Design and construction of an energy efficient modular home can be a challenge, but with the rising cost of energy coupled with demand for sustainability, it is a challenge that builders and manufactures must meet. Energy efficient doors and windows, as well as appliances, have been a standard in home construction for some time, but with new technologies, there are more opportunities to build green. In the design and construction of any energy efficient modular home, the architects, general- and sub-contractors need to consider these seven building elements and design challenges.
1. A Sustainable Site Design
A sustainable site begins with site selection. Each location must be evaluated with an eye toward the house’s potential orientation to take advantage of passive solar design. In addition, site selection goes beyond merely a determination of how the project fits into the existing ecosystem. Affordable, energy-efficient modular home design also needs to consider access to services, transportation, and rapid transit.
2. The Foundation and Slab
Foundations and slabs are areas often overlooked in designing for energy-efficiency, but insulating these are as important as walls and roofs, especially in units where water and air heating units are housed in basements. Concrete made with fly ash and recycled aggregate can improve the sustainability rating. Finally, new technology is emerging in foundation materials, such as Structural Insulated Panels (SIPS) and Insulated Concrete Forms (ICFs). According to the Insulating Concrete Form Association, homes built with SIPs can help homeowners save hundreds of dollars each year on energy bills.
3. The Wall and Roof Assemblies
Walls and roofs in an energy-efficient building not only need to be well insulated, but the materials themselves should promote sustainability. Sheathing products and structural insulated panels are available using bio-based materials created from agricultural waste. Walls are another area where SIPs and ICFs can be utilized. New technology is gaining ground in wall materials, which provides energy efficiency in a cost-effective and durable product. And finally, old materials, such as prefab and modular components are seeing light in new ways, with modern, energy-efficient materials incorporated into the modules.
4. Insulation and Air Sealing
Regardless of the type of construction, insulation and air-sealing are at the heart of any energy-efficient design. Whether traditional fiberglass-based insulation, modular panels or a combination of the two, the R-values required to claim the home as ‘green’ is much higher than most local building codes require. Providing a proper external thermal envelope is the key to energy-efficiency.
5. Energy Efficient Doors and Windows
Traditionally, much of a building’s heating and cooling loss was through windows and doors, but improved technology in all facets of the window and door design is reducing this transfer. In the design and construction of energy efficient modular homes, particular care should not only be given to materials and coatings for windows and doors, but consideration for the orientation of the building. South-facing windows will want to take advantage of passive solar designs while those on the other sides need to minimize all heat transfer.
6. Controlled Ventilation
Modern well-insulated houses composed of modular materials, tend to be much more air-tight, so it is important to consider the ventilation process. Ventilation not only maintains the air quality inside the structure, but properly planned ventilation systems can help with the energy efficiency of the unit. Heat recovery ventilators can use heat exchangers to recover much of the heat lost through traditional ventilation systems. Instead of blowing the warm, but stale air out into the environment, this heat is trapped and recirculated as an energy-efficient way to warm the air inside, reducing waste and energy consumption.
7. Heating and Cooling Systems
At the heart of any design of an energy-efficient building, correct sizing of the heating and cooling system, where most of the energy is burned, is key. While correctly sizing heating and cooling units for any home is important, if proper energy-efficient design and construction has been utilized, it is essential that these units be scaled down due to decreased need. In many environments, relatively small heating units can be installed and supplemented by passive solar or replaced with heat pumps.
Designing and constructing energy efficient modular homes isn’t just about putting solar panels on the roof or using Energy Star appliances. Every facet of the design, development, and construction should keep “going green” in mind for cost savings to the owner and sustainability for the future.