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Wrong – Cars should never be left running in a closed garage. Air seal walls, install a garage fan, and inform home owners of the dangers of running a vehicle with the garage door shut

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A dormer with an openable window (not shown) can provide access to the roof if flood waters rise too high and too quickly; the dormer should be properly insulated, flashed, and air sealed

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Right – Structural insulated sheathing can provide racking strength (lateral load resistance), and serve as an air barrier and thermal barrier if installed according to manufacturer’s specifications with taped, sealed seams

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Wrong – Where possible, design walls and specify window sizes and placement to minimize the use of studs around windows; and seal all wood-to-wood seams to minimize air leakage through walls.

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A sill gasket is installed under the two layers of fire-rated gypsum providing air sealing at the foundation slab in this 2-hour fire wall separating two units in a multifamily row house building

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The dark purple areas and long streaks in this IR camera image show extreme cold spots along the top of the walls, indicating a lack of both air sealing and insulation above the top plates of these walls.

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Form an insulation dam of heat-resistant insulation with at least 3 inches of clearance around a flue pipe in the attic after air sealing around the pipe with sheet metal and fire-rated caulk or canned foam

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If an intermittent ventilation duct is connected to an air handler, the damper should be shut and the intake vent should not be covered when performing a duct leakage test; if the ventilation will be continuous, the intake should be covered and sealed.

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Wrong - The IRC prohibits the use of flex duct for kitchen exhaust and only permits PVC duct for downdraft systems that meet specific exceptions; also, gaps at the ceiling have not been air sealed.

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Right- This flue pipe has been air sealed with sheet metal and fire-rated caulk and an insulation dam has been constructed to keep insulation from touching the hot flue pipe

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Right – Spray foam air seals and insulates the walls including the walls behind the fireplace and covers the underside of the roof deck of this mixed-dry climate home to provide an insulated attic space for HVAC ducts.

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A floor cavity between the first and second floor can provide a conditioned space for HVAC ducts if the rim joists are insulated and air sealed, if sufficient space is available, and if open-web floor joists are used

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A 5,000- 6,000 Btu/hr air conditioner drawing about 500 watts can be installed in one window of a designated cool room (it is important that the installation is insulated and well-sealed

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Right – This crawlspace window was completely sealed off on the inside and outside with air barrier and water-proof materials and the window well was filled in to an above-grade height to prevent bulk water from entering the crawlspace

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This rigid duct connection was repaired using self-piercing/self-drilling sheet metal screws to mechanically secure the connection; then it was air sealed using UL-181 fiber-reinforced duct sealant mastic paste

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Right - Reduce condensation risks to blanket insulation by installing perforated vapor retarder covered fiberglass blankets over rigid foam that is air-sealed at all edges; staple the blanket to nailers and top/bottom plates and tape over the seams.

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Create a cool room to shelter from extreme heat by selecting a room in the basement or on the north or shaded side of the house, air sealing and insulating, providing low-wattage and battery-operated cooling, and reducing interior heat loads.

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Plan view (from above) showing how the existing garage wall gypsum board is cut away to air-seal the shared wall before adding rigid foam insulation on the garage and exterior walls of the home.

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Side view of an exhaust fan duct installed through an exterior wall showing flashing and air sealing details (the yellow layers are rigid insulation that was installed over the home’s original sheathing before installing new siding).

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Right – The window header is filled with spray foam and sealant is used to air seal wood-to-wood seams; however, it would be preferable to design the wall to avoid so many stacked studs around the windows because they prevent wall insulation installation.

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Basic components of a gas tankless water heater include a high-powered burner, fan, and heat exchanger; condensing gas water heaters also have a secondary heat exchanger and a piped air intake to the sealed combustion chamber

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Wrong – This roof membrane on a low slope roof is fluttering and may fail because it is not fully adhered and deck seams below are not sealed, allowing air to leak up into the assembly while the membrane is pulled up due to negative pressures from wind

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Sealed Attics?

Reference

Article describing how insulating and air sealing unfinished attic spaces can lead to reduced energy bills in some homes.

Wrong - Hole in duct is not sealed and duct joint to subfloor is not sealed.

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Why Seal and Insulate?

Reference

Introductory guide to air sealing the envelope of a home to reduce wasted energy and save on energy costs.

In many homes, heating and cooling ducts are not properly sealed and insulated which can reduce utility bills up to 20%, cause uneven temperatures throughout the home, and provide a pathway for moisture, dust, pollen, and pests. Duct sealing and insulation is often one of the most cost-effective measures you can take to improve your home’s performance. However, critical installation best practices need to be followed to ensure a successful project. Use this checklist to get the significant energy savings, enhanced comfort, health, and durability benefits possible with quality installed duct sealing and insulation.

Wrong – Cars should never be left running in a closed garage. Air seal walls, install a garage fan, and inform home owners of the dangers of running a vehicle with the garage door shut

A dormer with an openable window (not shown) can provide access to the roof if flood waters rise too high and too quickly; the dormer should be properly insulated, flashed, and air sealed

Right – Structural insulated sheathing can provide racking strength (lateral load resistance), and serve as an air barrier and thermal barrier if installed according to manufacturer’s specifications with taped, sealed seams

Wrong – Where possible, design walls and specify window sizes and placement to minimize the use of studs around windows; and seal all wood-to-wood seams to minimize air leakage through walls.

A sill gasket is installed under the two layers of fire-rated gypsum providing air sealing at the foundation slab in this 2-hour fire wall separating two units in a multifamily row house building

The dark purple areas and long streaks in this IR camera image show extreme cold spots along the top of the walls, indicating a lack of both air sealing and insulation above the top plates of these walls.

Form an insulation dam of heat-resistant insulation with at least 3 inches of clearance around a flue pipe in the attic after air sealing around the pipe with sheet metal and fire-rated caulk or canned foam

If an intermittent ventilation duct is connected to an air handler, the damper should be shut and the intake vent should not be covered when performing a duct leakage test; if the ventilation will be continuous, the intake should be covered and sealed.

Wrong - The IRC prohibits the use of flex duct for kitchen exhaust and only permits PVC duct for downdraft systems that meet specific exceptions; also, gaps at the ceiling have not been air sealed.

Right- This flue pipe has been air sealed with sheet metal and fire-rated caulk and an insulation dam has been constructed to keep insulation from touching the hot flue pipe

Right – Spray foam air seals and insulates the walls including the walls behind the fireplace and covers the underside of the roof deck of this mixed-dry climate home to provide an insulated attic space for HVAC ducts.

A floor cavity between the first and second floor can provide a conditioned space for HVAC ducts if the rim joists are insulated and air sealed, if sufficient space is available, and if open-web floor joists are used

A 5,000- 6,000 Btu/hr air conditioner drawing about 500 watts can be installed in one window of a designated cool room (it is important that the installation is insulated and well-sealed

Right – This crawlspace window was completely sealed off on the inside and outside with air barrier and water-proof materials and the window well was filled in to an above-grade height to prevent bulk water from entering the crawlspace

This rigid duct connection was repaired using self-piercing/self-drilling sheet metal screws to mechanically secure the connection; then it was air sealed using UL-181 fiber-reinforced duct sealant mastic paste

Right - Reduce condensation risks to blanket insulation by installing perforated vapor retarder covered fiberglass blankets over rigid foam that is air-sealed at all edges; staple the blanket to nailers and top/bottom plates and tape over the seams.

Create a cool room to shelter from extreme heat by selecting a room in the basement or on the north or shaded side of the house, air sealing and insulating, providing low-wattage and battery-operated cooling, and reducing interior heat loads.

Plan view (from above) showing how the existing garage wall gypsum board is cut away to air-seal the shared wall before adding rigid foam insulation on the garage and exterior walls of the home.

Side view of an exhaust fan duct installed through an exterior wall showing flashing and air sealing details (the yellow layers are rigid insulation that was installed over the home’s original sheathing before installing new siding).

Right – The window header is filled with spray foam and sealant is used to air seal wood-to-wood seams; however, it would be preferable to design the wall to avoid so many stacked studs around the windows because they prevent wall insulation installation.

Basic components of a gas tankless water heater include a high-powered burner, fan, and heat exchanger; condensing gas water heaters also have a secondary heat exchanger and a piped air intake to the sealed combustion chamber

Wrong – This roof membrane on a low slope roof is fluttering and may fail because it is not fully adhered and deck seams below are not sealed, allowing air to leak up into the assembly while the membrane is pulled up due to negative pressures from wind

Sealed Attics?

Wrong - Hole in duct is not sealed and duct joint to subfloor is not sealed.

Why Seal and Insulate?

Duct Sealing and Insulation

Sealed and Insulated Flex Ducts

Window not caulked or sealed

Connection in place but not sealed

Mechanically fastened and sealed