Category Archives: Energy Audit

Follow Up Thought for Friday’s Summer Cooling Tips.

DeeDee and I started outside. The info from the back deck did not make the cut and I let it slide when i did the blog summary of her story.  So …

Shade Works

This is an Infrared image on one of my first new homes.  The 2 foot cantilever bay clearly shows the effect of the shade. There is a 20° F difference in the temperature between shaded and unshaded areas of the wall. The high temperatures on the side of the house are in the area of 128° F.  It is 97° F when I took this one.

Shade works.  Building a new home with a south facing set of large windows. It is worth your money to have a deck with a roof, or pergola over it. If you have an existing home, the Pergola is a great idea.

Concepts like this have been recommending in my Home Energy Audits.

Why The Way your AC is installed Matters! Part I

Screen Shot 2016-06-24 at 8.49.56 AMThe Air Conditioning Contractors of America (ACCA) publishes ANSI Standards for HVAC Contractors to follow. These professional standards are well known in the Home Performance Industry and the HVAC Contractors.  I found a link on their website this morning to a study showing the problems caused with problems that can easily occur if the Industry Professional Standards are not followed.

I covered a study from California about these types of faults recently. This one was completed by NIST.  The National Institute of Standards and Technology, a part of the US Department of Commerce.

CookA quick review of the reports shows many technical details and mathematical formulae.  That forms the back ground for comparisons with other studies.  However, they did write in some plain English for the rest of us. Here is one of their findings, about the performance of heat pumps.

A Heat Pump provides both heat and air conditioning. It is efficient because it moves heat.  In the summer, it moves heat from inside to outside, just like an ac unit.  The same technology and principals. In the winter they move heat from outside to inside. Yes, there is heat outside at cold temperatures.

Think about your refrigerator. When it gets up to around 40° F inside, the unit turns on and finds the heat in that 40° temperature and moves it out of the refrigerator to keep your food cool and fresh. If you watch your temperatures outside, you know more heating is done at 40° and above than at 20°.

This findings for a heat pump cooling your home apply to geothermal heat pumps, regular heat pumps and to air conditioners. They are all working on the same principals.

The first fault they report on is having the wrong size unit.

Changing the size of the heat pump for a given house – either undersizing or oversizing – impacts the heat pump performance in several ways:

  • Cycling losses increase as the unit gets larger; the unit runs for shorter periods and the degraded performance at startup has more impact (parameters used in simulations are: time constant = 45 seconds, or CD ~ 0.15).
  • In the cooling mode, the shorter run periods impact the moisture removal capability (i.e., ability to control indoor humidity levels) because operational steady-state conditions are an even smaller portion of the runtime fraction.
  • In the cooling mode, continuous fan operation with compressor cycling greatly increases moisture evaporation from the cooling coil. However, this impact is minimal with auto fan control (indoor fan time ‘on’ and ‘off’ the same as that of the compressor), since only a small amount of evaporation occurs with the assumed 4 % airflow during the off-cycle with the indoor fan off. If the air conditioner controls include an off-cycle fan delay – that keeps the fan on for 30-90 seconds after the compressor stops – then the impact of off-cycle evaporation is in between these two extremes (Shirey et al., 2006). The results in this study assumed auto fan operation with no fan delay.
  • Heat pump sizing also affects the level of duct losses.

A improperly sized unit will run for shorter periods, and will turn on and off more often. That is just like driving your car around downtown Wichita. Lots of stop lights. Compare you gas mileage to highway driving at a steady speed of 55 mph or higher.

OK, I know efficiency isn’t as important as being comfortable. So the next item is the comfort side.  Running you AC like your car in Down Town, doesn’t remove the humidity as well. Your house temperature is cool, but the humidity is high and you turn down the thermostat again to get rid of the humidity. Pretty soon you are cold, and yet you are not comfortable because you feel the high humidity.  Then you go out and buy a de-humidifier.

The third item is also a comfort issue. That is the advice of many HVAC technicians to set your AC fan to run continuously. When the AC shuts off and the fan keeps running, the humidity the AC just removed from your house is put back in. Oops!

DadBabyESFinally the report mentions duct losses. They are important in a home that has no basement. In those homes ducts can be located in the attic or the crawl space, or both. If you have one of those houses, I would be glad to address that one in the comments. So leave a comment if your are interested.

How do you get a right sized AC unit?   Your HVAC contractor can run a series of calculation found in the professional standard from ACCA Manual J.  It is a Load Calculation.  For cooling it considers the insulation in your home, the windows and size of the home and other details. It can be done on a paper worksheet or a spreadsheet. Both are free from ACCA. Most contractors have a software program to run these Load Calculations.

Load calculations for cooling, are a balancing act. The homeowner wants a home that is cool in the summer and in Wichita, they want the humidity controlled.  Without a lot of formulae or detail, how do, the rest of us, understand a cooling Load Calculation?

My advice is to look at the out door design conditions that must be factored into the calculation.  For cooling, ACCA Manual J has 6 outdoor conditions.

  • Two relate to location. Cooling in Atlanta, is different from Wichita and is different from Denver.
  • One is the outside temperature. The choice is a temperature that covers all but 1% of the hours in a year that require cooling for that location.
  • There are four design conditions that relate to Relative Humidity.

This obviously requires a balance. If your contractor varies from these conditions, it still must balance.  You may or may not like the balance, if one item is changed without consideration of the others.

What should you as a consumer do?

Insist that professional standards be used.

Require that all the items of the standard be measured and reported.

For Air Conditioning the standards require measurements of:

  • Air Flow Actual compared to manufacturer’s requirements. (+/- 15%)
  • Air Flow Static Pressure (ESP)  Actual within the manufacturer’s acceptable range
    • AND
  • No more than 25% or 0.10 IWC over the design pressure for the duct system.
  • Refrigerant Charge Verification
    • Superheat method:  Within +/- 5% of manufacturers superheat value.
    • Sub cooling method: Within =/- 3% of the manufacturers subcooling value.
  • Measured line voltage and low voltage circuits for voltage and amperage. These values shall be within the manufacturer’s requirements.

If you have good air flow in some rooms and not enough air flow in other rooms, your home has an air balancing problem. Have your system checked and balanced. This is known as test and balance or TAB. I have done test and balance work. Generally, the air flows should be within 20% of the design or application requirements.

And, Ladies and Gentlemen, Here Comes The Sales Pitch ….

thermal metic headerSince 2007,  all of the large insulation manufacturers and trade associations have been funding research of the Thermal Metric Project.  This project was conducted by Building Science Corporation, a respected source of independence and factually based information about energy efficiency in homes and other buildings.Batt side

The project testing Spray Foam, Fiberglass, rigid foam and cellulose. It studied batts and blown in fiberglass. You can find their final report, issued in June, 2015 on their website.  There are a lot of detailed measurements, graphs and data in the report. It is a good report that will serve well over the years.  The headlines are now beginning to show up in various social media. These are taken from the Executive Summary of the Report. When you see these in literature or social media of either insulation manufacturers trade associations, or contractors —  take the presentation with a couple of grains of salt.

So which ones will be spun for public consumption and what can one do to avoid a sales pitch. Let’s look at the main conclusions.

  • When walls are constructed with the same installed R-value in the stud space, and are air sealed, both inside and outside (i.e. there is effectively zero air leakage through the assembly), they exhibit essentially the same thermal performance regardless of the type of insulation materials used.
  • All of the tested wall assemblies were subject to thermal bridging regardless of the they of insulation material used in the stud space. Thermal bridging through the framing resulted in roughly 15% decrease in thermal performance.

There are seven more bullet points in the Executive Summary that get more technical then most builders and almost all home buyers want to know. For those that do, it is another blog post or reading the report themselves.tweet1

Here is the Tweet that I saw this morning and thought it was worth a Blog Post.

Notice the comparison is Cost.  Does this cost include the cost of proper installation and air sealing?  I have no idea. Following the links back to the website, I did find a cost of $4,000 for the batt type insulation.  Nothing about the size of the home or other details to make a reasonable comparison.

There is also no indication that batts are rarely installed according to manufacturer’s directions.  In the picture at the beginning, the batt is not installed according to the manufacturer’s instructions. In this area Dry Wall installers, will not warranty their workmanship if batts are installed according to manufacturer’s directions.

15aI included the Project’s second bullet point about Thermal Bridging.  Too many times, we hear references to an R-13 wall or R-19 wall.  This only refers to the space between the studs, not the wall.  Thermal Bridging represents the decreased value of insulation because there is wood in the wall.  Wood is R-1 per inch.  So each stud is 1 1/2 inches of R3.5 in a 2×4 wall.  This is the 15% decrease in performance.

The 15 percent also uses the recommendations from NAHB from their 1977 research on Optimum Value Framing. The National Association of Home Builders conducted this research to find ways to remove expensive wood studs almost 40 years ago.  Wood Studs are more expensive now, and still increasing. This IR image shows batts not installed according to manufacturer’s instructions (The Dark Blue Areas). It also shows the wood framing as a thermal bypass, mostly green with some blue on the top plates.

In the end, for the home buyer, a way to sort through all the sales pitch exists. For new homes of half of the new construction in 2013 was verified independently by a HERS Rater.  I do this in the Wichita metro area for builders and new home buyers.

Previous Blogs of Interest:

Installing Fiberglass Batts

Insulation in Your Walls

 

 

What is an Energy Audit Worth?

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

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

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

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

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

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

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

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

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

IMG_1272 copy

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

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

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

 

This simple table will keep your home cool

Table 1 Jean-Sébastien Lagrange and Raphaël Ménard with their Zero Energy Furniture Climatic Table.

Consisting simply of a surface and legs, the table is one piece of furniture that has remained largely the same for thousands of years. But now, a French design duo has come up with a way to turn the humble table into a means of climate control that doesn’t use any electricity. Paris-based industrial designer Jean-Sébastien Lagrange teamed up with French engineer Raphaël Ménard to create the Zero Energy Furniture table, also known as the ZEF Climatic Table. The ZEF table looks like any other with a sleek design of a solid plank oak top and angled legs — but it could hold the secret to cutting energy costs by as much as 60%.

 

Table 2A close up of the ZEF table, which could cut energy needs by as much as 60%.

 

“We wanted to see if it was possible to address climate and energy issues on a furniture scale,” Lagrange told WIRED.

Beneath the oak table are a series of phase-changing materials (PCMs) placed between the wood and anodized aluminium bottom. The materials soften when the surrounding room reaches around 71 degrees, absorbing the excess heat, and then harden once the temperature dips back below 71 degrees, releasing the trapped heat with the help of the aluminium and causing a noticeable change in the room’s temperature.

Table SpongeThat means the table is essentially working like a “thermal sponge,” as Lagrange and Ménard put it, sucking up excess heat and then releasing it once the room becomes cool enough.

According to the inventors, the table has the potential to reduce heating needs by as much as 60% and cooling demands by as much as 30%, which could save a lot of money as well as energy.

It’s a feat of engineering that makes the most sense in homes that don’t have climate control.

In climates where the temperature can drastically swing from hot to cold in short spans of time, the ZEF Climatic Table is most useful. For example, if a room heats up on a sunny day and then the temperature drops at night, the ZEF table would make the climate in that room more consistent.

The ZEF table works best in rooms that undergo significant temperature changes frequently.

The Full Article on Business Insider Australia


 

This article is reprinted in part from the above digital source. It was originally from Wired and was brought to my attention by ASHRAE. Phase Change Materials have many applications in heating and cooling. One phase change material everyone uses is water.  At 32°F it changes from solid to liquid or liquid to solid. Of interest to energy efficiency are materials that act in this way around 70°F.

A New Generation of Smart Sensors Aim to Track the Air You Breathe

AQM bitfinder

HARDWARE STARTUPS WANT TO TELL YOU ABOUT YOUR ENVIRONMENT, IN A WAY YOU CAN ACTUALLY UNDERSTAND.

New gadgets are arriving that are designed to show you in real time just what you’re breathing in, with Internet-enabled indoor and outdoor air-quality sensors.

But one of these devices’ biggest challenges, their makers say, is keeping customers engaged by making sure they understand what the readings mean and how to act on them.

“What we think is really important with this kind of product and services, is that we really need to connect on the human level,” says Ronald Ro, cofounder of Bitfinder.

Having participated in the most recent round of the Internet of Things-focused R/GA Accelerator, Ro’s company plans to release its Awair indoor air-quality monitor this summer. The speaker-sized units will share the market with existing smart indoor-outdoor weather stations from French firm Netatmo, and ultimately with wearable environmental trackers from Vancouver-based TZOA, also slated for release later this year.

The Awair will monitor air temperature and humidity, along with levels of dust particles, carbon dioxide, and a class of chemicals called volatile organic compounds, which includes solvents like acetone and benzene and a range of various other substances of varying toxicity.

(Read More – Take the link below)

I found this article on Fast Company written by Steven Melendez The link will get you to the full story.

The Energy Guy Gets a New Ride …

EG 4

 

OK!  Why a new car?  200K miles on the old one maybe?  Then being able to carry most if not all the equipment I need in one trip?  A moving billboard?

Yes to all of those!  So I had a Party.  Our Derby Chamber of Commerce hosts a Business to Business time once a month from 8 – 9.  Coffee and stuff that is guaranteed to add to my waist line.  They do a Ribbon Cutting when you join.  So I had mine this morning.  Here is the crew that came out for the Ribbon Cutting.EG 5Look closely, those are wooden scissors. Ceremony! So here is the next one with real scissors.EG 2Lots of wonderful people here.  Did they all come for my Ribbon Cutting?  I’d like to think so. This month the sponsor was Nova Care of Derby.

I’d like to thank the Derby Chamber, Mark and his staff Tim and Lindsi for helping out with this party.  I’d also like to thank my Ang’s  –  I had two guests today from Wichita.  Angie Tejeda and Angee MacMurray.  I posted a blog post a few weeks ago about a Twitter Conversation with Angee, take the link. I wrote about Igloo’s and my future plans.  No, I’m not building an Igloo.

Jen and Rick Brown showed up also.  I teach Sunday School with them. Thank You, Jen for the fine photography here.  And Thank You to everyone that came out to my party.  I must also acknowledge the the great folks at Mighty Wraps in Wichita.  Justin and Lori were great to work with during the design and application of the wrap.

If you see my ride around town – please Wave!

Passive House Work in Wichita

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

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

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

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

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

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

 

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

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

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

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

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

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

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

Report from the Passive House Conference in Maine

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

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

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

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

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

 

A Healthy House Part 1b: How Dry is Dry

In the first installment of A Healthy House, we looked at water issues.  Specifically, water from the outside of the home.  Most of this type of water is directly from what the weather refers to as ‘precipitation’, or rain and snow.  Even the ground water we looked at were related to rain and snow.  There are other types of water issues.

pipe_leakFirst would be a plumbing problem.   You can have a leak in a water pipe, or a sewer line.  I know, sewer lines generally do no leak, they slow down, or plug up and then back up.  Either way there is water in the house, and someone is cleaning it up.

Many plumbing leaks like this or sewer problems are an ongoing maintenance issue. Not much can be done during construction.

Situations like the drain line, getting stepped on and thus the floor drain is the highest spot in the floor is a construction issue.  It takes all the trades to help finish the building correctly. The plumber may have done it right, only to have someone else step on the line.

A nail accidentally driven next to a supply pipe, may cause a problem later. If you have copper, 2 dissimilar metals touching will eventually cause a leak.  A nail next to a plastic line that moves, can also create a leak. You may find great work in a home and good, conscientious, plumbers, drywall installers, electricians and others. Sometimes these defects are hidden, like the tip of the nail inside a wall. So maintenance becomes an ongoing effort.

daltile-Bath-Accessories01Thoughtful design can help.  Specifying hard surfaces for areas within a few feet of tubs, showers, toilets, sinks and laundry facilities is important. Most leaks, spills and accidents will occur in these areas. An easy to clean surface that doesn’t hold the moisture is essential.  Carpet has it’s place, just not near water. Some floor coverings such as linoleum or cork type flooring may also not be appropriate for these areas. (Image to the right is courtesy of DalTile.)

 

Hard SurfaceAppropriately located floor drains can help.  Use of appropriate materials in the floor structure is a good thing. Most homes in this area have a basement, meaning a wooden subfloor is under and of these facilities on the main or upper floors.  The proper type of sub floor in these areas is crucial to keeping the home dry. It is also helpful in drying, when the floor does get wet and not encouraging mold growth, as many types of common building materials.

This post is part of a series of posts on A Healthy Home.

A Healthy Home

Healthy HomeBuilding a new home, gives the homebuyer an opportunity to build in all the things they want. The floor plan, bedroom arrangement, windows are all important.

Also right up there is a house that is healthy. Everywhere you look, someone is pitching, this is healthy for you.  We have lots of buzz words for healthy.  Organic, whole grain, anti-oxidant, reduced fat, low sugar, wellness, all-natural are but a few. How do you make a house into a healthy home?  It starts with design and a few simple objectives.   Ideally, a healthy home is:

  • Dry
  • Clean
  • Well Ventilated
  • Combustion by-product free
  • Pest Free
  • Chemical Care
  • Comfortable
  • Safe

read beforeIt seems fairly simple.  We want a roof over our head to keep the elements out.  Hot or cold, rain or snow, we don’t want them in our home.  The dry home starts with a well constructed roof.  That keeps the weather related water like rain or snow out. Then the walls, and the foundation.

Clean may be obvious, or not. Well Ventilated and Combustion by-product free, along with pest free, no toxic chemicals, comfortable and safe seem also to be obvious.  There is a saying about the Devil being in the details.  It is certainly that way in building a home. So a few details on these topics that make up a Healthy Home are important.

I will be posting a series based on the Healthy Home. We will take a look at each of the points listed above and what they mean to the home owner.

Part Ia   How Dry is Dry       Bulk Water from Precipitation

Part 1b  How Dry is Dry       Bulk Water From other Sources

Part 1c  How Dry is Dry       Water Vapor

Part II    The Home Starts Out Clean

Part 3    Well Ventilated

Part 4     Free of Combustion Byproducts

Part 5     Pest Free

Part 6     Chemical Care