levels in the slab and roof and adjusting the glazing ratios and glazing specifications.
What can I customize in my model home?
The range of model homes we offer is designed to appeal to a broad range of the home buying market. Interior modifications are provided at a modest additional cost. The cost for modifying the exterior walls and windows is provided on a case-by-case basis. Garages, sheds, breezeways, bris soleil and other shading devices for the southern façade can all be added at an additional cost.
What about the roof overhangs?
The wall assembly used by RPA I Ecocor is engineered to manage water and water vapor very well so our model homes can be designed with or without roof overhangs. Roof overhangs are largely an aesthetic and cost preference for the home owner. For example, one client may select a moisture-resistant exterior cladding with no overhangs while another selects natural wood cladding with overhangs that help maintain the original look of the exterior finish. RPA will help clients select the form and materials that work best for them.
What is included?
The square foot cost estimated for an RPA | Ecocor model home is indicative of a “turnkey project,” meaning the price estimate includes all that is required to take occupancy of your prefabricated Passive House.
For contractors or homeowners who may desire to manage completion of a home, the cost is broken down into two line items:
The first line item is for The Ecocor Shell, which includes the raft slab foundation, exterior wall panels, interior walls and doors, the ventilation system, the roof, air-sealing and insulation, windows and exterior doors, siding and exterior trim, equipment rental, travel and transportation cost, and consulting cost.
The second line item is for Elements Provided by Others (local contractors, owner/builders, etc.). This line item includes concrete and rebar, standing seam metal roof, interior finishes, mechanical, electrical, plumbing and the ventilation system installation as well as a number of miscellaneous construction costs.
The estimates provided are based upon average construction cost in the Northeastern United States (regional cost will vary). As with all types of new home construction, the homeowner may decide to alter certain design elements or select fits and finishes that have not been quoted.
What about permitting and inspections?
We provide a base set of approval drawings for you to submit for a building permit. Securing the building permit and all other approvals and inspections are the responsibility of the homeowner.
What are the foundation options?
The RPA I Ecocor base model homes are designed with a shallow frost protected foundation. The foundation includes insulation formwork which stays in place after the concrete slab is poured. This is the most efficient and cost effective type of foundation system for meeting the Passive House standard. Our wall panels and roof can be installed on any type of foundation system including a basement, crawl space, or even piers provided that the proper levels of insulation have been engineered into the foundation.