Do you find the second level of your home stays too hot while the first floor stays too cold? Tired of fighting over the thermostat or lugging a space heater from room to room? Do the large windows or vaulted ceilings in your home cause pockets of hot and cold air? It is not uncommon for even a well-maintained central HVAC system to have difficulty maintaining a comfortable, consistent temperature throughout a home. Zoning can solve a variety of these problems, plus offer up to 30% increased efficiencies, which translates into lower energy bills for you. A zoned HVAC system is a cost-effective alternative to having dual air systems (2 central HVAC units) that need separate furnaces and air conditioners for different areas of the home.
Zoned systems have become very popular on new home construction, but they can also be added to existing homes. Just about any forced-air system can be retrofitted for zone control. In this post, we’ll talk about what’s involved in retrofitting your single HVAC unit into multiple zones.
How Zoning Works
Multiple electronic thermostats – one in each zone - are wired to a control panel, or they may communicate with the control panel wirelessly. Electronically-controlled dampers are installed in the ductwork and wired to the control panel. Each thermostat continually reads the temperature in that zone and if it’s too low or too high, it sends a signal to the control panel to close or open the damper to that zone, thus regulating and controlling air flow to that zone.
Not only is system zoning helpful for houses with inconsistent room temperatures, but it's also great for saving energy by not heating or cooling areas of the home where it’s not needed. According to the U.S. Department of Energy, system zoning can save homeowners up to 30 percent on a typical heating and cooling bill. Maybe you have a whole area of your house that is seldom used now that your son/daughter has gone off to college, so why pay to heat and cool it? Maybe you’re having to turn your current system way up just to keep the lower level warm enough, while the upper level is sweltering. System zoning allows you to save money by running temperature-controlled air to rooms only when it is necessary.
Planning the Zones
The number of zones your home needs will affect the way you set up the system. In a two-zone system, with the zones being fairly equal in size, each zone's ductwork must be capable of handling up to 70 percent of the total CFM (cubic feet per minute) of air produced by your HVAC system. In a three-zone system, the zones need to be as close in total area as possible. In this case, each zone's ductwork should be able to handle up to 50 percent of the total CFM. Retrofitting more than 3 zones in a home may require ducts to be enlarged and/or to install a static pressure relief damper (also called a bypass damper), which will make retrofitting much more costly. So, when retrofitting, you’ll typically want to keep it to only 2 or 3 zones. Of course, if it’s a new install, the sky’s the limit, and it’s not unusual to have each room as a separate zone.
Not a DIY Project
Adding zoning to an existing HVAC system is not a DIY project, so you’ll want to consult an HVAC professional. Depending on your duct layout, you may need to re-work the ducts to add a second zone. But, before spending money on a zoning retrofit system, there are several things you can and should do which may help address many of these uneven heating and cooling issues, and may even eliminate the need for zoning. We’ll talk about these in an upcoming post.
If you live in the Nashville or surrounding areas and have questions about whether zoning is an appropriate solution for you, give us a call at 615-832-8500. We’re here to answer your hardest questions and to help make your home a little more comfortable.