Here's another great tip from BobVila.com. Whether you re building a whole house or just adding a new bathroom, one of your first decisions has to be how you re going to heat the new space. According to the U.S. Department of Energy, radiant heat is more efficient than baseboard or forced air systems. Rather than just blowing hot air around the room in bursts, radiant systems slowly and steadily charge the floor with heat, keeping it where you want it, longer. Hydronic, or water-circulating, radiant systems are best for new construction or large additions. They come in many forms, for installation just below the subfloor between the joists, directly under tile or hardwood flooring, or even inside a concrete floor slab. Where you only need to heat a small space, like a bathroom, electric radiant is an easy luxury option. Electric radiant mats can be installed directly under tile and are ideal over a concrete subfloor. Set the timed thermostat to turn the system on only when you ll be using the room, like the morning when you shower, and it ll use less than 15 cents of electricity per day. This way, you don t have to make room for ductwork or baseboard units when you add a bathroom. On a cold winter morning, your toes will thank you for choosing radiant heat! Find out more at BobVila.com: The ultimate home improvement web site! BobVila.com 2008

The PEX tubing is set in the concrete and will circulate hot water used to heat the addition. Jason McKinnon of Viega North America reviews the features of PEX tubing. PEX is electronically cross-linked polyethylene tubing that is made to be stronger and resistant to high temperatures and pressures. The PEX tubing was placed in the concrete slab. The concrete acts a low-temperature radiator for the tubing. High temperature water will be pumped through the coils and heat will dissipate into the slab. A heated slab acts as a radiant heat source for the home. Tim Cutler of TJ's Plumbing & Heating reviews how the tubing was placed within the slab. In a radiant-heat application, the tubing is evenly spread out across the floor. With radiant heat, the air is not heated, only the floor. The heat is modulated according to outside weather conditions so a precise amount of heat is sent through the coils to warm the building's interior to the desired temperature. A heat/loss analysis done on the home indicates that the tubing should have nine-inch spacing for five circuits. During manufacturing, the tubing has 10,000 volts sent through it which cause the molecules to cross-link. This makes the tubing virtually indestructible. An oxygen barrier is sprayed on it to protect the boiler and the heating system from oxygen infiltration, which causes cast iron boilers to deteriorate. A foam stapler pushes plastic clips with prongs into the foam decking to secure the tubing in place.

Bob visits with Mark Lundquist of Burnham Hydronics to check out the boiler for the hot-water heating system being installed in the Mashpee, Massachusetts, affordable homes. This Burnham Spirit model is a medium efficiency, easy-to-maintain, sealed-combustion unit. Since it is sealed combustion, it pulls the air it needs directly from the outdoors and vents to the exterior without the use of a chimney or flue. This enables a homeowner to close off the space surrounding the boiler without worrying about available combustion air for the furnace. This model uses standard parts, so any repairs will be fast and easy. The boiler is made of cast iron and has a 25 to 40 year life expectancy. It operates at 84 percent efficiency, so the homeowner will use energy dollars wisely. Charlie Delvecchio of Cape Plumbing breaks out the cost of the boiler to about $1,500 and the baseboard tubing for another $6,000, for a total cost of $7,500 for installation of the home heating system. The domestic hot-water tank is linked to the heating system as hot water from the boiler passes through a coil in the insulated hot-water tank, warming the household water through energy exchange. If the water is maintained at the proper temperature just from this passive exchange, the boiler will never be called upon to heat water for faucets and showers.

Bob is in the basement talking with Erling Andersen from A.I.M. Radiant Heating. A.I.M.'s "Boiler Room In A Box" has been installed and the baseboard tubing is being run throughout the house. Made of a cross-linked polyethylene material, the pipe is routed behind A.I.M.'s decorative baseboards. The baseboard itself has been trimmed out to fit the Colonial's design scheme. Technician Dave DuVerger is on location installing the last few stretches of tubing. Once the tubing is connected to the boiler system, hot water will run throughout the house to create radiant heat that maintains a consistent temperature in each room.

John Martin from WarmZone is on hand to show Bob how the medium density fiberboard (MDF) faced with reflective aluminum shielding and precut channels for the Pex hot-water tubing comes together to create a layout for the in-floor radiant heat system. One key advantage to radiant heat is the comfort level, since it is steady heat that is evenly distributed and free from the blowing, particulate matter that can come with forced-air systems. Martin explains how the WarmZone system comes ready-to-install with complete layout diagrams and directions that make it simple for do-it-yourselfers. The panels are set in adhesive, with spacers to temporarily align them and line up the tube channels until the panels are nailed in place. The heat panels then become the substrate for finish floor coverings. Unlike gypcrete, which is a skim-coat concrete application, these panels add very little weight to the floor. Since it is a 5/8-inch product, there is also no need to alter existing door openings. WarmZone specifies a 3/8-inch Pex tubing to deliver the heated water. Martin fits and taps the tubes in place in the channels to complete the installation. Bob then looks at the heat distribution system with supply and return pipes that come directly from the boiler room below. WarmZone has specified three short runs and circuits, which will give steady even heat throughout the space even with the heat loss calculations they have figured. Michael Willburn from WarmZone shows Bob the preassembled boiler-room manifold board and radiant-zone board that are created match the application and arrive ready-to-install from WarmZone. WarmZone takes the information directly from the homeowner, creates the system to fit the job, and then ships it to the site. The homeowner or installer can do all the work without the aid of a plumber until the system is connected to the boiler, at which point a professional installer should verify the connections and operation of the system before firing it up. Initial costs are about double the cost of a traditional baseboard-heat installation, but the operational savings are approximately 30 percent annually.

Bob meets with the plumber to look at the air handler and then goes upstairs to check out a bathroom floor heated with radiant heat.

John Marran of Energy Kinetics and heating expert Frank Iadarola review the System 2000 boiler system that will supply heat to the hydronic floors and units at either end of the garage. The sytem has various stages to allow for quick heat and controllers to monitor the temperature of the hydronic fluid. The System 2000 contains only 2.5 gallons of water. Since it only takes approximately 1 and a half minutes to heat up that small amount of water, there is no need for the water to be heated all the time. The boiler is activated only when you need heat or hot water. After it supplies the heat or hot water the boiler does not remain hot. This saves a lot of energy.

Bob Vila and building consultant Steve Easley examine how hot water is efficiently used and distributed in the EnergyWise House. Eemax tankless, on-demand water heaters supply hot water for bathing, cooking, and cleaning. Seamless PEX tubing from Vanguard Industries is used to distribute hot and cold water around the house. Radiant heat for the home is supplied by a zoned Wirsbo in-floor radiant heating system.

Bob talks with Jim Niehoff of the Portland Cement Association about building homes using concrete. For builders, constructing homes with concrete can save a lot of time and give homeowners a very energy-efficient home. Building a home with this combination of concrete and foam can save homeowners about 30-40 percent on heating and cooling costs. Building with concrete is particularly desirable in disaster-prone areas, because it provides stronger protection against hurricanes and tornados. Bob talks with the homeowner, Howard Brickman, about the experience of building the addition with concrete. The process has been very efficient. The crew has only been on the site for seven work days and has accomplished a great deal in that short amount of time. The construction process has eliminated the need for any exterior wall framing or insulation. The shell of the addition is already complete except for the rafters on the roof. The finished addition will look like a traditional shingled home and will be indistinguishable from the original section of the house. The radiant heating system put into the addition was downsized because of the energy savings involved with concrete construction. It is estimated the concrete addition will cost 30 percent as much to heat as the rest of the house.

Bob meets with Erling Andersen of AIM (Andersen International Marketing) in the basement of the modern Colonial to discuss the heating system. The Boiler Room in a Box has just arrived in its crate, fully assembled and ready to hang on the wall. Although the gas-fired system has a very small footprint, it has a 175,000 btu boiler and can heat a 4,000 sq. ft. New England home. The water heated by the boiler is distributed throughout the house in two ways: through radiant baseboard and in-floor radiant tubing. The slimline baseboard is made of aluminum and copper with the water distributed through PEX tubing. In rooms with no space for baseboard, such as the kitchen, the heated water runs through special PEX tubing with an aluminum core that is suspended between the floor joists using plastic nail clips. Bob points out that the home's structural system comes with pre-drilled holes to facilitate the tubing installation. Once the radiant tubing has been run between all the joists, reflexive insulation is nailed up into each void effectively creating heat ducts between the joists.