must meet. Several factors affecting overall efficiency and energy consumption are: • The various exhaust fans (attic, bath, and kitchen) and atmospheric (fireplace) and power vented appliances (clothes dryers) that can pull warm air out of the building and cold air in. A kitchen exhaust fan can remove all the warm air from a building in one hour of steady operation! • Draft regulation devices, such as draft hoods and draft regulators, draw air out of the building envelope during and after appliance operation. • The height of the building (number of floors) affects exposure to wind and heat loss as well as chimney height and draft. • The insulation of outside walls and window areas and their construction dramatically affect heat loss. • Air leakage into the house around doors, windows, and into the basement affects air infiltration rates and energy consumption. The location of the heating appliance and the distribution system affects efficiency. If the boiler and piping are all within the living area, then jacket and piping losses are not losses; they are gains in the winter. However, jacket losses from water heaters and 30 National Oilheat Research Alliance boilers in the conditioned space will increase the cooling load in the summer. A Princeton University study found that 60% of the heat in a typical home comes from the heating system, 15% is from solar gain. If the building occupants manage the solar gain by opening the drapes to let the sun in, then closing the drapes at night, the solar gain can be even greater. Twenty percent of the heat comes from the lights and appliances and five percent of the heat gain is from the body heat given off by occupants and their pets. People radiate between 300 and 420 Btuh, and pets radiate up to 300 Btuh. All of these building construction factors interact with the heating unit to produce overall heating system efficiency for the building/ chimney/heating unit combination. While some of these interactions are beyond an Oilheat technician’s control (Figure 2), by understand- Figure 2 Where the Heat Goes
NORA Advanced Efficiency
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