Updating state residential building energy efficiency codes
According to Blasnik, most modeling programs aren’t very accurate, especially for older buildings.
Unfortunately, existing models usually aren’t revised or improved, even when utility bills from existing houses reveal systematic errors in the models.
Surprisingly, Michael Blasnik's Simple spreadsheet proved to be more accurate than models that required far more inputs.
Energy consultants and auditors use energy modeling software for a variety of purposes, including rating the performance of an existing house, calculating the effect of energy retrofit measures, estimating the energy use of a new home, and determining the size of new heating and cooling equipment.
Low R-value estimates for existing single-pane windows.
“They assume that old single-pane windows are R-1, when they are probably closer to R-1.35 or R-1.4.
Most energy models require too many inputs, many of which don’t improve the accuracy of the model, and energy modeling often takes up time that would be better spent on more worthwhile activities.
Blasnik presented data to support these conclusions on March 8, 2012, at the North East Sustainable Energy Association.
I’ve spent a lot of time looking at energy bills, and comparing bills before and after retrofit work is done. Retrofit programs are instructive, because they show how the models perform.” According to Blasnik, most energy models do a poor job of predicting actual energy use, especially for older houses.States included in this region stretch from Maine to Maryland. Blasnik has worked as a consultant for utilities and energy-efficiency programs all over the country.“I bought one of the first blower doors on the market,” Blasnik said.A regional membership organization promoting sustainable energy solutions.NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field.
When calculating the outside surface film coefficient, they assume worst-case conditions — in other words, that the wind is always blowing away heat from the window.