Building Energy Software Tools
Formerly hosted by US Dept. of Energy    


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Older member of the HOT2000 family of energy analysis software. Its graphical user interface and simplified input make it a quick and easy tool for analysing energy use in houses. However, the underlying engine is that of HOT2000 and thus provides a state of the art analysis. The software is provided free, but user support is no longer available, and the program is no longer under development. The functionality of HOT2XP has been replaced by the "House Wizard" in HOT2000

Expertise Required: 

Basic understanding of the construction and operation of residential buildings.


Renovators, builders, utilities, home inspectors, design evaluators, engineers, architects, building and energy code writers, Policy writers, curious homeowners. HOT2XP is also used as the compliance software for the Canadian EnerGuide for Houses Program.


Building footprint, construction characteristics (above and below grade), HVAC and domestic hot water specifications, geographical location of the house, and fuel costs. The data is entered through a menu-driven interface. Internal structural libraries provide many defaults. The user can overwrite these defaults and add additional details (i.e. window descriptions), which will increase the accuracy of the analysis.


Graphical Home Owner Reports are available (text and graphics). Technical Reports on the house analysis can also be viewed. These include detailed heat loss by component, monthly tables, HVAC load results, annual heat loss, fuel consumption and costs. HOT2XP has a comparison report that allows for the display of results of up to 4 house files, side-by-side. All reports may be output to the screen, to a printer or to a file. The latter can then be loaded into a spreadsheet program.


An entire house can be entered in half an hour or less. Performs whole-house energy analysis very quickly which can be used to determine annual energy use and can help determine the cost effectiveness of energy efficiency upgrades. Takes into account thermal bridging through studs in assemblies; has a detailed air infiltration model and foundation heat loss model. Heat balances are performed on the basement, main floor and the attic. HOT2XP has a wide selection of HVAC and hot water equipment (including heat recovery ventilators and heat pumps) for five fuel types (natural gas, electricity, oil, propane, wood). Has been validated extensively against hourly simulation programs and monitoring of real houses. The program can be run in English or in French and in metric, Imperial or U.S. units.

Major Capabilities: 
Whole Building Energy Simulation
Load Calculations
Utility Bill and Meter Data Analysis
Building Type: 
Free for Non-Commercial/Academic Use
Last Software Update: 
29 January 2006
Last Entry Update: 
18 July 2018
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