Free Design Software

This suite of simplified HVAC software has been developed by the instructor and students of the HVAC and Energy Conservation courses at The University of Alabama. It attempts to follow basic ASHRAE calculation procedures. The programs are provided at no cost to the public. We welcome comments and suggestions.

Free HVAC & GSHP Programs


GshpCalc 5.0.5 Now Available FREE as GshpCalc 6.0  which was Expanded from vertical loops only to also include surface water and ground water heat pump systems. Updated to metric units, double u-tubes, new heat pumps files, alternative loop pipe materials, and many other new features.

While all the other software on this website can be directly downloaded, this package is provided by request from 

Download instruction guide for GshpCalc 5

GsphCalc Design Software

GshpCalc, a ground heat pump system design program available since 1993, is now provided
at no cost upon request. It has previously been expanded from vertical ground heat
exchanger design to also include surface water and ground water heat pump systems. It
was updated to metric units, double u-tubes, alternative loop pipe materials, and many
other features.

GshpCalc is now freeware along with the many other HVAC and GSHP programs on this website. It no longer
requires registration codes and can be installed on as many computers as you wish. Upon request to, a LoadGshp zipped file and instructions will be provided. Before opening the folder and
initiating setup, it is advised that you delete any previous versions of GshpCalc, including demo versions. If you
have zone (.zon) or ground loop (.glf) files from previous projects that you would like to retain, move them to a
temporary folder until after you install the attached version. Then you can move them back to the new GshpCalc

There is also the possibility that your company firewall may block the email with the program files. Check your
junk mail first and if it’s not there, please provide a personal email address to which the folder can be sent.
My only request is that you sign up to receive our newly revised newsletter, Outside the Loop, along with as
many of your associates as possible by sending names and email addresses to


NEW Air-to-Air Heat Pump (and Cooling Only Unit) Correction Program

This program corrects the performance of air-to-air heat pumps and cooling only units from AHRI rated conditions to that occur in actual applications. Values that can be corrected are outside air temperature, indoor return air temperatures, air flow rate, air filter loss above the 0.08 in. w.g. rated value, external static pressure (ESP) above the 0.1 to 0.2 in. w.g.  rated values, indoor fan wire-to -air efficiency, split system line set loss for lengths greater than 25 ft. and heating mode defrost reverse cycle (but not tempering heat) penalties between -5°F and 37°F.  Currently, the only certified published rating points are heating capacity (HC) and COP at 17°F OAT and 47°F OAT and total cooling capacity (TC) and EER at 95°F OAT.  All other reported rating values are seasonal and intertwined with gross building load assumptions and idealized outdoor air temperatures. SEER and HSPF cannot be corrected to actual performance at other conditions. This program is limited to full load performance since certified part load data are unavailable.

Download AAHPCorrector22


BinCalc20 is a bin energy calculation program for air source heat pumps (ASHPs), air cooling units with furnaces, and ground source heat pumps (GSHPs). The program allows for unoccupied (night, weekday, weekends) set back temperatures and unoccupied weeks (vacations). Furnace fan power is included along with GSHP pump power. Equipment performance values are corrected for realistic filter (0.3”w.g. @ 300 fpm), duct losses (0.2 to 0.4 “w.g.), and cooling mode entering air temperature (to 75°F from the rated value of 80°F). Results assume equipment performance matches manufacturer specifications but information is provided from a comprehensive study (819 samples) indicating substantial degradation is common.

Download BinCalc20

Heating, Water Heating and Cooling Energy, Cost and Carbon Dioxide Estimator

Heating, cooling, and water heating energy, demand, cost and carbon dioxide calculator for homes, offices, and schools.

Download Heating, Water Heating and Cooling Energy, Cost and Carbon Dioxide Estimator


E-PipeAlator22 is a program for designing water distribution systems and computing head losses. The program handles temperature corrected water, water-glycol mixtures, water-methanol & water-ethanol mixtures (a new feature) in steel, cast iron, polyethylene, PVC, copper and cross-linked polyethylene (PEX) (a new feature) piping. Equivalent lengths for common fittings are automatically entered. Heat exchanger, valve, and flow control valve losses also considered. New GSHP piping example calculations and figures have been added.

Download E-PipeAlator22
Download the E-PipeAlator user guide

System Cooling KW/Ton, EER, and COP Calculator

This is a simplified cooling mode only version of HVAC System Cooling and Heating Efficiency Calculator. 

Download System Cooling KW/Ton, EER, and COP Calculator

HVAC System Heating and Cooling Efficiency Calculator

This program is essential to determine the actual efficiency of Heating and Cooling system.  Unlike ASHRAE Standard 90.1, it includes the effects of auxiliary equipment upon actual system performance.  It is especially critical when designing GSHP systems since the large amount of fan and pump heat generated by some modern HVAC systems will require significantly longer ground loops to adequately balance annual ground heat exchange.  It also alerts designers to the deleterious impact of high static pressure air handling units, return air fans, and fan power VAV terminals have on system cooling efficiency. (See Table 14, Chapter 34, 2015 ASHRAE Handbook-HVAC Applications)

Download HVAC System Heating and Cooling Efficiency Calculator

Residential Heating and Cooling Load Calculation

ResLoad22 is a residential heating and cooling load calculation program. An important feature is the inclusion of electronic psychometric functions so humidity (sensible/latent) analysis can be seamlessly performed. This includes sensible and latent infiltration, ventilation rate, and energy recovery analysis. A computation worksheet is included to calculate wall, roof/ceiling, floor, and slab R-values. Duct losses are performed using a comprehensive energy (sensible/latent) balance that includes conduction, duct leakage, and attic (or crawl space) ventilation rates. In addition to internal heat load gains, the latent load values are included from the Moisture Management chapter of the ASHRAE 2019 HVAC Application Handbook. The ResLoad22 upgrade also includes a worksheet to correct the sensible/latent capacity of dehumidifiers in order to match the resulting values determined in the load calculation procedure.

Download ResLoad22

Download the ResLoad Instruction Manual

TideLoad Heating & Cooling Load Calculation Program

Eight Zones with condensed CLTD/CLF/SCL tables. Includes traditional sensible load calculations plus new latent loads, heat recovery unit adjustments, and duct loss/gain options. New Worksheet for computing ASHRAE Standard 62.1-2004 ventilation air requirements. Excel Program is unlocked so user can add more zones and expand capabilities if adventuresome. Program can create zone files (.zon) for GshpCalc5.0x

Download TideLoadFeb17


E-Ductulator09 is a program for designing air distribution systems and computing losses with the Equal Friction/Equivalent Length method. New equivalent length tables for rectangular and round duct fittings with friction options for metal duct, spiral duct, duct liners, duct board, and flex duct. Register, diffuser, and filter (for MERV = 4, 6, 8, 11, and 14) losses also included.

Download E-Ductulator09


PsychProcess20 is a program for computing the moist air properties (enthalpy, specific volume, humidity ratio, relative humidity, specific heat, and dew point). It also calculates resulting properties for air mixing, cooling, and energy recovery. Total, sensible, and latent capacities can be computed for cooling, heating (with or without humidification) and energy recovery processes. A worksheet for performing the traditional By-Pass Factor analysis of total cooling processes is included.

Download PsychProcess20


A spreadsheet to convert a wide variety of units from English (IP) to International (SI) and SI to IP.  The program contains many weird (but useful) units specific to HVAC and GSHPs (i.e. kW/ton, EER, gpm/ton, cfm/ton, fins per inch, ft/ton etc.).

Download UnitsConverter17


WAHPCorrector22 is a program to correct the rated performance of water-to-air heat pumps (WAHPs) to actual field conditions. Corrections included are entering water loop temperatures, water flow rates, return air dry ans wet bulb temperatures, air flow rates, indoor fan & motor efficiencies. The ISO 13256-1 rating standard does not include the power to circulate air and water through the distribution system. Provisions are made to correct this deficiency. The part-load rating conditions for multi-capacity and variable speed WAHPs are more favorable than for single speed (capacity) units. Corrections can now be made for this deficiency so that the highly inflated part-load performance of multi-capacity and variable-speed WAHPs can be remedied.

Download WAHPCorrector22


A Program to estimate the thermal resistance of vertical ground heat exchangers for various pipe materials, arrangements, and grout/fill conductivity.

Download BoreResistIP-SI14


A Program to calculate ground temperature at various depths, soil properties and time of the year.  The program also estimates the heat transfer to/from horizontal pipes of various diameters and materials.

Download GroundTemp&ResIP-SI14


HVACPowDen08a.xls is a program for quickly estimating the required capacity and electrical demand of cooling and heating equipment for 30 different building types in the 10 US climate zones. Results are expressed in cooling tons, Btu/hr-ft2, total kW demand, and W/ft2. Program is now integrated with HVACSysEff.xls. Developed as part of an EPA-sponsored Energy Star Buildings project.

Download HVACPowDen08a
Download HVACPowDen08a instruction guide

This is a decarbonization program to compare the CO2 emitted by air source and ground source heat pumps with natural gas and propane furnaces. The pounds of CO2 per emitted per kWh generated by power plants in every state (or region) are used to determine heat pump CO2 production. The CO2/lb values are also used to include emissions due to furnace fan power use in addition to CO2 emissions from natural gas or propane combustion at the furnace site. 

Download CO2Compare

Free Economics Software


Computes the economic value (Present Worth) of an Energy Conservation Opportunity (ECO) for a 10-year period.

Download EcoAnal-10-09.xls


Computes the economic value (Present Worth) of an Energy Conservation Opportunity (ECO) for a 20-year period.

Download EcoAnal-20-09.xls


Computes the economic value of financing an Energy Conservation Opportunity (ECO) with a 30-year fixed rate loan.

Download EcoLoan-30-09.xls


Computes a discounted 5-Year economic analysis with inflation, taxes, and depreciation.

Download EcoAnal-Tax-Dpr-5.xls


Computes the monthly and annual payments for a fixed rate mortgage.

Download Mortgage2015.xls