Version Release Notes

Modified on Fri, 8 Nov at 9:33 AM

Below is a list of Ekotrope algorithm versions along with some highlights of the changes in each version. The list may not include every change in each version, but generally includes the changes that will have a significant impact. If you have specific questions about a certain version please Contact Support.

Please note that when new patches are released, which are indicated by the 3rd number (e.g. 2.2.0 --> 2.2.1), the versions that are eclipsed by those patches (in this case 2.2.0) will be removed from the list of available versions, except for projects that currently use that earlier version. Patches are meant to be minimally invasive.

Version 4.2.3

Released in Beta on November 6th, 2024.

Version 4.2.3 includes the following changes:

Fixes an issue with not mandating mechanical ventilation for all paths in IECC 2021 following an interpretation from the ICC
Updates the NGBS 2020 reference home lighting and appliances
Fixes an issue with renovation and additions (R&A) reference homes for DTE and Connecticut programs around the duct leakage
Fixes an issue with ENERGY STAR Multifamily New Construction High Performance Insulation check to avoid including fenestration in the UA calculation
Fixes an issue with HVAC Grading in ENERGY STAR Multifamily New Construction V1.2
DOE ZERH builder ID’s are now validated against being numeric
Fixes bugs in the DOE ZERH reference home for slabs and ceilings
Fixed an issue with Duke NC 2017 Reference home around slab calculations

Version 4.2.2

Released officially on March 13, 2024.

Version 4.2.2 includes the following changes:

Fixed a bug in IECC 2021 reference home in the calculation of fan efficacy for projects with multiple mechanical ventilation systems.
Fixed IECC Prescriptive Path Fenestration SHGC QA check to include skylights in the calculation.
Updated all supported ENERGY STAR programs to the latest revision of ERI Target procedures and checklists.
Disabled HVAC Grading impact to Duke HERO NC 2018 program.

Version 4.2.1

Released officially on January 19, 2024.

Released in Beta on November 29, 2023.

Version 4.2.1 includes the following changes:

Fixed some small bugs in DOE ZERH SF V2 and ENERGY STAR V3.2 Target Home generation that caused the target ERI score to increase for ZERH SF V2 above ENERGY STAR V3.2.
Fixed an issue in LEED Source Energy Budget analysis related to Total Duct Leakage and HVAC Grading.
Updated ENERGY STAR MFNC V1.2 as per Rev 4 (to account for updated ceiling U-factor in Climate Zone 3).
Updated mass wall U-factor for IECC 2012 to 2021 when at least half of the insulation is on the interior side of the wall.

Version 4.2.0

Released officially on October 13, 2023.

Released in Beta on June 7, 2023.

Updated on October 11, 2023.

Version 4.2.0 includes the following changes:

Uses an improved heat transfer algorithm for the calculation of slab and basement loads.
Updates fan airflow in proportion to the capacity of the HVAC equipment in HERS Rated home.
Updates the calculation of distribution system efficiency to split the distribution system leakage evenly between supply and return side to comply with ANSI/RESNET 301-2022 Addendum C.
Updates the calculation of effective duct insulation R-values to comply with ANSI/RESNET 301-2022 Addendum C.
Changes the glazing adjacent shading to 100% for all proposed and reference homes.
Updates the conversion factors used for SEER2/HSPF2 to comply with MINHERS Addendum 71f.
Updates the emission rates in the emissions calculation as proposed by the Carbon Index calculation in MINHERS Addendum 66f.
Removes skylights in all IECC based reference homes, following Table R405.4.2(1).
Updates the backup fuel type of Air Source Heat Pumps to be electric with efficiency 1 in ENERGY STAR V3 and V3.1 reference home builders in certain climate zones, according to the ERI target documents.
Fixes the calculation of conditioned space gains from shared water heaters.
Fixes a bug in updating shared water heaters to federal minimum efficiency.
Changes the equipment type of a Ground Source Heat Pump to a Residential Water Heater if reference homes specify different equipment specifications. This only corrects reports and does not have any impact on energy modeling.
Fixes a bug in R&A reference homes related to updating duct locations such that the supply and return duct area does not exceed 100%.
Updates ENERGY STAR MFNC 2019 reference homes to set window operability the same as in the rated home and fixes a bug related to the infiltration calculation.
Fixes a bug in the following reference homes related to the application of capacity fault factors and sizing of HVAC equipment:
- HERS Rated and Reference homes
- Tax Credit Reference home
- ENERGY STAR V3.2 and DOE ZERH SF V2 Target home
- IECC 2018 and 2021 ERI Rated and Reference homes
- New York and Georgia 2020 ERI Rated and Reference homes

Version 4.1.2

Released on August 31, 2023.

Version 4.1.2 includes the following changes:

Fixed a bug in ENERGY STAR v3.1, v3.2 and ENERGY STAR Multifamily v1.0, v1.1, and v1.2 that allowed use of on-site power generation to meet the ENERGY STAR ERI Target.

Version 4.1.1

Released on June 2, 2023.

Version 4.1.1 includes the following changes:

Added support for mass floors for the ENERGY STAR Multifamily programs (version 1.0 and 1.1 (2019)).
Updated ENERGY STAR version 3.2 reference home to apply 0.3 SHGC in climate zones 4-8 as requested by EPA.
Updated Insulation Grade check for ENERGY STAR version 3.2 to fail, if the envelope components are not modeled using the assembly calculator. In the prior versions, it is shown as a warning.
Fixed a bug related to recirculation water systems in ENERGY STAR Multifamily program versions 1.0 and 1.1 (2019).

Version 4.1.0

Released on January 26, 2023.

We have published this article which describes how Version 4.1.0 impacts results and why.

Version 4.1.0 includes the following changes:

Incorporates the new federal minimum efficiencies set for Air Conditioners and Air Source Heat Pumps which will be in effect on January 1, 2023.
Added support for DOE Zero Energy Ready Home (ZERH) National Program Requirements Revision 8 to include target home updates for HVAC grading and Lighting/Appliances. Also includes an update for the target home to match rim-joists specifications to the above-grade walls.
Improves duct load calculations to more accurately calculate default airflow for forced-air distribution systems.
More accurately calculate wet bulb temperature for the water heating tank environment.
Updates federal minimum efficiencies for boilers (units manufactured after January 15, 2021).
Fixes a bug related to UA value calculation for foundation walls without continuous insulation. This also includes updates to HERS (and some other HERS-dependent) reference homes to use foundation walls with continuous insulation.
Fixes a bug related to the calculation of gross COP (Coefficient of Performance) by updating fan efficiency estimation in test conditions.
Corrects how total hot water energy consumption is calculated for homes using pumps with recirculation systems.
Corrects mechanical ventilation efficacy for the IECC 2021 Performance Reference Home.
Corrects the IECC 2018 and 2021 ERI Reference homes so that the infiltration value matches the rate specified in ANSI/RESNET 301.
Corrects the cooling efficiency for shared chillers in ENERGY STAR Multifamily V1.0 and V1.1.

Version 4.0.2

Released on September 3, 2022.

Version 4.0.2 includes the following changes:

Updated Duke HERO 2018 reference home to use an updated value for the glazing fraction in townhomes.

Version 4.0.1

Released on September 10, 2021.

Version 4.0.1 includes the following changes:

Added support for the ANSI 301-2019 version of the ENERGY STAR MultiFamily program, mainly to better support multifamily buildings and shared equipment.
Fixes a bug in heat pumps using a switchover temperature not equal to 0. This change may affect energy results for projects using heat pumps with switchover temperatures not equal to 0. The vast majority of heat pumps in Ekotrope have switchover temperature of 0 F, and those results will remain unchanged. If you have any questions, please reach out to us at support@ekotrope.com.

Version 4.0.0

RESNET is currently requiring that HERS rated homes permitted on or after January 1, 2022 use at least Version 4.0.0.

Released officially on April 1, 2021.

Released in Beta on March 14, 2021.

This version includes updates to support ANSI/RESNET 301-2019 including Addenda A & B and MINHERS Interim addenda 53i & 55i.

We have published this article which describes how Version 4.0.0 impacts results and why.

Starting with Version 4.0.0 you will be able to use Ekotrope RATER to perform HERS ratings of units in multifamily buildings of any height.

These updates include:

Significant changes to Dishwashers, Clothes Washers and Dryers. If you want to have a fair comparison between 4.0 and previous versions, you must set the Clothes Dryer to the HERS Reference default value and the Clothes Washer to the HERS Reference or ENERGY STAR default value. Otherwise the Clothes Washer and Dryer will have differing results across versions.
Support for HVAC Grading in accordance with ANSI/RESNET/ACCA 310 and 301-2019 Addendum B.
Support for dehumidifiers.
More accurately incorporating humidity and latent loads into energy consumption calculations.
More accurately incorporating the internal gains associated with water heaters.
Improved modeling of heat pump water heaters based on the temperature and humidity of the area the water heater is located.
Updated the modeling of infiltration and ventilation in the HERS Rated and Reference homes in accordance with 301-2019. These changes are most significant in multifamily units.
No longer using Furnace EAE value to determine the electric auxiliary energy of the furnace. Auxiliary energy will now be calculated using either the wattage value measured by the Rater or a default efficiency specified by Std 301.
* Improves heat pump algorithm to determine efficiency hourly based on weather conditions, heat pump specifications, and hourly required heat output.
* Improves heating design load calculation.
* Improves heating and cooling equipment sizing in IECC reference homes.
* Updates 45L Federal Tax Credit reference home to use window calculations according to RESNET Pub. 001-16. This makes the Tax Credit slightly more difficult to meet for MF homes or homes with basements.
* Updates the Minnesota Rebate Program Reference Home to have R-8 on all ducts outside of conditioned space. This will reduce savings for homes with ducts in Attic, Under Insulation.

* = change introduced in Version 3.3.0

Version 3.3.0

Released in Beta on June 28, 2019.

Deprecated on April 26, 2020.

Version 3.3.0 is only available through the API, though Version 4.0.0 includes all changes in Version 3.3.0

Improves heat pump algorithm to determine efficiency hourly based on weather conditions, heat pump specifications, and hourly required heat output.
Improves heating design load calculation.
Improves heating and cooling equipment sizing in IECC reference homes.
Updates 45L Federal Tax Credit reference home to use window calculations according to RESNET Pub. 001-16. This makes the Tax Credit slightly more difficult to meet for MF homes or homes with basements.
Updates the Minnesota Rebate Program Reference Home to have R-8 on all ducts outside of conditioned space. This will reduce savings for homes with ducts in Attic, Under Insulation.

Version 3.2.4

Released officially on November 19, 2020

Released in Beta on September 23, 2020.

This version can be used for HERS rated homes permitted prior to January 1, 2022.

This version includes the following changes:

Updates 45L Federal Tax Credit to comply with RESNET Publication 001-16. This only impacts window areas of multifamily homes and homes with basements.
Fixes a bug where sometimes the Quick Results could show slightly different results than reports and exports.
Fixes MERC Minnesota reference home behavior for ducts under attic insulation.

Version 3.2.3

Released on December 12, 2019.

This version includes the following change:

Only impacts Duke Carolina applications: updates the glazing ratio of the Duke HERO reference home used for compliance to 20% from 15%.

Version 3.2.2

Released on August 15, 2019.

This version includes includes the following changes:

This fixes a bug that was introduced in Version 3.2.0 where mechanical ventilation energy was not being taken into consideration for 2018 IECC Compliance Report.

Version 3.2.1

Released on July 31, 2019.

This version includes includes the following algorithm changes:

Corrects the 2018 North Carolina Duke HERO reference home duct leakage.

Version 3.2.0

Released on July 17, 2019.

This version includes updates to support ANSI/RESNET 301 Addendum L duct leakage exemption logic.

This version also includes the following algorithm changes:

Adjusts hourly lighting & appliance and internal gains load profiles to be more accurate.
Minor adjustments to kWh unit conversion factor in reports.
Improve estimation of solar flux in design load calculation.
Correct minor bug in ASHRAE 152 duct system efficiency algorithm.
Improve roof area calculation in roof temperature algorithm.
Improve home initial starting temperature for first hour of annual simulation.
Support thermal breaks in slab on grade modeling.
Fix bug in Mississippi and Michigan federal minimum air conditioner SEER rating.
Update DOE ZER envelope requirements to check against IECC 2015 UA instead of IECC 2012 UA without fenestrations.
Update DOE ZER wall U factor based on DOE ZER February 2019 amendment.
Change ENERGY STAR 3 & 3.1 ventilation check from warning to failure.
Update Michigan and Illinois 2015 federal minimum equipment reference homes to use the most recent federal minimum equipment standards.
Update Duke program HERO reference homes to use rated home slab covering R value in the reference homes.
Fix bug with tankless water heaters in Austin energy code.
Update and improve cooling equipment logic in the Mass Save R&A reference home

Version 3.1.1

Released on December 22, 2018.

Note: this includes many changes that were on previously on version 3.2.0 from July to December 2018 and were ported over to 3.1.1.

This version includes the following algorithm changes:

Adjusts DOE ZER target home electric water heater efficiency to EF = 1.5 for multifamily dwellings according to November 2018 DOE ZER update.
Updates IECC ventilation efficacy warning to be a requirement.
Updates Reference Home for Duke HERO 2012 calculations to use the worse performance between 4 ACH50 and 0.24 SFSA, rather than always using 4 ACH50.
Updates IECC reference homes to use mass wall values when the home specifies a high mass wall.
Removes radiant barrier for ducting in the North Carolina 2012 Reference Home.

Version 3.1.0

Released July 1, 2018.

Approved for RENET registry submissions starting July 1, after which a 6 month transition period will be allowed. This version is identical to Version 3.0.0 except that it fixes a fairly significant bug dealing with the wall area of the IECC reference home used for compliance with the IECC Performance Path and other reference homes derived from IECC codes.

The affects of this bug fix will be to make IECC Performance Path compliance more difficult for most homes. It is not mandatory to update to this version until January 1, 2019, so please take the time to prepare accordingly.

Version 3.0.0

Released July 1, 2018.

Approved for RENET registry submissions starting July 1, after which a 6 month transition period will be allowed. This version and subsequent versions include the House Size Index Adjustment Factor from Addendum E and LED lighting support from Addendum G of RESNET/ANSI 301. It also includes a few other minor fixes:

Updates water usage calculation for DOE ZER home and ENERGY STAR reference home to use HERS Reference water usage.
Fixes bug where doors on adiabatic walls would get treated as exterior doors.
Changes ENERGY STAR reference home logic for ceilings to leave the location of the ceiling in the reference home the same as the rated home.
Add QA check for R6 duct insulation for ENERGY STAR.
Update window calculation for reference home of IECC 2015 performance path to include Footnote (h), which was left out in the original version of IECC 2015.
Update federal minimum equipment for IECC 2006 - 2015 w/ Federal Minimum Equipment reference home. 2018 and later iterations of the IECC use updated equipment even if the version is before 3.0.0. This update includes changing the Furnace EAE in the Reference home to match the Rated home rather than the HERS Reference defaults.
Update lighting CFL % in IECC 2006 - 2015 w/ Federal Minimum Equipment reference home to equal the mandatory lighting requirements. 2018 and later iterations of the IECC do this even if the version is before 3.0.0.
Fix infiltration zone for n factor calculation for Colorado to be Zone 4 instead of Zone 1.
Update MassSave reference home duct R value to use proper parallel path R value calculation.

Version 2.2.5

Released April 10, 2018. Only affects MassSave incentive results.

Updates MassSave water usage calculations to use RESNET water usage equations rather than IECC equations.

Version 2.2.4

Released February 6, 2018. Only affects North Carolina code compliance and MassSave incentive results.

Fixes a bug with interior window shading coefficients by setting them to 0.9 in the Proposed and Reference homes for North Carolina energy code.
Updates reference home electric water heater EF from 2.16 to 2.08 and reference home air source heat pump HSPF from 10.05 to 9.63.

Version 2.2.3

Released Jan 17, 2018. Small change to how the HERS reference home's mechanical ventilation system's watts are calculated when ACH Natural is selected. May increase HERS scores slightly for some houses only if ACH Natural is used.

Version 2.2.2

(Does not affect HERS score) Released Jan 5, 2018. The same as Version 2.2.1 with some updates for ENERGY STAR (see the list of updates below). When version 2.2.2 was added, we chose to remove Version 2.2.1 from the normally visible list of versions and switched users' preferred version from 2.2.1 to 2.2.2. This is our policy for minor version updates to reduce the number of options in the version list.

Eliminates Size Adjustment Factor for ENERGY STAR Version 3.1
Changes furnace AFUE from 90 to 80 for the ENERGY STAR v3.1 reference home in Climate Zone 3.
Changes tank size of water heaters for the ENERGY STAR target home when the rated home has a non-electric tankless water heater from 40g to 50g.

If you have questions about this or would like to switch a project back to version 2.2.1, please email us at support@ekotrope.com.

Version 2.2.1

(Does not affect HERS score) Released early November, 2017. The same as Version 2.2.0, except for some relatively minor changes (see below). When version 2.2.1 was added, we chose to remove Version 2.2.0 from the normally visible list of versions and switched users' preferred version from 2.2.0 to 2.2.1. This is our policy for minor version updates to reduce the number of options in the version list.

For the Massachusetts MassSave program, if the proposed house uses a ductless distribution system, the reference house will now use a ducted system with ducts in the attic, insulated to R-8 with the proper reference home leakage.
For homes in North Carolina, the air sealing of the NC Code Reference Home has changed to use North Carolina specific logic rather than IECC logic. This should generally make it easier for homes to pass code compared to v2.2.0.
For homes in climate zone 4, the North Carolina prescriptive SHGC has been corrected from N/A to 0.3.
For IECC 2009, if a tankless water heater is specified, the reference house will now get a tank water heater with current federal minimum efficiency.

If you have questions about this or would like to switch a project back to version 2.2.0, please email us at support@ekotrope.com.

Version 2.2.0

Released August 29, 2017. The same as Version 2.1.0, with the following changes:

Fixes bug with ENERGY STAR target home. These fixes will reduce target HERS scores making ENERGY STAR more difficult to meet.
- Fixes % high efficacy lighting for target home.
- Fixes distribution system efficiency for homes with multiple distribution systems.
- Remove radiant barrier from target home.
- Switches floor covering R value to 1.23 from 2.
- Floor area used in the size adjustment factor calculation now excludes conditioned basement area where at least half of the wall area is below grade.
Smooths anomaly for duct losses for low capacity heating and cooling equipment. Should reduce consumption for some homes.
Updates water heater tank loss temperature to use hourly indoor house temperature rather than 75F.
Uses a more accurate water heater energy consumption simulation.
Minor change to basement wall UA calculation for partially insulated walls.
Removes crawlspace walls from HERS and IECC reference home window calculations.
Removes radiant barrier from IECC reference homes. Also, minor correction to duct losses in attics with radiant barriers which will slightly reduce consumption in those cases.
Fixes a bug where Dishwasher EF was used for water consumption calculation even if Dishwasher kWh was inputted.
Uses a more accurate estimate of crawl-space buffer temperature. In general, this change will reduce energy consumption for houses with crawlspaces.
Improves heating and cooling fan and pump consumption so that they now depend on total heating/cooling load and equipment capacity.
IECC Specific Changes:
- Updates IECC reference mechanical equipment to be sized according to the design load
- Uses sq feet served per distribution system rather than total CFA to calculate duct leakage for IECC reference homes.
- If a proposed house has a non-storage water heater it will now get a storage water heater, the same as the reference house.
Include adiabatic area in shell area calculations. This affects load due to infiltration if Effective Leakage Area or ELA / 100 sq. ft. are used.
Excludes the ASHRAE 62.2-2013 infiltration credit for multi-family homes

Version 2.1.0

Released September 13, 2016. The same as Version 2.0.0, with the following changes:

Fix bug with HERS Index rounding. HERS Index scores are now rounded to the nearest whole number.
Update IECC cost compliance path to use EIA state-average energy prices from 2014 rather than user-entered utility rates.
Update combined infiltration and ventilation load algorithm to use ASHRAE HOF Ch. 16 Eq. 51.
Adjacent and overhang shading now also reduces diffuse solar gains using proper view-factor equations.

Version 2.0.0

Released June 1, 2016 (Note that RESNET allowed using earlier versions on new projects until Jan 1 2017). Update algorithm to comply with RESNET/ANSI 301 - 2014. Major changes include:

Significant changes to hot water calculations according to ANSI/RESNET 301 Addendum A. These changes include, but are not limited to, support for Low-flow fixtures, Drain Water Heat Recovery and Re-circulation systems. These changes can both increase or decrease HERS scores.
Reduced the reference home specific leakage area (used for infiltration calculation) from 0.00048 to 0.00036. This causes an increase in HERS scores across the board.
Updates to calculations of energy and water consumption for clothes washers.

Unrelated to ANSI:

Adjacent and overhang shading only reduces direct solar gains, not reflected or diffuse.

Version 1.9.0

Released September 13, 2016. The same as Version 1.8.0 with the following changes:

Fix bug with HERS Index rounding. HERS Index scores are now rounded to the nearest whole number.
Update IECC cost compliance path to use EIA state-average energy prices from 2014 rather than user-entered utility rates.
Update combined infiltration and ventilation load algorithm to use ASHRAE HOF Ch. 16 Eq. 51.
Fix HERS Reference Home SHGC for climate zones 4 - 8 to be 0.55
Adjacent and overhang shading only reduces direct solar gains, not reflected or diffuse.
Fixed bug where HERS Rated home was not being re-simulated if combined mechanical ventilation and infiltration was below minimum.

Version 1.8.0

Original Ekotrope release.