A quick explanation of what zoning involves is needed first, so if you already know what zoning is…skip this part.
Zoning basically provides the ability to only heat or cool the rooms that need it by using separate thermostats and dampers to control where the hot or cold air is pushed. That is the simple explanation anyway.
So recently the California Energy Commission ( or CEC ) proposed a code change that would prohibit the use of bypass ducts in zoned heating and cooling systems, as well as some other things. It will be discussed further by the industry and possibly become effective Jan. 1 2014.
Basically they did a case study of about 80 homes built in 2007 or later , that examined multiple or zoned split systems. The basic conclusions of the study suggests that these systems have an inherent added energy cost which equates to a 17 % degraded SEER and EER, and 4.4% degraded furnace AFUE.
They decided that the use of bypass ducts not only doesn’t save energy , it actually uses more.
Opponents now say that because of the way the study was conducted and how they concluded that zoning provides comfort, but does not save energy, that it was flawed.
Members of AHRI point out that with the use of a zone damper system and setback thermostats properly installed and used appropriately that they really can save energy.
So are they saying the problem lies with shoddy installs and untrained end users?
well, not really. but sort of.
An investigation sponsored by Carrier demonstrated an average of 28 % energy savings thorough the 1993-1994 cooling and heating seasons in a fully instrumented and unoccupied 2,225 square foot home in Maryland. The test home utilized thermostat setup/setback strategies in five zones and was monitored using 150 unique data points.
Can you imagine saving 28% off you yearly energy bill?
The bottom line for most people in the HVAC industry is that the CEC would rather kill any incentive to push zoning and bypass than learn the proper way to bypass and fix a poorly designed system.
What all this means to you and me:
Zoning in most homes can save a good enough percentage of money each year to be well worth it not only from the cost savings but from the added comfort level a properly zoned and properly adjusted system can provide.