Do You Know About the Four Different Airs Inside Our Homes?

If you’ve been studying the concepts of building science, you’ve probably heard of the four control layers, water, air, vapor, and thermal.  Thinking about each of these building envelope control layers individually, and how they interact together helps in the planning and execution of building a better home.

This concept of separating a home’s assemblies can also be applied to a different topic, the air inside a home.  Most of us probably take air for granted, we breathe it, it’s always around us, but with regards to inside our homes, airflow needs to be managed.    I recently caught a presentation by Pat Huelman, a respected building science educator and researcher from the University of Minnesota.  Part of his discussion focused on the need for projects to include an “air manager”, someone paying attention to how air interacts with the built environment and mechanical equipment.  He discussed the importance of four different types of air in our homes and how each contributes to the quality of the indoor environment, energy conservation, and durability:

  1. Combustion Air
  2. Make-Up Air
  3. Ventilation Air
  4. Circulation Air

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Using S.W.O.T. to Help Develop a Scope of Work

Back in the early 1990’s, before I joined the construction industry, I was in college taking business classes.  I remember learning how to assess a business by using something called SWOT.  The SWOT acronym stands for strength, weaknesses, opportunities, and threats.  I’ve been developing this idea for assessing existing homes that are looking to undergo renovations.  I’ve found that working through a construction project using this theory can help in the development of the plan, the process includes pre-construction data gathering and developing and accessing a scope of work.  As far as I know, this is the first discussion of SWOT being used for analysis in the construction industry.

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What Happens to Your Home in Extreme Cold?

As I’m writing this blog post, a very cold air mass typically found at the North Pole has begun to move southward, into more temperate climates.  This latest polar vortex is forecast to affect much of the continental US with below average temperatures.

Here’s a question, what effect does that very cold air have on our homes?  Well, it depends!

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How to Prioritize Energy Upgrades to an Existing Home-Part 2

I purchased my home in the fall of 2018.  I could have decided to build something new or forgo all the maintenance that comes with home ownership and rent.  Instead, I chose to purchase an older home that needed updating, both in appearance and performance.

The 24’ x 32’ home was built in 1952, a Cape Cod design with the normal problems of a Cape Cod, attic knee walls that were both inside and outside the air control layer.  There was some evidence of past water damage and a few old clips on the roof where a heat tape would have been placed, suggesting an ice dam issue.  The high efficiency natural gas forced air furnace appeared to be from the 1990’s, the same year as the electric water heater.  There was also a natural gas fireplace in the small living room.  There was a weird-shaped room on the main level (behind the sun and where the sliding patio door is located, 9’ wide by 24 feet long.  Two bedrooms, and a bathroom were located upstairs, a bathroom on the main level, and an area in the basement that had an egress window well that would support another bedroom. Continue reading “How to Prioritize Energy Upgrades to an Existing Home-Part 2”

Blower Door Testing for Contractors, Should You Own One?

This post first appeared on the Green Building Advisor Website.

I had the opportunity to interview Gary Nelson, one of the founders of The Energy Conservatory and Minneapolis Blower Door a few years ago.  An Interview with Gary Nelson-NorthernBuilt.  During the interview, he made the comment that his hope for the blower door when it first started appearing in the market was that every contractor would own one and that testing both existing and new homes would become a common practice.  That was 40 years ago.

We haven’t got there yet, but there are more and more contractors purchasing the tool and there are many online videos and webinars showing how a blower door is set up and used.  In this blog, I’ll discuss how to perform basic diagnostics on a home using a blower door.  Methods used to find air leaks, a short discussion on zonal pressure testing, and different tasks that the manometer can perform, all topics I think a contractor that owns (or wants to own) a blower door should be familiar with.

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The Effects of Poorly Installed (or Missing) Insulation

I was taught many years ago by an older fiberglass insulation contractor the importance of a quality insulation job.  His biggest piece of advice, FLUFF, DON’T STUFF!  Poorly installed insulation can have a big impact on the overall performance of a home.  In this blog, I’m going to show you mathematically how a small insulation deficiency can have a big effect in how a home performs.

This thermal image is a good example.  This was a brand-new home where I was performing a code required blower door test.  I ran around the home with my thermal imaging camera before starting the test and thought I might be able to use this image to show thermal bridging, which it does a good job at, but if you study the pic a little closer, we see several areas where the fiberglass insulation was poorly installed.  Compressing (not fluffing) the product creates areas of cooler temperatures in the insulation batts.  The dark area (at the ceiling on the right side of the photo) shows an area of missing insulation.  What effect does this poorly installed insulation have on the overall (effective) R-value?  We can show the results mathematically.

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What is a Blower Door Test? An Introduction.

This blog post first appeared on the Andersen Windows ProViews Blog

We’ve known for a few decades that improving the air tightness of a home and installing a properly designed mechanical ventilation system can greatly enhance the performance of a home.  Having the ability to verify the airtightness of the structure is key, we perform verification by using a tool called a blower door.  This introductory blog will answer the questions; what is a blower door test?  Why do we perform blower door testing?  How is the test performed?  How do we interpret the test results?  What else can a blower door be used for?  Are there codes relating to blower door testing?  Before we dive into those questions, let’s start with that first question, what is a blower door test?

A blower door test is a test to confirm the continuity and integrity of a structure’s air barrier.

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A Crash Course on the Four Control Layers

This post first appeared on the Andersen Windows ProViews Blog.

Shelter is a human necessity.  A place to be warm and dry.  A place to be safe and healthy.  These are the main purposes for every new home that gets built.  As our species has moved out of caves and into, first, stone structures, then concrete and mass wood structures, and finally to what we live in today, our expectations for health and comfort have increased.  We want our homes to stay dry, but not too dry.  Temperatures are expected to be comfortable, and sometime consistent with little variation throughout the home.  The quality of the indoor air should be healthy to breathe.  And we want our investment to last for a long, long time.  A newer expectation is that we do not want to spend a lot of time, effort or money maintaining the structure.

This new, solid stone home has a much different longevity expectation than the traditional wood framed home. Then again, both the cost (about $10,000,000 and time to construct (3 years) are much different than the typical home we build today.

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Can Short Term Indoor Air Quality Testing be Effective?

This post first appeared on the Green Building Advisor Website.

I own a CPS IAQPRO Smart Air professional indoor air quality monitor that I use on nearly every energy audit and building investigation I perform.  The tool measures particulate matter (PM2.5 and PM10), volatile organic compounds (VOC), carbon dioxide (CO2), temperature, relative humidity, pressure and dew point.  The question is, can short term air quality monitoring provide any useful feedback as to the indoor air quality of the home?  The answer, yes and no.

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What’s the Difference Between R-Value and U-Factor?

This post first appeared on the Andersen Windows and Door Website.

We were taught in junior high that hot air rises, the key to that phrase is air.  Heat itself moves from someplace warm to someplace cool.  A good example of this happens often in cold climates.  When standing in front of an old window on a cold night, you feel a chill.  This chill is the result of heat leaving your body and moving towards the colder surface of the window glass, heat moving from hot to cold.  To slow this movement of heat, we use insulation, by putting on another layer of clothes, we reduce or resist the movement of heat, we have added R-value.

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