Savings from an expedited duct sealing program for mobile homes.

This paper documents the energy savings observed for a program operated by the Eugene Water and Electric Board which provided duct sealing for mobile and manufactured homes as its principal measure. Billing data and associated mean outdoor temperature data on more than 400 participants for one or more years pre and post was used as the basis of the savings estimate. The observed savings were used along with site treatment costs to estimate a levelized cost of savings of 12 mills/kWh exclusive of utility management costs. Clear evidence of a mean gross pre-post Normalized Annual Consumption (NAC) savings of 1258 kWh/yr. was observed with an error of +-150 kWh/yr., at 95% confidence. This study included 80% of the participant population. Although the amount of savings were small relative to overall consumption, they could be clearly demonstrated in a plot of cumulative distributions. The savings analysis was based on the fitting of a single break point function to both the pre and post billing data vs. temperature, i.e., PRISM® heating mode only. Results were normalized for conditioned area at each site to allow for an area weighted aggregation of results. Results were presented as NAC savings in the city of program activity and in the form of a temperature function which allowed the results to be estimated for other climates. Results were equivalent to about a 13% improvement in duct delivery efficiency. The contractor used site pressure diagnostics (blower door and pressure pan) during the sealing process to detect sealing opportunities and to confirm job completion. The diagnostics played a key role in expediting program cost effectiveness by detecting at the outset sites with limited savings potential.