Monthly Archives: July 2014

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.

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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.