There are many things to consider when planning and building a new home. Not only do you want the design and layout of the house to fit your needs, you want your home to have a comfortable and healthy environment, and be efficient and economical to operate. An energy efficient home is designed to meet all these goals and is built on the principles of building science, recognizing that a house is an interactive system. This system is made up of many components—the building structure, the mechanical systems and the occupants. These components interact in predictable ways and new homes can be designed and built to ensure a comfortable and healthy environment.

BASIC BUILDING CONCEPTS
Remember to ask these questions when selecting a builder:

• Controlling airflow: Does your builder test the house for air-tightness?
• Ensuring indoor air quality: What controlled ventilation technique does your builder use? Will your builder test the system to ensure it works properly? Will your builder teach you how to use and maintain your ventilation system?
• Minimizing heat loss: How does your builder ensure that the insulation is properly installed?
• Preventing moisture problems from external sources: How does your builder reduce and control moisture around the building shell and foundation, and under the basement slab? These concepts are essential to understanding the construction details of your new house and the choices you’ll need to make in selecting heating, ventilating and other mechanical systems.

CONTROLLING AIRFLOW
Building an air-tight house in combination with installing controlled ventilation is key to creating a durable, energy efficient and healthy home. Leaky houses are drafty and uncomfortable. Relying on cracks or unintentional openings to move air through a house is a recipe for high heating and cooling bills, comfort problems, and potential indoor air quality and moisture/durability problems. To control airflow it is essential to have a continuous and durable air barrier around the entire living area (the spaces that will be heated and cooled). Any holes or breaks in the air barrier will result in the loss of heated moist air, allowing moisture to be carried into the insulation and possibly condensing on or in the building framework. Creating holes in the air barrier is inevitable during the construction process (from electric wiring, electric receptacles or plumbing chases). It is essential that your builder seal around these openings before the construction process continues and they are no longer accessible.

Based on DOE estimates, the typical cost of operating a gas oven is $22 annually with a pilot light or $13 with electronic ignition. For electric ovens, the cost is about $29 for a self-cleaning oven and $27 without the self-cleaning feature. This is based on national average fuel prices.

Don’t assume your house is tight unless your builder has a procedure for measuring how much air moves through it. An effective test of air-tightness is conducted using a special fan called a blower door. Make sure your builder has a process for testing the air-tightness of your home before it is too late or too costly to address any problems.

ENSURING INDOOR AIR QUALITY
Controlled ventilation is the key to maintaining good indoor air quality. Don’t rely on natural air leakage to ventilate your house—you can’t control the quantity or the quality of the air. You want to control how much air moves through the house and where it comes from so you get adequate ventilation without airborne pollution.

• Spot or source-point ventilation: These include exhaust fans in the kitchen and bathroom that vent directly outside.
• Central heat-recovery ventilator (air-to-air heat exchanger): This system consists of an intake fan, an exhaust fan and a duct system with a heat-recovery core. Heat recovery reduces indoor heating and cooling loads by transferring heat from or to the exhaust air.
• Central energy recovery ventilator: This system is similar to heat-recovery ventilators, but in addition to recovering heat it also transfers moisture from the warm air to the cold air.
• Central intake and exhaust fans: This system is similar to the heat-recovery ventilator but without the heat recovery feature.
• Central powered exhaust with furnace supply intake: Stale air is exhausted from separate areas of the house through one central exhaust. Fresh air is brought in through a furnace inlet vent, mixed with household air and distributed through the home.

MINIMIZING HEAT LOSS
Heat flows naturally from warmer to cooler spaces. During the winter, heat from inside your home moves toward adjacent unheated spaces such as attics, garages and the outdoors. Conversely, in the summer, heat tries to move into the house from outside. Insulation is the home’s defense against heat loss. The ability of insulation to resist heat flow is expressed in terms of R-value. Higher R-value means greater resistance. Wisconsin’s Uniform Dwelling Code stipulates minimum R-values for foundation walls, exterior walls and ceilings/attic floors. Yet, effective insulation is dependent not only on adequate R-value, but also on full coverage, proper installation and a continuous and durable air barrier.

PREVENTING MOISTURE PROBLEMS FROM EXTERNAL SOURCES
Moisture can enter a house through the foundation as ground water or be forced into building cavities from wind driven rain. Moisture that gets into the building cavities may not dry quickly and can cause peeling or blistering paint, rotting wood and other structural damage. It is much easier and more cost effective to prevent moisture problems during construction than to correct them later.

Techniques to prevent moisture problems

• Site selection: A building site that has a high water table will be more likely to have moisture problems. Choose your site carefully and know where the water table lies.
• Surface drainage: Install a continuous and durable weather barrier under the siding. Properly flash windows and doors to shed water from the house. (Flashing is a material used to protect, cover or deflect water from places where two materials join or form angles.) Grade landscaping to direct rainwater and melting snow away from the foundation.
• Damp-proofing: Apply a high quality, durable damp-proofing coating or a drainage board on the below-grade portion of the foundation wall.
• Moisture-resistant concrete basement floor: Reduce water absorption through the concrete basement slab by pouring the concrete on top of three to four inches of washed aggregate. Insulate over the aggregate with rigid insulation to keep the concrete floor warm and dry.
• Drainage system: Include an effective drainage system around the foundation footings such as a channel of coarse rock, drainage tiles or mats.

SELECTING HIGH EFFICIENCY EQUIPMENT
The U.S. Department of Energy has established minimum efficiency standards for heating and cooling equipment and for most major appliances. The ENERGY STAR® label is awarded to those products that meet or exceed established standards for energy efficiency and are as much as 10 to 50 percent more efficient than their conventional counterparts.

Heating system

Selecting a safe and efficient heating system is essential to the efficiency and comfort of your home. A furnace or boiler requires air to operate and may produce carbon monoxide as a byproduct. For maximum safety it is important to select a sealed combustion heating system that does not use indoor air for combustion and discharges all flue gases directly outside. Select a heating system that has a high Annual Fuel Utilization Efficiency (AFUE). This rating resembles the miles-per-gallon rating for a new car. Since 1992, all furnaces have to have an AFUE of at least 78 percent. Look for the ENERGY STAR label on models that have AFUE ratings of 90 percent or higher. A 90 percent AFUE furnace is a good investment in Wisconsin’s cold climate. If you are shopping for a boiler, look for an ENERGY STAR qualified unit, which has an AFUE rating of 85 percent or higher.

Factors to consider

• Size: Select the right size furnace for your home’s heating needs. An oversized furnace will cycle on and off more frequently and be less efficient.
• Single-stage or multi-stage furnace: A single-stage or conventional furnace puts out a fixed amount of heat per hour and is either on or off. A multi-stage furnace produces heat at two or more rates to accommodate heating needs based on outdoor temperatures.
• ECM-equipped furnace: What makes this furnace unique is the fan motor used to circulate the air. These motors use electrically commutated technology (ECM), meaning the speed of the fan is infinitely variable. An ECM uses about 1⁄3 less electricity than one- or two-speed motors still common in new furnaces. These units may also provide greater comfort and can actually increase the efficiency of your central air conditioning as well.

Other appliances

• Air conditioner: Look for the ENERGY STAR label to select a central air conditioning unit that has a SEER (Seasonal Energy Efficiency Ratio) of 13.
• Water heater: Select a sealed combustion or power-vented water heater to ensure that combustion gases are vented outside the home.
• Appliances: Select a refrigerator, dishwasher and clothes washer that has the ENERGY STAR label.
• Lighting/ceiling fans: Select fixtures that have the ENERGYSTAR label.
• Windows: Choose windows rated for Wisconsin’s climate, look for the ENERGY STAR label, or look for dual-paned, argon filled windows with low-e coatings.