People look to different factors to determine what is the most ecologically friendly choice in insulation. You may look to reduce exposure to chemicals, prioritize waste reduction by recycling materials, or prefer using renewable natural materials. Since heating and cooling accounts for such a large percentage of a home's energy expenditures, high quality insulation is green with respect to energy conservation no matter what.
I had the peculiar experience of getting very excited about home insulation products at the Frederick County Fair. There was a small exhibit displaying sheep's wool in use as home insulation. It's a natural, renewable fiber and one of its appealing properties is that it is flame retardant. Wool requires treatment to be safe from insect damage, usually with boron, which is also a natural element and doesn't have known health risks. Other "cloth" fibers such as hemp and manufacturers' scrap denim can be used as well, but they need to be treated with flame retardant chemicals.
Cellulose insulation is made from about 80% recycled newspaper, and requires a fraction of the energy to produce it compared to traditional fiberglass material. It comes in loose fill that is blown in, and it also needs to be treated with boron like wool does.
Foam insulation is now available--both spray foam and rigid foam--in a soy based product that doesn't have any toxic gas emissions and is non ozone-depleting. Foam insulation is also an excellent sound barrier. You may also wish to consider acoustical properties when choosing an insulation product.
Mineral wool is made from molten rock that is spun like cotton candy. It has excellent fire retardant properties as well as being unattractive to insects and pests. It comes in batt, loose fill and board form. It is a great choice for those who are looking to avoid chemical toxins.
The U.S. Green Building Council offers this buyer's guide for green insulation products if you are interested in more information.
Saturday, September 28, 2013
Friday, September 20, 2013
Energy Modeling Software: Benefits & Drawbacks
People are becoming more familiar with energy modeling software. These programs predict energy consumption of homes, and they are more widely seen due to the popularity of energy audits that seek answers on how to reduce energy consumption for homeowners. Whether or not these software tools are worth the time and expense for a construction project is going to depend on the circumstances.
Energy modeling programs serve different purposes. Some are commissioned by manufacturers or industry organizations to help market their equipment. Others are specific to the green building industry, or have a narrower niche market like those catering to net zero home design. There are specific programs developed as tools for states or municipalities to ensure code compliance by calculating the energy efficiency during the design phase, and still others for energy audits and retrofitting during remodeling.
In general energy modeling involves plugging in different variables to determine if, for example, a window upgrade or a different insulation product will be the most effective at energy savings. Then you can decide where your investment is best made. The more time consuming the program is to use, the more variables it will cover and the more accurate the calculations should be. The downside of this is that the models that cover a lot of different factors often ask for details that can't be easily measured, leaving a lot of guesswork that can be a drain on accuracy.
Another weakness in energy modeling software tools is that when they are in the hands of someone who stands to benefit by up-selling materials, you don't know if you can depend on the accuracy of the figures being input. It is common for the quality of the existing construction to be underestimated. Worst-case conditions are typically assumed, when those may exist only on rare occasions. Many programs also have systematic failures where the complexity of home design simply cannot account for the calculations in a straight-forward spreadsheet formula.
What these programs do very well is calculate for new construction, where there is far less uncertainty in measuring quality and reliability. When the guesswork is minimized, energy modeling tools can do a great job of determining energy efficiency in a home without being overly complicated. At this time, you are likely to do best for a remodeling projects by making educated assumptions and choosing wisely to improve on the things you know are typically problematic in the type of home you own.
Energy modeling programs serve different purposes. Some are commissioned by manufacturers or industry organizations to help market their equipment. Others are specific to the green building industry, or have a narrower niche market like those catering to net zero home design. There are specific programs developed as tools for states or municipalities to ensure code compliance by calculating the energy efficiency during the design phase, and still others for energy audits and retrofitting during remodeling.
In general energy modeling involves plugging in different variables to determine if, for example, a window upgrade or a different insulation product will be the most effective at energy savings. Then you can decide where your investment is best made. The more time consuming the program is to use, the more variables it will cover and the more accurate the calculations should be. The downside of this is that the models that cover a lot of different factors often ask for details that can't be easily measured, leaving a lot of guesswork that can be a drain on accuracy.
Another weakness in energy modeling software tools is that when they are in the hands of someone who stands to benefit by up-selling materials, you don't know if you can depend on the accuracy of the figures being input. It is common for the quality of the existing construction to be underestimated. Worst-case conditions are typically assumed, when those may exist only on rare occasions. Many programs also have systematic failures where the complexity of home design simply cannot account for the calculations in a straight-forward spreadsheet formula.
What these programs do very well is calculate for new construction, where there is far less uncertainty in measuring quality and reliability. When the guesswork is minimized, energy modeling tools can do a great job of determining energy efficiency in a home without being overly complicated. At this time, you are likely to do best for a remodeling projects by making educated assumptions and choosing wisely to improve on the things you know are typically problematic in the type of home you own.
Thursday, September 12, 2013
High Efficiency Ductless HVAC
The HVAC industry has recently dubbed what were called mini-splits "ductless systems." They operate similarly to what you will be familiar with from some hotel rooms, although modern residential units offer remote control operation. Mini-split refers to the small size and the two units split, indoor and out. These systems can be a very economical choice for a remodel, and they are standouts in terms of energy efficiency.
The obvious advantage to these in remodel construction is that they don't consume the space required for the duct work. If the remodel is being done within an existing structure, you won't lose the area overhead or in corners. Some people don't care for the look of the indoor unit, and if it bothers you, there are ways to install a flat mounted grille by using some creative carpentry. Placing it in a discreet location or concealing it with built in shelving are both ways of dealing with this issue.
More and more frequently these systems are being used in new construction as a result of other advantages. A forced air system with ducts incurs roughly a 30% energy loss, whereas the ductless system will lose only 1 to 5%. They have become a popular choice for net-zero energy construction.
In addition to energy savings, the price of the units may be lower. The labor expenses required for these units will be significantly less because they are far simpler to install than a system that requires duct work. Savings on the HVAC system can then be devoted to improvements in insulation, windows and sealing in air, so that the construction is extremely efficient overall.
This video from Fujitsu discusses their mini-split and how it works for climate control and cleaning the air.
The obvious advantage to these in remodel construction is that they don't consume the space required for the duct work. If the remodel is being done within an existing structure, you won't lose the area overhead or in corners. Some people don't care for the look of the indoor unit, and if it bothers you, there are ways to install a flat mounted grille by using some creative carpentry. Placing it in a discreet location or concealing it with built in shelving are both ways of dealing with this issue.
More and more frequently these systems are being used in new construction as a result of other advantages. A forced air system with ducts incurs roughly a 30% energy loss, whereas the ductless system will lose only 1 to 5%. They have become a popular choice for net-zero energy construction.
In addition to energy savings, the price of the units may be lower. The labor expenses required for these units will be significantly less because they are far simpler to install than a system that requires duct work. Savings on the HVAC system can then be devoted to improvements in insulation, windows and sealing in air, so that the construction is extremely efficient overall.
This video from Fujitsu discusses their mini-split and how it works for climate control and cleaning the air.
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