Design and planning The design and planning stage is critical. Its important to talk to the homeowner and find out what they are trying to achieve. Is the homeowner most interested in comfort or saving money (on energy). With a zoning system it is either/or, said Mark Schilling, residential trade leader for Honeywell, Scarborough, Ont. Like any heating system, an accurate heat loss on the home is a critical first step. Equipment must be sized correctly and with zoning in mind. When only one zone is calling for heat, an oversized furnace will quickly short cycle. Probably the second step is to decide how to divide the home. Again, the homeowner will have significant input, but its important not to get carried away with too many zones. On most houses, dividing by floor and then by most occupied areas makes more sense than zoning each room. On a simple ranch-style house, for example, the bedrooms may be at one end while the living area is at the other. Simply dividing the house in half may be adequate, says Dyck. Unlike with a conventional system, each duct must flow enough air to fully heat/cool the zone it serves with all other ducts closed. Sealing the ducts becomes critically important. Dampers should be as close to the trunk  or the plenum  as possible. This allows better control, better access for service, reduces noise and minimizes leakage. If you can keep the dampers in the mechanical room, thats great. Access doors should be provided where not possible. Where a bypass is ducted into the return air, it is important that the air isnt coming back too hot or cold, causing overheating or freezing up of the equipment. Sensors should be installed to shut down the equipment when either condition exists.

Simple wiring Complex wiring created many headaches for contractors on earlier systems. Todays systems, with components that are designed to work together, are simple a,b,c,d connections or plug-and-play, often with telephone jack or snap type connectors. And because the equipment communicates through the zoning panel, setup and troubleshooting is now primarily a matter of configuring the software rather than changing components. The new Honeywell panel, for example, includes a digital checkout that allows the technician to check operation in each zone at the panel rather than having to run upstairs. The components of the Carrier Infinity system talk to each other, making setup dramatically easier than previous generation equipment. The reason I like it and others that function like it is that they are integrated with the equipment, adds Messenger.

Retrofits Adding zoning to an existing forced air system has also become easier thanks to a number of specialized products, reports Schilling. A good candidate for zoning is a home where the basement is open and the contractor can access the ductwork or, at least, the round takeoffs, says Messenger. If the basement is finished or partially finished, we do zoning but you are really restricted (to zoning by existing trunk duct.) Its not perfect, he adds, but the software with todays computerized equipment really helps in balancing it out. Another major advance are dampers that fit into existing round ducts. Basically just a blade and motor, they are installed by cutting a hole and attaching the damper to the duct with screws. Todays dampers draw significantly less electricity. They can all be connected to one zoning panel and one transformer. In a 2,000 sq. ft. home, you could be looking at 12-18 runs depending how it was designed& You could put a round damper into each run if you cant find an easier way& added Schilling. And variable speed furnace motors overcome one of the most common problems in retrofits  undersized ducting. A variable speed motor senses the static pressure and bumps up the speed, noted Dyck.

Selling zoning Homeowners understand the concept of zoning. They understand that when they flip a light switch, every light in the house doesnt come on, said Dyck. I wish I could find the magic pill that will help contractors understand that this will make them money& If the contractor was to offer it on every HVAC system, hes probably going to (sell zoning) on one or two of every ten systems. And given the price of homes today, its a relatively small cost for the comfort it adds. The way we like to sell it is: (In the summer) everybodys top floor is a little too warm, the main floor is just right and the basement is freezing. Its par for the course around here with new construction style heating and air conditioning. (With zoning), you can basically re-duct the basement and control the top floor as if it was a separate system, says Messenger. Offering options  humidity control, an HRV, etc.  will enhance both the contractors profit and the homeowners satisfaction with the system, notes Schilling. Computer control gives a zoned system a number of other advantages, says Messenger. In the near future, he expects homeowners will be able to communicate with their HVAC system through the Internet, allowing them to check temperatures and IAQ, making adjustments from work or when they are on vacation. With time shifting (electrical) meters coming along, you can tell it to behave differently when hydro rates are higher or lower. You can set it up to get the most efficiency or the most comfort, or somewhere in between & In the past, that would have involved changes that only a service tech could make. Now the homeowner can just go and reconfigure the system like they do their personal computer& But success with forced air zoning all boils down to careful design and the correct selection of equipment. Messenger is very specific about the product he will or wont use. Zoning is a high-end option and he doesnt expect to make do with an existing furnace or air conditioner where they dont meet his requirements. When people call us, I tell them that this is what Ill put in. If you dont want to go with this product, then I dont want to do it. Its expensive, not because of the zoning, but because you need to have this furnace and its nice to have this air conditioner& Todays government energy efficiency rebates have made the sale considerably easier, he added. Schilling urges contractors that had bad experiences with early zoning equipment to give the new technology a try. They are reluctant to learn. My feeling is that if they did one job and did it right the first time they would do it every time.