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

June 30, 2021

Use 6.1.09 – not earlier


2020 tax year

No current expiration

HVAC grading included


For homes permitted prior to June 30, 2021 you may use EnergyGauge version 6.1.09. This version may be preferred if you have not done any HVAC grading measures.

Note that the June 30, 2021 deadline is an extension from the original DOE deadline as indicated in their memo : https://www.energy.gov/eere/buildings/downloads/doe-memo-extending-use-software-validated-against-resnet-001-2016:  DOE had previously approved the use of listed software validated against RESNET Publication 001-2016 in 45L tax credit certifications for homes with building permits dated on/before 12/31/2020. This memo extends the timeframe during which DOE-listed software validated against RESNET 001-2016 may be used for 45L certifications, to homes with building permits dated on/before 6/30/2021.

For homes permitted after July 1, 2021 going forward you must use EnergyGauge version 7.0.01 or later.  

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

A. No. DOE has mandated HVAC grading as part of the 45L compliance after June 30, 2021..

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 July 1, 2021. You can then import that file into version 7.0.01 (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 minimum HVAC grading values will I have to enter in EnergyGauge 7.0.01 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 Grade III.

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 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 II/III defaults” for Blower Fan Airflow and BlowerFan Watt Draw if you have no plans to test the systemSelect Proposed Grade III for refrigerant charge. BlowerFan Airflow and Blower Fan Watt Draw have a range of measured values to achieve Grade I and II. By selecting Grade I default you will be selecting the worst case Grade I value. By selecting Grade II/III default you will be selecting a value at the worst end of the Grade II range or best Grade III. Thus for proposed rating there is no difference between Grade II and III. Note, the ANSI/RESNET/ACCA 310-2020 procedure has only Grade I and Grade III for refrigerant charge.

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 for homes permitted prior to July 1, 2021 – 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.