Category Archives: Comfort

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.

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.

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

 

Buying an Energy Efficient Home

HomePOHThe Annual Spring Parade of Homes is on the last week in the Wichita Metro Area.  There are some great homes out there. Lots of amenities to consider. Everyone has their own lifestyle and looks for a floor plan to fit. They all have their sense of taste and can look at the colors, finishes and visual effects.

POH_S15Every builder says they build an energy efficient home. Energy Efficiency is built in behind the walls.  It is usually not seen.  Energy Efficiency is about people and how they install the items that create the efficiency.  The specific items are less important then the way they are installed. Generally, the manufacturers install instructions must be followed.

Wichita – Sedgwick County has not adopted any code provisions for energy efficiency in new homes.  It may be legal to build a home with no insulation, but is that a wise decision? No one thinks so.  So how much is enough and is it installed correctly?  In this area we are reliant on the free enterprise approach energy efficiency in new homes.

Phoenix, AZ has an energy code, yet the free enterprise market based system has upped the game for buyers.  Here is a recent article in the Phoenix Newspaper about how a home buyer can see what is behind the walls.

Arizona-Republic-Features-of-ENERGY-STAR-HERS

Indoor Air Quality – Guideline Revision Public Comments Requested

imagesATLANTA – Public input is being sought into a proposed revision of ASHRAE’s residential indoor air quality guideline.

ASHRAE Guideline 24-2008, Ventilation and Indoor Air Quality in Low-Rise Residential Buildings, is the companion guideline to ANSI/ASHRAE Standard 62.2-2007, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings.  Guideline 24 provides information on achieving good IAQ that goes beyond the requirements contained in Standard 62.2 by providing explanatory and educational material not included in the code-intended standard.

Read Entire Article

 

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.

Passive House Verifier Training Part 1

PHIUSPHIUS (Passive House Institute United States) is one of two organizations in the US that promote and issue certificates for completion of a home that uses extremely small amounts of energy to heat and cool a home. The other organization is an affiliate of the German PassivHaus Institute.

This organization is based in Illinois. The goal is to make passive building principles the mainstream best building practice, and the mainstream market energy performance standard.

prosocoWhat is a Passive House? It is a home that people want to live in. It must be comfortable for the occupants and it must use very small amounts of energy to heat and cool; and for total energy use as well. RIGHT: A Passive House under construction.

Design for a Passive Home emphasizes energy efficient features that are installed during the construction of the home which do not have moving parts. The design relies on all parts to be installed to manufacturers specifications. These details are verified after they are installed.

Smith HouseThe idea is that insulation and air sealing are very cost effective compared to large and sometimes complex new technology in HVAC Systems. Instead of buying the expensive technology, use the money, that would usually spent on upgraded HVAC system, to increase the insulation levels. The details of how much insulation, what type and where are certainly of interested to  the builder and others involved in planning and construction. These details are less important to the home buyer, they just want things to work at a lower cost.

I am writing about Passive House construction since I just finished the training and testing to become a Passive House Verifier with PHIUS. You will hear more about the Passive House concept and how it might apply to any home.

Energy Efficiency is America’s No. 1 Housing Concern

Home-Insulation-300x225Safety, affordability and privacy – it’s no surprise that these were some of top housing needs identified in a recent national survey of more than 10,000 households. But the No. 1 unmet housing concern, which the Demand Institute that carried out the poll defined as the “satisfaction gap” between what respondents actually have and what they said was important, was not as easily expected: energy efficiency.

Survey respondents were given a list of 52 housing and community concerns and asked to rank them, on a scale of 1 to 10, by how important they felt the issues were and how much their current home satisfied these needs. The result: 71 percent of U.S. households polled placed a great deal of importance on energy efficiency, but only 35 percent felt their homes were very energy efficient with low monthly utility costs (the respondents making up percentages answered these questions with an 8, 9 or 10 ranking).

Based on these numbers, energy efficiency was the housing concern with the largest gap between the rates of importance and satisfaction – beating out consumer needs and wants for updated kitchens, storage space, safe neighborhoods, affordability, landlord responsiveness and more.

Why the strong desire for energy-wise homes?

“Utilities are a significant and regular part of households’ budgets, and spending on utilities has risen more quickly than overall consumer spending – 56 percent vs. 38 percent growth since 2000,” said Louise Keely, president of the Demand Institute, a nonprofit think tank jointly created and operated by Nielsen and the Conference Board to monitor consumer demand.

To read more of this report:  The Demand Institute Poll on Triple Pundit.