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AIR CONDITIONING & HEAT PUMP SYSTEMS

INSULATION INSPECTION & IMPROVEMENT
INTERIORS of buildings

ACOUSTICAL SEALANT CHOICES
AGE of a BUILDING - how to determine
AIR BYPASS LEAKS
AIR LEAK DETECTION TOOLS
AIR LEAK MINIMIZATION
AIR LEAK SEALING PROCEDURE
AIR SEALING STRATEGIES
ANIMAL ALLERGENS
ANIMAL ENTRY POINTS in buildings
ANIMAL ODORS IN buildings
APPLIANCE EFFICIENCY RATINGS
ARCHITECTURE & BUILDING COMPONENT ID
ASBESTOS FLOORING HAZARD REDUCTION
ASBESTOS-FREE INSULATION MATERIALS
ASBESTOS IDENTIFICATION IN buildings
ASBESTOS ROOFING / SIDING DUST
ASBESTOS REMOVAL, Wetting Guidelines

ATTIC LEAKS, CONDENSATION & ATTIC MOLD
ATTIC VENTILATION

BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BASEMENT LEAKS, INSPECT FOR
BASEMENT WATERPROOFING

BATH & KITCHEN DESIGN GUIDE
BATHROOM VENTILATION
BEST CONSTRUCTION PRACTICES GUIDE
Best Interior Finish Practices

BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BLOWN-IN INSULATION
BRICK LINED WALLS
BRICK VENEER WALL INSULATION
BRICK VENEER WALL Loose, Bulged
BRICK WALL DRAINAGE WEEP HOLES
BUCKLED FOUNDATIONS due to INSULATION?
BUILDING NOISE DIAGNOSIS & CURE

CASEWORK, CABINETS, SHELVING INSTALLATION

CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CEILING FINISHES INTERIOR
CEILINGS, DROP or SUSPENDED PANEL
CEILINGS, PLASTER TYPES
CEILINGS, PLASTER, LOOSE HAZARDS
CEILING TILES - Asbestos-Containing

CHIMNEY INSPECTION DIAGNOSIS & REPAIR
CHINESE DRYWALL HAZARDS
COMBUSTION AIR for TIGHT buildings
COOLING LOAD REDUCTION by ROOF VENTS

CRAWL SPACES
CONDENSATION or SWEATING PIPES, TANKS
CONDENSATION on WINDOWS & SKYLIGHTS

DECK & PORCH CONSTRUCTION
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DEFINITION of Heating & Cooling Terms
  Definition of BTUs, BTUH, & Calories
  Definition of K value K-coefficient heat transmission
  Definition of U value or U-coefficient heat loss resistance
  Definition of R-Values for Insulation or buildings
  Definition of Design Temperature for buildings
  Definition of Heating or Cooling "Degree Day"
  Definition of Tons of Cooling Capacity

ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR

ENERGY SAVINGS in buildings
  AIR CHANGE RATE ACH HEAT SAVINGS
  AIR LEAK SEALING PROCEDURE
  AQUASTAT OPTIMAL SETTINGS
  BIOGAS PRODUCTION & USE
  ENERGY AUDIT - How to Use a Free One
  ENERGY SAVINGS MAXIMIZE RETURNS ON
  ENERGY SAVINGS PRIORITIES
  ENERGY SAVINGS RETROFIT CASE STUDY
  ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
  ENERGY SAVINGS RETROFIT OPTIONS
  ENERGY STAR PROGRAM
  ENERGY USE MONITORING
  HEATING COST SAVINGS METHODS
  HIGH MASS TRADEOFFS, HEATING vs COOLING
  HOUSE DOCTOR, how-to be
  TIMERS for ELECTRIC WATER HEATERS

ENVIRONMENTAL HAZARDS - INSPECT, TEST, REMEDY

FIBERGLASS INSULATION
FIBERGLASS HAZARDS
FIBERGLASS INSULATION MOLD
FIREPLACES & HEARTHS
FLAT ROOF MOISTURE & CONDENSATION

FLOOD DAMAGE ASSESSMENT, SAFETY & CLEANUP
FLOODS IN buildings-mold

FLOOR, CONCRETE SLAB CHOICES

FLOOR, CONCRETE SLAB POURED FINISH
FLOOR RADIANT HEAT Mistakes to Avoid

FLOORING MATERIALS, Age, Types

FORMALDEHYDE HAZARDS

FOUNDATION BULGE or LEAN MEASUREMENTS
FOOTING & FOUNDATION DRAINS

FOUNDATION CRACKS & DAMAGE GUIDE
FOUNDATION WATERPROOFING
FRENCH DRAINS

FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
FROST HEAVES, FOUNDATION, SLAB

GREEN BUILDING CONSTRUCTION CODES GUIDES
GREENHOUSE DESIGN for SOLAR HEATING
GREENHOUSE / SUNSPACE GLARE

HEAT LOSS in BUILDINGS
  How to measure heat movement through a wall
  How to measure building insulation
  How leaky is the building
  BASEMENT CEILING VAPOR BARRIER
  BASEMENT HEAT LOSS
  ENERGY AUDIT - How to Use a Free One
  ENERGY SAVINGS MAXIMIZE RETURNS ON
  ENERGY SAVINGS PRIORITIES
  HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS RATE CALCULATIONS
HEAT LOSS DETECTION TOOLS
HEAT LOSS INDICATORS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION

HEAT TAPES & CABLES on Roofs for Ice Dams
HEATING SYSTEMS
HEATING COST FUEL & BTU Cost Table
HEATING COST SAVINGS METHODS
HEATING LOSS DIAGNOSIS-BOILERS
HEATING LOSS DIAGNOSIS-FURNACES
HEATING SYSTEM INSPECTION PROCEDURE

HOT ROOF DESIGNS: Un-Vented Roof Solutions
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSEWRAP INSTALLATION DETAILS
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HOUSE PARTS, DEFINITIONS

HUMIDITY LEVEL TARGET

ICE DAM PREVENTION

INDOOR AIR QUALITY & HOUSE TIGHTNESS
INDOOR AIR QUALITY IMPROVEMENT GUIDE
INDOOR HOUSE DUST & DEBRIS

INSULATION CHOICES
Insulation Air & Heat Leaks
INSULATION FACT SHEET- DOE
INSULATION for GREENHOUSE or SOLARIUM
INSULATION IDENTIFICATION GUIDE

INSULATION INSPECTION & IMPROVEMENT
  INSULATION R-Values & Properties
  Air Bypass Leaks, Thermal Tracking
  AIR LEAK DETECTION TOOLS
  AIR LEAK MINIMIZATION
  AIR SEAL STRATEGIES
  ASBESTOS IDENTIFICATION IN buildings
  ATTIC CONDENSATION CAUSE & CURE
  BASEMENT CEILING VAPOR BARRIER
  BASEMENT HEAT LOSS
  Blocked Soffit Intake Vents
  BLOWER DOORS & AIR INFILTRATION
  BLOWN-IN INSULATION
  BRICK or BLOCK WALL CAVITY INSULATION
  BRICK VENEER WALL INSULATION
  CATHEDRAL CEILING INSULATION
  CATHEDRAL CEILING VENTILATION
  HOT ROOF DESIGNS: Un-Vented Roof Solutions
  ENERGY SAVINGS in buildings
  ENERGY AUDIT - How to Use a Free One
  ENERGY SAVINGS MAXIMIZE RETURNS ON
  ENERGY SAVINGS PRIORITIES
  ENERGY SAVINGS RETROFIT CASE STUDY
  ENERGY SAVINGS RETROFIT LEAK SEALING GUIDE
  ENERGY SAVINGS RETROFIT OPTIONS
  ENERGY STAR PROGRAM
  ENERGY USE MONITORING
  FIBERGLASS DUCT, RIGID CONSTRUCTION
  FIRE PROTECTION FOR FOAM BOARD INSULATION
  FOUNDATION INSULATION OPTIONS
  FRAMING DETAILS for BETTER INSULATION
  FRAMING DETAILS for DOUBLE WALL HOUSES
  FRAMING METAL STUD PERFORMANCE
  HEATING COST SAVINGS METHODS
  HIGH MASS TRADEOFFS, HEATING vs COOLING
  HOUSE DOCTOR, how-to be
  Inspect Attics for Moisture or Mold
  Inspect Attics for Blocked Soffit Intake Vents
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  INSULATION PLACEMENT in buildings
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  LOG HOME WALL INSULATION VALUES
  MOISTURE in BUILDING WALLS, EFFECTS
  MOISTURE in CELLULOSE INSULATION
  Mold in Fiberglass Insulation
  Mold on Books, Book Conservation
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  MOLD RESISTANT CONSTRUCTION
  PASCAL CALCULATIONS
  PHENOLIC FOAM INSULATION
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  POLYSTYRENE FOAM INSULATION
  RADIANT BARRIERS
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  ROOF VENTING ENERGY SAVING DETAILS
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  PASSIVE SOLAR DESIGN KEY ELEMENTS
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  PASSIVE SOLAR ENERGY MONITORING
  PASSIVE SOLAR FLOOR TILES, PHASE CHANGE
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  PASSIVE SOLAR HOME, LOW COST
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  PASSIVE SOLAR Roof & Window Overhangs
  PHOTOVOLTAIC POWER SYSTEMS
  POLYCARBONATE GLAZING
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  ROCK-BED SOLAR HEAT STORAGE DESIGN
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  STUCCO OVER FOAM INSULATION
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  Urea Formaldehyde Foam Insulation UFFI
  URETHANE FOAM Deterioration, Outgassing
  VAPOR BARRIERS & AIR SEALING at BAND JOISTS
  VAPOR BARRIERS & CONDENSATION in buildings
  VAPOR BARRIERS & HOUSEWRAP
  VAPOR CONDENSATION & BUILDING SHEATHING
  VERMICULITE INSULATION

INSULATION LOCATION - WHERE TO PUT IT
  BLOWN-IN INSULATION
  INSULATION CHOICES
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  INSULATION LOCATION & QUANTITY for ATTICS
  INSULATION LOCATION for BASEMENT FLOORS
  INSULATION LOCATION for BASEMENT WALLS
  INSULATION LOCATION for BRICK or BLOCK WALL CAVITY
  INSULATION LOCATION for BRICK VENEER WALLS
  INSULATION LOCATION for CAPES, CRAWLSPACES
  INSULATION LOCATION for CATHEDRAL CEILINGS
  INSULATION LOCATION for GREENHOUSE or SOLARIUM
  INSULATION LOCATION for PASSIVE SOLAR FLOOR SLAB
  INSULATION LOCATION & EXTENT for SLABS
  INSULATION LOCATION for SOUND CONTROL
  INSULATION LOCATION for SUSPENDED PANELS
  INSULATION LOCATION for SWIMMING, INDOOR

INSULATION MOLD
INSULATION R-Values & Properties

LOG HOME GUIDE

MOBILE HOME INSPECTIONS

MOISTURE CONTROL in buildings

MOLD INFORMATION CENTER
MOLD ACTION GUIDE - WHAT TO DO ABOUT MOLD
MOLD APPEARANCE - WHAT MOLD LOOKS LIKE
MOLD CLEANUP GUIDE- HOW TO GET RID OF MOLD
MOLD DETECTION & INSPECTION GUIDE

MOLD EXPERT, WHEN TO HIRE
MOLD KILLING GUIDE
MOLD LEVEL IN AIR, VALIDITY
MOLD PREVENTION GUIDE
MOLD SPRAYS, SEALANTS, PAINTS
MOLD TEST KITS
MOLD TESTING SERVICES

Nanomaterials Hazards
NOISE / SOUND DIAGNOSIS & CURE

ODORS & SMELLS DIAGNOSIS & CURE

PAINT FALURE, DIAGNOSIS, CURE, PREVENTION
PASCAL CALCULATIONS
PLASTER & BEAVERBOARD & DRYWALL
PLASTER BULGES & PILLOWS
PLASTER LATH, METAL
PLASTER, LOOSE FALL HAZARDS
PLASTER TYPE IDENTIFICATION
PLASTER VENEER Best Practices

RADIANT BARRIERS
RADIANT HEAT
RADIANT HEAT Floor Mistakes to Avoid
RADIANT HEAT TEMPERATURES
RADIANT SLAB FLOORING CHOICES
RADIANT SLAB TUBING & FLUID CHOICES
REFLECTIVE INSULATION
RIGID FOAM USE INDOORS

ROOF VENTILATION SPECIFICATIONS

ROT, FUNGUS, TERMITES
ROT, TIMBER FRAME

SAFETY HAZARDS & INSPECTIONS
SEARS KIT HOUSES
SHEATHING, FOIL FACED - VENTS

SOLAR ENERGY SYSTEMS

SOUND CONTROL in buildings

STAIN & BIODETERIORATION AGENT CATALOG
STAINS on buildings - QUICK GUIDE
STAIN DIAGNOSIS on BUILDING EXTERIORS
STAIN DIAGNOSIS on BUILDING INTERIORS
STAIN DIAGNOSIS on ROOFS
STAIN DIAGNOSIS on STONE
STAINS & FINISHES, INTERIOR
STAINS on INDOOR SURFACES: PHOTO GUIDE

STAIRS, RAILINGS, LANDINGS, RAMPS
STONE CLEANING METHODS

STUCCO WAll FAILURES DUE TO WEATHER
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
STUCCO PAINT FAILURES

STRUCTURAL INSPECTIONS & DEFECTS
SUMP PUMPS GUIDE
SWEATING (CONDENSATION) on PIPES, TANKS

THERMAL EXPANSION of MATERIALS
THERMAL MASS in buildings
  THERMAL MASS FLOOR SLABS
  THERMAL MASS in UPSTAIRS
  THERMAL MASS WALL DESIGN
  THERMAL MASS in HOMES - STUDY
  THERMAL MASS TRADEOFFS, HEATING vs COOLING
THERMAL TRACKING Indicates Heat Loss
  Ceiling Thermal Tracking Marks
  Wall Thermal Tracking Stains
  Floor Carpet Thermal Tracking Stains
  Air Bypass Leaks Marks on Insulation
  Thermal Tracking to Diagnose IAQ
  Stains HVAC Supply Registers
  Pet Stains on Floors
  Pet Stains on Walls
  Human Occupant Stains on Walls
  Stains from Candles, Woodstoves, Fireplaces
  Other Stains on Indoor Walls & Ceilings
  What to Do About Thermal Tracking
THERMOSTATS, HEATING / COOLING
TRIM, INTERIOR INSTALLATION

TRUSS UPLIFT, ROOF
TRUSSES, Floor & Roof

VAPOR BARRIERS & CONDENSATION in buildings

VENTILATION in buildings
WALL FINISHES INTERIOR

WATER ENTRY in buildings

WIND WASHING INSULATION At EAVES

WINDOWS & DOORS

WINTERIZE A BUILDING
WOOD Burning Heaters Fireplaces Stoves
WOOD FLOOR DAMAGE

More Information

Photograph of  . How to Calculate Building Heat Loss Rate, Insulation Values & Heating Efficiency
InspectAPedia®  -         

  • How to calculate the rate of heat loss (or gain) in a building through insulation, walls, etc.
  • How to measure heat transmission in materials: definition of R-values, U-values, K-values, BTU, calorie, and rates of heat loss or gain
  • Building design temperatures & how to use a home energy audit or heat loss analysis
  • What insulation "R" values should be used in a building insulation?
  • Questions & answers about how to calculate building heat loss rate, R-values, Insulation Values, Heating Efficiency

This article gives details and formulas for calculating R-values, U-values U-coefficient of heat loss resistance, and K-values, all ways of looking at insulation values or building heat loss rates.

InspectAPedia offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at InspectAPedia.com/Contact.htm.

Related Building Heat Loss Articles

Beginning at HEAT LOSS in buildings article series explains how to insulate a building and how much insulation is needed including how to measure or calculate heat loss in a building, defines thermal terms like BTU and calorie, provides measures of heat transmission in materials, gives desired building insulation design data, and shows how to calculate the heat loss in a building with R values or U values

Also see HEAT LOSS INDICATORS (where is the building losing heat during the heating season, or gaining un-wanted heat during the cooling season),see HEAT LOSS DETECTION TOOLS for both tools and procedures, and see HEAT LOSS R U & K VALUE CALCULATION for a guide to calculating heat loss (or gain) rates for buildings and building insulation. At INSULATION R-Values & Properties we give a detailed table of insulating material R-values & properties.

Be sure to review the definitions of R, U, & K Values at Definition of Heating & Cooling Terms. Because no amount of insulation can keep a drafty building warm, also review ENERGY SAVINGS PRIORITIES. Also see our detailed table of Insulation R-Values & Properties and our list of building HEAT LOSS INDICATORS (where is the building losing heat during the heating season, or gaining un-wanted heat during the cooling season).

Formula-R™ and Owens Corning™ which may be visible in this photograph of pink Styrofoam™ insulation boards are registered trademarks of Owens Corning® and were photographed at a Home Depot® building supply center.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

Definition of & How to Calculate the R value or R-coefficient of Resistance to Heat Loss in a Building or its Insulation

The "R" value of a material is defined as the material's resistance to heat flow through the material. For purposes of insulation, you might think of "R" value as the opposite of thermal conductance, since it's described as thermal resistance or resistance to heat flow. And you'd be correct. If thermal resistance to heat flow is "resistance" we can say that the thermal conductivity of a material is equal to the reciprocal of its thermal resistance.

More practically, by convention we use thermal resistance or R-value when buying various insulation materials. You will almost always see an "R" value quoted for the material. In general, higher "R" means more resistance to heat loss and therefore lower heating or cooling bills for the building. [Assuming all other fadctors like air leakage are either equal or have been factored into the R-value calculation.]

Mathematically, but in painfully circular reasoning, "R-value" is simply the reciprocal of the two measures of resistance to heat flow "K-value" (R = 1/K) or "U-value" (R(whole building) = 1/U) that we define further below.

What do U and K values have to do with R-values?

As you'll read below "K" measures the heat flow through an individual substance and "U" as most folks use it measures the overall building heat loss by adding all of the various areas and substances together. U-values measure the thermal transmittance of heat in or out of a building and combines heat movement by all principles that are occurring at a building: radiation, convection, and conduction. So you can see that "U" values are more complex but really more complete than "R" values.

Escaping the Circular Reasoning of R=1/K

We can escape the horrible circular reasoning that appears in some writing about heat loss measurements if any one of the three values, R, U, K is defined independently. We'll take a stab at this just below.

The R-value of a material is typically expressed as R [resistance to heat flow] per inch of material thickness. More technically, "R-value" is measured in meter²·°C/Watt [metric system] or ft²·°F·h/Btu [U.S. measurement system].

Materials may be rated in R per inch or R per meter or similar measures.

Here are Some Basic Formulas for Calculating R-Values

R-value = temperature difference [in degF] x area [sq ft] x time [in hours] / heat loss[in BTUs]

Calculating R-Value [U.S. metrics]

R = (Heat Resistance x Degrees F x square feet) / BTUs

or stated in metric: (R-value) = t/k, measured in K·m²·W−1

Definition of & How to Calculate the U value or U-coefficient of heat loss resistance

Computing "K" values tells us the heat loss rate for a specific material, thickness, area, and temperature difference but while we need to be able to calculate "K" values, those alone don't tell us what's going on in an actual building. We need to be able to combine all of the rates of heat loss (or gain) across all of the types of surfaces, insulation, and building material for the whole building - at least for all of its external or perimeter surfaces including roofs, walls, and floors as well as windows and doors. That's where the "U" value makes its appearance.

A building's "U" value or U-coefficient of resistance of heat loss is a related measure of resistance to thermal energy or heat flow out of a building (if it's warmer inside than outside) or conversely the same concept works in a warm climate where air conditioning is in use, except that we expect outside heat to be flowing into the building.

A building's "U" value is much more complete, and therefore useful than "K" values alone because a building's "U" value combines the "K" factors for all of the building's surfaces and materials. In other words, we add the effects of heat loss (or gain), still expressed in the number of BTU's per hour per square foot of area, and still expressed per degree of Fahrenheit of temperature difference and still expressed per inch of thickness of material (just as with "K" values), for all of the substantial areas and surfaces of the exterior of a building's floors, walls, windows, doors, ceilings, or roofs (if cathedral ceilings are present).

To calculate the "U" value, or overall heat loss (or gain if we're air conditioning) for a building, we need to add the "R" values for each material in the structure, and to factor in the total area of each material in the structure. We discuss this procedure in more detail below at "Calculating Heat Loss for a Building".

U-value = BTUs / (hours x Degrees F x Square Feet)

A building's "U" value or U-coefficient of resistance of heat loss is a related measure of resistance to thermal energy or heat flow out of a building (if it's warmer inside than outside) or conversely the same concept works in a warm climate where air conditioning is in use, except that we expect outside heat to be flowing into the building.

A building's "U" value is much more complete, and therefore useful than "K" values alone because a building's "U" value combines the "K" factors for all of the building's surfaces and materials. In other words, we add the effects of heat loss (or gain), still expressed in the number of BTU's per hour per square foot of area, and still expressed per degree of Fahrenheit of temperature difference and still expressed per inch of thickness of material (just as with "K" values), for all of the substantial areas and surfaces of the exterior of a building's floors, walls, windows, doors, ceilings, or roofs (if cathedral ceilings are present).

To calculate the "U" value, or overall heat loss (or gain if we're air conditioning) for a building, we need to add the "R" values for each material in the structure, and to factor in the total area of each material in the structure. We discuss this procedure in more detail below at "Calculating Heat Loss for a Building".

Formulas Used to Calculate the Rate of Building Heat Loss Per Hour for a Building Using it's "R" Values or "U" Values

Formulas and an explanation of how we use R U or K values to determine the rate of heat loss at a building (or heat gain if we are cooling it) are at HEAT LOSS in buildings or within that articler at section Formulas to Calculate the Rate of Heat Loss Per Hour for a Building Using it's "R" Values or "U" Values.

Definition of & How to Calculate the K value or K-coefficient of heat transmission

A building's K value or K-coefficient of heat transmission is one way to express the heat loss in a building. "K" is defined as the number of BTU's of heat moving through any material with these details:

  • Per square foot of area of the material
  • Per degree Fahrenheit of temperature difference
  • Per inch of thickness of the material

So "K" takes a lot of variables into consideration and gives us the rate of heat loss per square foot of building surface, per inch of thickness of material in that building surface, per degree of temperature difference in Fahrenheit, in BTUs per hour.

By "degree of temperature difference in Fahrenheit" we mean that we are taking into consideration the difference in temperature on the two sides of our building surface. For example, if the indoor temperature in a building is 68 deg. F. and the outdoor temperature is 48 deg. F., then we have a 20 degree temperature difference on the two sides of the building (wall or roof for example).

This temperature difference on the two sides of a surface, say an insulated building wall, for example, is very important in understanding how a building loses heat (in the heating season) or gains heat (in the cooling season). That's because the rate of heat transfer through a material increases exponentially as a function of the temperature difference. This is intuitively obvious and is confirmed by physicists.

For example, if the temperatures on either side of a building wall were the same, there would be no heat loss or gain through the building wall. As the temperature difference on either side of that same wall increases, say from one degree of difference to 20 degrees of difference the rate of heat transfer increases.

An interesting version of this heat transfer theory was shared with the author in a class on how to minimize building heating costs when the instructor told us that "the thermal conductivity of finned copper heating baseboard is exponentially greater at higher temperatures".

He was saying that if we ran heating water from our heating boiler through the baseboards at 200 deg.F. we would see much more efficient heat transfer from the heating baseboards into the building. There are other factors involved in heating system efficiency such as the length of boiler "on" cycle (longer is more efficient), so there was more to think about, but the instructor was applying classic heat transfer theory that is reflected in the "K" values of building insulation as we've discussed here.

Computing "K" values tells us the heat loss rate for a specific material, thickness, area, and temperature difference but while we need to be able to calculate "K" values, those alone don't tell us what's going on in an actual building. We need to be able to combine all of the rates of heat loss (or gain) across all of the types of surfaces, insulation, and building material for the whole building - at least for all of its external or perimeter surfaces including roofs, walls, and floors as well as windows and doors. That's where the "U" value makes its appearance.

Sorting out the Definitions of U.S. k-values, lambda or λ values, and European k-values

Note: In the U.S. k-value when discussing the heat loss resistance of window glazing is equivalent to lamda λ value in Europe, and in case that's not confusing enough, an older European k-value (the total insulation value of a building) is currently referred to in Euripe as U-value. You'll recall from our notes above that U-value is a reciprocal or 1/R-value. - Wikipedia web search 03/11/2011 see "Thermal Conducitivity".

To convert U.S. R-values to European U-values:

[ (1 / R-value USA) x 0.176 ] / 1 = U Europe

and

U Europe = [watts / kelvin x meters2]

Questions & Answers regarding this article

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HEAT LOSS R U & K VALUE CALCULATION

  • Thanks to Sanjiv Malkan for correcting our formula for R-values 3/22/2009.
  • Thanks to Steven Muscato for correcting our formula for U-Values 7/31/2009
  • Asbestos pipe insulation in buildings
  • Brick "Insulation" in Building Walls
  • HEAT LOSS CALCULATIONS, Insulation Properties, Definitions of R, K, U values, Insulation Design
  • How to Choose an Air Conditioner - BTU Chart
  • How to Detect and Correct Attic Condensation & Prevent Ice Dam Leaks in buildings
  • How to Inspect Building Interiors and Building Insulation/Ventilation list of articles about building insulation inspection, defects, design, and ventilation requirements
  • Insulation Materials as Indicators of Building Age
  • Indoor Air Quality Investigations: Fiberglass in Indoor Air, HVAC ducts, and Building Insulation
  • Insulation Identification Photographs - Cellulose insulation photos, Mineral wool insulation photos, rock wool insulation photos, cotton insulation photos, balsam wool insulation photos
  • Insulation Identification Photographs - Vermiculite insulation photos
  • LP or Natural Gas Pressures & BTUH per Cubic Foot
  • Insulation Properties, Table of R-Values, density, moisture permeability, fire safety, aging effects on various insulation materials
  • Mold in Fiberglass in Insulation
  • Radiant Heat Floor Mistakes to Avoid
  • Rated Cooling Capacity - How to Determine Air Conditioning Equipment Rated Cooling Capacity
  • Un-Vented Roof Solutions - How to Prevent Attic Condensation, Ice Dam Leaks, Roof Mold, & Roof Structural Damage in buildings with Un-vented Roof Cavities
  • Vermiculite Building Insulation & Asbestos

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

  • Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
  • Home Reference Book - Carson Dunlop The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
  • "The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
  • "Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
  • Access Ramp building codes:
    • UBC 1003.3.4.3
    • BOCA 1016.3
    • ADA 4.8.2
    • IBC 1010.2
  • Access Ramp Standards:
    • ADA (Americans with Disabilities Act), Public Law 101-336. 7/26/90 is very often cited by other sources for good design of stairs and ramps etc. even where disabled individuals are not the design target.
    • ANSI A117.4 Accessible and Usable buildings and Facilities (earlier version was incorporated into the ADA)
    • ASTM F 1637, Standard Practice for Safe Walking Surfaces, (Similar to the above standards)
  • America's Favorite Homes, mail-order catalogues as a guide to popular early 20th-century houses, Robert Schweitzer, Michael W.R. Davis, 1990, Wayne State University Press ISBN 0814320066 (may be available from Wayne State University Press)
  • American Plywood Association, APA, "Portland Manufacturing Company, No. 1, a series of monographs on the history of plywood manufacturing",Plywood Pioneers Association, 31 March, 1967, www.apawood.org
  • Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
  • Asbestos: How to find and recognize asbestos in buildings - visual inspection methods, list of common asbestos-containing materials
  • Asbestos HVAC Ducts and Flues field identification photos and guide
  • Asbestos products and their history and use in various building materials such as asphalt and vinyl flooring includes discussion which draws on Asbestos, Its Industrial Applications, D.V. Rosato, engineering consultant, Newton, MA, Reinhold Publishing, 1959 Library of Congress Catalog Card No.: 59-12535 (out of print).
  • Asbestos Identification and Testing References
    • Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed the basis for current work by asbestos identification laboratories.
    • Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
    • Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone
  • Brick nogging used as soundproofing is mentioned in this article on Popular Forest
  • Brick Nogging, Historical Investigation and Contemporary Repair, Construction Specifier, April 2006. Historical use of brick in timber-framed buildings, drawing on the investigations of the Kent Tavern in Calais, VT. "Brick nogging is a European method of construction which was brought to the new world in the early-nineteenth century. It was a common construction method that employed masonry as infill between the vertical uprights of wood framing." -- quoting the web article review.
  • Photo of very rough in-wall brick nogging at an architects website
  • Building Research Council, BRC, nee Small Homes Council, SHC, School of Architecture, University of Illinois at Urbana-Champaign, brc.arch.uiuc.edu. "The Small Homes Council (our original name) was organized in 1944 during the war at the request of the President of the University of Illinois to consider the role of the university in meeting the demand for housing in the United States. Soldiers would be coming home after the war and would be needing good low-cost housing. ... In 1993, the Council became part of the School of Architecture, and since then has been known as the School of Architecture-Building Research Council. ... The Council's researchers answered many critical questions that would affect the quality of the nation's housing stock.
    • How could homes be designed and built more efficiently?
    • What kinds of construction and production techniques worked well and which did not?
    • How did people use different kinds of spaces in their homes?
    • What roles did community planning, zoning, and interior design play in how neighborhoods worked
  • The Circular Staircase, Mary Roberts Rinehart
  • Construction Drawings and Details, Rosemary Kilmer
  • "An Example of Colonial Paneling", Norman Morrison Isham, The Metropolitan Museum of Art Bulletin, Vol. 6, No. 5 (May, 1911), pp. 112-116, available by JSTOR.
  • Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
  • "Energy Savers: Whole-House Supply Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Supply_Vent.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11880?print
  • "Energy Savers: Whole-House Exhaust Ventilation Systems [copy on file as /interiors/Energy_Savers_Whole-House_Exhaust.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11870
  • "Energy Savers: Ventilation [copy on file as /interiors/Energy_Savers_Ventilation.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Natural Ventilation [copy on file as /interiors/Energy_Savers_Natural_Ventilation.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Energy Recovery Ventilation Systems [copy on file as /interiors/Energy_Savers_Energy_Recovery_Venting.pdf ] - ", U.S. Department of Energy energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11900
  • "Energy Savers: Detecting Air Leaks [copy on file as /interiors/Energy_Savers_Detect_Air_Leaks.pdf ] - ", U.S. Department of Energy
  • "Energy Savers: Air Sealing [copy on file as /interiors/Energy_Savers_Air_Sealing_1.pdf ] - ", U.S. Department of Energy
  • Falls and Related Injuries: Slips, Trips, Missteps, and Their Consequences, Lawyers & Judges Publishing, (June 2002), ISBN-10: 0913875430 ISBN-13: 978-0913875438
    "Falls in the home and public places are the second leading cause of unintentional injury deaths in the United States, but are overlooked in most literature. This book is unique in that it is entirely devoted to falls. Of use to primary care physicians, nurses, insurance adjusters, architects, writers of building codes, attorneys, or anyone who cares for the elderly, this book will tell you how, why, and when people will likely fall, what most likely will be injured, and how such injuries come about. "
  • Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
  • Humidity: What indoor humidity should we maintain in order to avoid a mold problem?
  • Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
  • Nogging: See this photo of exposed bricks on a building exterior on a building exterior in Canada. [Thanks to Carson Dunlop, Toronto - see References below].
  • Pergo AB, division of Perstorp AB, is a Swedish manufacturer or modern laminate flooring products. Information about the U.S. company can be found at http://www.pergo.com where we obtained historical data used in our discussion of the age of flooring materials in buildings.
  • Piquet Wall Construction: See this photo of piquet wall construction - involving timber-framed wall construction with long top girts, diagonal timber bracing, and small diameter logs placed vertically along with concrete chinking to fill in the wall plane.
  • Plank House Construction: weblog from plankhouse.wordpress.com/2009/01/25/plank-house-construction/ and where plank houses were built by native Americans, see
    Large 1:6 Scale Plank House Construction / P8094228, Photographer: Mike Meuser
    06/12/2007 documented at yurokplankhouse.com where scale model Museum quality Yurok Plank Houses are being sold to raise money for the Blue Creek - Ah Pah Traditional Yurok Village project.
  • Re-Bath, tub lining products is a bath tub relining manufacturer and distributor located in Tempe, Arizona - see rebath.com
  • Rubblestone Wall Filler: See this Lartigue House using exterior-exposed rubblestone filler between vertical timbers of a post and beam-framed Canadian building.
  • Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or ISBN 10: 1-933264-01-2, available from the publisher, Lawyers ^ Judges Publishing Company,Inc., www.lawyersandjudges.com sales@lawyersandjudges.com and also from the InspectAPedia Bookstore (Amazon.com)
  • The Stairway Manufacturers' Association, (877) 500-5759, provides a pictorial guide to the stair and railing portion of the International Residential Code. [copy on file as http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf ] -
  • What Mold and Allergens Look Like: mold identification photos to help identify mold - choosing what to sample in buildings
  • How to Clean Moldy Wood Framing & Sheathing How to clean/seal mold from/on exposed lumber or plywood subfloor or roof sheathing indoors - some suggestions based on our field and laboratory research
  • Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
  • Manufactured & Modular Homes: Modular Building Systems Association, MBSA, modularhousing.com, is a trade association promoting and providing links to contact modular builders in North America. Also see the Manufactured Home Owners Association, MHOAA, at www.mhoaa.us. The Manufactured Home Owners Association of America is a National Organization dedicated to the protection of the rights of all people living in Manufactured Housing in the United States.
  • Mold spores in the Home - a Photo ID Library for detection and identification of mold allergens.
  • How to Find and Test For Mold in buildings A "how to" photo and text primer on finding and choosing the right spots to test for mold in buildings
  • Stuff that is not mold but is often mistaken for it - things you may not want to test. Also, not all "black mold" is toxic - here are examples of harmless black mold.
  • Simple Adhesive Tape Sampling of Moldy Surfaces - how to send a mold sample to our lab
  • Mold Sampling Methods in the Indoor Environment - In-depth article: detailed critique of popular mold testing methods - Is your mold test kit worth the bother?
  • Mold-Resistant Building Practices, advice from an expert on how to prevent mold after a building flood and how to prevent mold growth in buildings by selection of building materials and by anti-mold construction details.
  • Slips, Trips, Missteps and Their Consequences, Gary M. Bakken, H. Harvey Cohen, Jon R. Abele, Alvin S. Hyde, Cindy A. LaRue, Lawyers and Judges Publishing; ISBN-10: 1933264012 ISBN-13: 978-1933264011
  • Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or ISBN 10: 1-933264-01-2, available from the publisher, Lawyers & Judges Publishing Company,Inc., www.lawyersandjudges.com sales@lawyersandjudges.com and also from the InspectAPedia Bookstore (Amazon.com)
  • Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
  • The Staircase, Ann Rinaldi
  • Common Sense Stairbuilding and Handrailing, Fred T. Hodgson
  • The Art of Staircases, Pilar Chueca
  • Building Stairs, by pros for pros, Andy Engel
  • A Simplified Guide to Custom Stairbuilding, George R. Christina
  • Basic Stairbuilding, Scott Schuttner
  • The Staircase (two volumes), John Templar, Cambridge: the MIT Press, 1992
  • The Staircase: History and Theories, John Templar, MIT Press 1995
  • Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
  • Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
  • "The Dimensions of Stairs", J. M. Fitch et al., Scientific American, October 1974.
  • "The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
  • "Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
  • "Weather-Resistive Barriers [copy on file as /interiors/Weather_Resistant_Barriers_DOE.pdf ] - ", how to select and install housewrap and other types of weather resistive barriers, U.S. DOE
  • Weaver: Beaver Board and Upson Board: Beaver Board and Upson Board: History and Conservation of Early Wallboard, Shelby Weaver, APT Bulletin, Vol. 28, No. 2/3 (1997), pp. 71-78, Association for Preservation Technology International (APT), available online at JSTOR.
  • What Style Is It?: A Guide to American Architecture, Rev., John C. Poppeliers, S. Allen Chambers, Wiley; Rev Sub edition (October 6, 2003), ISBN-10: 0471250368, ISBN-13: 978-0471250364
  • ...
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