A Home Owner's Guide to Home Energy Efficiency and Insulation
Homeowners, especially those who own homes in challenging climates like New Jersey with hot, humid summers and bone-chilling winters, face an ongoing battle with the merciless outdoors. It can seem like an uphill struggle to keep your indoor living space comfortable. Having top-of-the-line heating and air conditioning units are no guarantee of a comfortable living space. If your home is not energy efficient, outdoor temperatures will inevitably seep into your home making summers unbearably hot and winters unbearably cold. In energy inefficient homes, these units turn into money burning machines and the utility bills alone are enough to make a grown man cry.
There are a variety of ways to improve your home’s energy efficiency and save on your heating and air conditioning costs. The key is keeping in mind two major interrelated elements:
- Air sealing
Homeowners are sometimes hesitant to spend money on these “invisible” behind-the-scene improvements compared to other remodeling projects like kitchen and bathroom upgrades. But, your fancy bathroom remodel will quickly lose its appeal if it feels like you’re been transported to an Antarctica research station when you walk in there in the morning to take a shower. Fortunately, the cost of improvements in this area, like buying good additional attic insulation, is often recouped in a few years from lower utility bills.
Here is a guide to what homeowners need to know about home energy efficiency.
Air Sealing: What is it?
Air sealing is more than just plugging up air leaks. When someone thinks of air sealing, the traditional techniques of weather stripping and caulking pop into mind. There are better options. More air can be stopped elsewhere for less money. Air moving through doors and windows is far less harmful than air traveling through wall cavities, attics, and crawl spaces, often leaving behind damaging water condensation in its wake. When it comes to air leakage, whether outdoor air entering your home or heated or cooled air exiting your home, look to the top and bottom: attics and crawlspaces are the major culprits. Nothing else comes close. In the first blog of this series, we will start at the top and discuss attics.
Signs that Additional Attic Insulation is Needed
The benefits of adding insulation to the attic can be substantial. Your home may not be able to talk, but it has other not-so-subtle ways of letting you know that it needs a blanket of attic insulation as a barrier to outside temperatures. They include:
- drafty rooms
- uneven temperatures throughout the house
- hot or cold ceilings and walls or even whole rooms
- high utility bills
The Danger of Ice Dams
One of the most dangerous signs of an attic insulation problem is the formation of dangerous winter ice dams. Ice dams are caused by poor roof ventilation and a warm attic space. Warm air should be kept inside your living spaces, not escaping to heat your rooftop. Indoor heat loss can warm the roof’s surface temperatures to above-freezing levels. When this happens, water from snow melting off the heated roof surface turns into an ice dam once it flows down and hits the cold roof edge or gutters. You’ll see thick blocks of ice clogging your gutters along with thick stalactite-type icicles that makes your home look like an ice cave.
Ice dams can cause a host of structural problems.
- The ice can get under your shingles damaging your roof.
- The melting water can also leak inside your home, often into hidden spaces like indoor wall cavities.
- The water can saturate your insulation and cause mold growth in the attic.
- Wall paint can peel as the moisture in the walls tries to leave and pushes outward.
The only permanent solution to ice dams is proper roof ventilation and eliminating all heat sources in the attic. The underside of the roof must be kept close to the outside temperatures to prevent snowmelt. There are various potential sources of heat in the attic space such as bathroom vent fans that improperly vent to the attic, but the most significant cause of heat build-up in the attic is poor attic floor insulation.
Attic Insulation Options
There are a variety of insulation materials available including:
- polyurethane foam
- mineral wool insulation
Fiberglass rolls or batts pre-cut insulation panels, have been the subject of much criticism, especially among Green Building advocates. The American Lung Association lists fiberglass as a health hazard, stating that the inhalation of the glass strands can reduce lung function. Fiberglass also emits styrene, a possible carcinogenic. Some fiberglass still contains formaldehyde. Also, batts can be difficult to properly install, especially in small or irregularly shaped areas. Poor installation results in gaps, sags, and spaces, inviting air leakage. Vermaculite insulation may contain asbestos and should not be disturbed without the proper protective equipment. The dangers of contact with asbestos have been highly publicized, especially the deadly connection between asbestos and mesothelioma cancer.
Cellulose Insulation is better for the environment and better for your home. Cellulose insulation is among the oldest types of building insulation material. Modern cellulose insulation is made with recycled newspaper using grinding and dust removing machines and adding a fire retardant.
Environmental Benefits of Cellulose Insulation
Since cellulose has the highest level of recycled content in the building insulation industry, for those concerned with the environmental impact of building products and reduction of greenhouse gasses, cellulose insulation is the only real choice. It takes less energy to make, is regionally produced, and is recovered and recycled on site so it never reaches landfills. Designers of eco-friendly homes focus on wood-intensive construction because of their lower carbon footprint; cellulose insulation is integral to that design. Unlike close cell spray polyurethane, cellulose has no environmentally destructive HFA, HCFC, or HFC blowing agents. It has absolutely no harmful emissions after installation or drying. Foam products are toxic during installation are require respirators; several days are required for airing out the property before occupancy.
Performance Benefits of Cellulose Insulation
Cellulose easily insulates irregular or hard-to-reach spaces unlike batt materials that have to be cut and stapled. It can also be injected into closed wall cavities. In fact, cellulose insulation was the original material used for this application and remains the preferred material by the Federal Weatherization programs.
Cellulose Insulation and the Importance of R-Values
Cellulose has superior overall performance insulation because it reduces air infiltration and convection better than other fiber insulation products with the same R-value. R-value is only one of several factors to consider when choosing insulation. R-value, a measure of resistance to heat flow through a given thickness of material, is certainly an important factor in comparing insulation. But it’s not the be all and end all. R-values should not be treated as the sole criteria of an insulation’s effectiveness.
What are R-values?
We use insulation to stop the movement of heat. R-values are a quantitative measurement done in a testing lab. The higher the R-value, the higher the resistance to heat flow and the greater the insulating power. That is all well and good, but homes are built outside and not in a lab. In the outdoors, heat moves in and out of your home in a variety of ways. It does so by conduction, which R-Values do measure. But heat also moves by convection, radiation, and air infiltration. And none of these types of heat movement affect R-value measures.
Cellulose insulation performs exceptionally in real world conditions once you introduce wind, humidity, and temperature changes. For example, the stated R-value of a fiberglass batt does little good if heat bypasses the batt through convection because of gaps and spaces; the panels just can’t cover every space in your home requiring insulation no matter how talented the installer. Cellulose insulation, on the other hand, not only has excellent R-values, but it blocks all of the different types of heat movement. Since it is loose fill, it fully fills the building cavity to prevent heat loss via convection. It is also densely packed to prevent heat loss via air infiltration and radiation.
How much insulation should be installed?
The amount of insulation recommended in a home varies depending on where you live (climate conditions) and the age of your home (homes older than 10 years old likely need more insulation).
The 2009 International Energy Conservation Code (IECC) is the model building code for the United States. The North American Insulation Manufacturers Association developed a map showing thermal recommended levels of insulation. The United States is divided into eight different zones for the purpose of deciding the levels of insulation that are cost-effective for different climates and locations in the home. Zone 1 are the warmest climates requiring the lowest R-value insulation and Zone 8 are the coldest.
Most of New Jersey’s land mass is designated as Climate Zone 4 including Ocean, Monmouth, and Middlesex Counties. There are eight counties in the northwest part of the state with slightly harsher climates that are designated as Climate Zone 5 including Mercer, Hunterdon, Somerset, Warren, Morris, Sussex, Passaic, and Bergen Counties.
The recommendation summaries are as follows:
Zone 4 uninsulated attic R38 to R60
Zone 5 uninsulated attic R49 to R60
Zone 4 add to existing 3-4 inches of insulation R38
Zone 5 add to existing 3-4 inches of insulation R38 to R49