WHY IS BUILDING SCIENCE IMPORTANT?

OUTLINE Why Building Science is Important Building Science Key Components Controlling Air Flow Controlling Thermal Flow Controlling Moisture Flow ENERGY STAR Solutions Action Plan

WHY IS BUILDING SCIENCE IMPORTANT? We all want a home that is Affordable Comfortable Healthy Durable

WHY IS BUILDING SCIENCE IMPORTANT? For your home to do its job, it must separate The inside from the outside.

WHY IS BUILDING SCIENCE IMPORTANT? If those problem areas aren t addressed, you re probably letting in: Wind Rain Ground water Radon Uncomfortable temperatures Humidity Bugs and pests

WHY IS BUILDING SCIENCE IMPORTANT? To understand how to most effectively keep these things out of our homes, let s take a look at some key components to high performance homes

BUILDING SCIENCE KEY COMPONENTS

FORCES ON YOUR HOME wind heat humidity Stack Effect* Fans Pressure Heat Moisture rain water radon *Stack effect is a convective loop throughout the entire house cause by differences in pressure.

FORCES ON YOUR HOME Driving Forces always move in the same direction: More Pressure Moisture Heat to Less Pressure Moisture Heat

DRIVING FORCES Conditions needed for air leakage: 1. Holes 2. Driving Forces (pressure) Across the Holes air Air will take path of least resistance through largest hole.

FORCES ON YOUR HOME Keeping this simple rule in mind, there are three major driving forces that need to be controlled

BUILDING SCIENCE KEY COMPONENTS High- Performance Homes Control Air Flow Control Thermal Flow Control Moisture Flow (Vapor, Bulk)

HIGH PERFORMANCE HOMES Why: Affordable Comfortable Healthy Durable How: Control Air Flow Control Thermal Flow Control Moisture Flow Driving Forces Stack Effect Fans Conduction Convection Radiation Bulk Vapor What: In the sections the follow, we ll discuss these components and how they can explain common problems we see in homes.

CONTROLLING AIR FLOW

CONTROLLING AIR FLOW wind heat humidity Stack Effect* Fans Pressure Heat Moisture rain water radon *Stack effect is a convective loop throughout the entire house cause by differences in pressure.

HERE ARE THE LARGER HOLES Access Panels Ceiling fixtures Sill Plates Vents Door Openings Chases Dropped Ceilings Window Openings Plumbing Penetrations Ducts

CONTROLLING AIR FLOW: CHIMNEY CHASES Gaps between the chimney and flooring allow unwanted air flow.

CONTROLLING AIR FLOW : DUCT CHASES Gaps between the ductwork and flooring allow unwanted air flow as well.

CONTROLLING AIR FLOW: RETURN DUCTS A leaky return duct sucks in hot attic air, and an open bypass allows easy exit of that air.

LEAKY RETURN DUCTS leak Hot attic air enters your home in the summer!

AFFORDABILITY PROBLEMS: DUCT LEAKAGE CONTROLLING AIR FLOW: POOR BOOT CONNECTIONS Boot connection

CONTROLLING AIR FLOW One Out = One In Courtesy of Southface Institute

CONTROLLING AIR FLOW: ONE OUT = ONE IN = LOTS AIR FLOW Homes have many fans inside of them. Let s look at one that is often ignored: the exhaust fan for clothes dryers. 200 cfm (on average) 60 minute cycle 12,000 cubic feet out (from laundry room into dryer exhaust outdoors) 12,000 cubic feet in (from the holes with least resistance)

WHERE DOES AIR IN COME FROM? Homes often have their laundry rooms situated next to or near the garage. Dangerous fumes like carbon monoxide could be pulled into your home with unwanted air flow.

WHERE DOES AIR IN COME FROM? Carbon Monoxide poisoning is a leading cause of unintentional poisoning deaths in the U.S. Unintentional CO exposure accounts for an estimated 15,000 emergency department visits and 500 unintentional deaths in the U.S. each year. Health effects of CO exposure include: disorientation unconsciousness long-term neurological disabilities coma cardio respiratory failure death Morbidity and Mortality Weekly Report Centers for Disease Control and Prevention

CONTROLLING AIR FLOW: ONE OUT = ONE IN = LOTS AIR FLOW Here s another example: 1,500 cfm 30 minute cycle 45,000 cubic feet out 45,000 cubic feet in

WHERE DOES AIR IN COME FROM? Your kitchen fans could be pulling dangerous fumes through your fireplace in the living room.

CONTROLLING AIR FLOW: FANS/PRESSURES IN HOMES Exhaust CFM Clothes Dryers: 150 250 Bath Exhaust Fans: 50 100 Kitchen Exhaust Fan: 100 1,500+ Whole-House Fans: ~2,500 5,000+ Central Vacuums: ~100 Fireplaces (pull in air for combustion): up to 400 Stack Affect (convection loop): ~15-30

CONTROLLING THERMAL FLOW

CONTROLLING THERMAL FLOW wind heat humidity Stack Effect Fans Pressure Heat Moisture rain water radon

CONTROLLING THERMAL FLOW Heat can flow in and out of your home in several different ways: Conduction Convection And Radiation

CONTROLLING THERMAL FLOW: CONDUCTION Conduction is where heat energy is transferred from molecule to molecule by direct contact. By sitting on a cold rock, your body heat will transfer from you, to the rock through conduction.

CONTROLLING THERMAL FLOW: CONVECTION Through convection, heat in a gas or liquid is transferred by the circulation of currents from one region to another.

CONTROLLING THERMAL FLOW: RADIATION Through radiation, electromagnetic rays are emitted from the surface of an object due to its higher temperature as compared to its surroundings.

CONTROLLING THERMAL FLOW Mean Radiant Temperature (MRT) dominates comfort. (40% > than ambient temp.) So in other Remember the conduction words example we used earlier if you sit on If you lose control of a cold rock, the heat from surface temperatures, your body will be you lose control of transferred to the rock. comfort!

CONTROLLING THERMAL FLOW: SURFACE TEMPERATURES TOO COLD

CONTROLLING THERMAL FLOW Most insulation is NOT an air barrier* Resists Conduction Air Flow *any solid material that blocks air flow including sealing at edges and seams

CONTROLLING THERMAL FLOW: THE AIR BARRIER EXPERIMENT

CONTROLLING THERMAL FLOW: WHY ALIGN THE AIR BARRIER?

CONSIDER THE FORCES OF AIRFLOW ON YOUR HOME wind heat humidity rain Stack Effect* Fans Pressure Heat Moisture water radon *Stack effect is a convective loop throughout the entire house cause by differences in pressure.

CONTROLLING THERMAL FLOW: WHY ALIGN THE AIR BARRIER? Dropped ceiling

CONTROLLING THERMAL FLOW: WHY ALIGN THE AIR BARRIER? 70 o F

CONTROLLING THERMAL FLOW: WHY ALIGN THE AIR BARRIER? The warm surface of the dropped ceiling created a convective loop through the fibrous insulation lining the attic. 70 o F

CONTROLLING THERMAL FLOW: WHY ALIGN THE AIR BARRIER? As warm air flows into the attic, cold air flows back out (into the dropped ceiling) and lowers the temperature.

CONTROLLING THERMAL FLOW: WHY COMPLETE THE AIR BARRIER? Cold attic air 70 o F 30 o F When convection loops are allowed between the inside air and the attic, you lose control of surface temperatures Warm inside air 70 50 o F 30 o F Cold outside air This affects your comfort!

CONTROLLING THERMAL FLOW: WHY COMPLETE THE AIR BARRIER? Infrared cameras like the one shown here can tell us where air barriers or insulation are misaligned or missing, by showing differences in wall temperatures.

CONTROLLING THERMAL FLOW: WHY COMPLETE AIR BARRIER? Here is a infrared image depicting the convection loop within dropped ceilings which we just discussed. Notice the misalignment of air barriers by the differences in shading in this thermal image. Darker shades depict lower temperatures where cold attic air is passing through fibrous insulation.

CONTROLLING THERMAL FLOW: INSULATION & AIR BARRIER The Bathtub is a common place to leave out air barriers. This can cause major comfort problems where tubs are situated next to exterior walls, but is easily remedied with proper planning for construction & installation.

CONTROLLING THERMAL FLOW: TUB WITHOUT AIR BARRIER REVEALED Bathtubs on exterior walls, like this one, facilitate large amounts of conduction, allowing heat to escape your home in the winter.

CONTROLLING THERMAL FLOW: INSET STAPLING = MISALIGNMENT

CONTROLLING THERMAL FLOW: BONUS ROOM OVER GARAGE Summer Conditioned Room Garage Ceiling Without proper insulation and an air barrier in the floor, hot air flows in during the summer

CONTROLLING THERMAL FLOW: BONUS ROOM OVER GARAGE Winter Conditioned Room Garage Ceiling and out during the winter.

CONTROLLING THERMAL FLOW: BONUS ROOM OVER GARAGE Improperly installed insulation can drop due to gravity. This is a common problem in deep cavities in your home.

CONTROLLING THERMAL FLOW: BONUS ROOM OVER GARAGE

CONTROLLING THERMAL FLOW: BONUS ROOM FLOOR PROBLEM Courtesy of Fort Collins Utilities

CONTROLLING THERMAL FLOW: CONDUCTION THROUGH FRAMING inside outside RippleCraft Log Homes Thermal bridging occurs when materials that are poor insulators (i.e. wood) come in contact with each other as shown here, allowing heat to radiate through.

CONTROLLING THERMAL FLOW: CONDUCTION THROUGH FRAMING The infrared image on the right shows thermal conduction where several wood studs are lined up next to each other, rather than leaving room for insulation. Notice the cooler temperature where the studs are, indicating that heat is escaping more easily through the wood.

CONTROLLING THERMAL FLOW Ice damming, as shown here, is a direct result of warm indoor air leaking from the house into the attic. The warm air melts the snow which freezes again when it drips to the cooler attic eaves. Courtesy of Building Science Corp.

CONTROLLING MOISTURE FLOW

CONTROLLING MOISTURE FLOW wind heat humidity Stack Effect Fans Pressure Heat Moisture rain water radon

CONTROLLING MOISTURE FLOW While keeping the rain from leaking in your home is important, most moisture damage comes from air flow, because ALL air carries moisture.

CONTROLLING MOISTURE FLOW Example: 4 x 8 Sheet of Gypsum Board* *Interior at 7 F 1 in. sq. hole 30 quarts water

CONTROLLING MOISTURE FLOW: WHY MOISTURE IS A PROBLEM All action happens at surfaces Let s take a look at how this happens

CONTROLLING MOISTURE FLOW: WHY MOISTURE IS A PROBLEM The dew point is the temperature at which air must be cooled for water vapor to condense into water. The dew point changes based on the relative humidity in the air

CONTROLLING MOISTURE FLOW So, at a given relative humidity, and a given barometric pressure, if the outside temperature drops to the dew point ( F), you will see moisture, or dew, develop.

BUT HOW DOES THIS AFFECT MY HOME ON THE INSIDE? Great question! Holes and cracks allow inside warm air to reach an exterior sheathing surface. If the outside surface is below the 45 F dew point, moisture will condense out of the air.

CONTROLLING MOISTURE FLOW: ACTION AT THE SURFACES Without insulation, the inside temperature warms the outside sheathing, keeping it above the dew point

CONTROLLING MOISTURE FLOW: ACTION AT THE SURFACES With insulation, the outside sheathing remains cold (below the 45 dew point). If inside warm air reaches the outside sheathing, the moisture in the air will condense on the surface.

CONTROLLING MOISTURE FLOW: ACTION AT THE SURFACES With Insulation: Outside: 30 F 34 F Cold Surface Wall cavity Inside: 70 F, 45 F Dew Pt. Therefore, you must control air leakage.

CONTROLLING MOISTURE FLOW: ACTION AT THE SURFACES Crawlspaces provide perfect opportunities for condensation: Driving forces push hot, humid air in this small basement to meet the cooler, conditioned spaces above. This image shows the damage that action at the surfaces can cause. Courtesy of Building Science Corp.

CONTROLLING MOISTURE FLOW: ACTION AT THE SURFACES Courtesy of Building Science Corp. Combine moisture, wood, and the dark environment inside the wall assembly and you have the perfect conditions for mold and dry rot.

SOLVING PROBLEMS

HOW TO APPLY BUILDING SCIENCE: ENERGY STAR QUALIFIED HOMES Proper Insulation Complete Air Barrier Air Sealing Tight Ducts Advanced Windows = Efficient Equipment Right Sizing Field Verification

PROPER INSULATION

COMPLETE AIR BARRIERS

COMPLETE AIR BARRIERS These builders have planned ahead for simple air barrier details by making their framers responsible for installing sheathing (e.g., dry wall or plywood) at dropped ceiling locations before they are framed. Courtesy of Building Science Corp.

COMPLETE AIR BARRIERS

COMPLETE AIR BARRIERS Courtesy of Building Science Corp.

AIR SEALING

Courtesy of Building Science Corp. AIR SEALING

AIR SEALING Courtesy of Building Science Corp.

TIGHT DUCTS

TIGHT DUCTS DUCT BOOTS & SEAMS SEALED WITH MASTIC Sealing duct connections prevents loss of conditioned air.

TIGHT DUCTS GASKETED DOORS & SEALED SEAMS

ADVANCED WINDOWS

ADVANCED WINDOWS Improved technology reduces heat transfer Multiple panes insulate better Low-E glass reflects heat & UV rays Inert gas fills insulate better Warm edge spacers reduce heat flow & condensation This keeps solar heat radiation out during the summer and in during the winter.

ADVANCED WINDOWS Winter Interior Images: Standard Camera: Standard Window Low-E Window Infrared Camera: Standard Window Low-E Window Warm 1/3 the heat loss! Cold Hot

ADVANCED WINDOWS Pictures of furnishing fabrics after two-years exposure

EFFICIENT EQUIPMENT

EFFICIENT EQUIPMENT As much as half of the energy used in homes goes to heating and cooling. Therefore, equipment plays a critical role in the efficiency of a home. Efficient, properly sized HVAC systems have: Lower Cost Increased Efficiency Longer Lifetime Better Moisture Control Improved Comfort

RIGHT SIZING

RIGHT SIZING If a system is installed that is too large for the home, it not only costs more up front, but also operates less efficiently, and can cause comfort and humidity problems. Let s take a look at the efficiency of equipment as run-time is examined

RIGHT SIZING If a cooling system is oversized 1. The inside temperature rises 2. The system switches on 3. The system works hard to blow huge volumes of cold air into the house 4. The temperature drops quickly 5. The system turns off

RIGHT SIZING If the cooling system is properly sized 1. The inside temperature rises 2. The system switches on 3. The system works moderately to lower the temperature over a longer run-time 4. The temperature drops steadily 5. The system turns off

RIGHT SIZING As run-time increases, the energy efficiency ratio increases as well. Therefore, if the temperature is Right-Sized Equipment lowered at a slower, steady pace, energy use, and consequently, cooling costs, will decrease significantly. Lower Operating Cost Energy Efficiency Ratio ~30% more eff. Increase cycle time from 3 to 8 min. Run-Time (minutes)

FIELD VERIFICATION

FIELD VERIFICATION Blower Door Test

FIELD VERIFICATION Duct Blaster Test Duct blaster test measures the leakiness of the home s duct system. The average new American home duct system has about 20-30% air leakage.

FIELD VERIFICATION Infrared Camera Diagnostics

HIGH PERFORMANCE HOMES: PUTTING IT ALL TOGETHER Why: Affordable Comfortable Healthy Durable How: Control Air Flow Control Thermal Flow Control Moisture Flow Driving Forces Stack Effect Fans Conduction Convection Radiation Bulk Vapor Air Sealing Air Barriers What: Air Sealing Air Barriers Air Sealing Air Barriers Tight Ducts Pressure Balancing Proper Insulation Low-E Windows Min.Thermal Bridging Proper Insulation Low-E Windows Air Sealing Air Barriers Low-E Windows Radiant Barriers Water Man. Roofs Water Man. Walls Water Man. Foundation Air Sealing Air/Vapor Barriers Tight Ducts Right-Sizing Tight Ducts Ventilation Dehumid.

EFFIECIENCY THROUGH ENERGY STAR Effective Insulation High Performance Windows Tight Construction and Ducts Efficient equipment Lighting and Appliances Third-party verification

Indoor airplus Program EPA has also created the Indoor airplus program to address indoor air quality in new homes. This label requires that the home first qualifies as ENERGY STAR, and then addresses several other health and safety issues in the home.

CONSIDER ADDING ON THE ENERGY STAR INDOOR AIRPLUS + Moisture Control Radon Control + Pest Barriers = HVAC Systems Combustion Systems Materials

FOR MORE INFORMATION Visit us on the Web: http://www.energystar.gov/homes Or call the ENERGY STAR hotline: 1-888-STAR-YES