this link takes you to get CONVERT freeware and you can mathematically
convert all your electrical heaters to BTU.

http://www.joshmadison.com/software/

Heating Degree Day - A form of degree day used to estimate the required
energy for heating. One heating degree day occurs for each degree the
daily mean temperature is below 65 degrees Fahrenheit.

now if your rooms are always comfortable in all seasons, this should
mean that there is sufficient heat available to you in each room.
looking at the electric heat bill can tell you how many KWH you bought
in the coldest month. if you have individual room heaters check their
electrical plates for the information you need. NOAA national weather
service posts degree days by date and month, use this data to compare
the cold weather month of billing to the degree days information and be
sure to use actual not calculated or estimated billings. remember that
simple electric heat is 100% efficient. compare the energy inefficiency
of a wood vented device [perhaps at 70% ? find out]and know before you
buy input and output btu comparison info. you can also read the
electric meter daily and compare to the degree days for daily
factoring.

example of buffalo climate info at:
http://www.wunderground.com/history/....html#calendar

lots of degree day months and cities at:
http://www.nrcc.cornell.edu/ccd/nrmhdd.html

or for your area search google for degree days climate nws noaa city