Residential Comfort & Energy Efficiency

Building science principles are fascinating. When it comes to Maryland residential indoor air quality it all makes very good sense and Maryland homeowners should have basic knowledge of three important things around the house and how they are connected.

Three building science principles every homeowner should know

• Air Changes per Hour
• Energy Efficiency 
• Indoor Air Quality

Read on to learn how they all connect to one another...

Air Changes Per Hour (ACH)

Air changes per hour (ACH) can be defined as the amount of times the volume of air inside your home changes with the outside air.  It is the house "breathing" in effect. If your house is calculated at 7 ACH then you can expect that on any given day and during any given hour, the inside air will exchange with outside air seven times. 

ACH in new construction homes has to be very low (3 or less).  New building codes for energy efficiency are making builders install energy efficient measures at the time of construction so that all of the typical leakage points are sealed before walls and ceilings go up which makes those areas very difficult to treat after they are in place (like in preexisting homes).

Energy Efficiency - Controlled vs. Uncontrolled Fresh Air

But, when we tighten up the envelope and don't allow the house to "breathe" as much we have to find solutions to create the right amount of ACH for healthy indoor air quality.  The key to this is to make sure the introduction of fresh air into the building is controlled so that less energy is consumed to maintain good indoor air quality (the right amount of fresh air) rather than allowing it to infiltrate uncontrolled causing heating and cooling systems to work much, much harder.

Indoor Air Quality - What is it Actually?

So in considering indoor air quality, it is important to know that measuring indoor air quality is NOT to measure the amount of particles in the air.  Indoor air quality is actually making sure that a building has enough fresh air and in a manner that is cost-effective.  Good indoor air quality also goes a long way towards sustainability and the longevity of the buildings structural components.

Get Your Score Today - Home Energy Audit - BGE or Pepco

The best way to check your indoor air quality is to get a BGE or Pepco energy audit with Hometrust Remodeling.  We are certified to test and calculate your indoor air quality as part of your comprehensive energy audit.

An comprehensive energy audit is a great way to have your home evaluated.  Measures can be prescribed in a way that will address indoor air quality as well as energy efficiency and comfort.  It is the whole house approach that ensures that you can have the best indoor air quality and a less drafty house at the same time.
 

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Written by Eric Gans
I have over 2000 energy audits under my belt in Maryland.  I like to take my personal experiences with each of my audit customers and try to get the things that concern them out into the world so others can make good home improvement decisions - in the right order - according to their needs.
 

What do you think about the indoor air quality in your house?  We want to hear in the comment section below!

If you live in Maryland long enough you will experience a cold winter. During extreme cold events most untreated houses in our area will give in to the "pressure" and feel drafty. The heating bills go up and you may never feel warm. Before you know it the winter is over and you spent a whole lot, but you didn't end up getting much comfort in return.

Unless the envelope of your home has a pressure boundary to go along with the thermal boundary then extreme winters are likely to be costly and uncomfortable. The missing part of an insulated home is sealing up all places where air can flow from the outside to inside (infiltration) or inside to outside (exfiltration).

Most Maryland houses are in this category and are considered to be leaky.
 

Check out this 1952 Maryland Attic with a Large Thermal Bypass
 

Typical Characteristics of the Houses that Grade the Worst

As a certified professional home energy auditor with over 1000 home energy audits completed, I understand the common configuration problems that cause issues for different style houses. Having this experience gives me good insights into how to solve issues and not make them worse.

Below are a list of characteristics found in the houses with the biggest winter comfort issues:

• Recessed Lights in Top Floor Ceiling
• Open Chimney Damper
• Large openings at the attic floor like this one
• Unsealed Attic Access Hatches
• Fiberglass Batt Insulation Installed at Attic Floor
• Closets with Doors to Attic Areas
• Houses Built on an Open Crawl Space
• Homes with Kneewalls and Sloped Ceilings
• Houses with Uninsulated Ducts
• Poor Overall Attic Ventilation

This is Why it is Happening - The Stack Effect

To understand how to get a hold of the winter cold in your home, you must first understand the Stack Effect. The stack effect happens in every building and it gets its name from a fireplace and chimney. The physics behind the name is that at the base of the chimney - at the fire level - there is a "pull" or negative pressure. At the top of the chimney the smoke and heat billows out. That is the "push or burst" - the positive pressure.

In the winter our heat in our homes rises upwards. Much like a hot air balloon. We all know that hot air rises. What we have been missing for all these years is that the hot air is escaping through holes in the ceiling. And when it gets pushed through the top it gets pulled in at the bottom (crawl space, untreated basements).

To make a Maryland home more comfortable in winter the focus must be on sealing the attic floor. Disruption to the flow of warm air escaping through the ceiling will also disrupt the negative pressure, or cold air streaming in at the basement. Less negative pressure means less cold air infiltration - or less drafts. By sealing the attic, the heat can't escape and the furnace/heat pump does not have to run as long.

An energy audit through the BGE Home Performance with ENERGY STAR program is a great way to get up to speed. An energy audit, done with a great energy auditor, will guide you to how your home fares. Usually, we intrigue homeowners with easy to fix finds and advice that puts them in control.

Conclusion

In sports, one expression to describe a team or a player that is performing at peak is to say there is a "science" behind what they are doing on the court or field. 

When it comes to home comfort there is a true science behind it and Hometrust has the training, knowledge and diagnostic tools to test and finally get to the source of your home comfort issue.
 

Considering an energy audit, but not sure if it will help your issue or concern? 

________________

Written by Eric Gans
I have over 1000 energy audits under my belt in Maryland.  I like to take my personal experiences with each of my audit customers and try to get the things that concern them out into the world so others can make good home improvement decisions - in the right order - according to their needs.
 

I would like to hear your comments about this article.  Feel free to post something below...

Positive customer feedback!

Get to the Root of the Problem

A doctor always wants to get the the source of the issue. Let's consider a lower back ache as an example. If you hurt your lower back chances are the doctor will give you a muscle relaxer for the symptoms. A good doctor will likely give you a pamphlet on core strengthening exercises to get to the root of the problem.

Specialized Contractor Needed for Damp Basements

Some issues inside the home can be confusing and confounding for many contractors. A damp basement and high humidity are hard to solve.  As a homeowner, knowing where to turn for help might be difficult to figure out. Making matter worse, getting the wrong contractor can waste time or cost extra money.

Indoor Humidity and Seasonality

The recommended indoor humidity level - year round - is between 40-60%.

To get a handle on indoor humidity, the first thing to understand is the seasonality of indoor humidity.

In the summer the air outside is hot, humid and sticky in Maryland. We run our dehumidifiers in the basement. If you have not gotten around to attaching the hose most likely you are dumping water on the regular.  This effort pulls extra moisture from the air.

In the winter everyone talks about the Polar Vortex. Aside from being very cold, the Polar Vortex is also very dry! In winter our hands are cracking, lips get chapped and we need to introduce moisture into the inside air.  In this case a humidifier is used.

So, I will be clear. High indoor humidity is more of a summer issue.

Home Energy Audit

The key to solving a high indoor humidity issue is to look at it like a doctor. We need to find the source of the humidity in the air. We need to attack the problem. Where is the humid air getting in?  Waterproofing will not completely solve the issue.  Industrial strength dehumidifers are the muscle relaxer and treat only the symptom.

Having your home evaluated by a certified Building Analyst (BA) is a great way to identify home air leakage. It is important to understand that air leakage works both ways. Not only does air leak out of a house (exfiltration) air also leaks in (infiltration).

A blower door test can uncover air leakage points around a house.

Working with a Building Analyst is a great place to start for a damp basement due to a high indoor humidity issue.

Did you know that at any given time there are around forty approved BGE contractors to do energy audits for Maryland homes?

Every once in a while I get a call from a Maryland homeowner that already had an audit performed and they want to get another quote.  It happens quite often and what I can report to you is that I am amazed at the lack of details in the audits that I get to review.

Once a homeowner gets an energy audit, their home's "scenario" is registered in the BGE database.  All approved contractors can request access to the file if the homeowner authorizes it.  So, I get to see my peers final product and I can say, I have been less than impressed.

Providing a comprehensive energy audit is a specialized service. It takes many hours of training, hands on experience and practice to give a great all around energy audit.

With so many houses in Maryland and so few BGE auditors how can you be sure to get a great auditor that hits on all points? After all, you only get the audit one time for the discounted price of $100.

Here are the questions you can ask the company (including us) you choose for your BGE energy audit:
 

1. How many BGE energy audits has the assigned auditor performed?

2. What is the auditors background before becoming an auditor?

3. What level of detail does the auditor plan to add to the energy audit report?

4. What is the physical condition of the energy auditor assigned to my house?

5. Is the auditor a good communicator and willing to engage?

Let's explore each of these questions a bit further.
 

1. How many audits have you completed?

Collecting the necessary data points during an energy audit is important. Having the repetition and experience allows a great auditor to assign time to the issues. If an auditor is new, taking accurate measurements may be a challenge. The auditor is learning on the job.

Everyone has to start somewhere, but do you want your one-time discounted audit to be the one? A great audit can unlock amazing concepts that will put you in control of comfort and energy usage.

2. What is the auditors background?

An energy audit looks at a house in a different way than a window consultation or roof estimate. An energy auditor is a three dimensional thinker whereas a window salesman has a one track mind. And, I am not even talking about making the sale.

An energy auditor needs to know a little bit about everything around a typical house. Having a background as a home contractor helps, but also being a homeowner is important. Experiencing and problem solving around your own home generates great learning experiences. These experiences along with learned concepts can go a long way towards helping you!
 

3. How is the final report going to look with a mediocre BGE energy auditor?

It is going to be a complete bore. The template for the BGE energy report is well designed and the information is good.

A great energy auditor will add details that pertain to discussions you had. Your BGE energy report final copy will be something you can keep for reference.

4. Should I really ask about my auditors physical condition?

Believe it or not, but doing a BGE energy audit the way it needs to is demanding work. An auditor must be able to get in small spaces, climb in attics and inspect crawl spaces. An auditor must be in good physical condition to perform a great audit.

5. Communication Pulls it All Together

An energy auditor needs to be so many unique things and on top of that if they are not personable, then it is a waste.

An energy auditor must be able to articulate key concepts in easy to understand ways. If the auditor cannot complete this task, the BGE energy audit could end up being useless.

Why does Mold Form on Plywood?

Typically, condensation in the attic starts due to a moisture issue created by introducing two completely different air masses.  Here are the two possible reasons this problem is happening in your attic.

1. No air sealing at the attic floor to stop warm, conditioned air from escaping into the attic (warm air/ winter issue) coupled with a lack of adequate attic ventilation creating conditions that are right for condensation that adheres to the plywood and eventually forms mold.

2. In summer, a leaking AC HVAC duct in an attic and other HVAC-related inefficiencies can allow air to seep out and interact with the hot, humid attic air, mainly if the attic is not well vented.

If you find this helpful, check out more info on my YouTube Channel @hometrustremodeling

Warm Air Exfiltration - Winter Issue

Signs that you have an attic moisture issue problem during cold months can sometimes be seen on the plywood.

Winter Problems - What to Look out For

Frozen droplets on the tips of nails and hurricane clips signify that warm, humid air is migrating from inside the home into the attic and settling in the wrong places.

Poor ventilation is trapping the air rather than allowing it to organically or mechanically be exhausted (through a ridge vent or attic fan).

But, how is the warm, humid air getting into this attic?  The usual suspects...can lights and top plates!

Recessed light thermography taken at the attic floor reveals heat from inside the home escaping into the attic.

  
This is a close-up image taken of a recessed light. I took it from the attic during cold weather.

   
This is the same recessed light. I took a thermal image of the recessed light.

Top plates are also leaky spots if not appropriately air-sealed.  Top plates in the attic will exist above the hallway, between rooms, and other areas separated by a wall.

Close-up of a top plate. 

Thermal image of top plate close up.

Summer Condensation - How it Formed in This Attic

This example is one I came across during the attic inspection at a home energy audit.

At first, when I got up in the attic, I could see the stains. It was apparent quickly that there was an issue beyond what I usually see.

I have been in many attics and seen a lot of roof sheathing over the years.  I was not exactly sure about this one at first.  I have not had a mold case. Overall, is is pretty rare, at least in Maryland.

At first, I considered the possible interaction of the cool conditioned air in the living space below and the warm, humid attic air.  Maybe I could find a large opening or bypass where the air interacted, but why would be so high up?  Then I turned around.

I saw a huge HVAC supply duct lying completely undressed and the picture was getting clearer.
 

Summer Moisture - 4 Things to Lookout For

Here is the recipe for mildew and mold growth on the plywood in warmer months:

1. HVAC Ducts

*Second HVAC system located in the attic or crawl space. 
*The connected ductwork is also in the attic or crawl space. 
*The ducts are leaky and improperly insulated, allowing cold air to escape.

2. HVAC System Size

*The second HVAC system is improperly sized. 
*Too large for the space/square footage it is servicing. 
*The larger blower pushes cooler air through leaky ducts and into the attic.

3. Poor thermostat location.

*The thermostat is located in an area reported to be a "hot spot" on the floor so the machine was running longer. 

4. Poor Ventilation

*Improper baffle placement.
*Blocked eaves (air intake).
*No ridge vent.
*Inoperable attic fan.

A baffle is supposed to act as a channel for the open soffit intake below.

The soffit opening is covered with insulation, not allowing good flow.
 

Here is what it is supposed to look like.
 

How to Remove Mold from Attic Plywood

Answer: Control the humidity and the mold growth disappears.

Here are the steps recommended to solve this issue in the long term.

1. Remove the insulation around the soffit/eave areas - the entire perimeter

2. Reinstall baffles at the eaves to promote the best possible organic attic ventilation. 

3. Re-position the insulation so as not to cover the openings.

4. Seal the duct seams and tightly insulate the supply plenum (central AC duct) to eliminate leakage (lost energy) into the attic.

________________

Written by Eric Gans
I have over 2000 energy audits under my belt in Maryland.  I like to take my personal experiences with each of my audit customers and try to get the things that concern them out into the world so others can make sound home improvement decisions - in the correct order - according to their needs.
 

Do you have something going on around the house? Maybe my YouTube Channel can help.
 
 

YouTube Channel @hometrustremodeling

I would like to hear your comments about this article.  Feel free to post something below...

Duct leakage inside a home can account for as much as 30% of energy loss.  But, how do you fix a problem that mostly lives behind walls and in hard to reach locations?

Most homeowners that have a knee wall in their home don't know they have a knee wall in their home.  This article discusses the different type of knee walls, the issues knee walls present in terms of comfort and energy efficiency and how to properly treat knee walls for peace of mind.

Common Construction Philosophies

Maryland crawl spaces can be a giant source of comfort issues in summer months.  Crawl spaces are typically intentionally connected to the outside humid air with vents around the foundation wall.  The idea was that installing vents will create ventilation.  Unfortunately, due to pressure dynamics that in many ways are related to meteorology pressure highs and lows, the air in the crawl space becomes more humid and damp and issues are compounded with the steady infiltration of stale, humid air.  If there are ducts running through a crawl space it is more important to consider what measures can be taken to treat the crawl space.  Spending a little money up front on crawl space encapsulation will save much more money in the long run if you consider duct leakage, overworking HVAC equipment and extra infiltration of warm, humid air in summer and cold, dry air in winter. 

Check out this before and after crawl space encapsulation project with blocking and sealing open vents.

Crawl Space Encapsulation Maryland - Smart Thinking
In the simplest terms, to encapsulate a crawl space is cutting it off from the outside air.  When I was young we had the Weather Channel that was just a table with today's temperature and conditions and it would cycle through each city in the U.S.  San Diego, no matter the time of year it seemed, was always 70 degrees and sunny.  We want the crawl space to be 70 degrees all year round - without the sun, of course.  By doing so, you are bringing the space into the "envelope" of your home.  If ducts exist in the crawl space, the ducts don't have to work as hard to service the rooms above. 
 

Overall, the HVAC system is asked to do less as a result of crawl space encapsulation and yet the inhabitants are more comfortable.  

Imagine if that was a formula for everything in life.  Work less and gain more!

Learn more about common sources of home comfort issues.

Hometrust Remodeling recently completed an insulation job in Laurel, MD 20723.  The project consisted of the following measures:

• Air seal the attic floor
• Install soffit baffles at eaves for ventilation
• Cut soffit holes to add air intake for attic ventilation
• Seal 4 recessed lights
• Add 10" of loose fill blown cellulose insulation
• Treat the main attic access hatch
• Treat the garage attic to encapsulate the space
• Sealed accessible HVAC duct connections

For most insulation to be effective it is important to stop the flow of air by sealing up holes and cracks in as many accessible areas as possible. 

Insulating the accessible skylight kneewalls to R13 after sealing smaller crevices/cracks and adding sheathing (air barrier) over the insulation will maximize boundary effectiveness and reduce air communication between the living space and the attic (outside).

                                 
Completed attic insulation & skylight kneewall 20723                                      Garage roof encapsulation in Laurel, MD                   

Most of the largest leaks in homes occur where framing (such as floor joists or wall studs) span from an area inside conditioned space to an unconditioned or vented space, such as the attic,crawlspace, garage, or roof. Appropriate blocking is needed in these instances.

Untreated recessed lights are invisible gateways for air to communicate between the inside (conditioned space) and outside (attic).  Covering and sealing accessible recessed lights will eliminate this issue.

Encapsulation, using open cell spray foam, was completed for this project so that the space below, including the HVAC unit in the garage attic, would become part of the overall "envelope".  The garage is going to be converted to living space (in-law suite) so by encapsulating the area above the space, it will make it easy to complete the job once the work gets done and when the space is changed, the HVAC will also benefit from being enclosed inside the house rather than outside (garage attic).