Available at: http://digitalcommons.calpoly.edu/theses/1091
Date of Award
MS in Architecture
Currently 10% of all single family homes produced in the U.S. are manufactured homes with 75% of these households making less than $50,000 in annual income (Manufactured Housing Survey). Manufactured homes typically use twice as much primary energy per square foot than site built homes yet there is no agenda within the industry or its governing bodies to address this excess energy consumption. The research presented in this thesis compares the thermal envelope performance of the typical wood stud framing used in the manufactured home industry to the thermal envelope of structural insulated panels (SIPs). This comparison examines the energy savings a SIP manufactured home could create for a home owner while speculating on the financial and technical feasibility of using SIPs in the manufactured housing industry. Ultimately, the comparison reveals the short comings of the Manufactured Homes Construction and Safety Standards (HUD Code) regarding thermal envelope requirements and energy use intensity.
These short comings are revealed when the energy use of HUD compliant manufactured homes is scrutinized and compared to the energy use of a similar home built with SIPs for the thermal envelope. The continuous insulation and airtight qualities of the SIP home allow it to use 32%-46% less energy than the HUD compliant homes in the same locations. Manufactured homes require much more energy to heat and cool because the HUD code does not require a certain performance criteria be met for the airtightness of manufactured homes and the overall U-values it requires for the thermal envelopes of such homes is too high for the varying climate zones found in the U.S. If SIP panels were to be used for the thermal envelope of the manufactured housing industry, low income manufactured home owners could be saving $300-$700 annually in energy costs. These savings are not insignificant to low income households and could create a 5-8 year payback period of additional ownership costs under $2500.
Unfortunately, the SIP industry cannot offer its product at a low enough price to compete with the economies of scale achieved by the manufactured housing industry when buying raw construction materials. The value of this research then, is the exposure of the manufactured home’s inferior envelope performance when compared to more modern construction technologies and the speculation of how the manufactured housing industry could begin to incorporate a more robust building envelope without putting its customers at a monetary disadvantage.