Building with Energy Efficient Insulation – How It Helps Save Money
DEAN: – Look, Mike, we’re out here on the exterior wall here. And I see something different than I normally see in houses. Most houses I see Tyvek, the real thin stuff, and it’s kind of floppy. This stuff is pretty heavy-duty, hardcore. Tell us a little about this blue board.
MIKE:– You are correct, Dean. This is special rigid form board that we get from Dow. It’s a half inch of insulation value that you get around the whole entire house. So, unlike just the Tyvek, which is just paper, which just gives no r-value, this gives you that continuous r-value through around the whole entire house.
DEAN:– Mike, I know a little bit about r-value. But, you know, tell the people at home what r-value means.
MIKE:– Yeah, real simply, r-value is the heat resistance, you know, through this wall cavity. So the higher r-value, the more energy efficient this wall cavity will be. This has an r-value of three. This half-inch piece of rigid foam that we got around the whole house, giving that continuous air barrier. And unlike Tyvek, which has no r-value to it at all, this is giving you that extra r-value of three with this wall cavity.
DEAN:– Just so people know, show us, I mean, what is this heavy duty taping, this stuff right here? What is this doing for us?
MIKE:– Well, again, since it’s acting as the weather resistant barrier for the home, you have to tape-up all the seams. You have to flash all your windows properly.
DEAN:– Great job out here, Mike. Let’s go in.
DEAN:– All right, Mike, we came from outside, talked about the exterior. Now this frame-in package, I noticed this house was like, it’s two by six walls instead of two by four walls.
MIKE:– Correct, again maximizing your r-value in your walls, and they’re spaced 24 inch from center, so we have a whole lot more r-value in these walls than a traditional two by four framed house. Again, you can see we’ve used the spray foam pod, which has given us that ultimate air barrier on this house.
DEAN:– When I do a heat loss seek gains, we figure this in as a tight house. And we size our unit accordingly. Now if this would have been standard insulation, I know for a fact, it would have probably took another ton and a half, maybe two tons more of air conditioning. Is that not the case?
MIKE:– That is correct.
DEAN:– By lowering the tonnage, we lower what? You’re an Electrical Engineer?
MIKE:– Yep. You’re gonna lower your electric bill.
DEAN:– We’re gonna lower that electrical bill. So we’ve got a Yeti cooler here versus a Igloo cooler. Ice goes at ten dollars a bag, what do you want?
MIKE:– You want the Yeti cooler.
DEAN:– You want the Yeti cooler, baby. Now, I see that you got some unique framing here. Is this a two by six? What’s behind this? Is that all foam?
MIKE: – Yeah, in a traditional frame dome, you’d typically have kind of a studded pocket back here where you wouldn’t get installation. But with the new framing techniques now we are able to put horizontal members in here.
DEAN:– Now, with a blue board outside, and a two by six foamed wall, we stop almost all infiltration, all moisture. Now I want to give you guys a little something to think about. If you’re living in a home as 15 to 20 years old that doesn’t have foam, if you would go look around your door jams, if you go look around your little electrical boxes, you’ll notice little brown stuff that’s the infiltration from outside. And that’s where outside air is filtered in your house. So not only are you heating up on your house, but you’re heating the whole world.
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Building with energy efficient insulation is one of the best ways to save on energy consumption and bills. Spray foam insulation is one of the best and most effective insulations on the market right now. And not only will it help save you money, but it also has the additional benefits for the energy efficiency and value of your home.
With energy costs rising, many people are now including energy efficient insulation in their new construction. Despite this surge, 90% of American homes are still under-insulated containing cracks, holes, and gaps that allow air to escape, driving up energy costs. In warmer climates like Raleigh, NC, losing that conditioned air in the hot summer months can make your home incredibly uncomfortable and easily cost hundreds of dollars. Energy saving insulation provides defense against these losses by sealing and blocking potential areas of heat transfer.
Insulation is more than just what’s in your walls. How your home is designed and laid out, and the materials used to construct your house, are all factors in creating an energy efficient home. Considering these factors before you build will help you make well-informed decisions on the construction of your new home. We will go over methods for both interior and exterior insulation, but before we do that, let’s explain the basics.
How Does Insulation Work?
Understanding how insulation works mainly comes down to understanding how heat flow works. Heat flows in three different ways:
Conduction – Conduction is the way heat moves through materials, like when a spoon placed in a hot cup of coffee conducts heat through its handle to your hand.
Convection – Convection is the way heat circulates through liquids and gasses. It’s why lighter, warmer air rises, and cooler, denser air sinks.
Radiation – Radiant heat travels in a straight line and heats anything solid in its path that absorbs its energy.
Heat will continue to flow until there is no longer a temperature difference. This means that in the winter, the heat in your home will flow to wherever the least insulation is (i.e. trying to warm the coldest spots).
What Does R-value Mean?
R-value is a way to measure insulation’s rate of thermal resistance, otherwise known as the general rating system that measures insulation’s effectiveness. R stands for “resistance” to conductive heat flow. A higher R-value means more thermal efficiency and better insulation.
How Energy Efficient Home Insulation Helps Save Energy
Heating and cooling account for more than half of home energy consumption in the United States. Inefficiently insulated homes can produce energy losses roughly the same as leaving one of your windows open year-round! But, properly insulating and sealing your home can save an average of 15% on heating and cooling costs, and 11% on total home energy bills.
What Is the R-value for Exterior Walls
The R-value for exterior walls can vary depending on several factors, including the type of insulation, the thickness of the insulation, and the construction materials used. For Raleigh, NC, exterior walls must have an R value of at least 10 (that is: R-10) according to NC building codes (See Chapter 11 Energy Efficiency).
R-Value of Tyvek
Tyvek has no R-value as it is not an insulation material. Tyvek is a brand of synthetic house or building wrap designed to serve as a weather-resistant barrier to protect homes and buildings from moisture infiltration while allowing water vapor to escape. Its primary function is to enhance the building envelope’s performance by preventing air and water infiltration, not act as insulation.
How Does Framing Affect Insulation?
Framing is another important element when it comes to energy efficient insulation. It can have an impact on insulation in several ways and is something to consider and discuss with your builder in the design phase of your new home build.
- Wall Cavities: The size and spacing of the framing can affect the amount and type of insulation that can be installed. Narrower spacing or irregularly shaped framing can limit the thickness or coverage of insulation, reducing the insulation’s overall effectiveness.
- Thermal Bridging: Framing members can act as thermal bridges, allowing heat to transfer through the building. Wood or metal framing can create paths for heat to escape or enter the building because they have higher thermal conductivity compared to insulation materials.
- Air Leaks: Framing can affect the tightness of the building, which relates to its ability to prevent air leakage. Properly sealed and insulated walls and roofs can significantly reduce air infiltration and heat loss. Poorly constructed or uneven framing can create gaps that allow air infiltration.
Where to Insulate in Your Home
There are several important areas of your home to insulate if you want to achieve maximum efficiency from your insulation. However, every home is different, and not all areas should be treated equally. Remember that insulating while your new home is being built will be easier and less costly. Some of the most important areas include:
- Unfinished or finished attics
- Exterior walls
- Crawls spaces
- Band joints
- Duct work
- Windows and doors
Spray Foam Insulation Compared
Spray foam acts as both insulation and an air barrier. Spray foam can be best described as a plastic spray that is installed as a liquid then expands upon application, helping to seal spaces and prevent air flow through seams and cracks.
Compared to other major forms of insulation, spray foam is one of the best options for home insulation due to its high R-value.
What Is the R-Value of Spray Foam Insulation?
With R-values ranging from 7 to 9 per inch, spray foam insulation is typically 2-3-times higher than fiberglass or cellulose insulation.
Beyond simply the R-value, it’s important to consider all factors when comparing the different types of insulation for your new home. The Department of Energy conducted case studies on the major types of insulation. Using both the Department of Energy studies’ results and our insulation values at Casey Services, we created a chart breaking down the primary differences. The results show a clear winner.
Spray Foam vs. Other Insulation Types
|Seals heat within buildings?||Yes||No||No|
|Installation||Sprayed by a professional applicator to conform to the structural layout.||Folded, cut and placed within the walls and ceilings.||Blown into the walls and held in place with glue and water.|
|R-value||7 to 9 per inch||2.2 to 4.3 per inch||3.0 to 3.8 per inch|
|Performance in Extremes||Contains conditioned air reliably year-round.||Loses 40% of capacity if temperatures fall below 20 degrees F.||Weather will cause leakage through the insulation.|
|Energy Efficiency||Most efficient||Less efficient||Less efficient|
|Health Problems||Chemicals undetectable after one hour. No long-term hazards.||Fiberglass can spread particles throughout the home. These can cause serious respiratory illness if inhaled.||May allow mold and mildew in wet climates. In dry weather, it can create dust which is hazardous if inhaled.|
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Though spray foam insulation proves superior in most fields, the primary downside is its cost – it tends to be more expensive than other insulation types. That being said, because of the long-term savings spray foam insulation provides, it can be a worthwhile investment.
Benefits of Spray Foam Insulation
Many of the holes, crevices, and air leaks that hike the cost of energy bills can be prevented with spray foam insulation. The U.S. Environmental Protection Agency’s (EPA) ENERGY STAR® program estimates that by adding insulation and sealing air leaks, you could save up to 20% on your monthly energy bills.
Keeping your HVAC system in good working order can also help you save energy in your home. Thankfully, spray foam insulation helps reduce the workload on your HVAC system, and, in fact, can reduce HVAC sizing by up to 35% without any loss of efficiency and comfort! Additionally, by reducing your energy usage through insulation, you significantly reduce greenhouse gas emissions associated with your home.
Better Indoor Air Quality
Another benefit of polyurethane spray foam is superior indoor air quality. Since the spray foam seals all gaps and holes, it prevents unwanted outside air from entering the home. This reduces the possibility of pollen and allergens being carried into your home by the wind, which is especially important if you live with someone who suffers from allergies or respiratory problems.
Spray foam insulation also helps keep pests out of your home. The foam blocks the gaps throughout your home where insects and small rodents usually enter.
Spray foam insulation has the ability to resist moisture absorption and can even act as a moisture barrier when properly applied. By reducing moisture infiltration, it helps prevent mold and mildew growth, which can negatively impact indoor air quality and, over time, the structural integrity of the building.
Improved Structural Integrity
Foam insulation can strengthen the structure of your home due to its density and hardness. Spray foam adheres to surfaces, improving the overall structural integrity. For example, insulating your attic helps make your ceiling and roof more resistant to storms and extreme weather conditions.
According to FEMA, spray foam insulation classifies as a Class 5 insulator (the highest possible rating), which means that it is extremely resistant to flood damage — “These materials can survive wetting and drying and may be successfully cleaned after a flood to render them free of most harmful pollutants.”
To check your area’s risk of flooding, enter your address at the FEMA Flood Map Service Center.
Can I Add Spray Foam Later?
While adding spray foam insulation after construction is still a viable option to improve energy efficiency and comfort in existing homes, it can be incredibly expensive and at times impossible without removing walls, redoing electrical and plumbing, and a whole host of other issues. Integrating it into the initial building process offers superior benefits in terms of insulation performance, moisture control, air sealing, and structural enhancements.
We Care about Optimizing the Energy Efficiency of Your Home
At Casey Services, we care about educating those looking to build their own home, or those who already own one, on how to make their home as sustainable and efficient as possible. Improving the thermal efficiency of your home not only helps reduce the costs and usage of energy, but helps elevate your overall quality of living. Whether you’re building a new custom home or reevaluating an existing one, Casey Services understands the value of proper insulation and all of the benefits it provides beyond simply efficient heating and cooling. Talk to one of our professionals about the most energy efficient options for your home.
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If you are building your home and looking to manage the humidity levels, a whole house dehumidifier can greatly improve your comfort at home and save you money on your energy bills.
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