there are two reasons to consider zoning:v1rtu0s1ty said:Looks like zoning can be done even if we only have one furnace like what you just have mentioned guys. That's a good news. However, does having zone more efficent in single furnace house?politics123 said:There are many types of zoned systems. In my house, I have two units, one for upstairs/one for downstairs. That's two zones.
eg: In other houses, they only have one unit. Within the ducts they have dampers that control the rate and direction of airflow. Your house probably has a central stack going to the upstairs registers. You can put a damper (controlled by separate thermostat) that opens and closes to heat/cool the upstairs separately from the downstairs.
Comfort is defined as having your house feel good to you as you use its different rooms. In most houses, insulation is so-so, ducts aren't sized correctly, etc and this causes some rooms to be draftier or colder in winter (or warmer in summer). Common problem: you want a 70 degree house in winter. You set your thermostat to 70, but your MBR is draftier/over the garage/etc and feels too-cold. So, you turn up the thermostat. You've now got a 70 degree MBR and a 74 degree kitchen. You decide the kitchen is too warm, so you turn the termostat back down to 70, but then you have a 65 degree MBR. Zoning tends to eliminate temperate differences on different floors, and depending on how many dampers, can eliminate the temperature differences between rooms on the same floor.
The efficiencies for zoning come from you heating or cooling rooms you need (only) and only to the extent they need to be. In my case, I work from home a couple days a week (my office is upstairs). So, in winter, I have the heat set to 67 upstairs, and 60 downstairs. I'm not downstairs... I don't care if its 60, and I'm saving 56 degree hours (8 hrs * 7 degrees) each day I work from home by not having to condition that downstairs.
You can also save money on annual utility bills by having a high efficiency furnace or A/C, improving your insulation in the attic, etc.