Field testing and certification for the 45L federal energy-efficient home tax credit — blower door, duct leakage, refrigerant charge, and HVAC efficiency, with the certified report that satisfies IRS and program requirements.
Section 45L of the Internal Revenue Code provides a tax credit of up to $5,000 per qualified energy-efficient new home. To claim the credit, the home must meet specific energy-saving thresholds and be certified by a qualified third party using RESNET-approved software and field testing procedures. The deliverable of record is a certified report — not a model, not a worksheet — that documents the field tests, the HERS Index, and the certification of record.
HECS delivers 45L documentation as an integrated engagement: pre-construction energy modeling, on-site field testing at final, and the certified report that satisfies IRS requirements and the energy-rating software of record (REM/Rate, Ekotrope, or TREAT). We work with builders, developers, and tax credit aggregators across the region — producing reports that pass the IRS review and that close out the credit on schedule.
45L applies to new construction of single-family, multifamily (4 stories or fewer above grade), and manufactured homes that meet the qualified energy savings threshold. For multifamily, the test is run on each unit or on a sampling per RESNET 380. HECS staffs both single-unit and multifamily 45L projects with calibrated instruments, RESNET-accredited raters, and the same NCI-formatted reporting.
HECS delivers three engagement scopes depending on the project type, the unit count, and whether the credit is bundled with another certification program (ENERGY STAR, NGBS, EarthCraft). All three produce a certified report that satisfies 45L.
One unit, one report
Single-family or manufactured home, one RESNET-accredited rater on site, one certified report.
Best for: Single-family, manufactured, custom homes
Per RESNET 380
Multifamily project with sampling per RESNET 380, qualified energy savings threshold, and ENERGY STAR MFNC or NGBS cross-certification.
Best for: Multifamily, LIHTC, HUD, USDA
ENERGY STAR, NGBS, or EarthCraft
45L field testing bundled with another certification program — one schedule, one report set, one team.
Best for: Developers pursuing 45L + program certification
From pre-construction modeling to the certified report that satisfies the IRS, here is what HECS delivers on a 45L engagement.
HECS reviews the architectural plans, the mechanical equipment schedule, and the target energy model. We work with the design team to right-size the energy model, identify the most cost-effective efficiency measures, and confirm that the design will clear the 45L qualified energy savings threshold before construction commits to the spec.
HECS conducts on-site inspection at pre-drywall (insulation, air-sealing, duct rough-in) to verify the energy model assumptions match the as-built conditions. We document any deviations and recommend corrective action if the threshold is at risk.
At final, HECS runs the certified field tests: blower door, duct leakage, refrigerant charge verification (where applicable), and the inspection of the as-built HVAC system. Every test is run with calibrated instruments, with current calibration certificates, and the test results feed the HERS Index of record.
HECS issues the certified 45L report: the energy model, the HERS Index, the qualified energy savings percentage, the field test results, the instrument calibration, the rater signature, and the certification of record. The report is the deliverable the builder or tax credit aggregator files with the IRS.
Every HECS 45L report includes the following calibrated measurements, formatted to the IRS and the program of record.
Calibrated blower door test at 50 pascals. CFM50, ACH50, and ELA reported per ASTM E779 or RESNET 380. Required for the building-envelope tightness credit.
DuctTester measures total duct leakage to outside at 25 Pa per RESNET 380. Required for the duct-leakage credit.
On installed AC and heat pump systems, HECS verifies the as-found charge against the manufacturer submittal. Required for the HVAC-efficiency credit on most 45L projects.
Equipment efficiency (SEER, EER, HSPF, AFUE) verified against the energy model and the manufacturer submittal. Required for the equipment-efficiency credit.
Pre-drywall inspection of insulation, air-sealing, window U-factor, and envelope continuity. Required for the building-envelope credit.
Energy-rating software of record (REM/Rate, Ekotrope, or TREAT) produces the HERS Index. Required for the qualified energy savings threshold calculation.
A certified 45L report is the deliverable that releases the federal tax credit, satisfies the IRS review, and transfers performance risk from the builder to a qualified third party.
The 45L credit is up to $5,000 per qualified unit. The certified report is the deliverable the IRS requires to release the credit — without it, the credit cannot be claimed. HECS reports are accepted by all major tax credit aggregators and pass IRS review on the first submission.
On LIHTC, HUD, and USDA multifamily projects, the 45L credit can be stacked with the program certification (ENERGY STAR MFNC, NGBS Green, EarthCraft). HECS delivers both as a single integrated engagement — one schedule, one team, one set of reports.
The 45L program was updated for 2025 with new qualified energy savings thresholds, new equipment requirements, and updated HERS Index targets. HECS stays current on every program update and flags changes that affect the credit value, the threshold, or the documentation requirement.
Field-measured performance that matches the engineer’s design intent — verified, documented, and accepted by the certification program of record.
An unverified system runs hot, cold, or short-cycled, wasting 15–30% of energy. HECS verification catches the under-performing dampers, mis-set thermostats, and oversized fans that drive energy waste.
A certified third-party report transfers performance risk from the builder to a qualified third party. It is the deliverable that releases the credit, satisfies the IRS, and closes out the engagement.
HECS is an NCI-certified testing and balancing firm. We work with general contractors, mechanical contractors, property developers, and certification programs across the region — delivering field measurements, certified reports, and the documentation owners and inspectors actually need.
Every HECS field technician holds current NCI certification. We use calibrated instruments, follow NCI-formatted reporting, and produce the documentation that commissioning authorities, code inspectors, and certification programs accept on the first review.
HECS serves commercial, multifamily, institutional, and light-industrial projects across Kentucky, Indiana, Ohio, Tennessee, Illinois, and Missouri. We staff jobs of every size — from a single building balance to a 12-building multifamily rollout — with the same team and the same reporting standard.
Blower door, duct leakage, refrigerant charge, combustion analysis, decibel, infrared, TAB, and 45L documentation — HECS delivers all of them. One contract, one schedule, one set of reports that line up with each other and with the certification program of record.
HECS 45L documentation is the right fit for:
Tell us about the project — program, scope, schedule — and we will respond with a written proposal inside two business days.
Section 45L of the Internal Revenue Code provides a tax credit of up to $5,000 per qualified energy-efficient new home. The home must meet specific energy-saving thresholds and be certified by a qualified third party using RESNET-approved procedures. The credit applies to single-family, multifamily (4 stories or fewer), and manufactured homes.
The 45L credit is up to $5,000 per qualified unit. The exact credit value depends on the qualified energy savings percentage and the HERS Index relative to the 2006 IECC baseline. HECS provides a project-specific credit estimate with the proposal.
45L requires blower door testing, duct leakage testing, refrigerant charge verification (where applicable), and HVAC efficiency verification. The tests are run at final, and the results feed the HERS Index of record. For multifamily sampling, the test is run per RESNET 380 on a defined sample of units.
45L must be certified by a RESNET-accredited Home Energy Rater using RESNET-approved energy-rating software (REM/Rate, Ekotrope, or TREAT). HECS is a RESNET-accredited HERS Rater. We staff the field testing, the energy modeling, and the certified report on every 45L engagement.
Yes. 45L applies to multifamily new construction of 4 stories or fewer above grade. For projects above 4 stories, the energy-efficient commercial building deduction (§179D) may apply instead. HECS delivers both 45L and 179D — we can advise on the right credit for the project.
Yes. 45L can be bundled with ENERGY STAR Multifamily New Construction, NGBS Green, EarthCraft, or LEED. HECS delivers 45L + program certification as a single integrated engagement — one schedule, one team, one set of reports that line up with each other.
The qualified energy savings threshold is the minimum percentage of energy savings above the 2006 IECC baseline that a home must achieve to qualify for 45L. The 2025 program update revised the threshold — HECS stays current on every program update and flags changes that affect the credit value or the documentation requirement.
Most single-family 45L engagements take one field test day plus two weeks for the certified report. Multifamily 45L projects run longer — HECS provides a project-specific schedule with the proposal.
The RESNET-accredited rater runs the field tests, operates the energy-rating software, signs the certified report, and is the qualified third party of record. HECS raters carry current RESNET accreditation and current calibration certificates on every instrument.
Call (859) 983-7382 or email hecs@hecsusa.com with the project name, address, unit count, program of record, and the target credit. HECS responds with a written proposal inside two business days.
NCI-certified TAB that verifies design airflow and water flow at every terminal. Calibrated instruments, certified report.
Whole-building and duct leakage to RESNET, ENERGY STAR Multifamily, NGBS, and code. Blower door + duct tester.
Field verification, sampling, and documentation for ENERGY STAR MFNC. HECS is an ENERGY STAR MFNC verification partner.
Tell us about the project — program, scope, schedule — and we will respond with a written proposal inside two business days.
Free consultation, fast turnaround, and audit-ready reports. Same-day callback during business hours.
Pick a time that works for you. We'll confirm within an hour during business hours. Free consultation, no obligation.