Von Löwen Designs

It’s much easier to turn a remodel green for a house when you understand how heat and cold move from one object to another, and how air and moisture move inside our home. Green remodeling practices and design, in addition to the selection of appropriate materials, revolve around a few basic principles.

• Thinking of the house as a holistic system of interrelated parts.

• Energy loses some of its potential each time it is converted from one form to another, which helps explain why passive solar heat is much more efficient than electric heat.

• Form follows function when it comes to design, meaning that construction should be tailored to the environment in which the house is built.

• Air leaks in the building envelope represent a significant loss of energy and open the door to moisture damage inside wall and ceiling cavities.

• Controlling the movement of heat, air, and moisture involves every part of the home and everyone on the construction and design team.

Nothing is more central to the notion of the home as a holistic system than heat flow, or to get a bit more technical about it, the First and Second Laws of Thermodynamics (thermo = heat, dynamics = movement). Once we see how these principles are applied to remodeling, construction, and design, we’ll never look at a house the same way.

Energy cannot be created or destroyed, only changed. That’s the first law of thermodynamics. All the energy we have is in one of many forms: electrical, chemical, mechanical, solar. The second law says that every time you convert energy from one form to another it’s degraded in the process.

Some forms of energy are more concentrated than others are. Electrical energy, for instance can do all kinds of miraculous things, like make computers work or turn heavy motors. Woodstoves. on the other hand, convert a lot of energy potential from the wood into heat, but you can’t run a laptop with it. So there is a hierarchy of energy forms that we can convert to accomplish the work we want to do.

What the second law tells us is that each time we change the form of energy (chemical to heat – heat to mechanical) it becomes less useful. This is called entropy. Efficiency is converting energy from one form to another with as little waste as possible In the end, we can measure the ‘net energy’ of any given process – the percent of the original energy potential versus the actual work we have accomplished.

Does this have anything to do with remodeling houses? Actually, it does. Our challenge as designers and builders is to make the building as efficient as possible in all energy conversions – that is, to keep energy in its most useful form and not let it escape or degrade more than necessary. In other words, to create the least entropy. The closer the building is to the source – the bottom of the energy food chain – the better.

A classical example of high entropy versus low entropy lies in the contrast between a house that is electrically heated and one that is designed to be passive solar. Electricity makes a long journey before it arrives at the baseboard heater.

Suppose the electricity we use comes from coal. Coal itself is a very concentrated form of chemical energy that was created over millions of years in a process of photosynthesis that converted atmospheric carbon dioxide into a hydrocarbon fossil fuel. Enormous amounts of energy are required to run the extraction equipment, trucks, and processing equipment. Then coal is transported to a power plant that burns the coal to boil water that creates steam. The steam spins a turbine that creates the electricity. The electricity then passes through a transformer to create 240,000 volts for high transmission lines. As it runs through the lines there are line losses until it reaches its destination. It then passes through another transformer where it is stepped down to 240 volts that we can use in our homes.

Passive solar, on the other hand uses radiant heat directly from the sun to heat a home. Here the energy makes only one simple conversion from light to heat. The sunlight passes through south facing windows, strikes a solid object, and turns into heat that is re-radiated to human bodies. There is only one energy conversion.

The efficiency of the process is determined by the transparency of the glass. At a minimum we get 50 percent of the potential heat and with well designed glass, we can get up to 75 percent. And, it’s all free! That’s eating low on the energy food chain.

In green remodeling, having an appreciation for entropy helps us select the best form of energy for the task at hand, using the most efficient appliances or designs that make energy conversions with the least amount of degradation (to heat) and retaining heat where we need it and in the form we want it. This is where the building shell comes in.

Heat Transfer and Thermal Transmission.

Energy moves in three ways – conduction, convection, and radiation – and energy movement is always a combination of all three. While we refer to insulation in terms of its conductive resistance to heat movement, convection and radiation are also taking place on a more subtle level. All of these are important in a house for different reasons and the principals help explain why some design techniques and materials work better than others.

Conduction.

Heat moves through solid substances by this process. It is typically measured with an R-value (the higher the number, the greater resistance to heat flow). Anything that conducts electricity typically has a low R-value. Metals of all kinds fall into this category. Wood, not a good conductor, has a higher R-value than metal. The insulation we use in our houses works because it traps air, giving it a much higher R-value.

So when insulating a house from hot and cold, we look for materials that allow the least amount of conduction or take steps to shield conductive materials so they do not become energy transmitters. Light steel framing for example, can move tremendous amounts of energy through the exterior walls of a house because it is such an efficient conductor. That’s why a steel framed house should be sheathed with rigid foam insulation. Cellulose, foam, cotton, mineral wool, and other types of insulation conduct very little.

Convection.

Convection is the movement of liquids and gases because of differences in density. Convection explains why warm air ends up in the upper floors of a house while the basement stays cold, or why a chimney draws smoke up and out of the house.

Our houses are filled with convective currents, some of which we feel and some of which go undetected. Convection is more subtle than conduction, but when it is not controlled, it can result in a drafty, uncomfortable house. Worse, convection can carry moisture exactly where we do not want it – into wall cavities and attics where it condenses into water and encourages mold and deterioration.

When we become more aware of how convection works, we can take steps in designing and remodeling houses to reduce its impact on comfort and health.

Radiation.

Radiation is the movement of energy from a hot object to a cooler one via waves. Think of the sun on a hot summer day. The air temperature is the same in the sunshine as it is in the shade, but we feel more comfortable when we get out of the sun and out of reach of all that radiant energy. A fireplace can keep us warm even as a great deal of hot air escapes up the chimney.

Radiant energy heats objects rather than air. That s why people are often happier with radiant floor heat than they are with a forced air furnace. Their bodies feel the heat directly rather than feeling the warm air.

Controlling Heat Flow.

We design, build, and remodel houses so we can stay comfortable and to keep the weather at bay. Over time, we’ve gotten better and better at disconnecting our houses from the climate that surrounds them. Houses today can look the same whether you’re in Alaska or Florida, and that doesn’t make a lot of sense. More logistically, houses in those vastly different climates would be designed to respond to the environment around them and thus have very different appearances.

Insulation is a key part of designing for climate. How much insulation we can get between outside and inside is partially determined by the structure of the building. Wood frame buildings were once framed with 2×4s on 16 inch centers, an approach so common that architects and designers referred to this detail simply as ‘typical.’ So this is the place to start with remodeling.

I won’t be getting into framing right now, but the important thing here is to try to avoid ‘TYP’ on construction drawings – it means that too little is being done to fit the house to its environment. A house should be designed to meet the requirements of the local environment. This means that insulation levels, or the overall R-value of the house, should be higher than the minimums required by the local energy code. In a good green home, the R-values of insulated floors, walls, and ceilings are often 50 percent higher than what the building code requires.

They say a picture is worth 1,000 words, so before you leave be sure to visit Von Löwen Designs to view an assortment of refreshing examples in kitchen and bath design concepts, refined palette and interior finishes, and sustainable yet chic, green remodeling ideas that may encourage and inspire your next remodel or home improvement project.

MYTH: Scientists aren’t sure radon really is a problem.

FACT: Although some scientists dispute the precise number of deaths due to radon, all major health organizations (like Centers for Disease Control and Prevention, American Lung Association and World Health Organization) agree with estimates that radon causes thousands of preventable lung cancer deaths every year. This is especially true among smokers, since the risk to smokers is much greater than to non-smokers.

MYTH: Radon testing is difficult, time consuming and expensive.

FACT: Radon testing is easy. You can test your home yourself or hire a qualified radon test company. Either approach takes only a small amount of time and effort.

MYTH: Radon test kits are not reliable and are difficult to find.

FACT: Reliable test kits are available from qualified radon testers and companies. Reliable testing devices are also available by phone or mail-order, and can be purchased in hardware stores and other retail outlets. Call your state radon office for help in identifying radon testing companies.

MYTH: Homes with radon problems can’t be fixed.

FACT: There are simple solutions to radon problems in homes. Hundreds of thousands of homeowners have already fixed radon problems in their homes. Most homes can be fixed for about the same cost as other common home repairs; check with one or more qualified mitigators. Call your state radon office for help in identifying qualified mitigation contractors.

MYTH: Radon only affects certain kinds of homes.

FACT: House construction can affect radon levels. However, radon can be a problem in homes of all types: old homes, new homes, drafty homes, insulated homes, homes with basements, homes without basements. Local geology, construction materials, and how the home was built are among the factors that can affect radon levels in homes.

MYTH: Radon is only a problem in certain parts of the country.

FACT: High radon levels have been found in every state. Radon problems do vary from area to area, but the only way to know your radon level is to test.

MYTH: A neighbor’s test result is a good indication of whether your home has a problem.

FACT: It’s not. Radon levels can vary greatly from home to home. The only way to know if your home has a radon problem is to test it.

MYTH: Everyone should test their water for radon.

FACT: Although radon gets into some homes through water, it is important to first test the air in the home for radon. If your water comes from a public water system that uses ground water, call your water supplier. If high radon levels are found and the home has a private well, call the Safe Drinking Water Hotline at (800) 426-4791 for information on testing your water.

MYTH: It’s difficult to sell homes where radon problems have been discovered.

FACT: Where radon problems have been fixed, home sales have not been blocked or frustrated. The added protection is sometimes a good selling point.

MYTH: I’ve lived in my home for so long, it doesn’t make sense to take action now.

FACT: You will reduce your risk of lung cancer when you reduce radon levels, even if you’ve lived with a radon problem for a long time.

MYTH: Short-term tests can’t be used for making a decision about whether to fix your home.

FACT: A short-term test followed by a second short-term test can be used to decide whether to fix your home. However, the closer the average of your two short-term tests is to 4 pCi/L, the less certain you can be about whether your year-round average is above or below that level. Keep in mind that radon levels below 4 pCi/L still pose some risk. Radon levels can be reduced in most homes to 2 pCi/L or below.

To learn even more about radon, don’t miss my previous posts: National Radon Action Month – Part I, Part II, & III.

They say a picture is worth 1,000 words, so before you leave be sure to visit Von Löwen Designs to view an assortment of refreshing examples in kitchen and bath design concepts, refined palette and interior finishes, and sustainable yet chic, green remodeling ideas that may encourage and inspire your next remodel or home improvement project.