How to Seal HVAC Ductwork

Sealing ductwork can be one of the most cost-effective remedies for increasing energy efficiency. Yet it must be done thoroughly. Leaky ductwork can increase your costs and make your home less comfortable. If your duct system isn't sealed properly, carbon monoxide and other toxic fumes can build up in the home, creating an unhealthy living space. Another problem can occur when fumes from household cleaners, solvents, paints, etc., are pulled into the home's return air system through poorly sealed joints. Once these dangerous fumes are drawn into the hvac duct system, they can be re-circulated throughout the home.

The best solution for ensuring a proper seal and energy efficiency is to apply mastic and tape to every joint in the ductwork. The first step is to make sure the joint is clean and has been wiped down. This will allow the mastic to adhere properly and create a tight seal. You then want to apply a generous portion of mastic to coat the entire duct surface over the joint. You can use a brush or trowel to spread the mastic on. Then work the mastic into the joint, pressing and spreading lightly to achieve an even coat. You should strive to achieve a 1" overlap beyond the joint.

Then apply a mesh tape to reinforce the mastic. It's critical to make sure the mesh being used is designed for the brand of mastic used, so don't forget that!

By making these simple improvements to your home's ductwork, you'll save energy from day one and improve the comfort in your home! If you'd like help with this, we'd be happy to offer an analysis and estimate for your home's energy needs.

Green Space Construction Co. is a general contractor and energy efficiency firm in St. Louis with a focus on green building and renovations, weatherization, energy efficiency improvements, as well as traditional building practices. Our core values are composed of eco-friendly building, superior craftsmanship, and dedication to excellent customer satisfaction. Visit our website at GreenSpaceConstruct.com.

Energy Efficiency Doesn't Have to be Expensive

When most people think about energy efficiency, they think about expensive window replacements or HVAC system upgrades. But the reality is that big improvements can be realized from smaller investments. Many homes can realize dramatic improvements in efficiency by focusing on sealing major air leaks, installing better insulation in the attic, and insulating pipes.

These improvements often require caulking, spray foam sealant, selective installation of rigid foam board insulation, weather stripping and attic insulation. The cost is often under $2,000 and can be recouped through energy savings in 5 to 10 years. And your home will be more comfortable on day one.

Upon close inspection, many homeowners find that they have been living in a very drafty home for years. Pipe and duct penetrations into the home and between unconditioned/conditioned spaces are a big culprit. Poorly sealed windows and doors, mailbox slots, attic access hatches, and other cracks/gaps are also typical areas where air infiltration occurs. Sealing these gaps is cost effective, and provides long term value.

Weatherstripping and ensuring that exterior door thresholds are properly functioning is also important. Poorly sealed exterior doors are a typical cause of leaky homes. Similarly, windows are often poorly sealed. We typically caulk and seal windows from the exterior, and sometimes from the interior to remedy this problem. There are also solutions to better insulate the window itself, including foam and rubber gasket products.

In addition to these cost-effective improvements, installing new insulation in attic spaces can have a dramatic impact. Depending on your home's needs, we will recommend a range of thicknesses to achieve desired results. We also take time to seal various air leaks in the attic, and recommend insulation covers for your attic access.

Performing these minimal improvements can be expected to save you at least several hundred dollars per year on your utility bills, and in many cases much more.

Green Space Construction Co. is a general contractor and energy efficiency firm in St. Louis with a focus on green building and renovations, weatherization, energy efficiency improvements, as well as traditional building practices. Our core values are composed of eco-friendly building, superior craftsmanship, and dedication to excellent customer satisfaction. Visit our website at GreenSpaceConstruct.com.

Labadie Weatherization and Insulation Project

Green Space Construction recently partnered with an energy auditor on a project in Labadie, Missouri. The homeowner was paying nearly $800 per month to heat their home in the coldest months of winter. After a blower door test was conducted, it was determined that the air leakage was equivalent to a 24x24" window being open all year. Thermal imaging revealed numerous areas throught the residence which had insufficient insulation and air leakage.

After the initial audit was conducted, Green Space performed the following improvements:

Attic:

Air sealing package

Insulated attic w/ blown cellulose at R-38

Dense-packed attic knee walls with blown cellulose

Custom fabricated truss insulation

Custom attic fan cover

Custom attic hatch

Removal of attic windows and install of gable vents, installed new siding.

Windows & Doors:

Interior & exterior window and door caulking package

New energy efficient exterior door at basement

Weather stripping package.

Basement foundation walls:

Removal of drywall at basement foundation walls

Insulated walls with rigid foam board insulation, insulated bandboards

Air sealed these locations, and installed new drywall.

Bathrooms:

New bath exhaust fans vented through roof.

Mechanical room:

Insulated bandboards at mechanical room and air sealing package

Denspacked exterior walls

Insulated hot and cold water heater lines.

Chimney Chase:

Insulated open chimney chase with fiberglass batts

Applied fireblocking.

Roofing:

Removed improper ridge vent and capped with new roofing.

Garage:

Insulated and sealed HVAC duct exposed to outside climate.

Exterior cantilevered windows:

Dense-packed cellulose insulation

Air sealed location.

For pictures of this project, please click here to visit the picture gallery.

Green Space Construction Co. is a general contractor and energy efficiency firm in St. Louis with a focus on green building and renovations, weatherization, energy efficiency improvements, as well as traditional building practices. Our core values are composed of eco-friendly building, superior craftsmanship, and dedication to excellent customer satisfaction. Visit our website at GreenSpaceConstruct.com.