Zoned Heating and Cooling

How a Zoning System Works

Even though you may have a basement that is cooler or an upper level that is warmer, technology is available today that can help deliver the right amount of cooling and heating to the rooms where it is needed to improve your comfort, indoor air quality and improve your system’s efficiency. It is called zone controls.

This technology allows you to designate specific temperature zones in multiple areas in your home. Zoning also enhances airflow in individual zones allowing your system to more efficiently clean the air and exchange stale air. And, if used properly, a zoned system also has been shown to reduce energy use by 25 percent to 30 percent because it can deliver just the right amount of conditioned air to the areas of the home that need it.

Zoning a home is actually quite simple. If you have a central forced-air heating and cooling system in your home, it uses a system of ducts that move air throughout the rooms in your home. Usually, there is a main duct combined with a series of branch ducts, which carry air to different rooms. Installed within these branch ducts are dampers that act like a door that opens and closes to allow or prevent the flow of air depending on which zone is calling for conditioned air.

To do this, a programmable thermostat is installed on each level of the home. Thermostats should be placed at a central location in each zone, on an interior wall. Your contractor will look for a place where lamps, sunlight, or other artificial heat can not affect the thermostat.

If you adjust the thermostat for that zone to make it warmer or cooler, a signal is sent to open a damper for that particular level and shut the dampers that control other zones, which don’t need additional cooling or heating.

This allows just the right amount of conditioned air to go to that zone that needs it. Programming your thermostats to specific temperature conditions for each zone, or having your contractor do this when the system is installed, lets the controls and dampers take care of everything.

Damper Types in Zoned Heating and Cooling Systems

Your forced-air heating and cooling system has a system of ducts that moves air from the blower throughout the home. The system is typically controlled with a centrally located thermostat, which delivers the same amount of conditioned air to all the rooms in the home. This may cause some rooms in your house to be too hot or too cold. In fact, some homes can experience a wide range in temperatures from one area of their home to another.

One way to address this problem and deliver conditioned air where it is needed, and not to places where it isn’t needed, is by adding zone control technology.

Instead of a one temperature fits all rooms approach, a zoned heating and cooling system provides improved comfort and encourages energy conservation by using a system of dampers and programmable thermostats to deliver conditioned air only to areas when they are occupied.

Working with a heating and cooling contractor with experience installing zone control systems, you can determine the number of zones you would like in your house. Each zone gets its own programmable thermostat you set to whatever temperature you want for that area.

Even if your home is not currently zoned, if you have a forced-air system, it can be zoned. An ideal time to consider zone controls is when you are replacing your heating and cooling equipment. But even if you're not ready to replace equipment now, your contractor can usually recommend an economical way to add zoning.

This is done by adding dampers to the ductwork and some wiring for additional thermostats. Dampers installed in the ducts give the user control over how much air is distributed to a particular zone. A zone can be a room or floor of a building; you can work with your contractor to decide on the number of zones you want in your home.

The damper system works differently than just closing a vent on a floor or wall. When you shut the vent, the heated or cooled air still must travel the length of the duct to reach the outlet. When it is denied an exit, the air usually sits in the pipe and becomes room temperature.

A damper is usually installed at the mouth of a distribution duct and either permits or allows airflow at that point. This maintains the pressure in the duct and redistributes the airflow to the rest of the structure. HVAC zone control dampers range in size to fit your ducts and can be round or rectangular depending on your duct style. They can be powered by electricity or by compressed air. They also are available in "normally open" or "normally closed," depending on their intended location.

Obviously, temperature and energy savings are the key benefits to having a zoning system. With fuel prices going up, zoning can help you save energy while enhancing your comfort. Zoning can pay for itself through additional energy savings. A single zoning system can save 20 percent to 30 percent on a typical heating and cooling bill. Most installations are in larger homes with an estimated savings of over 5000 kWh per year, depending on energy use and climate conditions.