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Home Heating Energy Use. ClimateHeating Degree DaysThermal lossesHeating unit typeFuel heat content Seasonal efficiencyEnergy Use and Cost. Heating Degree Days. Albany, New York = 6,888 @ 65 F base. Thermal Losses. Size of structureThermal envelopeInfiltrationOrientation. Heating Unit t
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1. Home Heating Myths CREF Meeting
August 11, 2008
2. Home Heating Energy Use Climate
Heating Degree Days
Thermal losses
Heating unit type
Fuel heat content
Seasonal efficiency
Energy Use and Cost
3. Heating Degree Days Albany, New York = 6,888 @ 65 F base
4. Thermal Losses Size of structure
Thermal envelope
Infiltration
Orientation
5. Heating Unit types Forced Air furnace
Hot Water boilers
Steam boilers
Electric resistance units
Heat Pumps
6. Fuel Content # 2 Fuel oil, 141,000 btu/gallon
Natural gas, Therm= 100,000 btu’s
Electricity, 1 kwh =3413 btu/hr
7. Seasonal Efficiency Manufacturer Efficiency is not the same as seasonal efficiency
A conventional fuel oil fired forced air furnace that is over ten years old may have a manufacturer efficiency of 85%.
Assume it is installed in a home that has a heating load of 56,000 Btu/hr
Then,
8. Seasonal Efficiency It is likely that the unit was oversized to insure that it would always meet heating demand. A typical case is where the unit would be 120,000 Btu/hr input.
The unit will start and stop more frequently due to being oversized.
Outcome, Seasonal efficiency is lower
9. Energy Use Energy Use =
U x A x HDD/yr x 24 hr/day
________________________
Seasonal efficiency x heat value
10. Energy Use Example with SE = 0.6
1755 Btu/h/F x 6,888 HDD/yr x 24
__________________________
0.6 x 141,000 Btu/gal
=3429 gallons/yr
11. Energy Use Example with SE = 0.8
1755 Btu/h/F x 6,888 HDD/yr x 24
__________________________
0.8 x 141,000 Btu/gal
=2572 gallons/yr
12. Energy Cost Energy use with SE = 0.6
3,429 gal/yr
Fuel oil at $3/gal
Cost is $10,287 yr
Fuel oil at $5 gal
Cost is $17,145
Energy use with SE = 0.8
2,572 gal/yr
Fuel oil at $3/gal
Cost is $7,716 yr
Fuel oil at $5 gal
Cost is $12,860
Savings =$4,285/Yr