Category Archives: Blower Door

What is an Energy Audit Worth?

Hose and bucketSeveral years ago, I wrote a post about the value of an Energy Audit.

The story behind that audit was one side.  Improved Comfort. This time it is about the other side.  Decreased Cost of Operation.

An home energy audit reviews the ability of your home to retain the heated air from your HVAC System in the winter and the cooled air in the summer. The best metaphor I’ve seen is to compare the Thermal Enclosure to a Bucket of Water. The picture above is a good example.  The hose is like the HVAC System. It fills the house with hot air in the winter and cool air in the summer.  The Bucket allows the conditioned  to leave the home.

The result of the energy audit is to prioritize which holes to fix first, second and third. Some of this is about how big a thermal leak the hole is, and some of this is about cost.

Attics are less costly to insulate than walls.  There is room for more insulation, it is not a lengthy process, and there is nothing like patching holes after you have insulated.

This home had the improvements made as recommended by the audit, in February 2012.  The energy usage for 36 months prior to and now 36 months after the improvements is now available.

The 3 year average for annual energy use before the improvements is 34,972 KWH.

The 3 year average for annual energy use after the improvements is 18,940 KWH.

A decrease of 45% in energy used.  The bills are paid in dollars, so why refer to an energy measure.  Using energy measures means future increases in Utility Rates are not considered.  Will those increases happen?  Yes! Not counting on them is important. Did they happen during this 6 year period.  Yes, several times. So the results are about actual savings.

IMG_1272 copy

Here is Brian, blowing insulation into the walls. The walls before the work started were uninsulated. If this home had been stucco or brick, this step would not have been cost effective.  The material is cellulose, providing an R-13 in the wall. Cellulose is easy to install in this application. This crew had done this many times and the experience is worth a lot.

IMG_1340 copyThe image on the right is the attic. As you can see there is a little insulation in there before work started.  That meant the crew could do the air sealing first.  Fibrous insulation like the rock wool you see, or the cellulose that was added, does not stop air movement.  Warm air from inside easily goes up into the attic and outside. Good crews air seal before they insulate. They are already up there.  A caulking gun is not hard to carry along.  See those wires,  the electrician drilled a one inch hole to put the wire through.  Lots of air leakage.

Here is a picture I took last winter.  New snow the night before  on the roof of this house. Note the hole near the edge of the roof in the snow cover.  That hole in the snow is right over the outside wall and there is a light switch, or outlet on the wall below it.  Air Leak copy

 

Millennials Seek Smaller Homes, Energy Efficiency, Won’t Sacrifice Details

Originally Published on the NAHB Website
http://nahbnow.com/wp-content/uploads/2015/01/507029289.jpg

Laundry Room

The survey says: No laundry room = no sale.

 

As Millennials begin to enter the home buying market in larger numbers, homes will get a little smaller, laundry rooms will be essential, and home technology increasingly prevalent, said panelists during an International Builders’ Show press conference on home trends and Millennials’ home preferences last week.

NAHB Assistant VP of Research Rose Quint predicted that the growing numbers of first-time buyers will drive down home size in 2015. Three million new jobs were created in 2014, 700,000 more than the previous year “and the most since 1999,” Quint said. At the same time, regulators have reduced downpayment requirements for first-time buyers from 5% to 3% and home prices have seen only moderate growth.

“All these events lead me to believe that more people will come into the market, and as younger, first-time buyers, they will demand smaller, more affordable homes,” Quint said. “Builders will build whatever demand calls out for.”

Quint also unveiled the results of two surveys: one asking home builders what features they are most likely to include in a typical new home this year, and one asking Millennials what features are most likely to affect their home buying decisions.

Of the Top 10 features mentioned by home builders, four have to do with energy efficiency: Low-E windows, Energy Star-rated appliances and windows and programmable thermostats. The top features: master bedroom walk-in closets and a separate laundry room.

Least likely features include high-end outdoor kitchens with plumbing and appliances and two-story foyers and family rooms. “Consumers don’t like them anymore, so builders aren’t going to build them,” Quint said.

When NAHB asked Millennials what features fill their “most-wanted” shopping list, a separate laundry room was clearly on top, with 55% responding that they just wouldn’t buy a new home that didn’t have one.

Storage is also important, with linen closets, a walk-in pantry and garage storage making the Top 10 – along with Energy Star certifications. In fact, this group is willing to pay 2-3% more for energy efficiency as long as they can see a return on their power bills.

If they can’t quite afford that first home, respondents said they’d be happy to sacrifice extra finished space or drive a little farther to work, shops and schools, but are unwilling to compromise with less expensive materials.

A whopping 75% of this generation wants to live in single-family homes, and 66% prefer to live in the suburbs. Only 10% say they want to stay in the central city. Compared to older generations, Millennials are more likely to want to live downtown, but it’s still a small minority share, Quint said.

Panelist Jill Waage, editorial director for home content at Better Homes and Gardens, discussed Millennials’ emphasis on the importance of outdoor living and that generation’s seamless use of technology, and how those two trends play into their home buying and home renovation decisions.

Because they generally don’t have as much ready cash or free time as older home owners, Millennials seek less expensive, low-maintenance choices like a brightly painted front door, strings of garden lights and landscaping that needs less watering and mowing, like succulent plants and larger patios.

They’re also very comfortable with their smartphones and tablets, and increasingly seek ways to control their heating and air-conditioning and security and lighting as well as electronics like televisions and sound systems from their phones. “They want to use their brains for other things, not for remembering whether they adjusted the heat or closed the garage door,” Waage said.

Get more details about the NAHB survey in this post from Eye on the Economy.

I emphasized the two comments about Energy Efficient Features NAHB found.  If you would like help in addressing these in a cost effective manner for your buyers, Call The Energy Guy!

Indoor Air Quality Evaluations

The quality of the Indoor Air of our homes and offices is an important part of our health and comfort.

There is not much sense in putting a lot of good insulation into a building if it is:

  • Not Structurally Sound
  • Not Healthy

What types of things can be done to improve the Indoor Air Quality of any home or property?

  1. The immediate environment of the structure must be kept separate from the inside.
  2. The required fresh air that is needed, in every one of our buildings, should be filtered and otherwise treated for comfort and to remove pollutants.
  3. The pollutants that are created during the normal operation of our building must be eliminated, removed, replaced, diluted or neutralized.
  4. Moisture in any form must be controlled , and then removed avoiding any accumulation.
  5. Any and all accumulations of moisture damage or animal infestation must be cleaned up and damaged building components replaced.
  • A Full Indoor Air Quality evaluation must address all of those concerns.
  • Full interior visual inspection
  • Full exterior visual inspection
  • Testing of the building enclosure to ensure the outside stays outside
    • Infrared Evaluation as part of the above testing
  • Inspection of HVAC Duct Work and systems that move air.
  • Combustion Safety Inspection on open combustion appliances
    • Moisture, Carbon Monoxide, N02, SO2 and others
  • Infrared and other testing for moisture accumulations.
  • Sample Collection of suspended and/or deposited material that are potential pollutants or irritants.
    • Examination and Evaluation by a certified Microbiological Laboratory of these samples.

This evaluation is typically completed in two visits to the home or business. Level I Evaluation and Testing is non-destructive and not invasive.

Level II Evaluation and Testing involves invasive inspections. These may be as simple as drilling a few holes for visual inspection or sampling. It may involve removing obviously damaged building material, that requires replacement, for example wet drywall.

Contact The Energy Guy for further information about an Indoor Air Quality Evaluation.

Who Is Building an Igloo in Wichita?

It all started on Twitter. @AIAWichita @moongodess316 and I had some fun over building an Igloo.

Igloo1

I saw this Tweet and immediately thought of a quote from Dr. Joseph Lstiburek: “The Igloo was the First Passive House.” Joe is an engineer by training and has been working with buildings, insulation and energy use for over 30 years. His Building Science Corporation, based in Massachusetts, conducts research and is one of the best sources of verified information on building energy efficiency in buildings.

So I tweeted back.

Igloo2

What is the difference between a Passive House and a regular house? What is the buzz all about?

Strawbale

When you build a home you can use lots of insulation to reduce the amount of electricity and gas to heat and cool the home.

GSHP Diagram

You can use a lot of high tech equipment to reduce the amount of electricity and gas to heat and cool the home. You can also do both.

PHIUSThe Passive House was developed in Germany, so you see it referred to at times as Passiv Haus.

We know that insulation works and that more insulation works better. As the cost of electric and gas goes up, it makes financial sense to add insulation to a home or business. In 2000, the local cost of Electricity was 8 – 9 cents, the recommended level of attic insulation was R-30. Today the cost of electricity is 12 – 13 cents and the recommended level of insulation is R-49.  Both have increased about 1/3 in 1 years. We also know that air movement, cold drafts, makes people uncomfortable and causes insulation to not work as effectively.

Round Metal TubeThe sources of air entering a home are usually related to corners. Since we like living in buildings that have square corners there are a lot of them in a home. Windows do not usually cause air leakage. How they are installed can cause air leakage. The age or the quality of the window does not seem to matter when installation mistakes occur.

PHIThe primary requirements for a passive ouse certification are based on Energy Usage and creating a structure that needs very little energy for heating and cooling. These standards are effectively summarized with these two limits.

  • Total primary energy (source energy for electricity, etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year (37900 btu/ft² per year)
  • The building must not leak more air than 0.6 times the house volume per hour (n50 ≤ 0.6 / hour) at 50 Pa (N/m²) as tested by a blower door.

In our Twitter Conversation, Angee McBustee tweeted a question about how is building a igloo in Wichita. Then I responded with the offer to run the blower door test. As you can see from the primary requirements the Blower Door result is very important to a passive house.

Igloo4

How good is a Blower Door Test of 0.6, as required by Passive House? Energy Star New Homes require a Blower Door Test of 5.0 or less. New homes in Wichita routinely test around 4.0. In the blower door testing, lower is better.

For standard construction, I have tested several homes at 1.0. There is one home that I have tested with a lower result. A custom home in Butler County is under construction. They had me do a Blower Door test after it was sheathed. No insulation, no drywall. The test result was 0.62. We were able to find several leaks using biometrics and the infrared camera. That was last September. I returned in December to test it a 2nd time, the results were so low, that I didn’t have the right test equipment to measure the result. I would estimate it to be in the 0.30 range. I now have the equipment to test a home like that.

In February, I have been accepted for training and certification as a Passive House Rater/Verifier. Christine is building the home in Butler County, I want to thank her for the push to obtain this certification.

In the Twitter Conversation, AIA Wichita came back and said they were posting an information tweet.

Thanks to Angee and AIA Wichita for a nice idea for a Blog Post.

What Counts? Product A or Product B

Blower Door Testing & Weather Resistant Barrier

Tyvek TopThe practice of covering sheathing with asphalt impregnated papers has given way to the use of synthetic fabrics, known as house wrap; or spray on coatings. There are factory applied coatings on some brands of sheathing and some types of coatings are field applied. Along with the discussions of fiberglass / cellulose in the insulating of homes, there has been plenty of discussion about the merits of one form or another of WRBs.

As with any step in the building process, I believe it is less about the product and more about the people. Products that are hard to install will be less successful then others. Installers that are not properly trained; work that is not verified in some manner can defeat the proper performance of the best products.

WRBWhat does the WRB do for a home. First it provides a drainage plane behind the siding to divert rain and other weather related moisture from wetting the sheathing. Second, when all manufacturers install instructions are followed it can act as an air barrier, reducing infiltration. For the house wrap type fabrics, this means properly lapped, using capped fasteners, and then taped. Finding house wrap installed according to manufacturer’s install directions is rare.

When all three of these directions are not followed, not only are the potential qualities of an air barrier not present, the potential for water to run behind an uncapped fastener, or an incorrectly lapped joint, which is also untaped. Repeated wetting of the sheathing over time, will eventually result in rot and the accompanying problems.

Country HollowA local Wichita Home Builder, G.J. Gardner has just finished two homes based on the same floor plan. These homes went through the independent verification process involved in obtaining a HERS Rating. These homes utilized the same sub-contractors and types of insulation. The only difference in construction was the use of a job site applied spray on WRB, in place of a house wrap type fabric.

One part of this verification process is a Blower Door Test. This test simulates the effects of a 20 mph wind on all sides of the home at the same time. Blower Door testing has been completed on homes since the late 1970’s. Energy efficiency programs and building codes have consistently recognized the value of a Blower Door test on each home.

BlowerDoorThe value of doing a Blower Door test on each home is primarily to check the work of all subs has not compromised the Builder’s plan for an energy efficient home. Many existing homes, have a test rate of 7 – 12 or higher rates of air exchange during the test. The 2012 code requirement is 3 on this scale, and lower is better.

The use of 4×8 sheet goods for sheathing and other simple, and inexpensive techniques have brought the infiltration rates down. This reduces the cases of cold drafty homes, and significantly lowering the energy use of a home.

The Blower Door test can verify the quality of work involved with installing the WRB, specifically the degree of sealing of the outside of the sheathing. In the case of the two homes involved in this comparison, there was a change of 20% in the measured infiltration rates of the two homes.

In completing the Blower Door tests, we used the ANSI / RESNET published standard of a Multi-point test. These results were entered into a software package provided by the maker of the blower door, The Energy Conservatory, Below is a comparison screen between the two Blower Door Tests.

Tectite 2 Bldg Comp Data

I would like to thank Wade Wilkinson, with GJ Gardner of Wichita; his subcontractors and their technicians for building quality energy efficient homes. I enjoy being able to verify the quality of their work.

If you would like to see this home, it is currently in the Fall 2014, WABA Parade of Homes.  It is located in the Country Hollow Development.  Between Kellogg and Harry on 127th and East to Glen Hills Court, on the corner.  Find out also about the HERS Index earned by this home. It will save you operating costs on your Energy Bills.

Passive House Work in Wichita

In the last two weeks, two national groups that certify construction for Passive House Standards conducted their annual conferences.  PHIUS was held in Portland, OR; and PHI was held in Maine. Locally, I have completed the first of 3 planned Blower Door tests for a passive concept home under construction; discussed the planned construction with another builder to start later this year; and discussed passive building concepts with another builder planning his first homes next year.

PassivhausDarmstadtKranichstein-300The Passive House concept started in Germany, with construction starting in 1990 on several homes. In German, it is Passiv Haus,  PHI for Passiv Haus Institute.  The standards followed by this concept require an attention to detail in design and construction of the thermal enclosure.  Historically referred to as the envelope, the thermal enclosure involves the exterior bottom, sides and top of the structure.

  • Higher than commonly used levels of insulating material,
  • windows meeting specific standards and very
  • Effective work on air sealing
  • Attention to the Solar Orientation of the home to maximize the use of solar heat in the winter

PHIThis results in an extremely low energy bill.  How low? In the Wichita area, this would translate to an $88 – $110 annual natural gas bill, instead of $500 – $900 bills that I routinely see on Home Energy Audits.

The passive term comes from the idea of using insulation and construction techniques to create a significant energy savings instead of relying on fancy machinery to create that savings. Dr. Wolfgang Feist of Dahrmstat, Germany founded the Passiv Haus Institut in 1996.

Smith HouseThe passive house concept arrived in the US in 2003.  Katrin Klingenberg, a licensed architect in Germany, She built a home meeting these standards, 2 hours south of Chicago.

 

Most countries have a local organization that trains and certifies homes and commercial buildings to the Passive Standard. Yes, passive concepts apply to buildings other than homes. These groups train people to apply and measure the standards. They also review the reports on specific buildings and accept or deny actual certification for a specific building.

PHIUSIn the US, this organization has been known as PHIUS.  Passive House Institute, US. Ms Klingenberg has been the leading light of this group, which was founded in 2007.  There are some things in each country that differ from the original German model of Passiv Haus.

The experience of the professionals working with PHIUS in the US has resulted in some changes to how the concept is applied in the US. For example, the metric units used in the German (and most others in the world) have been translated to the Imperial units used in the US. The collaborative nature of US business groups has been essential to moving the passive concept from being used by a relative few to becoming a market force in the US.

Because these adaptations by PHIUS to the US market, were not acceptable to the original PHI, a divide between the approaches has occurred in the US.  It is mostly technical, and both groups agree the concept is still primary.  Effective building resulting in low energy use.

Some claims have been made that these concepts are two expensive for the US market. The original Passive House in Illinois was built at a 2003 cost of $94/ sf.  That is very favorable with current US construction costs. Since additional people are using the concept and the resulting products that manufacturers are producing, the mass production will bring some drop in costs.

If you wish to read more about the two national conferences for both the PHI and the PHIUS organizations that just finished, you may use these articles.

The 9th annual North American Passive House Conference (PHIUS)

Report from the Passive House Conference in Maine

I will keep you updated on activity in this area about Passive House building activity, as it progresses.  Three projects is a great start.  I’m glad that builders are willing to try new concepts and that home buyers are willing to step up and buy these homes.

In the introduction of this post, I mentioned a house under construction with the Passive House concept. I conducted the first of 3 Blower Door Tests last week.  This test was after the framing and exterior sheathing was completed.  Insulation, plumbing, electrical and trades had not started.  The second test will be in a few weeks after these trades have done their initial work and put holes in the enclosure.  Electric wires, plumbing, HVAC and other necessary conveniences of our lives will be installed in passive concept homes. The third test will be done at the end of construction.

The PHI/PHIUS standard for Air Infiltration as measured by the Blower Door Test is 0.60 –  The current 2012 recommended code requirement for this is 3.0 — Wichita/Sedgwick County does not have an energy code in place, but the Kansas City area does. They enforce a 5.0 standard.  Typical homes built from 1980 and prior are in a range of 10 – 38 from my testing.

The goal of the builder on this passive concept home was to reach 1.5 on this first test. Then using the Infrared Camera to find areas to caulk, and fixing the penetrations mentioned above, have the next test come in lower.

Blower Door62This test, actually came in at 0.62 —  almost the standard.  Much better than the expected 1.5 .   While the blower door was running, the Infrared found some places that could be fixed.  Dan, the carpenter, was right there with a caulking gun.  We also found some leakage with biometrics. A back of your hand that is wet, will show you extremely small amounts of air movement.  Most builders like to use expanding foam to seal the actual window to the rough opening.  We found some of these foamed openings were still leaking. Again the caulking gun was a good answer.

 

A Healthy Home Part 3 — Well Ventilated

Fresh AirA Healthy Home is well ventilated.  Everyone knows fresh air is important. This should be easy.  Well ventilated in more than just bringing in fresh air. The concepts are certainly easy, the details on the other hand take some thought and planning.  A new home ventilation strategy is fairly straight forward to design and implement. An existing home needs the input from the occupants and good analysis to address the problems. An effective ventilation strategy should address these issues in either new or existing homes.

  • Remove humidity, odors,, or significant problems from specific areas.
  • Remove stale, musty or other objectionable air.
  • Allow the occupants to choose fresh air sources that can be filtered or treated in other ways
  • Allow the occupants to choose to open windows when outside weather is appropriate
  • Allow the occupants to operate a system that can provide the amount of fresh air, to the appropriate places, in adequate amounts when needed
  • Provide fresh air when the outside air creates potential problems, such as Ragweed season or when other allergens are active
  • Provide air movement within the home, without the use of the expensive blower on the furnace or heat pump.
  • Allow minimal use of heating or cooling equipment during the shoulder seasons, when temperature changes are minimal, while keeping the home comfortable.

Billings QuoteHow much fresh air is needed?  Going back to the 1890’s, the number has been pegged at 30 CFM (cubic feet per minute) per person. This number was validated in a number of different studies and with the public health authorities in larger cities, dealing with large apartment buildings and recurring respiratory diseases.  I was pointed to the quote at the left by Allison Bailles. he located the original book on Google Books, page 20.

Beginning in the 1930s, research into changes in building techniques began to show the optimal number was closer to 15 CFM per person.  Some of the changes in construction included the increased use of forced air heating, moving from balloon framing to platform framing, increasing square footage, and the use of insulation in walls and attics. The formula changes from time to time and everyone has an opinion on details. The common point remains, fresh air is needed in every house.

Part of the Ventilation is removing air with a problem. Where is that?  Humidity is found in rooms that use hot water and basements.  Showers, tubs and cooking are the large sources of humidity.  The smells from food preparation and cooking can be very mouthwatering.  When the meal is finished and the refrigerator is full, the lingering smells become odors.  The answer is some spot ventilation in these areas. If your basement has a humidity problem, you can tackle that with a fitted sump pump cover to contain the humidity, and work to eliminate any water seepage.

vent fanSpot ventilation is a window that opens and an exhaust fan. The size of these fans is part of the formula that is specific to each home. The features of the fan are common to all homes.  It must be quiet. Builder grade fans are noisy. Noise in fans is measured in ‘Sones’. The Sone is a linear measurement of noise, compared to the decibels used by OSHA and others which is an exponential measurement.  Linear is better for quiet sounds, and decibels is better for loud noises. Fans should be less than 3 sones, and preferably less than 1 sone.  Reasonably priced fans are available that rate a 0.3 sones. A 1 sone fan is very quiet.

UnknownFans are certified for air flow and noise levels by the Home Ventilation Institute. HVI certification is very common and includes both the Sone rating and CFM rating.  When installing a fan, you must consider the duct losses that will occur in meeting the required air flow.   The rates for bathroom air flow  are 50 CFM, and 100 CFM for a kitchen.  Do not expect to buy a 50 CFM fan for a bathroom and connect it to 6 or 8 feet of duct work, and obtain 50 CFM.  I have measured 30 CFM routinely in these set ups.

Most people understand that various parts of their body are just a part of the whole.  If you start some type of therapy, there may be a side effect. Physical Therapy starts and you end up with some sore muscles, aha!  Side Effect!  Start a therapy for cancer and your hair may fall out, aha! Side Effect!  Your home works the same way.  Each part is just part of the whole. Change something, aha! What is the side effect?

House-System-imgAll of the items in the list above are part of the whole. For an existing home, some specifics of that house may indicate concentration on one or another of those areas.  A home built in the 1920’s will benefit from a different approach then a house built in the 1980’s.

A new home should have the ventilation system that meets the general points above.  The natural ventilation provided when windows and doors are opened, or the mechanical ventilation system that allows filtered and perhaps treated fresh air brought in from specific places and in specific amounts, allow the occupants to make the system work as they need.

 

This post is part of a Series on A Healthy Home

 

 

A Healthy Home Part 2: The Home Starts Out Clean

This should be a no brainer!  Have you ever walked into a brand new home and found it dirty?  I haven’t.  The larger issue is really two things:

  • What gets designed into the home to assist the homeowner to keep it clean?
  • What goes on in the home before the cleaning service arrives?

Is there a small dirt factory installed in each new home when the builder isn’t looking?  No?  Well how does all that dust and dirt get in there?  If there is no conspiracy among the cleaning products industry to put dirt factories in our homes, then the dust and dirt must come from outside.  If that is the case,  a clean home should attempt to stop the dust and dirt at the door!

Mat A sidewalk, driveway  or patio should be included to enter the home. This can be swept or hosed off from time to time. It also provides a place for you to put your Welcome Mat!  Having one by each door is optimal in keeping your interior clean. Everyone in the family should learn to leave the gritty stuff in the mat.  It also needs to be cleaned regularly.

The designer should provide some type of entry area for people to remove and store coats, out door type shoes or boots, like a mudroom, hooks, baskets, or entry closet. Some type of seating for smaller, and experienced people, would be a nice touch.

laminateInterior design should utilize easy to clean materials. Floors, window treatments, wall finishes that are easier to clean will get cleaned more. The current trend with hard surfaces, like laminate and hardwood, are perfect examples of cleanable materials.  The move from the shag type carpet to the berbers and other short napped carpets is also great for being easier to clean.

The use of semi-gloss latex paints instead of flat or matte finishes is helpful, because such surfaces are easier to clean using mild soaps. I know some interior designers will want to use the flat or matte types. Those should be limited to places that small peoples fingers do not try to decorate. If flat paint finishes are inevitable; wiping the areas down with a set sponge instead of a rag will help keep the finish intact.

Hole In WallThe other place to keep dust outside are the holes in the house.  Windows, places pipes, wires, and other parts need to go from inside to outside.  These should be sealed.  Most builders do a great job on these places in the walls.

Instead of covering the outside of the framing with 1×8 boards, as my home was, they use 4×8 sheet goods today. These provide structural strength and cut down on the holes for dust to get in. The use of house wrap type coverings also helps with dust control.

Infrared Image Infiltration in Knee WallThe remaining area is the attic.  This is a challenge for most builders. Some of it can be done before the drywall is up. That part is fairly easy.  Some of it must be done after the drywall is in place.  Attics are not exactly a great place to work. The work must still be done. The Infrared image on the right show air leaking into a home from unsealed attic joints. Yes, it is a cooling problem in the summer, it is also an opening for dust to enter the home.

1 Inch drillGap Not SealedHoles in the attic don’t have to be small.  The picture on the left shows one type of hole. These can be filled before the drywall is hung. They are some of the easier holes.  Electrical, plumbing and others need these holes. They also need to be sealed.  A little caulk or foam in a can does the trick. Other holes are smaller, and this picture shows them also.  Look carefully at the 2×4. On each side of the wall is drywall, (the white stripe) This needs to be sealed also. These holes occur on both interior and exterior walls. Both types of walls need to be sealed. Where do the wires go, light switches and plug outlets.  You have seen the foam gaskets sold at the home supply sections for these.  Sealing at this point is better, and in new construction is easier. The image on the right above, is a better image of drywall gaps. There are clearly two.  The first I saw from the attic side, because light from the room below was coming through. These were the small holes you see on top of the edge of the drywall. The flash on the camera makes them show as dark spots. The larger gap between the drywall and the top plate must be sealed also. Drywall Air leak

The thermal image above shows both types of leaks. It was taken during a blower door test from inside the home. The picture in the attic, above right, was the other side of this vaulted ceiling.  On the right side of the wall ceiling joint the air leakage is very defined, these are the small holes noted above. Climbing a ladder with the blower door running, allows you to feel the air movement.

The left side of the image shows the effect of the gap on the back side. The air movement fills the whole wall cavity and degrades the performance of any insulation present. This wall separates the garage from the house and was insulated. Because the attic was not properly air sealed at construction, the infiltration from air leakage, was causing the walls to leak heat as if they were not insulated at all.

The way to verify these holes, the big ones, and the small ones, are not left, is a Blower Door Test.   One of the last steps in finishing any house should be a blower door test.  The builder can use these results to verify the quality of workmanship from all subcontractors on the site. The homeowner can rest assured the builder testing all homes with a Blower Door is not getting a house with big holes. And the house doesn’t have very many little ones either.

A Blower Door Test is part of a HERS Rating on the house. The current cost of a new home in the hundreds of thousands of dollars, the cost of a blower door to the builder is rather minor, compared to the peace of mind that results from a job well done.

A short Blower Door Video on You Tube. This will open in another tab. It is less than 3 minutes.

This post on one in a series on Healthy Homes.