Summary by End Use

The energy consumed by devices in each of the major end-use categories (Heating, Cooling, Water Heating, Major Appliances, Small Appliances and Lighting) is summed by utility fuel (Equation 38) and presented in three forms, as an annual bill, as energy consumed and as pollution, in the form of carbon emissions (as CO2). Some end-uses have subdivisions that can also be presented to the user. This information is shown when the user has changed the inputs in the more detailed area. For example, if the user doesn’t customize the inputs for Lighting, only one number, Annual Lighting Consumption will be shown. If the user gives general information about the lighting in each room of their house, then the information shown will include summaries of consumption at the room level. If a user goes further to specify actual fixtures in the various rooms, the summary report for Lighting will show this fixture level, as well as summed consumption by room and for the entire house. For a list of the devices in each end-use, see the associated calculation section above.

            Equation 38

                      where

           UEC = Energy consumption

           d = Device

           e = End-Use category (e.g heating, cooling etc.)

           f = fuel in utility units (kWh, therms, gallonslpg, fuel oil)

To arrive at the final bill and pollution for each end use, the energy consumption for each fuel is multiplied by the price and emissions factor for each fuel (Equations 39 and 40). These values are summed across all fuels to get the end use bill and pollution.

            Equation 39

                      where

                        UEC = Energy consumption

                        bill = annual bill (dollars)

                        e = End-Use category

                        p = energy price (dollars)

                        f = fuel in utility units (kWh, therms, gallonslpg, fuel oil)

            Equation 40

                        where

                        UEC = Energy consumption

                        pollution = annual pollution emissions (lbs/C)

                        e = End-Use category

                        c = emissions factor (lbs/C)

                        f = fuel in utility units (kWh, therms, gallonslpg, fuel oil)

Total house values for energy, bill and pollution emissions are calculated by summing across end uses. These resulting values are displayed to the user on the results pages shown in Technical Specification of the Home Energy Saver website(Appendix D).