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A technician assembles the spray sealant injection system to seal HVAC ducts from the inside

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The duct sealing spray injection system application tunnel inflates as the injection system operates

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Exhaust terminates to the outside away from air inlets

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Building Science Introduction - Air Flow

Information Guide

Information guide describing the concept of air flow in residential buildings and its effects on occupants, building durability, and efficiency.

Wrong: The door and filter were removed, allowing unfiltered air to enter the air handler leading to premature failure of the system due to dirt accumulation.

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Compact Air Distribution

Guide

Guide describing design and installation of compact duct systems for central heating and cooling systems.

Non-hardening removable putty can be used to seal around wiring holes in the HVAC cabinet

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Right - Insulating sleeve for small through-the-wall HRV unit with sealing gasket; 3 of 14.

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Wrong - Metal tape is poorly adhered and metal duct and duct-to-subfloor seam is not sealed.

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Vented Attic vs Unvented Cathedral Attic Air Flow

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Duct boots sealed to floor, wall, or ceiling using caulk, foam, mastic tape, or mastic paste

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The duct sealing spray injection system includes a blower/heater (background) and the sealant injection unit (foreground)

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Seal seams in fiber board ducts with out-clinching staples, UL-181A-approved tape, and mastic

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SMACNA HVAC Air Duct Leakage Test Manual (first edition)

Reference

Manual that identifies certain leakage limits for ducts and outlines procedures for testing ducts for conformity with air leakage limits that are set forth in a designer’s project specification.

Proper Installation of Furnace and Air-Handler Filters

Guide

Guide describing proper sizing and installation of high-MERV furnace and air-handler filters.

Cold-Climate Air Source Heat Pump Install Guide: Part 13 - Odds and Ends

Video

Video describing air source heat pump installation; part 13 of 14 describes miscellaneous items including air sealing, pest protection, environmental protection, checking attachments and supports, labeling, and double-checking for missed items.

Emergency Air Conditioning and Food Refrigeration

Guide

Guide describing methods for providing space cooling and refrigeration during extreme heat events and/or power outages.

ECM Air Handler Fans

Guide

Guide describing the use of electronically commutated motors (ECMs) in HVAC central air handler fans to reduce power consumption compared to a single-stage fan motor.

Wrong - The seam around the duct boot where the duct boot enters the trunk duct has not been completely sealed with mesh tape and mastic.

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Building America Top Innovations 2014: HVAC Cabinet Air Leakage Test Method

Case Study

Case study describing a 2014 DOE Building America Top Innovation on development of a standardized testing method for testing the air leakage of HVAC air handlers and furnace cabinets developed by Lawrence Berkeley National Laboratory.

Ventilation air comes directly from outdoors, not from adjacent dwelling units, garages, crawlspaces, or attics

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The hole in the drywall was cut overly large for this heating register, allowing air to leak into or out of the wall cavities.

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This air register has noticeable gaps between it and the floor; use canned spray foam to fill in the gaps.

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Wrong: open wall cavity connected to this return air plenum is allowing cellulose attic insulation to be pulled into the furnace

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The dark streaks seen in this infrared camera image of a return vent in a ceiling indicate cooler air is leaking in around the vent.

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Wrong: This wall cavity is open to the attic allowing unconditioned, attic air to enter the HVAC system, bypassing the filter, and degrading system life and performance

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With the register grill removed, very large gaps are visible around the edges of this duct boot between the duct boot and the drywall; the gaps can be closed with screw or heavy staples then sealed with caulk, mastic, or metal tape.

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Wrong- A tie strap should not be used over the duct outer liner because it can compress the insulation. Tuck in the fibrous insulation and seal the outer liner to the connecting duct with mastic or foil tape (Steven Winter Associates 2013).

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ANSI/RESNET/ICC 380: Standard for Testing Airtightness of Building, Dwelling Unit, and Sleeping Unit Enclosures; Airtightness of Heating and Cooling Air Distribution Systems; and Airflow of Mechanical Ventilation Systems

Reference

This ANSI/RESNET/ICC standard provides a consistent, uniform methodology for evaluating the airtightness of building, dwelling unit, and sleeping unit enclosures and heating and cooling air distribution systems, and the air flows of mechanical ventilation systems.

Injected Spray Sealant for Existing HVAC Ducts

Guide

Guide describing how to thoroughly seal HVAC ducts to ensure air delivery without leakage, and to ensure economical and quiet performance of the HVAC system.