Because our homes are major polluters and users of natural resources, making our homes greener is an important step toward a healthier environment and the preservation of our planet. But what does “building green” really mean? Is it practical? Is it affordable? What can individuals really do? In a series of three articles describing the process of building our home we hope to answer these questions.
Here’s a quick check list of elements of green building:
1) Water and land conservation
2) Energy efficiency
3) Building materials (recycled or natural with a point-of-origin within 500 mile radius)
4) Interior furnishings, finishing and fittings
5) Indoor air quality
6) Building site management and conservation
There are several green building programs which have emerged in recent years but the most comprehensive and rigorous is the LEED (Leadership in Energy and Environmental Design) rating system established by the non-profit U.S. Green Building Council. LEED for Homes is a relatively new certification. There are 18 requirements that a home must fulfill to be a LEED home. The rating is done by points with a maximum of 100. The number of total points accumulated determines whether a home earns a Certified, Silver, Gold or Platinum rating. We are shooting for Gold.
You have probably already guessed that it costs more to build a green house. But costs must always be weighed against benefits. We will offer some cost comparisons and also discuss benefits and return on investment as we go along. In this first article we will discuss the foundation, the building “envelope”—its walls and roof, and the windows and doors.
We chose Insulated Concrete Forms (ICFs) manufactured by LiteForms. The forms are like hollow, foam legos which are glued and stacked together, interlocked, reinforced with steel bars, and then filled with concrete. Our ICFs are 12” thick (2” of insulating Owens Corning foam on each side and 8” of concrete between). The construction of the foundation and walls was done by Peter Lord, LLC, a licensed ICF professional in Annapolis, Maryland.
The cost of building an ICF foundation is roughly 10% more than standard block. Here are the benefits
- Energy Efficiency—Compared to a concrete block wall, ICFs have a heat gain in summer which is seven times less and a heat loss in winter which is six times less. This results in at least a 20% savings in heating and cooling costs for our walk-out basement. Additionally, ICFs have a thermal conductivity which results in an R-Value of 25 or more! (Note: Insulation is rated in terms of thermal resistance called R-Value. The higher the R-value, the greater the insulating effectiveness).
- Lower insurance rates—ICF walls are highly fire resistant, which lowers premiums
- Superior sound insulation
- Resistance to water absorption for a dry basement
- Very strong, sustainable construction which ensures a long and stable life span
- Minimal energy required in the transport of ICFs because they are light compared to common foundation materials. They are also compact because they come “knocked-down”
Walls and Roof
There was never a doubt we would build with Structural Insulated Panels (SIPS). The system consists of solid, one-piece, pre-cut panels. Each panel consists of a core of molded expanded polystyrene (EPS) insulation which is laminated between two pieces of engineered oriented strand board (OSB). This construction, when done correctly, results in a strong, air tight building envelope which reduces energy costs. We hired Panel Wrights, based in Shenandoah, West Virginia for our construction, one of the best in the business, an opinion that has been borne out by the quality and speed of our house construction.
SIPS building materials are roughly 18% more expensive than those associated with a stick-built house. But the long-term cost savings and the benefit to the environment far outweigh the initial costs. Here’s what we discovered:
- Our house blueprints were loaded into computerized factory equipment and the panels were manufactured by Insulspan to our specifications, with all window and door openings pre-cut. The manufacturing process results in minimal waste and off cuts are recycled.
- The SIPS arrived on flat-bed trucks. Our house was “ready-to-assemble” by Panel Wrights. The pre-manufactured panels result in less construction-site waste and less time in construction saving on-site labor and related costs. Our house was under roof in 19 working days!
- Because SIPS panels are computer engineered, they are extremely precise. And their unique design ensures a house “envelope” that is very tight. Air infiltration in a home is the greatest source of energy loss and is a greater factor in heating and cooling costs than R Values. A SIPS house has 90% less air leakage than a traditional, stick-built 2x6 house using fiberglass insulation. In fact, a SIPS house is so tight that it is necessary to introduce treated fresh air into the house to ensure air quality!
- SIPS panels have R Values which far exceed stick-built houses. For example, our house compared to a 2x6 stick-built house with fiberglass insulation: our 6 1/2” SIPS walls rate R26 verses R11 and our 8 1/2” SIPS roof is R34 verses R11!
- Because SIPS create a solid, thermal envelope around the house, a much smaller HVAC system is required. This saves money on the purchase of the system initially and continues to save through its lower cost operation.
- SIPS houses don’t “move” like traditionally built houses do. They are solid and stable from the beginning. With SIPS walls and roof on top of an ICF foundation, our house is a fortress!
The bottom line is that a SIPS house is easier and faster to build, as well as sturdier and tighter. It dramatically reduces energy usage, increases in-home comfort and contributes to a healthy environment. And, as you will see, when you factor in energy efficient windows and doors, the return on investment is dramatic.
Windows and Doors
A tight, energy efficient house built with ICFs and SIPS would be quickly compromised without quality, energy efficient windows and doors. And, naturally, since you get what you pay for, high quality windows and doors are going to be more expensive. But again, we looked at up-front costs verses payback over time. We chose Weathershield Zo-E Shield windows and doors. In addition to having great appearance and high functionality they:
- Exceed Energy Star Ratings for energy efficiency
- Reduce energy costs by 30% per year
- Reduce noise from outside
- Greatly reduce problems associated with frost and condensation
- The Zo-E coating:
- blocks 99.9% of harmful UV rays
- keeps heat out in summer and reflects warmth back into house in winter
- reduces need for exterior cleaning
So, that’s the house envelope. In total, it cost about 20% more to build than traditional concrete block, stick-built walls and roof, and average windows and doors. The clincher? Our 5,500-square foot house has an HVAC load calculation of 3 ½ tons. It is estimated that our cost to heat and cool our house on the Northern Neck will be approximately $700 per year! We expect a return on our investment in less than ten years. In the meantime, we will live in a supremely comfortable, well built, quality home with the knowledge that we are contributing every day to a healthier planet.
In the next two issues, we will discuss heating and cooling, generation of hot water, water conservation, green building materials, and interior finishes.
Follow Lorraine and Judd Horbaly in our next two issues as they share with The House and Home Magazine their journey to completing construction of a “green” dream house.
Lorraine and Judd Horbaly are owners of Walmer Enterprises in Alexandria, Virginia, a firm that designs and manufactures fine cabinetry.