I'm getting error messages; what does this mean? We are automatically notified of most errors and we make every effort to correct them if the cause is on our end. In some cases, errors will be caused by inappropriate user inputs. Input combinations that are known to cause errors include entering a window area on a side of the house that is larger than the opaque wall on that side (excluding doors and garage), entering non-rectangular house dimensions that are physically not possible, or entering a thermostat start time that is not at least one hour after the previous period.
Pull-down menus don't work. Internet Explorer 7 creates a problem. We are working on it.
Why are the "whole house" (total) savings shown on the upgrade report not the same as the sum of the individual measures in the table? Each of the upgrades the table above are evaluated in isolation from the others. If the efficiency level is changed for one upgrade, its potential impact on other upgrades will not be counted in the row-by-row estimates. However, these kinds of interactions are included in the "package" totals associated with the whole-house totals and chart at the top of the page. In the an example in which furnace efficiencies are raised, the energy savings from wall insulation will not change in the row estimate, but a lower lower savings from insulation will be reflected in the package totals due to the more efficient furnace's impact on reducing the energy required to make up heat losses through the wall.
Technical FAQs (and answers) here:
Why don't you model XYZ, and is there a way I can estimate the energy implications anyway? We are always operating on a limited budget, and trying to balance and prioritize a very long "wish list". In some cases, there are reasonable "work-arounds" to estimate the energy use of systems or features that we don't explicitly model.
Can I make a link to your site? Sure. No permission is required.