Technical Bulletins

Tips and guides for getting the most out of the Dominion Energy RNC Program

2025 Program Updates

We are excited to announce some major changes coming to the Dominion Residential New Construction Energy Star Program. The program has been approved by the Virginia State Corporation Commission to continue through 2029. The incentive structure will be changing in order to give our builders larger rebates for their homes. The requirement for the rebated will also be increasing from Energy Star 3.0 to an amended Energy Star 3.1. These changes will start January 1st, 2025, and we will no longer be accepting applications for the old program after that point. This Technical Bulletin will outline the changes in incentives and the changes in the Energy Star requirements.

Posted December 2025

Ductless Mini Split Systems

Ductless mini-split systems offer an effective, energy-efficient solution for heating and cooling in new homes. A ductless mini-split system is a heating and cooling system that consists of an outdoor unit connected to one or more indoor units without the need for ductwork. They are commonly used in residential settings to condition areas that are too small for ducted HVAC systems such as additions or lofts. This bulletin provides an overview of ductless mini-split systems, their benefits, and best practices for installation in compliance with Energy Star guidelines and Dominion RNC program standards.

Posted November 2024

Attic Access Insulation

When insulating an attic, the opening for access whether it be a hatch or drop-down ladder, can be a major weak point and source of leakage between the attic and the conditioned living space. It’s important that the insulation be uniform across the entire surface of that attic as areas with lower insulation R-Value areas allowing for greater heat transfer. The attic access is often the most overlooked area of the attic when it comes to complete insulation. The Energy Star National Rater Field Checklist outlines attic access as follows. Item 4.9 - Doors adjacent to unconditioned space (e.g., attics, garages, basements) or ambient conditions made substantially air-tight with weatherstripping, or equivalent gasket. Item 4.10 - Attic access panels, drop-down stairs, & whole-house fans equipped with a durable ≥ R-10 cover 1 that is gasketed (i.e., not caulked). Fan covers either installed on house side or mechanically operated.  This technical bulletin will outline the correct ways to properly insulate the attic access to keep with Energy Star standards.

Posted October 2024

Basements and Crawlspaces

In the Dominion RNC Program, correctly modeling basements, crawlspaces, or slab foundations is important to properly assess savings. If these zones are incorrectly modeled, it may cause a conditioned basement to be excluded from the model or an unconditioned basement to count against the total savings. An error in modeling could even cause a house to fail to pass the requirements for a rebate. According to ANSI/RESNET/ICC 380-2016, raters should model a basement by first determining the thermal boundary, identifying where the basement is sealed, and checking if the HVAC design includes the space. When modeling a crawlspace, it is essential to determine whether it should be considered conditioned or unconditioned space. First, identify the thermal and air barriers. If the two barriers are in the frame floor over the crawl, assume the crawl is unconditioned. However, if these two barriers are in the crawlspace walls and floor, model the crawlspace as conditioned. This technical bulletin will cover the modeling of basements and crawlspaces.

Posted September 2024

Insulation Grading Revisited

Grade 1 insulation around the whole house is a requirement for this RNC program as well as Energy Star 3.0 and beyond. During QC inspections the simplest insulation issue we come across are problems with the insulation not being Grade 1. The most common insulating errors are due to compression of the insulation by pipes, wires, and cabinet blocking. This causes the insulation to not be able to make full contact with the wall leading to lower R-values and hot/cold spots where the compression occurs. Many of these compression points can be easily and quickly fixed by cutting the insulation around the obstruction. It is important for builders and raters to notice these issues to educate and inform their insulators. This technical bulletin will demonstrate proper grade 1 insulation and highlight common problem areas to look out for when inspecting insulation.

Posted August 2024

Rim Joist Air Sealing and Insulation

Complete air sealing and insulation of a house’s rim joists is an important step in controlling the air infiltration and comfort of the home. Due to the natural whole-house convective loop, during the heating season, cold air can easily infiltrate the home through a poorly sealed rim joist. This process is reversed during the cooling season when conditioned air leaks out through the rim joist bringing in humidity and condensation. In an average two-story home, the rim joists are located above the basement wall and above the first-floor wall. Both these areas need to be completely air-sealed and insulated to the same level as the above-grade walls. This technical bulletin will outline the most important areas to air seal on the rim joist and give recommendations on the correct ways to insulate.

Posted July 2024

Blower Door Testing Guide

As part of the Dominion RNC Program, houses are required to pass the blower door test at a rate of 5 ACH or lower. During QC inspections we occasionally see small mistakes made during testing that can have small but measurable effects especially if the house is on the edge of failing. Raters should understand the best practices when testing whole home infiltration. It’s important for all participants in the program to follow similar protocol to produce accurate and replicable testing results. This technical bulletin covers basic preparation for blower door testing, manometer configurations, and air leakage calculations.

Posted June 2024

Properly Sealing Tray Ceilings

During field QC inspections we often find that, due to their odd angles and difficulty of sealing, tray ceilings are a commonly overlooked area and lack consistent grade 1 insulation and air sealing. Tray ceilings are typically located in the master bedrooms and require complex framing with unusual connections that can be hard to reach with a foam gun. Improperly sealed tray ceilings can cause unconditioned attic air to enter the building envelope, increasing infiltration. It can also cause the insulation to quickly reduce in quality due to unconditioned air mixing with and filtering through the insulation. The Dominion RNC program requires grade 1 insulation and an ACH of 5 or lower to be eligible for the rebate. This Technical bulletin will show commonly encountered sealing issues and give guidance on how to properly air seal tray ceilings.

Posted May 2024

Heat Pump Water Heater

Water heaters are on average the second highest energy-consuming appliances in a home.  The average household spends $500 a year on water heating with a standard electric water heater. As new rebate opportunities become available like the Inflation Reduction Act’s 45L tax credit, a heat pump water heater can be a smart choice for builders to install. It is an easy and relatively inexpensive way to lower the HERS score on a house and provide comfort and savings for the customer.

Posted April 2024

Spray Foam Safety and Inspections

Spray polyurethane foam (SPF) is starting to be used more often in the residential construction industry for its ability to provide high R-value insulation, a water barrier, a vapor barrier, and an air barrier in a relatively easy to apply treatment. However, during application and curing time, SPF can be hazardous to health and raters should be aware of potential hazards and careful when collecting data on SPF. All safety recommendations should default to RESNET standards and guidance. It’s also important for raters to properly inspect the installation to see if it’s properly cured and set.  In this bulletin, we will cover safety considerations, how to measure the depth of foam insulation, calculate the approximate R-value, and what to look for when inspecting the quality of installation.

Posted March 2024

Attic Insulation

Properly installed attic insulation is an important part of completing the building envelope. Various aspects of attic insulation affect the home’s energy modeling and performance. Insulation, roof decks, and baffling should be noted and inspected by raters for the type and quality of the installation. This technical bulletin will help raters identify insulation issues that can affect the rebate and serve as a guide for modeling of attics in Ekotrope.

Posted February 2024

Attic Air Sealing

Improperly sealed top plates and bathroom fans that open into attics are often a major source of leakage in any house and are the main cause of a house failing to pass the blower door test. Due to the stack effect, most leakage leaves through the attic. This makes the attic a pivotal place for complete sealing to diminish the stack effect and increase comfort in the home. In the technical bulletin for December 2023, we covered how to properly seal top plates during rough-in. If these techniques fail to achieve the desired effect and there is still leakage, there are options for sealing the top plate during the final. This technical bulletin will cover proper methods of installation for top plate and bathroom fan sealing and what raters should look for when inspecting the attics.

Posted January 2024

Rough-in Top Plate Air Sealing

Proper sealing of top plates leading into unconditioned spaces is essential for a well-sealed house that meets the requirements for Energy Star 3.0. Many houses that fail to pass the blower door test have the greatest amount of leakage coming from unsealed or poorly sealed top plates. There are two main techniques to seal top plates during rough-in, sill seal with framing tape or using a foam bead as a gasket. Each technique comes with its own installation difficulties. This technical bulletin covers some frequently overlooked items that raters should check when inspecting top plate gasket installation.

Posted December 2023

Dominion Meter Numbers

When submitting applications to the Dominion Residential New Construction Program, providing a correct electric meter number and a photo of the meter are crucial to provide speedy processing of the application.  The way that the Dominion system matches applications to the builder is by matching the meter number provided to the meter number in the system. Even a single mistyped digit can stall an application in the processing chain for days to weeks, slowing down the rebate. If an application is stalled, we will reach out to the rater to confirm the meter number and ask them to provide photos of the meter to check the number. This is why it’s so important to get a good photo of the meter so that in the case of a stuck application, the meter number can be confirmed, and the rebate can be paid.

Posted November 2023

Slab Insulation

Slab insulation is an often overlooked but essential part of a complete thermal boundary on any new construction home. The Nation Rater Field Checklist section 3.2 requires that all homes in climate zone 4 (Virginia’s climate zone) have “100% of slab edge insulated to ≥ R-5 at the depth specified by the 2009 IECC and aligned with the thermal boundary of the walls.”  The 2009 IECC depth requirements are 12 inches below grade for single-family homes and 24 inches below grade for multi-family homes. These requirements need to be documented by the builder as the rater will be unable to verify proper slab insulation at the time of the rough inspection. This technical bulletin will outline the most common ways to insulate slabs and common issues that occur with each method of insulation.

Posted October 2023

Garage Air Sealing

Proper garage air sealing is a crucial aspect of maintaining energy efficiency, indoor air quality, and overall comfort in residential homes.  During QA inspections, attached garages have been a major source of excess air leakage while doing the blower door tests. If builders are struggling to get their houses testing under 5 ACH or they’re pushing for under 3 ACH, proper garage air sealing is a top priority.  Garages can also be a major source of volatile organic compounds or VOCs entering the living space.  VOCs like carbon monoxide and benzene are common byproducts of incomplete combustion from car engines and can enter the house through unsealed or improperly sealed openings. Unsealed garages can lead to higher blower door test numbers, energy loss, increased utility bills, and the infiltration of VOCs and allergens

Posted September 2023

Radiant Barriers

Attic radiant barriers are an essential component of energy-efficient building systems that help mitigate heat transfer through the roof of homes. The three types of heat transfer are convection, conduction, and/or radiation. In the attic, insulation will mostly stop conductive heat flows and sealing top plates and other gaps will slow convective heat flows.  A properly installed radiant barrier will greatly reduce heat transfer through radiation.  Radiation is the primary source of heat transfer in an attic and can reduce the overall energy efficiency of a home. Radiant barriers work most effectively in hot and sunny climates where heat gain from the sun can significantly impact indoor temperatures. The barriers consist of a highly reflective material, such as aluminum foil, which reflects radiant heat rather than absorbing it. This results in a cooler attic and reduces the load on air conditioning systems, thereby enhancing energy efficiency.

Posted August 2023

Benefits of Polyurethane Spray Foam

Spray polyurethane foam (SPF) is one of the most effective materials used to seal and insulate walls. It offers numerous benefits in terms of energy efficiency, an improvement in the comfort of the home, and building durability. The two most common types of SPF are Open Cell and Closed Cell. Each type has its own advantages and disadvantages. Choosing to upgrade your insulation to SPF can be an important choice in building better more energy efficient homes. This technical bulletin seeks to help guide homebuilders and contractors in understanding the benefits of open and closed cell SPF.

Posted July 2023

The Six Sided Wall

A common issue we come across during QC inspections is insulation not following the method of the six-sided wall. By ensuring that the insulation goes from floor to ceiling, stud to stud, and is covered with an exterior sheathing and interior barrier the insulation will work at its highest efficiency. Air sealing, insulation, and fully aligned air barriers comprise the majority of the Rater Field Checklist’s items, and following this method of insulating helps to ensure these items are easily met. Pre-drywall inspections are the best time to catch and fix issues with the insulation, understanding the concept of the six-sided wall will help in identifying issues.

Posted June 2023

Insulating Advanced Framing

Advanced framing methods optimize lumber usage without compromising structural integrity. These techniques allow for maximum insulation in the wall area, which results in a reduction of thermal bridging. The ENERGY STAR Rater Field Checklist Item 3, Reduced Thermal Bridging, lists the framing requirements under 3.4.3. This technical bulletin outlines some best practice examples along with some examples to avoid.

Posted May 2023

Diagnosing Blower Door Problems

One of the main requirements for Energy Star 3.0 and the Dominion RNC rebate program is a blower door test result at or below 5.0 ACH50. For builders, preparing each lot to pass the blower door test can help to avoid costly fixes after the house is completed.  For raters, being able to assist the builder in fixing these issues when the test fails is an important part of the job. This month’s technical bulletin will give guidance on diagnosing blower door problems when the test results are over 5.0 ACH50.

Posted April 2023

2 over 2 condo Air Sealing

The small units of a 2 over 2 style condo blocks can be difficult for builders to properly air seal, leading to homes that fail the rater’s inspection and need to be fixed before they can qualify for rebates.  When conducting field QCs this style of home, we are seeing a higher percentage of air infiltration failures at final inspection than other type of house. It is far cheaper to take a few extra steps in sealing the house during the rough phase than to fix these problems once the house is completed

Posted March 2023

Ekotrope Data Entry

As part of the RNC Program, raters should model homes as accurately as possible. Small things are often overlooked and can compound to large losses in savings over time. This technical bulletin will cover how to accurately model slabs, floors, rim joists, and walls. 

Posted February 2023

Townhome End Unit Air Sealing & Insulation

Townhomes, especially end units, can struggle to reach current requirements of five air changes per hour (ACH) for VA code and ENERGY STAR v3.0 if the thermal and pressure boundaries are not treated correctly. It is important for raters and homebuilders to understand and inspect for these conditions to ensure they are addressed correctly as described within this bulletin.

Posted January 2023

New SEER 2 Efficiency Standards

Beginning January 1, 2023, the DOE is updating air conditioner and heat pump minimum efficiency standards. Within this technical bulletin, the Dominion Energy RNC Program is reminding our builders and raters of this upcoming change and what to expect when purchasing new HVAC equipment for new residential construction.

Posted December 2022

Whole-House Mechanical Ventilation Strategies

Whole-house mechanical ventilation is defined as an exhaust system, supply system, or combination thereof designed to mechanically exchange indoor air with outdoor air (either continuously or intermittently) to satisfy whole-house ventilation needs. This bulletin provides four commonly used whole-house mechanical ventilation strategies focusing on the respective benefits and potential drawbacks for each application.

Posted November 2022

Air Sealing - Thermo-Ply Installation

Proper air barrier installation is vital when building a tight home. Homebuilders can use many different air barriers, but a popular material choice in the Virginia ENERGY STAR New Homes Program is Thermo-Ply, also known as T-ply. This technical bulletin will cover instructions for T-ply installation based on the manufacturer’s specifications.

Posted October 2022

Duct Sealing

While duct installation and sealing methods have dramatically improved in recent years, it is not uncommon to have initial duct leakage tests fail due to a variety of reasons. This technical bulletin will provide reminders as well as discuss tips for resolving common problems that may occur while testing duct systems.

Posted September 2022

Townhome Air Sealing

Townhome air sealing is one of the top items found untreated in the Dominion Energy RNC Program. Gaps along core walls in a typical townhome can add up to 250-300 linear feet of cracks, which can account for as much as a 2-4’ hole. This technical bulletin will focus on tips for air sealing townhome core walls.

Posted August 2022

Laundry Room Air Sealing

The laundry room in homes is often overlooked, but it is a common source of air leakage. While it isn’t always the cause for failure, ensuring the home is completely air sealed is the best way to achieve positive blower door results. In this technical bulletin, we will cover tips for sealing laundry rooms and double walls at the pre-drywall and final stages.

Posted July 2022

Top and Bottom Plate Sealing

Preventing air infiltration is integral to residential ENERGY STAR® construction practices that promote lasting and positive impacts on energy savings, operating costs, comfort, and building durability. This technical bulletin will cover areas of top and bottom plates seen in the field that have been found to be either overlooked or incorrectly treated during the air sealing efforts of residential construction.

Posted June 2022

Blower Door Testing Reminders

Blower door testing is key in allowing for a homeowner to avoid increased energy consumption, comfort issues, low indoor air quality, and moisture concerns. This Technical Bulletin will list several tips and reminders while conducting a blower door test for a home.

Posted April 2022

Cutting Insulation to Fit Obstructions

To ensure batt insulation achieves its maximum performance, installers need to avoid the unnecessary compression of batts when installed in exterior wall cavities. This Technical Bulletin will show proper and improper examples found during field inspections.

Posted April 2022

Common Walls

Common walls in attached homes such as townhomes, duplexes, and two-on-two condos are areas of preventable air infiltration between adjacent units. This Technical Bulletin will show examples of proper and improper air sealing techniques found in the field.

Posted February 2022

Duct Testing

Testing a new home’s duct system during pre-drywall and post-construction phases is essential for a home’s energy efficiency and the homeowner’s comfort. This Technical Bulletin will go over requirements that must be met while conducting a duct blaster test.

Posted January 2022

Key Reminders While Submitting a Home in Ekotrope

Ensuring the data from a Rater's home analysis is inputted to the correct corresponding fields in Ekotrope is a crucial step while submitting a project. This Technical Bulletin will go over some commonly seen issues when entering data and submitting a home in Ekotrope.

Posted December 2021

Commonly Overlooked Inspection Items

While a Rater is conducting an inspection for an ENERGY STAR home, here are a few things to keep in mind to look for that can be commonly overlooked and for better practices.

Posted November 2021

Attic Knee Walls

Attic knee walls are areas in a home that can be commonly overlooked for the correct application of air barriers and insulation which help decrease air infiltration during blower door testing and comfort issues for the homeowner. This Technical Bulletin explains better practices for applying air barriers and insulation at a knee-wall.

Posted October 2021

Air Sealing

Air Sealing throughout a home is a critical step during the new home building process to help meet the stringent ENERGY STAR air infiltration requirements during blower door testing. This Technical Bulletin will further show examples of good air sealing techniques during new home construction.

Posted September 2021

Insulation Grading

ENERGY STAR Version 3.0 requires that all homes must meet Grade I insulation during inspection and for all homes participating in the Dominion Energy Residential New Construction program must meet this condition as well. This Technical Bulletin further explains how to achieve Grade I insulation during construction.

Posted August 2021

Air Barriers

Properly installed and aligned air barriers contribute to the overall durability, indoor air quality, reduction of heating and cooling loads, and preventing comfort issues for homeowners. This technical bulletin will provide photo documentation examples of proper and improper installation of air barriers commonly seen during field quality assurance checks.

Posted July 2021

Ekotrope Meter ID Photo Upload

This technical bulletin shows how a Rater can utilize Ekotrope’s Site Photo section to upload an image of a home’s Electric Meter ID. This will reduce any delays on incentive payments due to an incorrect Meter ID submitted.

Posted June 2021

Dominion Energy RNC Electric Meter ID

Using the correct Electric Meter ID is essential when when submitting homes for rebate in Ekotrope. This technical bulletin is a guide to help identify an individual home’s unique electric meter ID.

Posted May 2021