Category Archives: Energy Efficiency

Considering a new home

With all the homes on the market these days, new home construction has slowed dramatically – that is no secret. And some say that it is ‘greener’ to buy an existing home rather than building new. While this may be true in some circumstances, it is not always the case. Most existing homes need considerable remodeling to make them desirable and functional to the new owners – there is waste and the purchase/production of new materials involved. And what about energy efficiency? Most older homes will require new heating and cooling systems and their ductwork can be sub-par, not to mention the possibility of older windows and the gaps in the building envelope contributing to a loss in efficiency.

“New construction affords the opportunity to go beyond this for a higher degree of sustainability, with the focus on better vapor and air barriers for a tighter building envelope and the design of more efficient heating, cooling, and domestic hot water systems. Architects can also play a major role in new construction by designing a building form that can help to retain heat or even increase solar gain in colder months.”
-Joseph G. Metzler, AIA, CID, LEED AP of SALA Architects in Minneapolis, MN

While I love a good “fixer-upper”, I am also excited to see the progress that is being made in new construction and the focus on building better, healthier, more functional structures for living.

 

Capture savings through resource efficiency

Capture savings through resource efficiency

By Richard Stone, Extension Educator in Housing Technology
Reviewed 2010

You may have read in the morning paper or noticed at the pump that the price of gasoline is on the increase again. If you drive very far to your job sites it may already be affecting your bottom line enough that you are really starting to feel it. In the construction industry, the cost of energy impacts a lot more than the price of filling up your gas tank. Every other person who works on those job sites is also facing the same increased costs of getting there. Every piece of equipment used for excavation and materials handling now costs more to be trucked in and out and is operating on site at a higher cost. Every component, no matter how small, that is used to assemble the building is trucked in from somewhere at those rising fuel prices. Before shipping, all of those building materials were manufactured from natural resources or recycled resources in a plant somewhere using still more energy. Could using locally or regionally produced products reduce the cost? How far has each product used in a home traveled from its point of origin or manufacture? Just pick up any item on a construction site and consider the source of its components, including the resources and energy required to put it in your hand. Is everyone on your project team thinking about improving resource efficiency? Should they be?

24 inch framing

Photo by Richard Stone, University of Minnesota

There are opportunities for increased resource efficiency at every stage of new home design and construction. Excess materials are removed at the design stage by architects and designers who integrate resource efficiency and durability concepts into construction details and specifications. Plans with this level of detail lead to more accurate material take-off lists and on-site execution of the work, saving time and materials. When I began the shift to “advanced framing” over twenty years ago, our electrical contractor told me that the changes made our homes a lot faster to wire because of the detailed specifications and reduced amount of lumber that he had to drill and pull cable through. That provided an additional cost savings that I had not anticipated. It also showed me that there were additional advantages to be gained by planning thoroughly and keeping to the plan instead of allowing mechanical system design to be determined on site based on the space and materials that happened to be available on any given day. We started with small changes and then, as our comfort level increased, expanded our application of the principles, identifying new opportunities to reduce cost and at the same time improve the durability and energy performance of the homes we built.

Advanced framing graphic

When the subject turns to advanced framing, most builders think immediately of two foot on center 2 x 6 framing and California (3 stud) corners. While these are two of the time proven and widely accepted advanced framing practices, they are only a couple of examples of possible savings. Other resource efficient components have been accepted into common practice with hardly a second thought. Roof trusses, from the simple to the very complex, dominate today’s construction market. Floor trusses and floor systems using composite joist and decking materials have also captured major market shares. The use of composite framing members, particularly in headers and tall wall assemblies, is increasing as well. As shown in the framing illustration, all of these components can be efficiently combined in “stack framing” where the designed load path is continuously aligned from the foundation through the wall systems to the roof trusses. This engineered approach allows for much more efficient and cost effective use of lumber. A few builders have adopted the practice of using only a single top plate when stack framing. More are shifting to the use of single top plates on all interior, non-bearing walls. Some are using 24 inch on center floor truss spacing with a thicker sub-floor while others are more comfortable using 19.2 inch floor truss spacing or staying with the traditional 16 inch spacing. Their decisions are driven by what choice works best for them. Other factors in these decisions are the availability of materials and familiarity with different advanced framing styles.

Rimheader

Building America (DOE) photo

An easy change to make is the incorporation of headers into the floor or roof system above windows. Because the floor or ceiling joist is already in place, some material savings can be realized. The opportunity to move these large thermal bypasses up into a floor or roof system and increase the amount of insulation in the walls over windows is another advantage gained that can impact comfort and thermal performance. In the photo showing floor framing, you can see that the band joist has been doubled to provide the header for the window below.

Other options are also available to increase resource and energy efficiency by reducing materials or changing framing style. While reducing the amount of lumber used to frame homes can result in savings, any changes considered should always be evaluated at the very earliest design stage and through the entire process to assure that all structural requirements are met and codes are satisfied. The old maxim for the most efficient use of time and other resources still holds true today. First, plan your work: Then work your plan.

Capture savings through resource efficiency: University of Minnesota Extension.

Green Remodeling – Part II

Steps to take to make your home greener with Energy Efficiency.

Step 1: Reduce demand for heating and cooling

  • Sealing air leaks with caulk, expanding foam, or weatherstripping
  • Upgrading insulation – note that if your insulation is not installed correctly you will not be getting the performance you think; you may lose up to half of the product’s stated R-value for improper installation.
  • Replacing Windows

Step 2: Use efficient mechanical systems

  • Less is more: Oversized heating and cooling equipment is much less efficient than “rightsized” systems because it will cycle on and off too quickly which loses efficiency, causes more wear and tear on the equipment, leading to more servicing and shorter life span.
  • Kicking the fossil fuel habit: Think electric.  There are lots of ways to make it, some dirty, but in the coming decades more and more electricity will be from clean, renewable sources such as wind, solar, geothermal, small-scale hydroelectric, wave energy, and methane recapture from landfills or from biomass.  As these technologies scale up, the price will come down.
  • Geothermal heat pumps work just fine in colder climates like ours!

Step 3: Reduce electrical demand

  • Upgrading appliances: example, if you own a refrigerator more than 15 years old, it is gobbling up a hideous amount of electric current every day.  New Energy Star rated refrigerators use a fraction as much electricity… so much less that the savings will be enough to pay for a new, energy-efficient refrigerator in as little as three years!
  • Phantom loads: many appliances use power even when turned off.  A simple solution is a switchable power strip to cut the power to those power vampires.  Or if you have an outlet wired to a switch, you can use that outlet for your TV, stereo, etc. and power is cut just as you would switch off the light.
  • Change your light bulbs to long-lasting CFLs (compact fluorescent bulbs).

Step 4: Capture waste heat

Step 5: Harvest free energy with solar panels & small wind turbines.

From “Practical Green Remodeling, Down-to-Earth Solutions for Everyday Homes” by Barry Katz, 2010 Taunton Press

Green Remodeling – Part I

What makes a remodel green?

Every Green Remodel is different, and each one requires individual solutions to its unique challenges and opportunities.  But they all have three things in common: energy efficiency, resource conservation, and healthy living environments. Let’s take a quick look at a few of the features that fall into each category.

Energy Efficiency

  • A tight, well-insulated building envelope
  • Efficient lighting and appliances
  • Efficient water heating and space heating and cooling
  • Passive solar heating
  • Natural ventilation
  • Ample daylight

Resource Conservation

  • Efficient use of construction materials to minimize waste
  • Materials with recycled content
  • Reclaimed materials
  • Rapidly renewable materials
  • Water-saving plumbing fixtures

Healthy Living Environments

  • Formaldehyde-free plywood and particleboard
  • Low-VOC or zero-VOC paints and finishes
  • Properly vented combustion heating equipment
  • Kitchen range hoods vented to the outside
  • Humidity control

There are a great many things you can do in each category to make your remodeling project greener.  But how many of them do you need to be able to call your remodeled home green?

You don’t have to do everything.  Some things won’t be applicable to your particular project, and some may not make sense to do for other reasons.  But the bottom line is this: To call a remodel green, it needs to address each of the three fundamentals in some way.  If it’s not energy efficient, it’s not green.  If it doesn’t conserve materials or water or reduce the strain your home places on the environment, it’s not green.  And if it’s not healthy to live in, it’s not green.

-From “Practical Green Remodeling, Down-to-Earth Solutions for Everyday Homes” by Barry Katz, 2010 Taunton Press