How Can You Save 27% on Your Heating Bill This Year??

Winter's Coming! - How Can I $ave on Heating Co$t??

     Ok, let's get practical for a sec. Mech E's that have chosen to specialize in HVAC/R are just full of equations. So, let's pull out our handy-dandy equation for Furnace Fuel Consumption. It says:

Furnace Fuel Consumption = (24 * Q * DD) / (deltaT * HV * Eff)

where,

Q** is the amount of heat being lost to the bitter cold outside in BTU per Hour ~ 85,708 BTU per Hour,

DD^^ is the number of Degree Days in the Heating Season ~ 6,696 Days,

deltaT is the difference between the outside and inside temperatures in degrees F ~ 37.2 degrees F,

HV++ is the Heating Value of the Fuel (for Natural Gas HV ~ 1,100 BTU per cubic foot)

and Eff is the efficiency of YOUR furnace (this is something you'll probably find on that yellow sticker to the side of your unit)

(I'm using the "Annual Fuel Utilization Efficiency" or AFUE) ~ 80%

Note: These estimates are for Northern Virginia but you can gather your own information @

^^www.wrcc.dri.edu

**www.calculator.net/btu-calculator.html

www.noaa.gov (available when the government re opens)

++I simply Googled the Heating Value (HV)

     Pretty simple, right? Well, not really. The heat being lost is dependent on deltaT, the time of day, the physical orientation of your home and the insulation of your house. However, you can greatly simplify your life by making a few assumptions & estimations - as you'll see, this is perfectly fine (and expected if you're an ME).

     So, the result is…(drum-roll, please)……….420,748.4 cubic feet of natural gas per annual heating season.

     So, how much can you save by turning down the thermostat to 65 degrees F during the winter?

  Q ~ 62,208 BTU per Hour,

DD ~ 4,896 Days,

deltaT ~ 27.2 degrees F,

HV ~ 1,100 BTU per cubic foot),

and Eff is ~ 80%   

     So, the result is…(drum-roll, please)……….305,384.7 cubic feet of natural gas per annual heating season. (a 27% savings on your bill)

     OK, freezing your family this winter might not be what you had in mind...BUT....if you look carefully at the equation above, there are a host of things that can be done to save on you heating bill this winter. You can calculate your potential savings by comparing the cost of a more efficient system (one with an AFUE of say 90%). You can also replace your windows with ones that have a better "U-factor"...I'll explain that when I have more time to blog again.

     Until then, Cheers!