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Air Sealing Experts - Hometrust

Home Performance Services

Air Sealing  -  Insulation  -  Crawl Spaces  -  Ventilation  -  HVAC Ducts  -  IECC Compliance Testing  -  Exterior


How is Air Sealing Similar to the Zipper on a Jacket?

Stop and think about this for a second...

If you head outside on a cold and windy day chances are you will throw on a jacket.

Lets focus on the jacket for a moment.  You have two choices.  Zip up or leave it open.

Either way - you are glad you have the jacket - you feel warmer than if you had nothing.

But, if you zip up then you will be "bundled" up. The jacket keeps the warmth in and the cold air out.  The system works better.

A key ingredient to making any amount of insulation work much better for your inside environment is to seal up all of the important places where air is likely to infiltrate and exfiltrate - in other words - we need to zip a few things up.


maryland attics need air sealing


contiguous thermal - pressure boundary

Building Science 101

Air in - Air out
When any amount of air enters your home - an equal amount of conditioned air is ejected out. 

One of the most important building science principles that causes air leakage is the stack effect

As seen in this figure, warm air rises in a building.  This concept is not new.  What is important to know is that the warm air that rises, if left unchecked, leaves the house through the gaps in the ceiling. 

As the warm air leaves - cold air gets drawn in from down low. That's one reason basements and crawl spaces are so cold in winter.

This pressure set-up inside your home is a conveyor belt of never ending energy waste. As your warm air sneaks out at the top the cold air makes its presence felt in the places you tend to spend time.

The good news is that the problem can be controlled. Air sealing is the solution to stop unwanted "flow" around your home. By sealing the right spots you can have more even temperatures, less draftiness and lower energy bills.

basement air sealing maryland

Why guess where your drafts are starting?

Get a blower door test today!




Air Sealing Rebates Available
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 I am convinced my windows are the source of my problems.    You are saying less costly fixes are better?

One of the fascinating things I have discovered is that when the temperature drops across the country, I get an unusual number of clicks on my article detailing the 5 reasons your brand new windows are drafty.

Common Problems Due to Lack of Proper Air Sealing

High Energy Bills Despite Taking Some Actions

If you spent a good sum of money to replace old windows or old HVAC and you find yourself still dealing with high energy bills - you are not the only one!

So don't feel bad or lose hope that you can actually have an energy efficient home. You just might have to look in a few other places to get to the real problems.

Soon, you will be the mose efficient neighbor in the hood! 

High energy bills are a sign of low insulation

Unrelenting Draftiness

The lower the temperature drops outside the higher the pressure turns inside. There are really a lot of things working against good energy efficiency unless you seal up the right spots.

Windows in a vertical wall are not going to do much for the increased pressure at the ceiling of the top floor.


attic air sealing maryland
This classic plumbing pipe (green arrow) has been "made" by the dirty insulation (yellow arrows).


Poor Overall HVAC Performance

Often times new HVAC energy efficiency promises are not delivered as expected. The law of diminishing returns kicks in and the whole experience could become quite frustrating.

Think about a simple birthday balloon. If your task was to blow up the balloon for the party and you noticed that it had a hole in it would you continue to blow air into the leaky container?  No!

Air Sealing Techniques to Bundle Up Your House

Two-Part Spray Foam

Two-part spray foam is a great solution for insulating surfaces that are not easy to reach because it air seals and insulates in one motion. The "spray" helps it can get into hard to reach places.

Decisions to use two-part spray foam should be based on the situation and location of use. Some areas can be treated equally effectively with less costly materials.


Basic Attic Air Sealing

If you don't have air sealing in your attic now then you definitely need air sealing ASAP!

If you are not sure whether your attic is air sealed there are several things you can look for around the house that will tip you off.

The first tell tale sign is spider webs.  Another is if you are feeling drafts around your home then you likely need air sealing in your attic and around other key areas of your home.

Proper Treatment Techniques

At first thought it may not seem so obvious that insulation projects require attention to detail and a mastery of several important skills.

Sealing and insulating a building shell requires technicians to work in tight spaces. Crews must be in good physical condition.

Crawl space features in a house are perfect examples of where knowledge and conditioning come into play.








Eric Gans - Certified BPI Pro

About Hometrust

Learn to Think Like a Building Scientist

Our mission is to help Maryland homeowners create a more comfortable home and save energy by using building science principles and modern air sealing and insulation techniques.


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Consultations in Pretty Much Any Town in Maryland
Call Today!  301-957-6532

MHIC # 114593
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Envelope Professional Certification

Contact Us in Maryland

Yes, we want to connect with you!  No matter what stage of living in your home you happen to be, we want to partner with you to make it more efficient and comfortable.


MHIC 158968
8345 Sperry Court
Laurel, MD 20723

Building Analyst Maryland Consulting Services
Eric Gans - Certified BPI Pro

Specialized Maryland Contractor


  • MHIC Licensed
  • Building Analyst Certified
  • Envelope Professional Certification
  • EPA Lead Renovator Certified
  • YouTube Learning Channel


Our mission is to help Maryland homeowners create a more comfortable home and save energy. We achieve this by applying building science principles and modern air sealing and insulating techniques.

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Services & Service Areas

Anne Arundel County, Baltimore County, Baltimore City, Carroll County, Charles County, Harford County, Howard County, Montgomery County, Prince George's County



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MHIC 158968
8345 Sperry Court
Laurel, MD 20723


Hometrust Remodeling

Proudly working in BGE & Pepco's Home Performance w/ ENERGY STAR program in Maryland to deliver whole-house energy savings to improve comfort & help protect the environment.
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An Energy Auditor's Purpose 
"Energy auditors visit residential buildings and talk to owners and residents.  They inspect, test, and measure to decide what energy-efficient retrofits are practical and cost-effective." Residential Energy