Playlist – 10 Insulation Secrets You Must Know

ABOVE – 25 Min Compilation of the 10 Insulation Secrets You Must Know.

Learn what you need to know to make an informed and intelligent decision with your home’s comfort & energy efficiency.

Start with the #1. Each video references concepts from the previous. Shawn reveals the essential framework needed to understand the cause of your home comfort & energy efficiency problems.

At Stellrr, we believe in fixing the root problems. Fix it once, fix it right, fix it for life. We do not practice “putting lipstick on a pig” like the other guys do unknowingly.


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Individual Secret Videos 1-10

Discover what usually needs to be done and why.

Looking for a specific video? Find each one below…

Length 3:19 – Transcript Below

Secret 1

  • The epic fail in most Austin area homes
  • How $0.30 of every $1 spent on cooling is wasted
  • Why some rooms are hotter than others

Length 4:09 – Transcript Below

Secret 2

  • The replacement windows myth
  • Which holes are most important to seal
  • What causes indoor air quality problems

Length 4:09 – Transcript Below

Secret 3

  • The recessed lights problem
  • Finding the holes in your house
  • Insulation malpractice – not what you think

Length 1:10 – Transcript Below

Secret 4

  • Why remove existing insulation
  • How to trap pollutants inside a home
  • Avoid growing mold after insulating

Length 1:10 – Transcript Below

Secret 5

  • What grows inside homes due to Austin’s humidity
  • How to effectively manage humidity 24/7/365
  • Stop creating a dust mite grow house

Length 2:11 – Transcript Below

Secret 6

  • 40% of your breathing air comes from this nasty place
  • Why rooms above the garage are so uncomfortable
  • What types of insulation must never go in a crawlspace

Length 1:38 – Transcript Below

Secret 7

  • Why the other guys install product that are not effective
  • Why we usually don’t work with contractors or builders
  • Why new construction homes are often uncomfortable

Length 3:12 – Transcript Below

Secret 8

  • Why fiberglass is so popular and terrible
  • What causes spray foam to be more expensive 
  • How does cellulose compare to fiberglass

Length 2:49 – Transcript Below

Secret 9

  • How our blown insulation detours pests & rodents
  • What Stellrr does when we make a mistake
  • Avoid this insulation that smells like urine

Length 2:14 – Transcript Below

Secret 10

  • How to properly and permanently fix your crawlspace
  • When it is okay to insulate the underside of the floor decking
  • How we manage mold, wood rot, & foundation problems

Transcripts of the 10 Secrets Videos

Secret 1

Here is an epic fail. Putting air ductwork an attic in Austin Tx is a terrible idea. Yes tens of millions of homes built this way which means a terrible idea spread like wildfire. Since we almost never have basements in central Texas, the attic is the place where there is enough space to put large ducts that can distribute conditioned air to each room. What is the problem?

Have you ever hung out in your attic on a summer afternoon? If you have, then you know what I imagine hell feels like. Do you remember burning yourself with hot water from the sink? You get the same feeling when touching surfaces in the attic on a hot summer day. Meaning an attic is the most hostile environment for your ductwork. Let me explain. 

When it is 90-degrees outside, the attic is 125 or more because the sun heats up the roof itself to 160 degrees with the heat radiating into your vented attic. 

The problem is that your Air Handler produces 55-degree air, and then pushed your conditioned air through the hot ductwork to the register in each room. 

Your ductwork has a thin fiberglass wrap between the 55-degree air and the 125-degree air. As the air you paid to cool travels through the hot ductwork it heats up. Meaning you are blowing 65-75 degree air into rooms further away from the Air Handler.

Let’s say you are comfortable when the room is 72 degrees. How long is it going to take to cool a room to 72 degrees when you are blowing 75 degree air? How much quicker would the room cool if you were blowing 55-degree air? What if you could blow 55-degree air in every room, can you see how that would provide much more even cooling? 

The problem is our conditioned air is in a hostile environment. We need to create a better environment for our conditioned air. Will replacing your ductwork with better insulated ducts fix the problem? Nope. They will still be re-heating lines in the cooling season. Here is why. 

According to the US Dept of Energy, the average house air duct leakage is 30%. Meaning, 30 cents of every dollar spent to condition the house is lost. Wasted. It leaks out at all the plenum, seams, duct connections, register connections, and through the fiberglass itself. Fiberglass insulation does not stop airflow – it filters air. Conditioned air going through the fiberglass makes it useless. Replacing old fiberglass wrapped ducts with new fiberglass ducts can get you thicker air filters. Replacing your ductwork and sealing it with mastic will get you mediocre results.  The mastic sealant is thin as paint and brittle. To get maximum results, you need Tight-N-True Duct Encapsulation or to turn your vented attic into an air-tight Yeti Cooler. 

Secret 2

How much air leaks from your walls, attic, ductwork, floor, etc? Well, the most important leak to seal is the ductwork since it is a pressurized leak. Ductwork is pressurized by the blower in the air handler, and pushes the air into each room.

Here is a home performance myth for you. It is important to have great windows, completely sealed up. False. Contrary to popular opinion, windows are one of the least important place to seal up. New windows look pretty, but they exist along the neutral pressure plane of the home. This means windows have little air infiltration because there is neither positive or negative pressure there. Let me explain the law of holes. 

The amount of air going through a hole depends on two things – the size of the hole, and the amount of pressure difference on both sides of the hole. 

In the cooling season, hot buoyant attic air expands, creating positive pressure pushing air through holes at the top. Heat moves from more to less. The air you paid to cool is more dense than hot air, and moves toward the floor. Then it is pushed out the cracks and holes at the bottom of the house. As the cool air is pushed out, negative pressure is created, allowing more hot attic air to move from more pressure to less pressure, being pushed into your conditioned space. With the hot air comes all the junk residing in your attic insulation. What’s in there? Carcinogens and formaldehyde if you have older fiberglass. All the pollen, cedar, mold spores that collect in your vented attic over the years. The humidity. All the rodent dropping bacteria and urine. Yep, you’re breathing it! This is part of why indoor air is often more contaminated than outdoor air. 

According to the EPA, levels of indoor air pollutants are often 2 to 5 times higher than outdoor levels. In some cases these indoor pollutant levels exceed 100 times that of outdoor pollutant levels. Can you start to see how it makes sense to vacuum out everything in your attic and then sterilize everything? 

So if hot air in your attic expands, pushing itself into your conditioned space and creating positive pressure. Then at the bottom of the house is negative pressure where the conditioned air escapes out. That means that somewhere in the middle of the wall is where it changes over from positive to negative pressure. It is at that point where there is no pressure. This is called the Stack Effect.

The leaks farthest up in the conditioned space in your house leak in the most, and the leaks farthest down leak out the most. So sealing a 1” hole in the very top is way more important than sealing the equivalent hole in the middle. Which is why windows are a low priority for home performance compared other leaks. 

The law of the stack effect states that by sealing air leaks in the top of the house, we can stop hot musty allergen filled air from coming into the house. This results in rooms at the bottom of the house also becoming less drafty without actually touching the bottom half of the house. 

That is why we have the A, B & C priorities. 1. Attic (attic, ceiling, and roof), 2. Bottom (below grade or crawlspace), and C. Conditioned Space (walls, doors, windows). 

How much air is leaking through your ceiling? According to the US Dept of Energy, the average house air leakage equals to a 2ft x 2ft window being open 24/7. If you are trying to cool your house, don’t you think it would be smart to close the window and stop leaking all the air you paid to heat or cool?

What is it that needs to be sealed up? Your top plates. A top plate is at the top of your wall, and is the wood that your ceiling joists sit on.

Secret 3

Did you know your top plates have a 2” plumbing hole cut out for drainage air in sinks, toilets, tubs, showers. You also have a hot and cold supply pipe hole for these plumbing items. How many sinks do you have? Toilets? Tubs? Showers? Ok so how many holes are there? 

Every electrical outlet, light switch, & cable has a hole drilled out in the top plate above it. How many electrical outlets do you have in the room you’re in right now? And how many rooms do you have in total? Don’t forget the clothes washer and dryer.

Now you know that there is a hole behind every ceiling light. How many of those? And what about recessed lights?   Recessed lights are like little chimneys with the damper left open.

The fine print on “Insulation Contact” or “Air Tight” Rated recessed lights have a disclaimer on them stating that the average air leakage is 2-CFM (Cubic Feet Per Minute). 

This means they leak 2 basketballs of conditioned air every minute. In a years time that is equal to a line of basketballs from Austin to Dallas. 

How many times could your house can light leakage go from Austin to Dallas? To go from here to Dallas would require thousands of linear feet. Or a long line. So let’s make this more visual. 

Where the wall and ceiling meet is the top plate. This is where all the holes are. But we have not yet discussed the crack between your 2×4 top plate and your drywall. When your house was built, the lumber was new and moist. The Sheetrock was slapped up against the moist lumber & secured. Over time, the lumber dries out and shrinks. The lumber pulls away from the drywall, making a crack. A crack at the top of the house leaks air. It is not uncommon for me to be able to drop a coin between the top plate and the drywall. If I can put a coin through there, what else can go through there? That’s right. Air. 

So how many feet of top plate do you have that needs to be sealed? Ok, let’s check out the linear feet. Let’s say your house is 35ft long by 40 ft wide which is a 1,400 sq ft house footprint. That is 75 ft. And you would double that to get all 4 walls of top plate. So 150 linear feet. Now let’s add up the interior wall top plates. It is common to have as many linear feet of interior walls as you do exterior walls, so let’s call it 150 ln ft of interior walls. So 150 interior, and 150 exterior. That is 300 ln ft total. That is almost a football field long. 100 yards. Now, how far is it from your house, to your neighbors house across the street? Unless you are in the country, your top plate air leak crack could go from your house to your neighbors house a handful of times. Don’t you think it would be smart to seal that high pressure plane up, closing that theoretical 2×2 window in the ceiling?

At Stellrr, we believe that insulating without air sealing is mal-practice. You can have a 24 inch blanket of insulation, but without air sealing, all you have is a really thick air filter. Did you know that many HVAC air filters are made out of fiberglass?  Yep. We don’t install fiberglass anywhere, but we do remove dumpsters full of filthy fiberglass every week. 

Secret 4

Why do we remove insulation? 

First, to get a proper seal on the top plates & drywall, you have to be able to see where you need to seal. You can’t see everything when it is covered in a blanket of insulation. 

Second, the surface needs to be clean for adhesion. Otherwise it is like laying caulk on the beach. Then pulling it up. It’ won’t stick. 

Third, by putting insulation on top of existing insulation you are trapping in all the allergens and feces that used to float out of your vented attic. The intensity of which those pollutants come into your indoor air will multiply.  

Fourth, if the roof gets spray foamed, we are moving the thermal boundary from your attic floor to your attic ceiling (the under side of your roof decking). If the floor insulation is left in, then you have two thermal boundaries. Which will hold more moisture, leading to mold, and wood rot. These reasons are why we usually won’t insulate a house without removing the existing insulation in the space where we are working. 

Secret 5

Let’s talk more about moisture in the air. Austin is a very humid environment, often 80-90% humidity. This creates a great environment for all sorts of things to grow. If we are constantly bringing in humid air from outside, then we are creating a not so healthy environment inside. We need to seal up the house air leaks not only for energy savings & comfort. But we need to seal up the house for our health. Then we can manage the humidity more effectively. And we can stop mold growth, wood rot, and protect the house structurally. 

Do you need a dehumidifier? If your house is sealed up properly, your HVAC unit will pull the humidity out of the air effectively in the summer, while avoiding bringing in excess outside humidity. But, in the cool part of the year, if your house is efficient, you won’t be running your HVAC enough to pull the humidity out of the air. In Austin, it is a good standard practice to have a self-draining dehumidifier like SaniDry installed either in your crawlspace or attic. 

Secret 6

If you have a pier and beam house instead of a cement slab foundation, you have double trouble. If you have insulation in your attic, and nothing in your crawlspace under the house, then we probably have some serious moisture issues, musty smells & cold floors. The talk about the top plate earlier, well you also have that bottom plate that is not sealed. 

According to the National Center for Healthy Housing, 40% of the air you breath comes from your home’s humid, dirty crawlspace. 

8 out of 10 Austin area crawlspaces I go into have zero insulation. The ones that do have fiberglass batt insulation. Listen up if you have an uncomfortable room above your garage, you have the same thing going on here. Why is the fiberglass batt ineffective between crawlspace joists as well as second floor joists in the attic ceiling? 

It’s called gravity. To be effective insulation must be aligned, intact, & sufficient. When a batt is installed, it is friction fit to the underside of the floor decking between the joists. Code requires a 3.5 inch thick batt. But how thick are your joists? 2×8, 2×18? Either way, there is a lot of space for gravity to work, allowing the batt to fall down from the top of the joist to the bottom of it. When the insulation is no longer intact or properly aligned with the floor decking, it is no longer providing any protection. All the air traveling, goes between the batt and the floor decking, causing cold floors, hot rooms, and humidity issues like buckling wood floors.

In a garage ceiling, we would dense pack the drywall covered ceiling with our all boric cellulose to solve the problem. 

In a crawlspace, we must install a vapor barrier. What is NOT a vapor barrier: Fiberglass, denim or cotton batts, cellulose, open cell spray foam. None of these product should ever be in a crawlspace. But my competitors sell these options everyday. 

Secret 7

Why do the other guys install products that we believe should never be installed? And why do they go put insulation in that won’t be effective at all?

Why? They don’t know any better. They don’t understand the building science. They sell based on a low priced but don’t solve anything. Money down the drain. The fact is that most insulation companies in Austin are guys who worked for other insulation companies. Most all of them only worked on new construction. They knew how to install insulation, but they don’t know why. Then knew the blueprint’s asked for certain R-values and materials, but not why.

The architect spec’d the insulation based on the clients budget (putting more importance to the pretty backspace and doing bare minimum code required insulation). My competitor’s were never the guys designing the plans. They simply blew in some insulation and never had to problem solve to fix the issues that other trades create. 

Remember the electrical, plumber, drywall crew, HVAC? They stayed in their lane. At Stellrr, we rarely work on new construction. The motto is, “They’ll keep building homes, we’ll keep fixing what they build.” They build ‘em, we fix ‘em.  Addressing the building as a system, which means taking care of the problems created by other trades. On a new build, the insulators never talk to the Sparky. Electricians never talk to the HVAC Techs, Plumbers never talk to the Insulators. No cross trade collaboration. 

Secret 8

Why fiberglass is so popular even though we believe it should never be installed?

Fiberglass is a weak insulator, won’t stop air leaks, is not a vapor barrier, rodents love to eat it, pests love to nest in it. So why is it so popular?

Fiberglass is cheap, quick, and easy. Cheap materials, Cheap equipment to install it. Installs very fast. Anybody can do it. Have you ever heard of Owens Corning or John’s Mansville? They produce most all the fiberglass in the US. These two companies are giant multi-billion dollar companies that own much of the building products market. They get builders to buy their full line of products. The shingles, the tar paper, the siding, the insulation, and the list goes on. So in order to get deeper discounts, what does the builder do? Yep, they spec out OC or JM fiberglass. On the other hand, cellulose companies are very small, and only do cellulose. So you won’t recognize any of their names. More on cellulose in a minute. First let’s talk about the HGTV favorite… foam. 

Polyurethane spray foam is a plastic. It is manufactured on the job site. Materials are more costly than fiberglass. Foam rig equipment is very expensive to purchase and even more expensive to keep running properly. To operate a spray foam rig and install foam takes years to learn. Installing foam is very hard. We had a Marine tell us that the job was harder than bootcamp, and he couldn’t handle it. The first few years of Stellrr, I learned and installed it all myself. I felt like a ninja every day I sprayed. Needless to say, I knew I couldn’t grow the business effectively if I was also the one doing the labor every day. The sprayers I hire are in the top 10% of best installers in the country. And yes, they are young. It is rare to find a sprayer  over the age of 40. It is just too demanding on the body.   

Cellulose requires stronger equipment than fiberglass. The material takes up more room, requiring a larger more costly rig. Installing cellulose is very dusty compared to fiberglass. Installing cellulose takes a lot longer than fiberglass. I have tried to hire several great blown insulation installers that flat out refused the job because it was cellulose. So again, we pay more to have guys willing to work with the product. 

Why I like cellulose? Blown fiberglass has an R-value per inch of 2.2 whereas cellulose is 3.7. If you have a low pitched roof, you can often get very close to the proper R-value all the way at the top plates where your rafters rest on the top plate of your exterior wall. Whereas with fiberglass, you won’t get the proper R-value until you are a few feet away from the wall below. Leaving you with under-insulated hot spots along exterior walls. 

It is more dense than fiberglass, slowing air infiltration. It performs significantly better at higher temperatures than fiberglass. 

Secret 9

Did I mention that insects & rodents hate it? Yep. Cellulose is ground up paper, newspaper (well ok more likely Amazon boxes) and other paper goods. So it is 85% recycled content. Then the other 15% is the fire-retardant. We use an All Boric Fire Retardant Cellulose. Most cellulose is 5% boric, and 10% ammonia. We don’t install that anymore. We used to buy our cellulose locally. The only cellulose that is sold locally is the different formulas that contain ammonia. Why don’t we like ammonia? Well, we live in a hot humid environment which can cause you to smell the ammonia. Ammonia smells like urine. I don’t want your house to smell bad. 

Unfortunately we had an incident when we bought locally (like everybody else does). We installed the cellulose. It was moist outside. The client and his wife were due to give birth 3 days after our install. The odor bothered his wife. He asked us to remove the boric and ammonia formula cellulose insulation that we purchased locally. So we had an emergency situation, pulled the crew off another job, sucked out the ammonia treated insulation. Replaced it, and made everyone happy before the baby came. 

I committed to never repeating that learning experience. Now we buy All Boric cellulose by the semi-truck load. This is excessive, but it allows us to control the quality of materials. And the all boric formula gives it better anti-microbial properties, which means the insulation manages moisture properly and is not impacted negatively. 

So let me back up to the rodents & insects hating cellulose. What they hate is the boric. Which is another reason why you want an all boric formula (15% boric & 85% recycled paper). Boric is a mineral that is mined from the earth. You can find it around volcanoes. It is used for the fireproofing properties. Boric is used in cleaning products like laundry detergent, eye drops, and other household products. So it is safe for us. But it has pest control properties to it. Let’s take a rat for example. A rat finds or chews a new hole in your soffit. Comes into your attic and starts tunneling through the cellulose. The cellulose gets on it’s fur. Now rats are mammals and mammals lick themselves to clean themselves. And when they do, the boric gets in their mouth. It dries them out. The rodents leave your house in search of water and don’t come back. 

Secret 10

If your crawlspace has no skirting, then we could spray closed cell foam to the underside of the floor decking because it is a vapor barrier.  However, I highly recommend that you have skirting around your crawlspace. Why?  Spraying closed cell between your joists will warm your feet, but it will still have thermal bridging. The joists do not get insulated. And you will still have a damp, dirty, crawlspace creating a great environment for wood rot, and foundation damage. 

I highly recommend installing a 20-mil polyethylene stranded vapor barrier on the dirt floor. Or we could do our drainage matting for extra support with the liner on top. Then we would convert your vented crawlspace to a sealed, encapsulated crawlspace using closed cell spray foam on the skirting walls and rim joists. 

A properly encapsulated crawlspace eliminates thermal bridging that you would have by foaming the underside of the floor decking. It blocks out the vapor & helps manage humidity. It stops all the air leaks at the bottom of the house. It allows a clean space to see if there is ever a plumbing leak, or repair that needs to be done. It dries up the pier & beam structure managing mold and wood rot. It stops floors from cupping. It gives you cleaner breathing air. And I highly recommend a dehumidifier in every Austin crawlspace to keep things dry, especially in the more moderate season when we don’t run our HVAC as much. Set it and forget it. I love mine.  Now in some homes we will also install a sump pump. But usually we can fully manage rain water by addressing the gutters, gutter covers, downspouts, and downspout extensions. Keeping crawlspaces dry is a big reason why I started our gutter company Gutterilla. The house is a system, and there is a huge disconnect between the gutter guys and the foundation and crawlspace guys. We want to prevent any further foundation shifting.