USE YOUR HOUSEHOLD GAS BILL TO COMPUTE YOUR HOME HEAT LOSS

Discussed by Steve Miller near end of recording on 2022-4-21 Building Electrification Recording ; Invitation ; Description ; Miller slides. ALSO, discussed using this data: 10 to 15 minute mark, from begining of recording, & on updated slides #10 and #11 on 2024-1-18 Building Electrification Announcement; Recording; Steve Slides-updated.

  1. Look up coldest month gas consumption (from gas company records);
  2. subtract your minimum monthly summer gas consumption (representing cooking, water heating, clothes drying);
  3. subtract gas furnace inefficiency (sutract the 20% of gas which is wasted by an 80% furnace- look up efficiency on furnace nameplate).
  4. Your gas bill specifies number of therms per 100 cubic feet: 100 ccf of gas = 1 therm
  5. Convert thermal content of gas to BTUs (1 therm = 100K BTUs).
    Divide BTUs by # of degree days on coldest month.
    Degree-days is often supplied on gas or electric utility bill (degree days - DD)
    also available by googling on-line records of your city or county.
  6. Finally, divide by 24 hours per day to determine BTU usage per degree hour.
  7. Look up the NEEP.org full page graph for the selected cold climate heat pump (enter manfacture and model; then scroll down for graphs
  8. Print the page; add your line representing heat loss in winter, and a 2nd line representating heat gain in summer.