A modular unit frame sits in VerMod's Wilder, Vermont, factory b…
A modular unit frame sits in VerMod's Wilder, Vermont, factory bay on a freezing February day. Units take about a month to construct, according to VerMod founder Steve Davis.
Ted Cushman
An OSB panel serves as the top plate for the bodular unit's doub…
An OSB panel serves as the top plate for the bodular unit's double-wall construction, minimizing thermal bridging across this framing juncture. Here, a worker applies a bead of adhesive sealant to the wall plates.
Ted Cushman
A worker in the VerMod plant applies the OSB top plate to a unit…
A worker in the VerMod plant applies the OSB top plate to a unit's 10-inch-thick double stud wall. The thin OSB plate minimizes thermal bridging at this location. "Optimum Value Framing" methods are used throughout the unit's shell, according to VerMod executive Chet Pasho.
Pill-Maharam Architects
This cutaway wall framing comparison, created by architect David…
This cutaway wall framing comparison, created by architect David Pill (Pill-Maharam Architects), shows the advanced framing details (right) employed in the VerMod modular units. Allthough the VerMod units are the same length and width as the HUD-Code trailers they replace, their double-stud walls with airtight detailing drastically reduce the energy consumption of the product in service.
Peter Schneider/Efficiency Vermont
This photo provided by Peter Schneider of Efficiency Vermont sho…
This photo provided by Peter Schneider of Efficiency Vermont shows the interior face of a double-stud VerMod wall under construction. Super-insulated construction with minimal thermal bridging gives the wall system drastically improved performance, compared with traditional house-trailer construction.
Peter Schneider/Efficiency Vermont
This photo supplied by Peter Schneider of Efficiency Vermont sho…
This photo supplied by Peter Schneider of Efficiency Vermont shows the double-stud wall assembly from the exterior viewpoint. Taped ZIP sheathing serves as the air pressure boundary for the structure, as well as the drainage plane.
Peter Schneider/Efficiency Vermont
This photo supplied by Peter Schneider of Efficiency Vermont sho…
This photo supplied by Peter Schneider of Efficiency Vermont shows the wall top plate of the VerMod unit at a corner. OSB gussets laid flat on the wall top connect the inner and outer 2×4 plates, minimizing thermal bridging at this location.
Ted Cushman
VerMod exec Chet Pasho explains the use of a company-devised ins…
VerMod exec Chet Pasho explains the use of a company-devised insulation density sampling device, cut from a section of vent pipe. The teeth on the end of the tube allow the inspector to bore into the insulated wall and extract a measured volume of insulation, which is then weighed to calculate density of the material as installed. Walls are tested at several points during construction to ensure uniform quality of insulation density.
Ted Cushman
VerMod's Chet Pasho demonstrates how wall insulation core sample…
VerMod's Chet Pasho demonstrates how wall insulation core samples are weighed on a digital scale to ensure uniform density of the insulation application.
Ted Cushman
VerMod founder Steve Davis stands in the open-plan kitchen-livin…
VerMod founder Steve Davis stands in the open-plan kitchen-livingroom of a recently completed unit. "It's a thousand-square-foot two-bedroom, two-bath ranch house," he says. To Davis' rear is a duct chase that supplies fresh conditioned air to a bedroom and bath.
Ted Cushman
A view of the indoor head of the 9000-Btu Mitsubishi Mr. Slim mi…
A view of the indoor head of the 9000-Btu Mitsubishi Mr. Slim mini-split heating and cooling unit for the 1000-square-foot VerMod unit. The Mr. Slim is the home's primary heat during the cold part of winter. In swing seasons, a heat pump booster on the building's "Conditioning Energy Recovery Ventilator" (CERV) carries most of the heating or cooling load.
Ted Cushman
Steve Davis in the mechanical room of the modular dwelling. A th…
Steve Davis in the mechanical room of the modular dwelling. A three-component system incorporating three different heat pumps serves the unit's needs: There's a Mitsubishi mini-split for primary heating and cooling, a heat-pump water heater, and a heat-pump-boosted Conditioning Energy Recovery Ventilator (CERV) that maintains air quality and distributes heat and fresh air to distant rooms.
Ted Cushman
Steve Davis demonstrates the function of the remote control unit…
Steve Davis demonstrates the function of the remote control unit for the building's Conditioning Energy Recovery Ventilator. Once charged at the wall, the control can be unplugged and used anywhere in the building.
Ted Cushman
The CERV's "black box" sensor and control system conti…
The CERV's "black box" sensor and control system continously monitors CO2 levels, VOC levels, and temperature in the occupied rooms, and implements air exchange as needed to keep air quality within parameters selected by the occupant.
Ted Cushman
A tractor-trailer unit from Field and Sons (Grantham, New Hampsh…
A tractor-trailer unit from Field and Sons (Grantham, New Hampshire) rolls out of the VerMod factory parking lot on a winter morning as Steve Davis stops traffic on Vermont Route 10 and serves as ground guide. The team has to wait until 8 AM, after school buses have finished their routes, to hit the highway with their police escort from the Windsor County Sheriff's Department. The VerMod units are considerably heavier than HUD-Code homes, and require a beefed-up trailer.
Ted Cushman
After a 96-mile highway trip, the VerMod home makes its turn off…
After a 96-mile highway trip, the VerMod home makes its turn off the road into the driveway of a trailer park in Shelburne, Vermont, under the watchful eye of Steve Davis.
Ted Cushman
Steve Davis and Tyler Boice place a lumber ramp in front of the …
Steve Davis and Tyler Boice place a lumber ramp in front of the trailer wheels in order to help the modular unit get past a curb as the rig exits the roadway and enters a driveway.
Ted Cushman
Under time pressure to get his rig through an awkward spot, Stev…
Under time pressure to get his rig through an awkward spot, Steve Davis crawls under the trailer to place a wooden ramp so that the trailer bed can clear an roadside obsttruction.
Ted Cushman
Steve Davis hustles to keep up with his VerMod high-performance …
Steve Davis hustles to keep up with his VerMod high-performance modular unit as the tractor-trailer rig carrying the home pulls into the driveway of the mobile home park.
Ted Cushman
The truck driver and ground guide for Field and Sons (Grafton, N…
The truck driver and ground guide for Field and Sons (Grafton, New Hampshire) work together to get the rig pulling the heavy modular unit through snowbanks next to the narrow driveway of the mobile home park.
Ted Cushman
Steve Davis guids the truck and trailer carrying the modular uni…
Steve Davis guids the truck and trailer carrying the modular unit into the moblie home park.
Ted Cushman
Tyler Boice unbolts the modular unit base from the trailer rig a…
Tyler Boice unbolts the modular unit base from the trailer rig after arriving at the home site.
Ted Cushman
Steve Davis works with the ground crew for the crane company to …
Steve Davis works with the ground crew for the crane company to ready the spreader bar, clevices, and cable for lifting the modular unit and placing the home onto its foundation.
Ted Cushman
Steve Davis guides lift cables for the modular unit into place.
Ted Cushman
Crew members connect the modular unit to its lifting cables in p…
Crew members connect the modular unit to its lifting cables in preparation for setting the house.
Ted Cushman
Steve Davis places a protective lumber bumper to keep the lift c…
Steve Davis places a protective lumber bumper to keep the lift cables from damaging the brand-new home's eave overhang.
Ted Cushman
Crane crew members work on hooking up the lift cables.
Ted Cushman
As a ground guide works the tag line, the crane lifts the heavy …
As a ground guide works the tag line, the crane lifts the heavy modular unit off the trailer. From this point of view you can see the taped ZIP Sheathing underside of the trailer, which forms part of the unit's air-tight high-performance envelope.
Ted Cushman
The crane lifts the 70-foot-long unit off its trailer and swings…
The crane lifts the 70-foot-long unit off its trailer and swings it slowly toward its intended location on the new foundation.
Ted Cushman
The team watches as the crane maneuvers the heavy modular unit t…
The team watches as the crane maneuvers the heavy modular unit toward the foundation, working around streetlights, wires, and trees.
Ted Cushman
Crew members work to view the unit from all angles as the crane …
Crew members work to view the unit from all angles as the crane negotiates the path to the foundation.
Ted Cushman
Peter Schneider of Efficiency Vermont passes signals to the cran…
Peter Schneider of Efficiency Vermont passes signals to the crane operator as the team carefully eases the 70-foot house onto its stemwall foundation.
Ted Cushman
Crew members pass signals and haul tag lines as the crane cautio…
Crew members pass signals and haul tag lines as the crane cautiously maneuvers the unit around ground obstructions.
Ted Cushman
The crane eases the modular unit down into position on the stemw…
The crane eases the modular unit down into position on the stemwall foundation.
Ted Cushman
Steve Davis pulls the unit into line with the foundation as the …
Steve Davis pulls the unit into line with the foundation as the crane lowers the building a few final feet toward the foundation sill.
Ted Cushman
The crew applies bituminous polyethylene vapor barrier tape to t…
The crew applies bituminous polyethylene vapor barrier tape to the underside of the unit frame before lowering the home onto the treated wood sill.
Ted Cushman
Crew members push to line the unit up with the foundation as the…
Crew members push to line the unit up with the foundation as the crane lowers the building through the last few centimeters.
Ted Cushman
Ground crew members for the crane operator congratulate each oth…
Ground crew members for the crane operator congratulate each other on the successful outcome of a tense and tricky operation.
If you wanted to upgrade a whole state’s home energy performance, where would you start? For Peter Schneider, an energy consultant with Efficiency Vermont, the housing arm of the state’s first-in-the-nation energy efficiency utility non-profit, Vermont Energy Investment Corporation (VEIC), one way that makes sense is to start at the bottom — with some of the worst-performing homes in the state.
Schneider runs the State of Vermont’s Mobile Home Replacement Program. The inspiration for the program came in the form of a disaster: the devastating onslaught of Tropical Storm Irene, which brought catastrophic flooding to southern Vermont. The storm washed out hundreds of mobile homes in low-lying trailer parks. As the state struggled to recover, Governor Peter Shumlin recalled, citizens and policy-makers had a key insight: “Why, for the most vulnerable Vermonters — the ones who are living in mobile home parks — would we go and put those mobile homes back the way they were, the same places they were, at the same height, with the same incredibly inefficient buildings? Why would we do that? They are cold in the wintertime. They are warm in the summertime. They take huge amounts of money to heat and cool when we know we are asking the folks who have the least, who struggle the most, to pay the biggest bill? It makes no sense.” (See October 28, 2013, Rutland Herald story : “Vermod mobile home wave of the future,” by Eric Francis).
The state’s solution was to evolve a new generation of housing units the same size and shape as a traditional HUD-Code mobile home — but constructed entirely differently, with airtight super-insulated double-stud walls, state-of-the-art heat pump heating and cooling systems, and innovative “Conditioning Energy Recovery Ventilation” equipment that recovers heat from outgoing or incoming air as needed using a heat pump, not just a passive heat-exchanger core. (The CERV units, supplied by Illinois startup Build Equinox, also come with a sophisticated “black box” control unit that responds to indoor carbon dioxide or VOC content, exchanging air with the outdoors whenever indoor conditions warrant — but not if they don’t.)
The advanced units were designed with input from existing mobile home residents by David Pill of Pill-Maharam Architects (Website – Profile). Schneider’s job is to manage the mobile home replacement effort’s technical requirements, program planning, and implementation. Steve Davis, founder of Wilder, Vermont, company VerMod, Inc., has the job of getting the units built and delivered. So far, VerMod has set more than 20 of the units, and is pumping them out at a rate of about one a month — for a price of about $105 per square foot at the factory gate, or about $140 a square foot installed and move-in ready.
JLC visited the VerMod plant in Wilder in February, and accompanied Davis on a trip to Shelburne, Vermont, to set a brand-new unit. For a look at the process, view the slideshow.
