by Don Otto, DPO Construction LC
Living in harmony with our environment means we should be more than just wise consumers of our natural resources, we should be their stewards. If we are to keep planting our home’s foundations in the ground, it’s only responsible that those homes make a small environmental footprint. We make a difference in the rate we use materials, and in the energy we consume to keep us comfortable.
Green building starts with good design— not just curb appeal, but homes that meet our functional and emotional needs. Settling for less is poor value, and building spaces that are seldom used is a waste of resources; yours as well as nature’s.
In designing a home, I like to form a design team, composed of the owners, a designer and myself. Owners define the goals and the budget; the designer provides the experience and creativity to make all the pieces fit. I provide the details that ensure energy efficiency, air quality and durability, keep a pulse on the costs, and during construction, manage the project until you move in.
I encourage clients to make all the spaces count, and build only the floor space they need. (If you’re not going to use a formal dining room, for example, don’t spend the money to build it. Use the savings instead to reduce the cost, or to better afford nicer things, like custom cabinetry, efficient appliances, or a geothermal system.)
The savings can be eye-opening. Here’s a real-life example: The original size of a home plan in Solon started out at 2,500 sq. ft. Using Sarah Susanka’s “Not-So-Big” techniques— providing abundant light, long sight lines, and creating private spaces within larger rooms, for example— we whittled off 500 sq. ft., creating a home with spaces that are well used and a have comfortable human scale. Giving those 500 sq. ft. a conservative value of $100/sq.ft, we saved the owner $50,000! The savings allowed him to afford many luxury upgrades that only a larger budget would have permitted. I don’t know of anything else in home building that has such a significant effect on both up-front, and lifetime-operating costs.
We spend well over 90% of our time within enclosed spaces. With respiratory diseases like asthma ever increasing, maybe we should pay attention to where we do most of our breathing. In contrast, have you ever opened a bedroom window in winter and noticed, after only a short time, how much fresher the room feels? Imagine having your whole house feel that fresh year round, but without cold drafts or high utility bills. Because I believe a healthy indoor environment is most important, I start the energy design with an ERV, an energy recovery ventilation system.
The ERV brings in all the fresh air you need, recovers the heat from the exhaust air, and works to keep the indoor humidity at conditioned levels. Simple controls allow you to tailor operating the system to your own comfort level. As a bonus, locating the system’s exhaust ports in bathrooms eliminates the need for bathroom fans, and it’s almost silent when it’s on
THE BUILDING ENVELOPE
Since all the fresh air comes in with the ERV, it only makes sense to make the building envelope as airtight as possible. I’ve found that Structural Insulated Panels, (SIPs) provide that tight envelope, along with being stronger, they are faster to build with, better insulating, use less wood and cost about the same as stick built. SIPs are built from slabs of foam insulation with oriented strand board (OSB) panels adhered to the faces. There are no studs. The only lumber used is in the top and bottom plates, corner reinforcing and the around doors and windows. Other systems, such as insulated concrete forms (ICFs) also work well.
Sprayed polyurethane foam insulation helps to complete the tight envelope. It’s sprayed continuously from the top plate, up the under side of the roof deck, and down to the opposite wall, creating an airtight cap. This also allows design freedom to have vaulted ceilings and recessed lights without any additional air sealing or loss of energy. It also allows heat ducts or plumbing to be installed above the ceiling without extra insulation. The same kind of insulation is sprayed on the basement’s rim boards, walls and under the basement floor, creating an airtight building “cocoon”.
WATER MANAGEMENT AND DURABILITY
When it rains, materials get wet. If organic materials stay wet, they promote mold growth and they rot. Water is necessary for all organisms, like molds, to grow. The key to making materials durable is to keep them dry, let them dry, or use materials that don’t rot. Luckily, making things last is something we can control with good water management practices, like proper flashing and drainage planes. Consider this: doubling the durability of a material decreases its environmental impact by half.
HEATING AND COOLING
Geothermal systems use a renewable resource—the heat from the sun and the core of the earth—to heat and cool your home. While the up front costs are roughly twice that of a natural gas system, they are extremely efficient and cost much less to operate. Since the cost of heating equipment is included in a mortgage, the lower utility costs can more than offset the increased mortgage payments. For the seven months between October 2005 and April 2006, which included two sub-zero spells in December and January, the heating bills for a home I built in Solon totaled $181.00, or about 86 cents a day!
PUTTING IT ALL TOGETHER
We want our homes to be comfortable, keep us safe and healthy, and be durable and efficient. The weather imposes conditions that all homes have to live with, and following good building science principles provides the best methods to handle them. Good design provides that emotional connection that makes our homes truly enjoyable places to live. Paying respect to both is the best way I know to build a home.