This calculator will provide an estimate of the heat loss for your home, including:
A few changes have been made to the calculator - details...
Please note these important sources of error.
Fill in all the input boxes.
(the light blue boxes)
Then, click on the button below that looks like this When you click "Calculate", the output cells will be calculated and displayed. You must click the Calculate button to see the effect of any changes you make.
Worked examples here.
This software is provided "as is" -- use at your own risk. I am not responsible for any errors, inaccuracies or omissions in the software. Under no circumstances am I liable for direct, indirect, special, incidental, or consequential damages resulting from the use, misuse, or inability to use this software, even if I have been advised of the possibility of such damages -- Gary
Definitions of the Output Columns:
- Design Heat Loss -- This is the total heat loss from your house per hour when the outside temperature is at the Design Outdoor Temperature that you input. This can be used as a rough guide for sizing your furnace -- but see the discussion on Internal Gains above. (BTU/hour)
- Year Heat Loss -- This is a rough estimate of the total heat loss from your house for a typical year. It is based on the number of Heating Degree Days you entered. (BTU/year)
- Fuel Cost -- This is the cost of the fuel to heat your house based on the Year Heat Loss from the previous column, and the fuel type, fuel cost, and furnace efficiency you entered. (Dollars)
- Ten Year Cost -- This is the cost of fuel for 10 years with the assumption that fuel costs will rise 10% each year of the 10 years. (Dollars)
- Greenhouse Gas Emissions -- This is the yearly green house gas emissions from your heat plant. It is based on the type of fuel you selected, the furnace efficiency you entered, the Year Heat Loss. For electricity, it is assumed that the electricity was generated at an average US rate of 1.5 lbs CO2 per KWH. (lbs of CO2 per year)
your browser to run this calculator (Tools -> Internet Options -> Security)
- For the Design Day heat loss calculation, the inside temperature is assumed to be 70F.
- Remember that you must click the Calculate button to see the effect of any changes you make to the inputs.
HINT: if you want to save the output use the Print function on your browser to either print it, or save it to a pdf, and sometimes other types of files. One way to access the Print function is to right click anywhere and select print off the right click menu. The right click menu on MS Explorer browser will also export the data to OneNote, which works well.
Gary 5/5/07, 3/2/08, 12/18/2008
Updated: April 17, 2008 Clarified slab effective R value, added two examples.
Nov 7, 2009 Added some more help files
April 4, 2011 Fixed some formatting and nav menu issues
August 15, 2012 Added plot and title, many cleanups, formatted for better printing and clearer look.
December 3, 2012 added a few clarifications to the labels.