Over 25% of your A/C’s cool air is lost through leaky ducts. Seal and insulate your ducts to save money on your energy bill.

Ducting and Insulation

The average home ducting system has a leakage rate of 28%. Leaks in ducting may be as small as pin holes, or they can be large gaps between the joints of ducting pieces.

There are a few different problems that leaky ducts can cause in your home.

First of all, leakage drops your home efficiency dramatically. When you run your A/C through a leaky ducting system, roughly one-third of the cool air never even makes it into your living space. Your A/C will have to work much harder and use more energy to keep your home at the same temperature.

Secondly, leaky ducts can be dangerous as they have the potential to spread harmful pollutants throughout the air in your home.

When you run your HVAC, the pressure within the ducts creates a vacuum that can pull in particles from your attic such as dust, dirt, and pollen. Worse yet, your ducts may suck in more harmful toxins such as asbestos, mold, or animal droppings.

Ducting system leakage in one of the top contributors to poor indoor air quality. By re-sealing your ducts, you will be able to breathe easy.

How we fix it


Even a brand new ducting system can be leaky. There are always micro-penetrations through which air can escape.

That’s why Zero Energy Contracting uses a duct blaster and sophisticated measurement equipment to eliminate as much leakage as possible.

We start by sealing off all ducting entrances and then pressurize the system and measure how many cubic feet per of air are escaping per minute. We can then detect and repair any holes.

One of the reasons that ducts are so frequently leaky is that the extreme cold and hot temperatures cause the ducting pieces to expand and contract. These changes can create tears or disconnect one piece of ducting from another.

We use a pliable putty when repairing ducting penetrations that will expand and contract at the same rate as the ducts to ensure a lasting seal.

Through this method, we can guarantee a ducting leakage rate of 5% or less.


When ducts are uninsulated they can lose a lot of energy even without leaks. For example, when you turn on your A/C in the summer, the cool air first has to pass through ducts in your attic that have been sitting in hot air all day. Your A/C will have to cool the hot ducts before it can cool your living space.

Increase your home’s HVAC efficiency by insulating your air ducts.

Zero Energy Contracting also offers insulation services for your entire home. Most homes in California, especially those built before 1978, still don’t have proper wall insulation.

When exterior walls are not insulated, they leave an open space between your walls and siding. When the sun shines on the exterior of your house, it turns that space into a convection oven, heating the inside of your home.

Normally insulation is built into the walls of a home during construction, but Zero Energy is able to insulate the exterior perimeter of your home without removing any walls or making major renovations.

By insulating your home’s exterior walls and roof, you can save 14% annually on your energy bills. You will also experience the added benefits of noise cancellation and better temperature control.

Together we can help you save money by building a safer, more comfortable home for a greener, more sustainable world.