Decker Home Services, LLC

Home Energy Inspection, Energy Auditing

 

Common Home Heat Loss Areas

This winter has been a very cold one.  Together with record cold temperatures and wind chill factors, there has also been record snow fall.  And, as we all know, there has also been a large increase in heating costs.  The energy efficiency of your home, once a very low priority, has become more important.  Whether your concern is helping the environment, increasing your house's market value, saving money on your heating (and cooling) bills or just making you home more comfortable to live in, everyone is much more aware of energy efficiency and how your house stacks up.

 

There are new standards, and even additions to local building codes, that are now in place.  There are also many new groups and associations that are lobbying to get their standards set in place to receive government approval (and government money).  These moves are needed, but the standards must be set based upon the sound principles of building science and physics, not just political correctness and fly-by-night "green" fads.  There must also be standards set based upon the different weather patterns and climate conditions that exist in different areas of the country.

 

And, now you can get big savings, if you live in the Chicago area, for upgrading your house's energy efficiency.

See details here.

 

The Chicago area is unique in its weather.  Around here, the prevailing winds that can come from the moist Gulf Stream, across the Great Plains or down from the frigid areas of Canada.  When these different air masses come in contact with the huge heat sink that is Lake Michigan, anything can happen.  High winds, lake effect snow, heavy rains, brutal wind chill effects and basement flooding must all must be taken into account.

 

Here are some common problems we see in local houses, even (and sometimes, especially) in newly built houses:

 

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Improperly installed house wrap:  We have all seen new houses being built and the wooden structural framing being covered with house wrap (Tyvek, Typar, etc).  This covering is designed to provide a barrier against liquid water as well as to allow water vapor (from inside the house's sheathing) to escape.  But most contractors do not properly install the house wrap.  The wrap must be properly installed, so as to allow water to drain off it and away from the house, and it must also be properly taped and sealed.  The window and door openings through the wrap must also be properly sealed House Wrap and Flashing Installationand the drainage flashing must be installed under the house Improperly Installed Housewrap

 

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Improperly installed insulation:  There are many different kinds of insulation available, but not all insulation products are proper for use in every kind of house or in every climate area.  The R factor (heat loss resistance factor) grading of insulation is NOT the best determination of the effectiveness.  More important is how well the walls and ceiling are sealed against air, water and moisture.  Wet or cold air flow will greatly decrease the effective R value.

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The R value of insulation is an overly stressed concept.  There is a point at which more insulation does not mean more energy savings payback.  One inch of insulation lowers heat loss by 80%.  Adding an additional inch lowers heat loss to 89%.  At about 3 1/2 inches, more insulation does not become as cost effective a solution.  More is not always better.  It make better sense to put the extra cost and effort into making sure that the proper kind of insulation is used and that it is properly installed.

 

 

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Cellulose insulation - Manufactured from recycled newspaper, cellulose insulation (whether "blown-in" to an existing wall or sprayed on to a new wall, is "green" (in that it is a recycled product) but it also has its down sides.

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Cellulose settles, over time, leaving a gap or 1 to 2 feet at the top of the wall.

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Cellulose does not provide a great deal of insulation value per inch (only about  R 3).

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Cellulose is ideal mold food.  If the house is not properly sealed against water and moisture intrusion, the insulation will get wet and mold will start to grow.

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Fiberglass insulation - This is the most commonly used insulation, manufactured of spun glass fibers and, usually, with a vapor barrier paper (called Kraft paper) that should face inward, towards the heated portion of the house.

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Fiberglass insulation is, usually, not properly installed.  The Kraft paper "vapor barrier" facing should cover the inside face of the studs, but most installers staple it to the sides of the studs so that they can apply glue to help hold the drywall.  This defeats the purpose of the Kraft paper and allows moisture to enter the insulation from the house's interior humidity and greatly reduces its insulation ability.

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Fiberglass insulation must be installed uncompressed.  Standard R 13 insulation requires at least 3 1/2" of space.  Too often, this insulation is compressed and not properly installed around outlets and switch boxes.  If the fiberglass is compressed, it will not give the proper insulation value.

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Foam insulation - Foam insulations not only insulate, but also provide the needed air, water and vapor barrier and at the best location, against the inside face of the wall sheathing.  There are three types of foam insulation products.

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BioFoam - A newer, supposedly "green" product, BioFoam is manufactured from soybeans.  While providing all the benefits of a foam insulation product, BioFoam is organic and is susceptible to mold growth.

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Polyurethane foam - Just like the spray in foams, polyurethane seals and insulates very well,  It does, however, off gas volatile hydrocarbons and CFCs into the house for a few years after installation.  It is also flammable and must be treated with a fire retardant coating.

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Icynene foam - A fairly new product, in the U.S., Icynene foam is water based, easy to install, provides a superior air, water and vapor barrier and stays flexible (unlike polyurethane) to conform to the house as it settles.  Icynene can also be used to retrofit an older house with a "pour in" version that can be installed through small holes (about 5/8"), thus eliminating the need to replace the walls.

 

Heat Loss, Insulation Defect in New HouseRemember, it is just as important to have the house's walls sealed against water, air and moisture intrusion s it is to have good insulation.  Insulation with cold air blowing through it or that is wet does not insulated very well.  Many houses we see, have good insulation, but were not properly sealed.  As this thermal image of the ceiling and wall area of a new house shows, water and air from the exterior can seriously degrade the insulation, as well as lead to condensation and water leakage problems.  In this thermograph, we see a new house's entryway atrium wall and ceiling area.  The blue area is a cold surface.  This house's exterior was not properly sealed against air (and, thereby, moisture) intrusion.  As a result, there is a 10 degree difference in the heat loss.  This defect could have been easily avoided if the builder had followed the manufacturer's installation instructions.

 

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Improperly installed furnaces:  There are 3 types of gas forced air furnaces, defined by their energy efficiency and related to how the create the "draft" from the combustion chamber to the outside air:

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Conventionally drafted:  This furnace has an open draft hood which takes air from inside the house, mixed with the combustion gas, and allow this mixture to "draft" up the chimney of flue.  These furnaces are older, no longer manufactured and have about a 65 to 70% energy efficiency.

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Mid efficiency furnaces:  Technically referred to as Category 1 or Category 3, these furnaces employ a fan to force the draft up the flue.  These furnaces provide about 80 - 85% efficiency.

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High Efficiency furnaces:  Technically referred to as Category 4, these furnaces also use a draft fan, but they also take fresh air from outside the house to support combustion as opposed to house air.  These furnaces provide 90 to 95% energy efficiency.

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Outside combustion air is usually higher in oxygen content and has not already been heated.  Using already heated house air for combustion means that you are just throwing away heat, and money.

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A very common mistake is when the outside combustion air vent is not installed so as to take air from outside the house.  If not installed, a 90+ efficiency furnace becomes an 80+ efficiency furnace.

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If the furnace takes inside air for combustion (conventional, Cat 1 or 3) the room where the furnace sits has to be big enough to supply enough air.  Small furnace rooms should be equipped with 2 steel vents to allow proper air circulation and combustion air supply.

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The furnace filter should be the inexpensive blue fiberglass type.  The so-called air quality, HEPA, cartridge or anti-allergy filters do not really work AND they restrict the proper flow of return air to the furnace.  The purpose of the furnace filter is NOT to regulate indoor air quality, but to keep dust and hair out of the furnace's heat exchanger and air conditioning coil.  The furnace filter should be replaced every 30 days.  There is no such thing as a 90 day or one year filter (at least not that work).

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Too often, furnaces and A/C compressors are not sized right for the house or condo unit.  These units must be properly installed, sized for the specific cubic footage to be heated / cooled and heating / cooling loads must be calculated for each room, not just for the house.

 

We partner with qualified, licensed and professional HVAC contractors because we see it done, too often, the wrong way.  See here.

 

If you have any questions about your house's energy efficiency or how to improve it, please feel free to call us.  We are happy to give advice over the phone, free of charge.

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