Thats Not How HVAC Zoning Works!

I find technicians who don’t know how to
explain to their customers how to properly use their zoned heating and air conditioning
system. They tell their customers to just set the
temperature to 75 on both floors and leave it. That’s not how zoning works! If you wanted to have both floors, or both
zones at 75 degrees, why not just take the zoning out and cool the whole house at one
time? Why do we even need zoning at that point? We’re talking about the do’s and don’ts
of zoning coming up next on Fox Family Heating and Air Conditioning If this is your first time watching our channel
please click subscribe down below here on the bottom right, and if you click that little
bell next to it, you’ll be notified of all our videos as they come out. Zoned houses, or houses with two or more thermostats,
are usually found in homes that have two floors or sprawling ranch style homes.

In this blog we're going to talk about older
homes that have had zoning added to their now oversized system. We’ll also talk about what kind of lifestyle
fits best with a zoned system. And finally, we’ll be discussing how to
use zoning to save you money, which is really why zoning in a home is even a thing. So many homes in the Sacramento area are big
enough to support family sizes in the range of 2 people to 6 people. Homes with a designated living area that include
the kitchen, dining, family rooms, common area restrooms, entryway and other common

The other part of the house consists of the
master bedroom, master bathroom, larger closets, the kid’s bedrooms, their bathrooms and
sink areas, and the laundry room. You could easily break this home down into
two “zones” with a thermostat to control each one. Now, your system is oversized
Let’s just say you have a typical 1950 sq ft home of conditioned space. So, that’s not including areas of the house
like the closets, pantry, and other rooms that don’t have registers supplying air
to them. This house is two stories and originally came
with a big 4-ton air conditioner that would satisfy the whole house at one time. Ten years later, the owner decides they want
to add a thermostat to the upstairs area, so they’ll have two zones.

One for upstairs, one for downstairs. 10 years later the system is 20 years old,
and the new owner of the house is ready to change the system out for a new one because
the system doesn’t cool like it should anymore, but doesn’t understand why he’s being
told the new system should be smaller. Much smaller! Because that’s not how to use zoning! Zoning is a great idea! But keeping that big old 4-ton system there
is a mistake! If the 1950 sq ft home is divided into fairly
similar sizes, let’s say, 1150 downstairs and 800 sq ft upstairs, and only one zone
is calling for cooling, then we have that big 4-ton system (which remember was designed
to cool the whole house at one time) overwhelming the temperature change in that one zone, (half
of the house!) over pressurizing the ducts for that zone, sending a high velocity of
air though the registers of that one zone and generally putting a big strain on the
entire system, except the zone not being used.

High Blood-Pressure Isn’t Good, Right? This strain comes in the form of something
like high blood pressure for the human body. You can run on high blood pressure for a while,
but if it’s not regulated, the body can suffer and fail earlier than usual. The same goes for the compressor which is
a lot like the heart of the human body. It pumps refrigerant to and from the indoor
coil and outdoor coil. Too much short cycling, turning on and off
quickly, makes the motor see an enormous amount of damaging heat and energy on every start
up, time after time after time. When your system is twice the capacity that
it needs to be, because only one zone is needing air, it’s going to satisfy that one zone
way too fast. On/Off, On/Off, all day long. See, your AC wants to run for longer periods
of time at less amperage to cool your house effectively. One to two degrees change for every 15 minutes
is not unusual according to Honeywell. But 2 to 3 degrees in five minutes is too
fast. I won’t get to into this too much as I have
other videos on this topic, but we want to condition the whole room, not just the human.

This is how we keep proper humidity levels
and prevent wide temperature swings in the room. What Is the Right Size Then? If we were just conditioning that first floor
at 1150 sq ft., what size would we need. Without getting too technical, we would need
about a 2.5-ton system. There are factors that would make it smaller
or larger, but again I’m trying to keep this short and simple. And what if we were trying to cool just the
upstairs bedroom areas at 800 sq ft? We would need about a 2-ton system. Now, what if both zones happen to be calling
for air at the same time. This is where it can get tricky, but for God’s
sake, we are NOT doubling the size of the system.

My rule for our technicians is to size the
system a half-ton larger than the largest zone in the house, which in this case is 2.5
tons. So, we size the whole system at 3 tons. This is a full ton smaller than the original
one installed, which surprises some perspective buyers, but it’s right. Because of sizing issues already mentioned
in this blog, I can stomach a 3-ton system blowing through the smaller 800 sq ft zone
without doing major damage in the long run to the new system, especially if some bleed
off dampers like the new Honeywell ARD dampers are installed. This allows the right amount of air to get
to the small zone and any extra bleed off to the other zone in very small amounts.

pexels photo 3964704

Now what happens when both zones reach a point
in the day when they are both calling at the same time? That extra half ton will satisfy one zone
or the other first. When that happens, that’s zone closes its
damper and allows the other zone to continue until it’s satisfied. We’re not talking about the laws of thermodynamics
to the letter, here. And nothing I say is absolute. Of course, there are variables that your technician
will have to take into consideration when it comes to your particular home, but an experienced
installer will know what is right and what’s not when it comes to zoning your house. I’m going to leave a coupe cards at the
top of this video screen.

One is on What Temperature You Should Set
the Thermostat in Your House and the other is about How to Cool Your Two-Story House. They have a lot of good information you may
not have known about your AC system, so I hope you enjoy them. – What Temperature
Should I Set My Thermostat? – How to Cool
Your Two-Story Home So, let’s talk about certain lifestyles
where it doesn’t make sense to have a two-zone air duct system. I just had a customer who has a nursery and
kid’s playroom upstairs while the caregiver and other relatives occupy the downstairs
portion of the house throughout most of the day.

What’s more is their demand for cooling
is considerable given that they like it to be 72 degrees upstairs during the day for
the kids, and would like it to be 70 to 72 downstairs at the same time of the day for
those downstairs. And they expect those temps even on the hottest
days of the year. That’s not the way zoning works… Here’s How Zoning Works
As I mentioned in the video about How to Cool Your Two-Story Home, the typical home we work
on is one where a parent stays home with a child, or retirees that don’t have to go
to work anymore, so there is usually someone home most of the day.

I tell people in these homes to focus on running
the AC downstairs where they typically are throughout the day. So, if you like it 75 degrees in your normal
living areas, make it 82 upstairs, in the area you’re not using. Run the AC primarily throughout the day downstairs
at whatever temperature you’d like, until about 6 or 7pm. Then, shut the thermostat off for downstairs
and have the upstairs start cooling off so that by the time you get to bed, it’s cool
enough upstairs to sleep for the whole family. It’s already 75 degrees downstairs when
it shuts off, so it’s not like it’s going to warm up super-fast and make it uncomfortable
for you. Nobody needs the AC downstairs during this
time so set the downstairs to be 82 degrees.

It won’t get there overnight, but at least
the system doesn’t come on downstairs, so the AC can focus its efforts on cooling your
second story down as quickly as possible. You can set it up however you want on your
thermostat’s schedule. If you need help with that, call or text us
and we’ll get out to you and set it up. The main idea of having two thermostats is
that the system is not sized big enough to cool the whole house at one time. Your home’s AC system with two thermostats
is designed a little smaller, because its designed to cool one floor, or one zone at
a time. We save money with smaller systems, and efficiency
is huge for a lot of people around here. The smaller the system, the less we pay for
the electricity it takes to run the AC.

We also save money and energy when we don’t
try to cool the entire house at one time. Well, I hope this helps explain a little more
about zoning, and how to use it properly. The intent of this video was to enlighten
folks that running both zones at 73 degrees all day isn’t the way zoning works. Think of it as two separate zones that we
are conditioning at two separate times of the day. If both zones happen to call for cooling at
the same time, a properly sized air conditioner will manage its way through it and satisfy
one or the other zone first, and then give the full system to the lagging zone. If this is your first time watching our channel
please click subscribe down below here on the bottom right, and if you click that little
bell next to it, you’ll be notified of all our videos as they come out.

Thanks so much for watching and we’ll see
you on the next video..

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