Q. What version of EnergyGauge should I use for 45L – new home tax credit compliance?

A. See following table for dates of use

Software Version

Start of Use

Last permit date for use



2013 tax year

August 1, 2020



2016 tax year

December 31, 2022

Use 6.1.09 – not earlier

7.0.01 or higher 7.X.XX

2020 tax year

December 31, 2022

HVAC grading included in tax credit rule. Use most current software. Can comply by checking "not tested" if HVAC systems were not tested.


Version 6.1.09 may be preferred if you have not done any HVAC grading measures. Note that the requirements for obtaining the tax credit include field verification methods. No Covid exceptions.

US DOE List of Approved Software for Calculating the Energy Efficient Home Credit

Q. Can I ignore HVAC grading entries for 45L in EnergyGauge 7.0.01 and later?

A. No. You can comply by checking "not tested" if HVAC systems were not tested. 

Q. What if I have a home and I have not done any of the HVAC grading requirements?

A. You may want to enter the home in EnergyGauge version 6.1.09 if it was permitted prior to December 31, 2022. You can then import that file into version 7.0.01 or more recent (Note this will not work the other way. Transferring from newer version to older version is not recommended). Once in 7.0.01 you will need to add some entries. But then you can compare results from each version.

Q. What if I have a home in a recent version 7.0.07 and later of EnergyGauge USA without HVAC grading and I want to see if it passes the 2016 tax credit calculation that was extended to the end of 2022?

If you have entered your home in version or 7.5 or more recent, and you are not measuring any HVAC airflow or other grading components, and you want to see if it passes the older tax credit you will need to convert the file to be able to be imported into EnergyGauge USA The older tax credit calculation was recently extended to the end of 2022. If you have been using EnergyGauge for a number of years you may have 6.1.09 on your computer, If not, contact tech support. A version 6 and a version 7 can both run on the same machine with one license.

We created a program that will convert your ENB files from 7.0.07 to 6.1.09 that you can download and use. You simply copy the Convert_ENB_7.0.07_to_6.1.09.exe application to the folder where you have your 7.0.07 ENB files. This directory by default will be C:\Users\*YourUsername*\Documents\EnergyGaugeUSA7\Bldgs\Backup.  Once you have copied the convert exe to that directory, double click to execute it. The program will create a v6.1.09 sub-folder and copy all the new 6.1.09 files into that v6.1.09 folder.


The program can be downloaded at:




On the search screen in the 6.1.09 software click on "Load *.enb/*.rgu File." Navigate to the subdirectory v6.1.09 and find the file or files of interest. When you open the files in 6.1.09 there are two input selections that will need to be made on each file to adjust for software changes made between 6.1.09 and 7.0.07.


  1. The occupancy radio button and dropdown will have to be selected on the project tab



  1. The ceiling type will also need to be selected on the ceiling tab for each ceiling. Once you ahve done that, you can run the tax credit to see if the home complies.



Q. What minimum HVAC grading values will I have to enter in EnergyGauge 7.0.01 and later to obtain tax credit compliance?

A. There are a number of new entries. We will start with a confirmed rating as selected under the Status field on the Project tab. We will assume you have made all your regular entries for cooling and heating and duct systems.

1. The 2020 45L calculation requires a total duct leakage test and the date ducts were tested. Previously EnergyGauge would accept just a duct leakage to outside for 45L. Without a total duct leakage test result HVAC Grading cannot be accomplished and the software defaults to a grade III duct system, which then defaults all HVAC grades to grade III. Enter total duct leakage test result on the duct tab and indicate if ducts were tested at Rough-in or Final. If you do not have test results or know when it was tested you will be defaulted to bad ducts and you do not want to do that. Grade III for ducts will negate any quality HVAC grades the house may have achieved.

2. If not already selected, select the radio button on the project screen that indicates Yes for HVAC Grading. This will enable the inputs needed for HVAC grading.

3. Go the Equipment > AHU tab – this is a new screen in version 7. You should see one AHU system for every pair of cooling/heating systems you have entered.

4. Select a test mode –cooling or heating.

5. Obtain the design load method used by the builder/HVAC contractor and indicate the design cooling and heating load for each system.

6. Enter the Blowerfan test method. If you know the design cooling or heating airflow, enter them.

7. Enter the Measured Airflow at Operating Conditions (CFM). Testing of airflow is highly recommended in order to achieve 45L.

8. Enter the measured BlowerFan Watt Draw value and how you measured it if you have measured it. Obtaining watt draw is highly recommended in order to achieve 45L.

9. Enter refrigerant charge. Even if you did not measure it you must enter something in version 7.0.01. Select test method non-invasive and enter 2 oz of refrigerant charge if you have not measured. Measuring refrigerant charge is highly recommended but if it is not measured it is still important to include tested total duct leakage, blower fan cfm and blower fan watt draw.

10. Leave the AHU screen - you will receive error messages for items you did not enter, but you can ignore them.

11. When completed entering all home entries, save your file and run Tax Credit > RESNET pub 001-20 from the Calculate menu. You will again be warned you did not enter some data and you will be defaulted to Grade III. You can ignore the messages as long as you have entered the minimum indicated above.

12. For a free short on-demand course on entering HVAC grading in EnergyGauge see our continuing education site. This site will also show the next offering of our on-site training for conducting the HVAC grading. https://energyresearch.ucf.edu/education/continuing-education/

13. For more information on HVAC grading tests see ANSI/RESNET/ACCA standard 310-2020. https://www.resnet.us/wp-content/uploads/ANSIRESNETACCA_310-2020_v7.1.pdf

Q. What if I am doing a proposed 45L from plans and I do not plan to test HVAC system, what entries do I need?

A. There are a number of entries. 

1. After selected New (From Plans) as the Status on the Project screen, you will need to select the HVAC grading radio button.

2. If you have entered all of the home’s cooling and duct systems, go to the Ducts tab and make sure to enter a proposed Qn total and when the ducts will be tested (Rough-in or Final) in addition to all your usual duct inputs. Testing of QN to outside is required and total is highly recommended.

3. Go to the AHU tab located on the Equipment notebook section. You should see an entry for each set of heating/cooling equipment you have entered. Select ‘Use Grade III /Not tested defaults” for Blower Fan Airflow, BlowerFan Watt Draw and Refrigerant Charge if you have no plans to test the system.

4. Leave the AHU screen. You should not receive any warnings. If all of your home’s data is entered, you can save your file and Calculate RESNET Pub 001-20 (HVAC Grading).

Q. By not testing am I penalized?

A. The Reference Home for ratings and tax credits has Grade III HVAC entries (not necessarily Grade III ducts). So you are not penalized if you have not tested the blower fan or refrigerants. Nevertheless, the blower fan default watts per cfm is higher in RESNET Pub. 001-20 procedures than in the historic default EnergyGauge has used and that may make some 45L untested homes do slightly worse in Version 7 than in Version 6. There are a number of other changes that may make some homes do better or worse, thus our first suggestion is EITHER test the HVAC systems so you can take advantage of quality HVAC installation grading system, which can result in multiple HERS Index points and increased in Tax Credit Energy Savings OR enter in Version 6.109 and export for loading into Version 7.

Q. If I do the HVAC tests will I be more likely to meet 45L requirements?

A. You will be much more likely to meet the Energy Use qualification criteria if you test and the test indicates grading better than grade III. A grade 1 HVAC system may result in an improvement of HERS index of a number of points and 45L savings of a few percentage points. 

Q. How will homes qualify in 2023 and later?

A. The IRA bill passed by congress extends tax credits until December 31, 2032. Beginning with homes built in 2023 the tax credit amount will be $2500 per home meeting the eligibility standards of the EPA's ENERGY STAR Single Family New Homes Program. We are awaiting guidance from DOE and the IRS as to the meaning of the language. There is also some conflicting language regarding what version of ENERGY STAR has to be met. Until such guidance is obtained, our recommendation for builders is to have homes in 2023 ENERGY STAR certified following the most recent version of ENERGY STAR  homes available in their state. EnergyGauge USA staff will continue to update the software for ENERGY STAR, DOE Zero Energy Ready Home and 45L guidelines as they are released.

Q. I heard some homes will be eligible for $5000 beginning in 2023 -is that correct?

A. Yes! The bill indicated homes that are certified to meet the DOE's Zero Energy Ready Home program will qualify for a $5000 tax credit. DOE’s Zero Energy Ready Homes program requirements are posted at Zero Energy Ready Homes Requirements. Note that we await the final guidelines from DOE and the IRS. The ZERH version 2 guidelines are in draft form as of August 2022.  

Q. Where can I learn more about the 45L tax credit?

A. The changes to the 45L tax credit can be found in Section 13304 of the Inflation Reduction Act. Section 13304 is titled Extension, Increase, and Modification of the New Energy Efficient Homes Tax Credit (45L).  This section begins on pdf page 361 (page # subject to change as file gets updated) of the legislation link:  Inflation Reduction ActRESNET has a Summary of 45L changes in the bill also.