I am trying to caculate my heat load based on electric and propane usage.
From my electric bill I have used 15132 Kwh in the period from March 2012 to March 2013. If I take away 450 kwh /month for non heat usage I get 9732kwh/year.
For the period from April 2011 to April 2012 I used 15182Kwh or 9782 for heat , so it is consistant in usage the 2 time periods. I used April because for March 2011. It was an estimated number. HDD for the periods were March 2011 to March 2012 4397degC 65F = 18.3C and 0F = -17.7C so dT of 36 used in caculations.
using the formula (heatloss/hr / dT) * HDDS for total loss /year in BTU's
Using a loss of 24000btus/hr of heat loss of ((24000btu's hr x24) / 36 ) * 4397= 70.35 Million BTU's You would need 70.35 million BTU's of heat.
From my utility bill i have used 9782kwh's x 3412 btu's/kwh = 33.37million for the year from electric baseboard heaters.
I also use propane and have used 750 liters per the time period. 750 x24603 btu's/l gives me 18.45 Million. a total of 51.8 Million.
Therefore my heat loss should be less than 24000btu's per hour.
Working backward's I have ((51.8million / 4397hdds) * dT 36C)/24 =17600 BTU's/hr. Is this the correct way to do this.
If I am missing something or doing it incorrectly please let me know.