Category Archives: IR Pictures

Hey! It’s Hot Out There! — A conversation with@KWCHDeedee

Interview

 

 

DeeDee from Channel 12 KWCH called Friday morning looking for someone to talk about holding the line on cooling costs as the summer heats up.  We met Friday afternoon at a home in NW Wichita. This 4 year old home was larger than most in the Wichita area. 1800 SF on the main floor with a full basement. The Heating and Air is provided with a ‘Geothermal’ Heat Pump.  This system uses the 55 degree water under ground to provide heating, air conditioning and during these oppressive heat days in July, 2016 – de-humidification.

When I got there, the HVAC techs were there working on the system. It had shut off. The temperature in the home was 80° F and the relative humidity inside was in the lower 50% range. They reported the system was now running and during my time with DeeDee we felt and saw the system working. After a couple of hours, the temperature had dropped to 78°F and the relative humidity was down to 48%. The outside conditions at 2:30 pm, while I was there were a temperature of 98° F and a relative humidity of 45%.  Remember that humidity is relative, thus a higher temperature has the capacity to hold more moisture.  At 8:30 am Friday morning the outside temperature was 81° F and the relative humidity was 75%. Much higher than the inside RH at the same temperature when I arrived.

Not Comfortable

Not Comfortable

I think everyone was glad that the air conditioning had been restored.

DeeDee wanted some quick, easy to do, items for any one to help hold the electric bill down during the hot days of summer.  So we went around the home and we looked at some simple, low cost, easy to implement changes that could be made. These would work in you home as a home owner or in a rental home or apartment. We also looked at several improvements that should be considered.

Where does our energy get spent? Here is a graphic that was in my training text.
HHPie

The variations in percentages are due to differing house sizes, energy costs and types, and lifestyle choices.

Under the quick and easy category, people usually look at lights, electronics, and the thermostat.  Each of these requires the person in the home to do something. Turning out the lights, or turning the TV off, or setting the thermostat higher in the summer.  All of them save energy and thus lower your bill.

I classify all of these and others under the heading of Conservation. Then there are those that fall under the heading of Efficiency. These are things like adding insulation to your home, replacing your weatherstripping on doors/windows, or replacing a furnace / ac unit that is over 15 years old.

The difference: Conservation is changing how people work! Efficiency is changing how things work!  Both are important.

A quick summary of the summer conservation items would be:

  • Turn things, like lights and electronics, off when you aren’t using them.
  • Turn the temperature in the house up and turn a fan on.  Ceiling fans are great. If you need some ideas on ceiling fans, I wrote about them.
  • Reduce or eliminate excessive heat sources in the home. Turning off lights is great. Changing an incandescent to a CFL or LED saves energy and reduces the heat put into the home.
  • Another Heat Source is the Water Heater.  Turn it down to 120 degrees. Most people take a shower at 105° F. A 50 gallon tank with a medium flow shower head will provide 1 person with a shower of more than 30 minutes, with a typical mid efficiency recovery time.
  • Cooking inside produces heat and moisture.  Use a kitchen exhaust fan to remove both of those. They make your AC work longer.
  • Use the fan in your bath room to remove the heat and humidity when you shower.
    • if your fans noise level bothers you, replace them with a quiet fan. In Wichita the bath fans are selected and furnished by the electrician. The code requires 50 CFM to be removed from the bathroom.  Since electrician’s are trained in volts and amps, our common practice, means the person selecting your bath fan will bring the least expensive one. You might consider telling your builder on a new home, to have the HVAC contractor bring a quiet fan that will actually remove 50 CFM.
  • Move tasks that generate heat, such as baking a cake or washing and drying clothes to cooler parts of the day. In the morning or after nine at night are good times.
  • Use a clothes line to dry clothes, instead of the dryer.  In the summer do not dry them inside. That will just increase the humidity and make your AC work more.
  • At least one area electric utility has a demand charge for using electricity in the hot day times of the summer.  It is not Westar Energy. If you use another electric Utility, check your bill inserts, check their website, call customer service, and know when not to use electricity. A demand charge is an extra charge for usage during a specific time. Instead of 15 cents, you could be paying several dollars per unit.

Turning electronics off, such as your TV or computer, also involves the various accessories.  Computers have a printer, and sometimes other items that are plugged in. Along side your TV is a cable box, a DVD player, and other plugged in accessories. using a smart strip will help. A smart strip is a power strip that is controlled by the main device in the group.  So you plug your computer into the primary, and the printer, the monitor and other accessories into the other plug ins.  Now when you turn the computer off, the smart strip shuts the accessories off.  The same with the TV, or a game center.

The longer term changes you make to your home, cost more, and can have a larger impact.  These are the efficiency items.

  • Buy Energy Star certified appliances when you replace your refrigerator, washer and other appliances.
  • If your refrigerator or deep freeze is over 12 years old, I would strongly recommend that you look at replacing it.  The technology is changing fast and competition is holding prices down. Those made in the last 2 years use considerably less electricity then older models.

The largest portion of your energy use from the Pie Chart (above) is heating and cooling your home. The chart shows 45 – 55% of your energy use for this.

The simplest, and easiest to work on, would be the insulation in the attic. Others would include replacing less efficient equipment, considering the use of an exterior solar shade, or other improvement. After the work is done, you can sit back and enjoy your home.

Exterior Shade is a great thing, sometimes easy to do. Trees placed with shade considerations are great. Sometimes the builder can build some shading features into the home.  A wider eve for example. 30 inches instead of the standard 24.  Then the gutter, all work to extend the shade. The link below is to an Infrared image of shade from some builder included features.

Follow Up Thought for Friday’s Summer Cooling Tips.

We did take a look in the attic.  I found an attic that could use some attention. Some levels were in the 14 inch range, some were in the 10 inch range. One place had obvious density problems.  Insulation should be installed consistently level, certainly not lumpy. The fibrous insulation, fiberglass, cellulose, or rock wool, must be installed to the density specified by the manufacturer.  If not, you are not getting what your paid for.

attic

This is the attic from the KWCH video camera. I am reaching into a hole in the insulation and I can see the ceiling at the bottom of the hole.

I found no insulation card in the attic.  I can tell it is fiberglass and it is white. In the past two weeks, I’ve seen 5 different types of white fiberglass insulation.  If you install Johns-Manville Fiberglass, the three products I’ve seen in the past two weeks require 20 inches, another 16 inches and another 11.25 inches of thickness.  These depths would provide an R-49 level of insulation. This has been the requirement for attic insulation in our climate zone.  Since there is no legal requirement for insulation in South Central Kansas, most new homes are insulated to R-30 or less.

Call IR

This was the Infrared Image you saw in DeeDee’s video. I have reproduced it here with the visual light picture to help understand what it is showing.

I would like to thank DeeDee and Betty and Jack Call for their hospitality and seeing their home. I offered the Call’s a no charge Utility Usage Analysis for their hospitality. I will go back with that when I get the gas and electric usage from the utility companies.  Jack expressed some interest in adding some insulation to his attic so I will get some quotes for them to consider.

You can view the story DeeDee wrote and the video shown on the 6:00 news at the KWCH website.

What Happens After You Finish Your Part of the house, and Then The House Is Finished?

images-2Modern home building takes a lot of people. Concrete, Carpentry, Heating and Air, Paint, Drywall, Insulation, Electrical, Plumbing and many others. These professionals work on the house at various times. Usually there is a sequence, the foundation is done before the framing, the roof is done before inside work gets very far. Toward the end, it can get somewhat hectic. Everyone is trying to finish. The deadline is looming. Painters, trim carpentry, flooring, plumbing, final electrical installations are all happening.

One of the last things is the final work on the Heating and Air Conditioning system. This cannot happen until after the electrician is finished, and if you have a gas furnace, the plumbing must be there. Some of the work by the HVAC contractor was completed before the drywall went up. The duct work was installed and the inside unit of the system was probably put in place and hooked up to the duct work.

If the home is built on a 120 – 150 day schedule, the initial work, rough-in, on the duct system would happen about 1/3 of the way. Then about 2/3 of the waywall_duct, the Heating and Air techs are back to install the thermostat, the outside unit, hook up the electric and finish the job.

Last week, I went out to complete a rating on a new home. I had completed some testing on the duct system at rough-in. I used a Duct Blaster unit and testing the duct system for Total Leakage. I got a great number. There is a professional standard, issued ACCA (Air Conditioning Contractors of America) for this test. It is based on the size of the amount of air flow pushed through the system by the fan; in this case it would have been about 1,200 cubic feet per minute.

The standard is 10% of system air flow or in this case 120 CFM. In a previous blog post, I discussed a test where the system leaked over 100% of system air flow. This is an important test, because it can be compared to the test done at rough in.ACCA_5

The rough in test for Total Duct Leakage came in at 4.8% of system air flow. This is a very good number and typical for this HVAC contractor. Now at final, the total leakage was 16%. Wow! What happened?

I cleaned up and left the house about 6:00 for the weekend. Sleeping on the ‘What Happened?’ seemed like a great idea. I did just that.

Tuesday, I went back to take another look. I would conduct some additional testing to see if the leak(s) could be isolated. I started by removing the grills that fan the air out through each room. That would be easy and fast. So, the first few looked pretty good. It was going fast, I kept going and half way through I found one that showed some problems. At the end 1/3 of these grills had a significant problem.

Duct BootAs you can see the vent in the wall, had the drywall cut too large for the duct. The openings ranged from a quarter inch to over an inch wide, all around the opening. The air instead of 100% leaving the duct system into the room, was being pushed back into the wall. The idea of the duct system is to put the hot or cooled/dehumidified air into the room where the people are. A grill can do a great job of sending the air into various parts of the room. A good grill for one place may be absolutely the wrong grill for another place. Grill manufacturers refer to this as ‘Throw’. If you have the wrong throw on your grill, you aren’t getting much comfort from your system.

The infrared image, below, shows the outside of a wall in the winter (It was 20° F that morning). The hot area below the window is from the grill directing the heat up the wall, not out into the room. I found this condition on an audit last winter and made two alternate recommendations for the home owner. The cost was less than $20.00 for either one. The problem was fixed the same day by the homeowner.exterior_wall

Back to fixing the leaks! I filled the cracks and gaps in the poorly cut openings, replaced the grills and then set up to re-test the duct system. The leakage was back to the original number.

This shows the value of testing your work. We work with Quality Control Systems in our everyday work life. As consumers we depend on the quality of the products we buy. We see how companies respond when they are faced with a quality issue. A number years ago a lot of Tylenol was recalled. A few bottles had been tampered with, not really the manufacturer’s fault. They recalled anyway and their customers were well served. In the past few years, several auto manufacturers have had some problems with their cars, and they did not promptly recall the cars to fix the problem.

qcApplying good quality control lets the customers and the management of a company know the level of quality. The company can make drugs, cars, or install your heating and air system. In this case the quality work done by the Heating and Air techs was changed by another person working on the job. Good quality control found the problem. The fix took only a few minutes. Now the home buyer will not experience the discomfort from a badly installed duct system. I will not get a call in a few years because the home owner is not comfortable. The heating and air techs will not have a lot of call backs.

My thanks today goes to the crew at Cooks Heating and Air in Wichita. They did the quality work and deserve the credit. I am lucky to be able to work with people like this.

Insulation In Your Walls

Poorly installed Batt Insulation

Poorly installed Batt Insulation

I’ve been working with a local builder on his insulation.  He decided to upgrade his standard package of insulation for the walls in his homes. Most homes in this area are built on site with 2×4 walls.  Insulation is almost always installed in the cavity between the studs. The insulation most commonly chosen is a Batt Type insulation.  I’ve seen some mineral wool batts installed during construction in Wichita, most batts are Fiberglass.  They come in white, pink, yellow and a brown.  Color is from the manufacturer, think advertising.

I’ve been working with a local builder on his insulation.  He decided to upgrade his standard package of insulation for the walls in his homes. Most homes in this area are built on site with 2×4 walls.  Insulation is almost always installed in the cavity between the studs. The insulation most commonly chosen is a Batt Type insulation.  I’ve seen some mineral wool batts installed during construction in Wichita, most batts are Fiberglass.  They come in white, pink, yellow and a brown.  Color is from the manufacturer, think advertising.

The concern with a batt type insulation is how it is put in the home. Workmanship is always an issue.  Is it installed to hold the price down?  Is it installed to maximize the Energy Efficiency. There is no code in the Wichita area requiring insulation.  Until two years ago, the recommended code for our climate was R-13 for walls located above the ground. In 2012, the recommendation changed, primarily due to increasing energy costs. The change was increased to R-20. While this a large change of approach for builders that have not had to comply with a code, it is not unreasonable given the cost increases of energy, since the R-13 was set back in 1992. Batts

Here is a typical FG batt wall, from 2013.  Notice the compressed and poorly cut areas on the bottom of the right side. Not the gap along the right edge from the top to almost the bottom. Insulation is missing in places. This home had 74 square feet of missing insulation, because batts are hard to install with maximum energy efficiency in mind. How many places on this wall is the insulation not going to touch the drywall.

Batt sideThis is a shot of a wall built in 1965 with batt insulation.  Not much different from today. The installers stapled the batt to the side of the framing. You can see the gap along the side of the 2×4.  This space allows air to move inside the wall and prevents the insulation from working as intended. This can be a lack of training, supervision, knowledge or in some cases trades working against each other. Some drywall installers will not guarantee their work if the batts are face stapled.

This raises the question the builder was asking.  How do I install insulation to maximize the energy efficiency and maintain the drywall guarantee and not drastically change the costs.

The answer was a Blown In System.  Using a loose fill fibrous insulation the contractor can blow the fibers into a netting material stapled to the studs.  There are contractors that do this regularly with mineral wool, cellulose and fiberglass, the three main forms of fibrous insulation. The insulation contractor uses a Blown-In-Blanket© System.  These certified installers receive training and certification based on Professional Standards published by the High Performance Insulation Pros.  Here is their website.  BIBS Sink

This picture shows Blown-In-Blanket© System on a kitchen wall.  I chose the kitchen wall because all of the electrical and plumbing running through it  Very hard to properly install batts. Very easy to install BIBS and maximize the energy efficiency.  BIBS blown in at 1 pound per cubic foot in a 2×4 wall provides R-13 insulation. At a density of 1.8 pounds per cubic foot it provides R-15 in a 2×4 wall. These ratings have been verified using testing standards from ASTM C.665, and C.518. How does the builder know it was done right. Visual inspection helps and the contractor can weigh a cubic foot taken right out of the wall.

In my case as an Energy Rater, the HPIP Association has provided me with a Density Checking Kit to also verify compliance with their professional standards.

I leave you with two Infrared Images.  The Right is a wall with Fiberglass Batt Insulation. The Left is a wall with a BIBS installed insulation.  If the Heat Transfer Resisting properties are consistent over the entire wall, the color will be the same or close.  Take a look and decide for yourself which works better.

Screen Shot 2014-07-11 at 5.09.57 PM

 

 

 

 

 

Those Pesky Directions

How many times have you started into a project and had to stop and redo some steps?  How many times have you finished and then realized that you had extra parts?  So what do we do?

Insulation RulerWe go back and read the directions! The manual!  It is so common there are several acronyms for reading the manual.  Directions written by the manufacturer serve several purposes. Some of the cynics around, including myself, realize there is a bit of self promotion and defense in these instructions.  We should also realize that the manufacturer has probably tried to put a few of these together. He may be sharing his wheel with us, so we don’t have to invent it ourselves.

Most importantly, the manufacturer knows how the piece was engineered. The directions take that knowledge and apply it to how the equipment is set up, used or installed. Equipment changes over time. New features are added, materials change and the way it used to be done, is not a good idea.  So, read the manual.

See the attic rafters above. This is the top of a vaulted ceiling, and the insulator has properly placed an insulation ruler.  In a few weeks, blown insulation will be installed and the tech needs to measure how much. The use of the ruler and blowing the insulation level are two of the biggest helps to installing blown attic insulation.  And Yes! They are in the manual!

The choice of this picture isn’t the insulation ruler, it is the nail grid on the ceiling joists. Machine applied in the truss shop, it is fast easy and effective.  Notice the upper right hand corner of the grid.  That is a sharp edge. Be careful, it will cut things.  Hands, pants, shoe tops. Yes! All of those and don’t ask me how I know that!  My wife makes me carry a first aid kit with lots of bandaids for a reason.Duct 1

The house I finished a rating on yesterday had these nail grids on the floor trusses between the basement and the main floor. It also had the HVAC Ducts run between and through the trusses.  The contractor on this job uses sheet metal supply plenums and take offs. He uses the flex duct to form the return air side of his duct system. Yes!  Flex duct gets torn also. Especially with a nail grid.

Two weeks ago, I tested this home. The duct system was very leaky.  According to the Quality Installation Verification Standard written by the Air Conditioning Contractors of America, it was leaking 100%. Wow!  I’ve tested this contractors work before. He always does better than this.  So I ran the test again. Checked my set up.  No change. So I called him.  Shon came right out.  He looked over the system and immediately saw a couple of problems. Including this section of flex duct.

ZeroNow, two weeks later, his crew has reworked their ducts. I’m back to test it again.  I run the same test and scratch my head.  What leakage –  I can get the readings right. The picture left shows no air flow, on the right side, and a very low pressure difference, on the left side of my manometer.  The procedure is to have the Blower Door depressurized the house. Then you depressurized the duct system with the duct blaster to equalize the pressure.  When the pressure difference comes down to Zero, you read the leakage to the outside of the house.

So I checked my set up and tested again. Still no readings.  So ….   I read the manual.  In this case a Field Guide from the Quality Folks at my RESNET Provider and The Energy Conservatory that makes my equipment. I read it twice.  Then it hit me.  This line: Check the duct pressure. A negative duct pressure indicates leakage to the outside. If the duct pressure measure Zero with the Blower Door running, then the leakage to outside is Zero CFM.

As you can guess, the leaks when I tested two week previous prevented this result. What changed?  The crew had found a small tear in the flex from one of the nail grids. Did you see it in the picture up above?  I can see it because I know it is there.  So I enhanced the image and that one is posted below.  To get around all the reflections of the silver colored coating, I placed a piece of white plastic inside the flex so the hole would show.Duct 2

So reading those pesky directions on a test that I routinely run, gets me the right answer. What about the Heating and Air Contractor.  Shon does good work on his jobs, because he follows the professional guidelines and tests his work.  In this case he knew the test, he knew what it meant and immediately saw how to fix it.  What would have been the result if this basement had been finished out and then he had to remove drywall to fix it?

Why is ZERO duct leakage to the outside important?  I don’t want to pay money to heat or cool the outside. If your ducts leak very much to the outside or don’t distribute the air properly, then you are spending more than you need to.  Installing ducts with no leakage to the outside in a new home is an easy process for the contractor. It give the home owner a much better value.

DuctLeak2 copyYes!  I have found duct leakage behind drywall also.  Here is an infrared image of a finished basement ceiling. The homeowners complaint is there is no air flow into his bedroom and it is cold in the winter and hot in the summer. To get this image I turned the furnace up to about 80° F. It was usually about 73° F.  I stretched out on the basement floor and waiting for the heat from the furnace to leak into the cavity between the main floor and the basement ceiling.  In a couple of minutes I had heat patterns showing.  You can see where the duct is running up and down next to the floor joist. Interesting heat spot to the right next to the other joist. Also across the joist and over to the left joist. So we are seeing the duct and hot spots on each side 16 inches away.  Lots of lost heat not getting into his bedroom.

The home with the infrared picture had the leaks on the supply side of the duct system. The one I tested yesterday had the leaks fixed on the return side. I could not have tested with the infrared in the same way yesterday.

So, on this Independence Day, we celebrate!  We celebrate our freedom to be in a business we love, where we can do some good, and make a difference.  And yes, where we can make a living for our families.  We also celebrate the freedom to know our job, to continue to learn as things change and to utilize our professional standards to keep our customers happy and satisfied.

Have a Safe and Happy 4th of July!

Credits:  Photos, myself.  Insulation Ruler –  Northstar Comfort Systems Install.  Duct system install tested yesterday with no leakage to the outside — Shon Peterman and Midwest Mechanical.  The audit providing the infrared image, my customer Craig. The new home tested yesterday courtesy of Sharon and Wade Wilkinson of GJ Gardner Homes. It is in Fontana.

 

Build Your Own Home Energy Audit

A comprehensive Home Energy Audit takes time and covers a number of areas. It provides lots of information and recommendations.  A homeowner may choose to limit the inspection to those items of their concern.

The energy efficiency of each home combines an analysis of the components of the home and how well they are installed.  Think of a bucket of water, the bucket is the walls and ceiling of your home. A pinhole in the bucket will drain the water from the bucket and the heat from your home!

A Home Energy Audit looks at the ability of each building component to resist the transfer of heat. The air tightness of each component is also reviewed.

This post covers a description of each part of a comprehensive Home Energy Audit.

Pricing, previously contained in this post, is posted separately.

Utility Analysis

The actual usage over the last 12 months of Electric and Gas is compared to the home size and evaluated. This requires information from the Utility Companies.

Infiltration Testing                 

(Multi-point Blower Door Testing with Thermal Imaging and Indoor Air Quality Analysis)

Everyone has felt a cold draft at one time or another. Since the air blew in and the house didn’t pop like an overfilled balloon, the air blew out somewhere else.  This test simulates a 20 MPH wind on all four sides of the home at the same time. It allows an actual measurement of leakage and it identifies the leaks. This allows a specific plan for the leaks in your home to be fixed.

The recommendations will include effective measures to improve indoor air quality, not just install what the salesman has in-stock. If you have de-humidifiers running this Testing is important.

Ceiling Evaluation:

The ceiling and attic areas are examined for insulation, ventilation and thermal bypasses. This is done from the outside of the home, the inside in all rooms and from the attic. It may involve remote camera usage. If Infiltration Testing is part of the package, information from the Thermal Imaging portions are applied to the ceiling Evaluation.

Foundation Wall Evaluation (below grade):        

In most homes a major source of heat loss is from the crawl space, the slab or the basement walls. There are generically referred to as the foundation of your home. Traditionally, builders have confused the thermodynamic principles involved, with hot air rising and heat loss, to falsely assume that basements cannot be kept warm.

Wall Evaluation (above grade):

Homes over twenty years old, or homes with a major insulation failure may benefit from a specific wall evaluation for walls above grade.  It is part of a comprehensive  energy audit. All wall evaluations are conducted with Non-Destructive-Test Methods to start. Depending on the home, the type of construction, access to various areas, further testing that involves minor holes being drilled will be discussed with and approved by the homeowner before the end of the evaluation.

The condition and energy efficiency of your exterior siding is done at this point.            

Equipment (furn. AC, hot water):                    (Includes safety checks on Gas Fired Equipment)

Your heating and cooling equipment is a large investment. What are the efficiency ratings on your existing equipment and what is available on the market? How does a home owner sort out fact from sales pitch.  This inspection includes safety testing for gas fired equipment. Furnace, Heat Pump, AC, Hybrid Heat Pump, are included.

Windows and Door Evaluation:           

Windows are advertised everywhere.  On the Radio, TV, the newspapers and other print media all carry large volumes of sales pitch for replacement windows. The FTC has fined some window companies for outlandish claims on energy savings.

Are your windows an energy problem? Can those energy problems be fixed or should the windows be replaced? What is the best for my home?  Low E, argon filled, double pane, triple pane? How does a double pane window save energy?  All these questions and more are answered. And you get the answers from someone that does not have a financial interest in your purchase or non-purchase of a product.

Windows and Doors are both holes in the wall.  From an energy loss standpoint there is not much difference. Doors are not as heavily advertised, but they are pushed after the salesman gets to quote your home.          

Computer Modeling and Reporting

The Comprehensive Home Energy Audit provides a complete energy usage model and reporting of problems, recommendations and solutions. Interactions between building components are considered in the computer model. You can go from the report to soliciting firm prices from a contractor or doing it yourself with this report. This reporting will qualify for applying for and Energy Improvement Mortgage if you are buying a home, or refinancing your current home.

If you choose various parts of the Home Energy Audit, written reports and recommendations will also be provided. These will all you can go from the report to soliciting firm prices from a contractor or doing it yourself with this report. The reports are limited to the selections made. Interactions between building components are not considered.

Duct Leakage Testing Not included in the comprehensive audit.

Some comfort and energy loss issues involve improperly installed ductwork. Testing is easy. Fixing these problems can vary in complexity depending on the home.      

Lighting and Appliances Not included in the comprehensive audit.

Incandescent, halogen, CFLs, LEDs, which is best for your home?  Not every fixture needs a high efficiency light! Should I get a new fridge or other appliance?  All these are part of the Lights and Appliances.

Bonus Room (over the garage, or in the attic) Included in the comprehensive audit.

Rooms placed over a garage or in the attic are a special case. They are part of a comprehensive audit. They can be an individual item, with infiltration testing, due to the unique construction problems with them.

For more information or to schedule a Home Energy Audit:  

V / T  316 641-5258  or  email:  info@efficientenergysavers.com

The Foundation of your Home: Slabs, Basements, and Crawl Spaces

What is under your home?  I hope you have some solid ground.  If you do great!  Now how did your home builder get to solid ground?

The first of a multi-part topic.
Left: Slab on Grade ready for walls. (courtesy of Wikimedia Commons)

That can be done with a slab on grade construction. It can be done with a basement.  It can be done with a crawl space. A home can use a combination of methods. It is not at all uncommon to see homes with 3 of the 3 approaches.

Above Right: A slab on Grade shows heat loss through the slab. This is under the front door. Inside temperature is 72 degrees, outside is 14 degrees. The cold (blue) pile is snow.

Basements are generally a below ground space that contain living area and is capable of being heated.  This does not include below ground spaces that are for storage or storm shelter. Basements may be full, view out, or walk out types.

Left: Typical craw space, showing rim joist. This has about 30 inches of concrete and a 2×8 floor joist.

Crawl Spaces are below ground space with no living area.  They are generally low head room spaces, hence the name – Crawl Space.  Some you can actually walk in.  I have seen several crawl spaces that are only 12 – 15 inches high, most are 30 – 48 inches high.  Crawl spaces generally have duct work for the HVAC system, plumbing, and wiring. Occasionally the furnace will be in the crawl space.

Below Right: This addition has 2×10 floor joists with support beams. It provides about 8 inches of clearance between the floor and the beam.

Many homes have a basement with crawl space. Builders in one geographical area tend to build with the same approach.  Another geographic area will find another approach being common. In places where the water table is only a few feet below ground you would be hard pressed to find a basement.  In places with large rock formations near the surface, the builder could use any of these approaches depending on how deep the rock is on the building site.  In tornado alley, basements are always welcome for a storm shelter, and some families use their crawl space.

How do these spaces impact the energy use in your home?

Depending on the age of the home, the below ground walls of the house could be of stone, block, rubble fill or concrete.  These are hard materials that have similar physical properties.  They have high thermal capacity; they will stand extended periods below ground in contact with dirt and moisture.

Thermal Capacitance

Thermal Capacitance is the physical characteristic of a material to hold heat. How long does an object stay hot after being heated? The longer is retains heat, means a higher thermal capacitance.

Above Right: The Rim Joist is where the basement window is. Note the heat transfer through this area. It is somewhat diffused by the brick veneer. Outside temperature is 20 degrees, inside temperature is 68 degrees about 10 pm.

Growing up in Southern Nevada, I lived in a house constructed of concrete blocks.  My bedroom was on the east side.  An 8 foot fence stood 4 feet from my bedroom wall. The sun did not shine directly on my bedroom wall until about 11:00 AM and by 1:00 PM it had passed over. I would go to bed at between 10:00 PM or 11:00 PM and the wall would still be well over 100 degrees. So that wall loaded enough heat during that 2 hour period, to still be over 100 degrees 9 hours later. If a material can hold heat like that, then it can also hold the absence of heat, or cold, in the same way. Concrete, and stone have a high thermal capacitance.

Any basement or crawl space wall will extend both above and below ground. It is not uncommon to see a wall 1 and ½ feet above ground and the rest below ground.  If that portion of the wall is un-insulated, the heat will flow through the wall. Heat will flow in during the summer and out during the winter.

The Infrared Image (Above Left) shows a concrete basement wall. The upper part is showing relatively cooler and the bottom relatively warmer. The mid-point of this image is about 4 feet below the top of the concrete wall. The outside temperature is 45 degrees. Imagine the difference at 20 degrees?

What can the homeowner or the builder do to these walls for energy savings?

Insulation is the obvious answer. What kind of insulation is a better question. I would specify the insulation, you choose, to be installed correctly, that it be durable and properly protected from damage.

Before we actually get the insulation, we need to make a stop.  Air movement through and around the insulation will significantly impair the effectiveness of the insulation.  So lets tighten up the area.  The first area to look at is the Rim Joist.

This is on the Rim of the foundation wall. The floor joists, 2×6 or larger or a truss system rests on the top of wall. If you look at any of your rim joist area you will see a number of things.

(Right) An IR image of a Rim Joist. Outside temperature is 70 degrees. This is a south wall and the sun has been shining on it. Lots of solar loading.

Usually your outside faucets come through here. The gas line enters the house at this point, the air conditioning copper tubing, and perhaps other utilities.  I’ve seen dryer vents installed here, and even the flues of conventional hot water heaters.  Those are usually easy to spot because the flue then goes up the side of the house above the roof.  If you have a tankless hot water heater, the PVC flue may well exit the area through the rim joist.  Then you have joints, knot holes and it is not uncommon to see actual holes where something was there and has been removed. All these holes and gaps need to be sealed up.

Remember that insulation does not stop air movement. Caulk is great for stopping air leaks.  You can use caulk straight from the caulking gun.  Some gaps, may need  backer caulk also called rope caulk.  This is ½ inch strands of caulk like material that you can push in by hand. Then come back over it with the caulking gun.  Smooth the caulk with a tool, or your finger to make it go a little farther, make it look a little better and to eliminate any bubbles that might have formed.

If the gap is larger you may wish to use some of the foam in a can. This one part expanding foam uses moisture to cure. Use along a rim joist would probably have enough moisture to cure properly. Take seriously the caution, to not wash with water if you get in on your hands or elsewhere.  Water will cure it.  It will take a couple of weeks to wear off.  If you don’t ask how I know that, I will not turn red in the face!

You can also use rigid foam on larger openings.  Just remember to caulk the edges.  Also remember to caulk the joint between the sill plate and the concrete. New builders use a gasket now,  a bead of caulk is always helpful.

If the rim joist has insulation, you can remove it to do the air sealing.  You can replace it after air sealing, just be sure to install it properly. It is most likely a fiberglass batt, it may have a paper backing on it, it may not.  The paper backing may be facing the inside or the outside. I’ve observed all these in the same house.  The paper backing is a vapor retarder. It should face the warm in winter side of the wall in this area of Kansas.  (Climate Zone 4)  The batt insulation should fill the space between the floor joists, the concrete rim and the subfloor. That space is probably 8 inches deep, 16 – 24 inches wide and 6 ½ to  24 inches high.  Most common would be 8x16x 7.5 inches.

Since the Rim of the foundation wall is usually 8 inches wide, that would allow, at R-3 per inch, insulation of R-24.  I see R-19 batts commonly used here, older insulation jobs or homeowner installed jobs will show R-13, or even R-11.   If you have a ceiling in your basement, you may only have access to part of this area.  You can work in the accessible area and make a difference.

To remove a finished ceiling and then replace after the air sealing and insulation is completing will probably not be cost effective, even if you do not consider the effort of the Do It Yourself labor.

This is the first of a multi-part topic. We will look at Basements, both finished and unfinished, crawl spaces, and slab floors each in more detail.

Insulation: Properly Installing Fiberglass Batts

The last two posts have concerned issues of properly installing Fiberglass Batt type insulation.  That discussion revolved around newly installed insulation.  Inspections were done after the insulation was there and before the drywall was installed.

In this post, I would like to address some of the problems I see after the home has been in use.  The Batts in these cases were installed anywhere from 10 years ago to 40 years ago.  We all have experienced the issues of time. What changes does time bring to a Fiberglass batt?  This leads to ‘Why proper installation is so important.”

I have audited home that were built more than 100 years ago.  My friend Bud, has discussed auditing homes that are much older, 150 – 250 years. A home lasts a long time.  Every month the home gets Energy Bills.  Are the Energy Efficient Features of the home keeping those bills at the level they were planned?  If a feature was improperly installed, probably not.

Best Practices for installing Fiberglass Batt type insulation include:

The insulation must be in contact with the Air Barrier.  In our Climate Zone the Inside wall is the Air Barrier.

This means the batts must be stapled to the face of the framing material; not to the side.  If you have the batts stapled that way, then they are not in contact with the air barrier.  This is illustrated in the Infared picture. Note the cooler colors near the top that are rounded and follow the framing down the wall, and the dark hole in the top of one wall cavity.

 

Batts showing air movement, not in contact

Batts not incontact with Air Barrier

A Fiberglass Batt must be covered on each of the 6 sides.

This one seems simple, in an exterior wall, the top plate, the bottom plate, the drywall, the exterior sheathing, and the framing constitute all 6 sides of the batt.  Now think about the wall that is formed between the end of the vaulted ceiling and the attic?  OK;  Drywall, Yes!; Bottom Plate, Yes; Top Plate, not usually; Framing, sort of; exterior sheathing, usually nothing.  So, we have 2.5 on these types of walls. Below is a picture of the end of two knee walls with no framing on a corner of a vaulted ceiling.

Knee wall from Attic Side

Solutions on Knee Walls:  Cover the top, back and the sides of the batts at the corners with an encapsulating material.  House wrap installed according to manufacturers directions is a good choice for an existing home.  Easy to get into the area and then apply.

A Batt should not be compressed.

OK!  Think about all the things running in walls.  Electric wires, pipes, CAT 5 cable; phone lines, cable TV, security system cables.

Poorly installed Batt Insulation

Poorly installed Batt Insulation

First, you have the installs that are done before the insulation is installed; typically the electric and plumbing.  The insulator can deal with these easily. The batt can be sliced, partly through, to allow the obstruction to pass through the middle, instead of stuffing the batt behind or pushing the batt into place on top the wire or pipe. It can be carefully cut to allow an electrical box.

Good Installation of Fiberglass Batts

Good Installation of Fiberglass Batts

For those tradesmen that follow the insulator, everyone else on the list above, it is not quite so easy. If they come before the drywall is up, then you may find holes in the kraft paper, and wires compressing the batt as it runs from 2x to 2x; or you may find something else. If they come after the drywall, your guess is as good as mine as to what the wall will actually be.

The infrared image below shows air infiltrating around improperly installed fiberglass batts on the other side.

Infrared Image Infiltration in Knee Wall

 

If you are renovating a wall in your house, and you choose to insulate; fantastic!  It will save you money.  Lots of insulation choices available, if you choose Fiberglass Batts, follow these concepts and you will maximize the effectiveness of your insulation.

 

The only other item you should do, when renovating and insulating is to air seal and stop those cold drafts. That is a subject of another post!

Thermographic Imaging

If you’ve been reading about Home Energy Audits, you’ve probably seen a thermographic picture of a home. These color pictures show temperature differences. The windows show up as white or red, the walls show a darker color. They’ve even been part of some TV Commercials.

Earlier this month the National Standard for Thermographic Imaging was published. The purpose of a national standard is to enable two different energy auditors to obtain valid results with the camera on the same building.

The use of a difference in temperature to show where a house is loosing energy is very interesting. It can be skewed, if the picture is not, taken with a proper understanding of the limitations and potential external causes of temperature changes. Wind can cause a change in the temperature difference. Is the wind blowing from the East and you are taking a picture of the North wall, so some of the temperature difference is blown away. If the wind is from the south, is the difference increased?

The answers to these and other questions will be revealed for me this week. I will be in Manhattan at the Kansas Building Science Institute, working on my certification as a Level 1 Thermographer.

I will try to post some information during the class, so you can follow along my journey.