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HVAC Zoning Cuts Air Conditioning Costs

Sometimes getting the most bang for your air conditioning energy dollar means thinking beyond the a/c unit itself.  Even if you have a newer, more efficient air conditioner installed in your home, if you are cooling or heating unoccupied rooms then you are throwing money away.  What if you could heat or cool specific areas of your house, blocking out vacant rooms so the a/c unit didn’t have to work as hard?

What is HVAC zoning?

Hvac zoning divides your home into different cooling and heating zones.  Here’s an excellent description from Mike Holmes in his article Get in the Zone at

“Zoning takes a home’s heating, ventilation and air-conditioning (HVAC) system to a whole new level by dividing the house into a number of separate regions/zones based on usage. Usually, that means one zone for the bedrooms, one for the main living areas, such as the kitchen and family room, one for the basement, and one for the less-used areas of the house, such as the dining room and study.”

How does zoning increase HVAC efficiency?

hvac zoningHVAC zone dampers control air flow to different areas of the house.  These dampers are right in the ventilation system, effectively blocking air flow at certain points.  Thermostats can be set to allow cool or warm air into designated areas of the house.  This way you never wastefully cool or warm an unoccupied section of the house.  Another bonus is the a/c system might not have to work as hard if its only cooling or heating one section of the home.  Far easier to warm up 1000 sq. feet of living space at night than 2500 sq. ft.  Estimated gains in efficiency are hard to nail down given the different types of houses and a/c systems involved, but some estimate zoned systems can save 30%, sometimes more, on your a/c bill.  Not bad.

HVAC zone control system installation

It’s best to install an HVAC zone control system when the house is being built or during a major renovation.  Adding a zone control dampers to an existing system is difficult and costly but can be done.  Make sure you go with a reputable HVAC company: done right and the zone system will pay for itself.  Done wrong and you may end up paying twice.

Which homes are best for a zoned system?

Larger homes over 2000 square feet are best suited to a zoned system.  Anything smaller and it’s not worth the trouble.  If you’ve only got two rooms you might want to consider a far cheaper “zone” system: two window units.  Just make sure to turn them off when not in use.

How much are they?

Here’s Mike Holmes again with the answer:

“Zoning also isn’t cheap. It requires the installation of dampers to control airflow, and new thermostats to be wired into the mechanical system’s controls. Expect to pay at least an extra $1,500 to $2,000 on top of your system design to get a home properly zoned. If that seems expensive, check if it’s worth it for you in projected savings.”

ACboy’s take on zone systems

HVAC zoning is a great way to go in the right situations.  Smaller houses, apartments, condos need not apply.  But larger homes and certainly, going forward, schools and other public buildings could really save energy dollars with a zoned system.  I remember my father closing off vents at night in empty rooms.  I think he was on to something.

Here’s a video describing hvac zoning.


See Mike Holmes’s original article, Get in the Zone, here.

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