To most homeowners, zoning is a vague concept. There are registers in the floor, right? Or maybe you have a mother-in-law apartment with its own space heater.
To the pros, zoning is a serious subject. They know that zoning your air conditioning or heating system can lower your utility bill; or please roommates with very different ideas about comfort.
Zoning allows you to keep upstairs bedrooms cool during the day (when heat would naturally rise and accumulate in those unused rooms). You can control the heat or AC in your house from your telephone, adjusting the temperature so the house is comfortable when you arrive home from work. You can arrange for the heat to go down automatically at night and rise again, an hour before you get up for work.
First the physics
It’s not rocket science, but there are a few basic principles to remember when you’re considering whether to rezone your home.
– Warm air rises. This is why the cathedral ceilings in your living room are warm and cozy while the floors are cool.
– Sunlight produces heat. If you have a room with southwest-facing, floor-to-ceiling windows, you will hear the air conditioning running constantly.
– Only condition used space. That spare room that’s only occupied when Grandma visits? The laundry room where nobody hangs out on top of the clothes dryer? Why pay to keep that space at 68 degrees?
The government figures that homeowners could save nearly a third of their energy bill with proper zoning. The initial cost might scare folks away. But if you compute 30% of your energy bill over the next few years, you’ll probably come out ahead pretty quickly.
Sometimes it’s a matter of just using what’s already there. That unused guest room? Close the door and close the damper. If you want more elaborate control, there are apps for that.
Low-tech problem, high-tech solutions
You can get a cheap app for your iPhone that lets you turn up the heat or the AC as you’re leaving the office. Or show the kids how to do it from school.
If you want more control, your HVAC tech can install multiple programmable thermostats so you can keep different areas of the house at different temperatures, rising and falling as each space is being used.
There are some caveats. One common concern is that unheated space will leach heat from the warmer areas of the house. Another is that leaks from ductwork will cancel out any savings from closing vents in unused rooms. Another issue is sizing: If your house was sized for 1500 square feet and now the system is only heating and cooling 1200 square feet, is this a problem?
Most contractors agree, though, that homeowners don’t benefit enough from smart zoning. So what are you waiting for? Call the HVAC guy!