Below is an Industry Article written by
Trey Miller, a veteran to the HVAC field, discussing the benefits of zoning:
For the past 13 years, I’ve been promoting and educating contractors on the
advantages of forced air zoning products. I have worked with contractors at both
the manufacturing level and the distribution level. I almost find myself on a
quest to make sure that every contractor I come in contact with truly
understands the advantages that zoning not only offers his customer, but also
offers the contractor himself. These benefits are the efficiency of the
equipment, the way the equipment operates, and the way zoning can help solve a
multitude of HVAC problems that have been facing this industry for many years.
Probably the biggest advantage for the contractor is that if you install a
forced air zoning system correctly, one thing you’re guaranteed to have is a
happy customer. Not just a customer who is satisfied with the job or
installation which the contractor performed, but a customer that is actually
excited about the new comfort system they have in their home. This customer is
excited because he is now able to control different areas of the home at
different temperatures to satisfy different comfort levels for different family
members. This is something that – until introduced to force air zoning – the
customers never even thought was possible
Before I get into the specifics of the individual zoning products, let’s talk
about the basic concept of why forced air zoning should be an integral part of
each contractor’s presentation – whether new construction or retrofit (job
permitting) – for each and every customer that they see. Throughout my travels
in the southeast, I’ve done many training seminars with contractors talking
about forced air zoning. In each of these seminars I ask them a simple question:
Who in this class has a zoning system in their home? The majority of the time,
no hands are raised. At this point, I like to remind them that each and every
one of them has a zoning system in their home.
I don’t care if you live in a 1,000 sq. ft. house, a 5,000 sq. ft. house, a
townhouse, or an apartment – everybody has a zoning system in their home. Point
in case, when you go to cut the light switch on at the front door, does every
light in the house come on? Of course not; we zone our lights. Why do we zone
our lights? The number one answer: To save money. Look at the energy consumption
of a 100 watt light bulb burning continually 365 days a year. At year’s end, it
would average $30; the cost is minimal. So are we really saving money by cutting
off our lights? Or is it something that we’ve become accustomed to? Have you
ever thought of a customer requesting only one light switch for their entire
Let’s also take a look at when we go to the kitchen and cut on that water
faucet. Does every faucet in the house cut on? Of course not; we zone the water
in our homes, too. Why? To save on our water bill.
Two out of three mechanical systems in our homes are zoned. But the most
expensive one to operate is the HVAC system. Yet as professional heating and air
conditioning companies, we will go into a home and place one thermostat in the
middle of the house, usually in a hallway with no supply registers and one
return. It will not sense east sun or west sun, it will not sense north wind or
south wind. But we expect that system to keep all the rooms on the perimeter of
the house the same temperature. This is virtually impossible!
Why do we install this type of system? Because of competition. We have to be
competitive. If our fellow contractors are only offering one thermostat and one
return, it would be very difficult for us to go into that same job and be
competitive offering multiple returns and multiple system alternatives. So we
are forced to sacrifice quality and comfort for profitability.
Some of the problems that our customer, the consumer, faces each and every
day are quite common in our industry. Let’s look at a two-story house with one
system and one thermostat located downstairs. The temperature difference between
upstairs and downstairs can be anywhere from 4 to 10 degrees. Why? Because heat
If the sleeping area is located upstairs, what will the customer do to the
downstairs thermostat to maintain a 72 to 75 degree temperature upstairs? Crank
it down anywhere from 65 to 68 degrees. That means that the downstairs living
area, which isn’t even being used, is extremely cold just to maintain a
comfortable level of temperature upstairs while we are sleeping. That’s not a
very efficient way of cutting back on the energy costs.
As a professional contractor in a retrofit application, what are our options
to solve this problem? The number one answer I get in my classes is: Add another
system. But think about what we just said. If we add another system, we have one
system downstairs for the entire house. Are we going to put another system
upstairs and then have a grossly oversized unit downstairs? Not a very
We can use a ductless split system – which is very expensive and not really
suitable for area application, it’s more suited for room application.
We could knock a hole in the wall and put in an incremental unit. Again, this
is more suited for room application rather than area application.
We could always suggest a window unit. Unfortunately, it’s hard for a
contractor to be competitive with your local hardware store.
How about a manual damper to divert more airflow upstairs in the summer and
allow for more airflow downstairs in the winter? Could help patch the problem,
but not solve the problem.
The only real way to solve this problem (if the duct work is accessible) is
to zone this two-story home. With a thermostat upstairs and a thermostat
downstairs, the concept is simple. As the thermostat downstairs satisfied, we
have the capability of diverting the capacity of the equipment upstairs and
controlling the airflow upstairs.
In this scenario, is the customer concerned about the temperature downstairs
in an area of the home that isn’t being used all night? Or would he be more
concerned about the comfort in the bedrooms which are being occupied each and
every night? Think about he potential savings. Before zoning, in order to be
comfortable upstairs, we had to set our thermostat downstairs anywhere from four
to ten degrees lower (in the cooling mode). Now that we have a thermostat
upstairs, we’re allowed to simply set our thermostat to our own comfort level
upstairs and set our downstairs back significantly.
So with the setpoint of 80 degrees downstairs every night for six to eight
hours while we are sleeping, we could virtually save ourselves thirteen to
fifteen degrees per night during the cooling season, in the largest part of the
home. What a huge potential for the energy savings!
Now let’s look at a ranch house with a centrally located thermostat. We have
one system, with the garage on one end of the house where the air handler is
mounted. And what’s on the other end of the house? The master bedroom. This
scenario could potentially create an airflow problem, as well as a temperature
problem. With the thermostat located in the center of the house, it usually
satisfies before the farthest run from the equipment has reached the desired
comfort level. How do we, as professional contractors, go in and offer our
customers a solution to this problem? I’ve heard a multitude of things; booster
fans, extra units, rip out the ductwork and install all new ductwork, relocate
the air handler to the middle of the house to equal out the airflow. Most of
these solutions are labor intensive and expensive, and still doesn’t guarantee
us a solution to our problem. The solution: Forced Air Zoning.
Separate the living area from the sleeping area. Again, as we satisfy the
areas that satisfy first with the normal system, those areas will shut down and
we have the ability to divert the capacity and control the airflow to the areas
that weren’t performing satisfactorily to begin with. We are solving the
problem, rather than patching the problem.
There are a multitude of applications to which zoning lends itself to be a
viable alternative to the common, everyday installation we’re accustomed to. The
room above the garage is virtually an impossible area to keep comfortable with a
centrally located thermostat. Florida rooms or enclosed porches, entertaining
areas, kitchens, bedrooms, areas with heat-generating equipment, in-law suites,
babies’ rooms; all of these, without zoning, are almost impossible to control
separately with only one temperature-sensing device in the home or commercial
The majority of zoning is sold in the northern part of the country. Why is
zoning more prominent up north? Because it’s a standard, they’re accustomed to
zoning their houses. Whether it be hydronics or baseboard heat, close to 80% of
the homes are zoned in one way or another. Just as we expect our lights and our
water to be zoned, we also need to expect our air-conditioning and our heating
to be zoned.
So from a comfort stand point, we’ve established the fact that zoning is
something that customers need for true comfort. But are customers willing to pay
the extra money for that comfort? If a customer utilizes a zoning system
properly, like they utilize multiple light switches in the house by cutting
lights off that aren’t being used, a zoning system can literally pay itself off
in two to five years in the majority of cases.
As a matter of fact, you can tell your customer: It doesn’t matter if you
install a zoning system now, you’re paying for it whether you have it in your
home or not.
So the question should not be: Can the customer afford to put zoning in their
home? The question should be: Can the customer afford not to put zoning in their
What other items do we promote as contractors that will actually pay for
itself in two to five years? I’ve asked a lot of contractors that question and
the only two items that we’ve come up with are a set-back thermostat (a fairly
low-ticket item) and a heat reclaim unit.
Some have mentioned high efficiency. But if you use the audit program on the
heat-load calculation software, you’ll find that the majority of high-efficiency
upgrades take around nine years to pay for themselves. Unless you’re going into
a retrofit job with a six SEER and improving it to a much greater SEER, then the
payback would be quicker.
An EWC Ultrazone Zoning System can pay for itself and even provide the
customer with return income. How? Because after the payback period, the money
saved on their bills each and every month, actually gives them a return on their
EWC strongly supports the bypass method of relieving excess air-pressure when
all zones are not calling. If you install a zoning system without a bypass,
you’ll never truly realize the maximum potential of the equipment that’s
installed in the home.
What is a bypass? A bypass is simply a branch of ductwork connecting the
supply to the return, usually mounted in the supply plenum. So as dampers close,
creating a back-pressure to the unit, the bypass damper is forced to open to
relieve this back-pressure and re-circulate the air through the return and back
to the unit.
EWC offers two types of bypass dampers. One is a barometric bypass, which is
simply a weighted arm which you set to the static-pressure to relieve the amount
of back-pressure needed to keep the system balanced and quiet. The other type of
bypass damper is a static-pressure-sensing bypass damper with a fully modulating
blade. This damper will automatically adjust to static-pressure increases and
decreases. The bypass damper will modulate to keep the ductwork at a constant
If you install a zoning system with a bypass, it is highly recommended to
install external high and low limits other than the equipment’s emergency
limits. This will make sure your equipment is always protected from undesirable
temperatures or pressures.
As we relieve this precooled or preheated air back through our return and
back across our coil or heat exchanger, realize the advantageous discharge
temperatures we can achieve.
Let’s take a look at the advantages of using a bypass in both the cooling
season and the heating season. In the cooling season, one of our main concerns
is dehumidification. The bypass will naturally increase dehumidification when
all of the zones in the house are not calling. When certain zones are not
calling, we will bypass that extra air and BTUs (which would normally be wasted
in zones not calling) back across our return, across our coil, therefore
naturally dropping the temperature of our coil to help increase
dehumidification. By taking the BTUs that normally would have been wasted in a
zone that didn’t need conditioned air, and reducing the temperature of our coil,
we will also reduce our discharge temperature, and thus reduce the run time on
our condenser outside.
Now, let’s take that one step further. If we reduce our coil temperature,
what are we doing to the amp draw of the compressor in our condenser? We’re
unloading it because we’re reducing the load on the condenser outside. If we
reduce the load on the condenser, then we will also reduce amp draw. Amp draw
can greatly be reduced during the bypass cycle, thus increasing efficiency.
Think about what we just said. We just increased the efficiency of the equipment
naturally by not using unneeded air in areas of the house that didn’t need
conditioning. And we are allowing our unit to perform at its peak efficiency
just by putting in a zoning system and giving us the airflow and temperature
where we want it when we want it.
The equipment manufacturers over the past few years have even designed a unit
– a variable-speed airhandler – to help accomplish better dehumidification. But
how does a variable-speed airhandler dehumidify? By dropping the fan speed on
the airhandler 20%, we slow the air across the coil. By having less air going
across the coil, we allow our coil to get colder. As the coil gets colder, we
increase dehumidification by pulling more moisture out. But we do this at a
price. At the same time we reduce static and reduce airflow in our ductwork by
20%, we reduce the throw from our registers by 20%, not giving us the coverage
in the areas where the registers were designed to throw the air. Also, by
reducing the airflow and the coverage, our run time on our equipment should be
extended while we’re in this 20% reduction mode.
Please don’t misunderstand me. Variable-speed air handlers have many
advantages other than dehumidification. The ultimate zoning system is a
variable-speed airhandler coupled with zoning. But if dehumidification is your
main objective, a zoning system will dehumidify much more effectively and much
more efficiently than a variable-speed airhandler.
The pitfalls of bypass are bypassing too much cold air or too much hot air,
resulting in undesirable scenarios for our equipment. But with EWC, we take care
of this with our SAS (Supply Air Sensor) integrated with our zone control
panels. We can internally control, through our board, the high and low limits
you, the contractor, wish to keep the equipment.
Our SAS low limit is adjustable from thirty-five degrees to fifty degrees (in
one degree increments). Our SAS high limit controls are adjustable from 100 to
170 (in one degree increments). Thus making sure that no matter what type of
equipment you’re using, EWC and Ultrazone is taking care of your needs and
protecting your equipment’s performance.
The position and sequence of operation for our Supply Air Sensor is very
simple. For non-heatpump systems, the sensor will be mounted in the supply air
plenum. For heatpump systems, the sensor will be mounted in the airhandler
between the coil and the heat strips, to make sure we do not pick up any
residual heat from our auxiliary strips when they are used. Here, our main
concern is going to be on the first stage of heatpump, what our coil is actually
producing in the first stage of heating.
Recommended Supply Air Sensor setpoints depend on the part of the country in
which you’re located. On the cooling side for the northern states, somewhere
between 38 degrees and 45 degrees. In southern states, somewhere between 45
degrees and 50 degrees. This greatly depends on the moisture content of the air.
Heating setpoints for heatpump mounted sensors inside the airhandler, we want
that to be between 110 and 120 degrees. This will make sure we don’t run high
head-pressure on the first stage of a heatpump system. For fossil fuel
furnace’s, somewhere between five and ten degrees below the emergency cut-off on
the furnace itself.
We want to make sure the EWC board controls the limit rather than the
equipment because of a possible lock-out scenario.
EWC is the only manufacturer that gives you intergraded adjustable high and
low limits, allowing you to tweak the system to overcome any obstacles specific
to your application.
Many of the manufacturers of zoning systems don’t recommend the bypass
method, predominantly because they don’t have the integrated high and low limits
which are an integral part of the bypass installation. With bleed-through
dampers, modulating dampers, and dump zones to relieve the excess pressure, none
of these avenues allow you to take total advantage of the capacity and the
efficiency that this equipment can achieve like the bypass method can.
Sizing, installation, and adjustments of the bypass damper; it is extremely
important to understand the right way to do this. This is covered in detail in
EWC’s literature titled Duct Sizing with Ultrazone. You can get this from
your local,. Stocking distributor. Or please call 1-800-446-3110 and we’ll mail
you a complete set of literature.
EWC is the oldest manufacturer of forced air zoning systems in the industry.
With over thirty-eight years of experience, knowledge, and research on zoning
system technology, the Ultrazone Zoning products are the most complete consumer-
and contractor-friendly zoning components available in our market today. The use
of any four-wire thermostats for single stage or multistage applications, makes
our system extremely user-friendly. The industry’s only fail safe position LEDs
mounted on the dampers (our URD and ND dampers) allow any contractor to know, at
a glace, the exact position of the damper he installed without having to
physically remove and inspect the damper for proper operation. Coupled with our
zone and system operation LEDs on the control board, this give the contractor –
the least experienced, as well as, the most experienced – the ease of
troubleshooting via LEDs rather than being forced to use an amp probe or meter
for all system analysis.
Here are some other unique feathers of the Ultrazone products:
- Zone control boards that will actually fix themselves. The control board
analyzes itself constantly, measuring inputs, outputs, and voltage. If a
problem exists, the control board will reset itself, fixing the problem.
- A control board with a one-button contractor test. The contractor simply
has to push one button and he can check the entire system for proper
- The control boards will accept virtually any 24-volt damper that’s been
made in the last thirty years, perfect for retrofit applications, allowing
you to replace any manufacturer’s old or malfunctioning board and use
- The bypass damper has flexibility and durability by using a gasket and
steel reinforcements, ensuring a long life.
- We offer the industry’s only five-year warranty on all products
manufactured by EWC.
- The EWC – Excellence Without Compromise – guarantee. We will guarantee
that if you install our products and they don’t work the way they’re
supposed to, we will buy the product back from you.
- The Ultrazone URD and ND dampers feature a double-stack motor with
stainless steel casing. One motor powers twenty seconds open, one motor
powers twenty seconds closed and drops power, without keeping constant
torque on the motor during normal operation. These dampers also feature
high-quality, gasketed material for low leakage, durability, and
EWC and Ultrazone have brought quality and reliability to our industry for
over thirty-eight years. Forced Air Zoning – Friend or Foe? EWC and You –
Friends for the Future. Together, we can make things happen.