That’s Not How Zoning Works!

how zoning works

How Heating and Air Zoning is Supposed to be Used

I find that some technicians 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 cool the whole house at once? Why do we even need zoning at that point? On today’s blog we’re talking about the do’s and don’ts of zoning.

Heating and air zoned houses, or houses with two or more thermostats, are usually found in homes that have two floors, or in 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.

Many homes in the Sacramento area are big enough to support families of 2 to 6 people. Such a home will have a designated living area that includes the kitchen, dining, family rooms, common area restrooms, entryway and other common areas. The other part of the house consists of the master bedroom, master bathroom, larger closets, the kids’ 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.

The System is Oversized

To illustrate my point, let’s just say you have a typical 1950 sq. ft. home of conditioned space. This doesn’t include areas of the house like the closets, pantry, and other rooms that don’t have registers supplying air to them. This hypothetical 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 adds a thermostat to the upstairs area, so they’ll have two zones; one for upstairs, one for downstairs. Another 10 years goes by and the system is now 20 years old.  Because it no longer cools as it should, the new owner is ready for a new system.  He doesn’t understand why he’s being told the new system should be smaller — much smaller! Because that’s not how to use zoning.

Heating and air zoning is an excellent idea!  But keeping that big, old 4-ton system there is a big mistake. If a 1950 sq. ft. home is divided into fairly similar sizes — 1150 sq. ft. downstairs and 800 sq. ft. upstairs, for example — then only one zone is calling for cooling.  That big 4-ton system (which remember, was designed to cool the whole house at one time) is overwhelming the temperature change in that one zone.  That’s half of the house!  It’s over pressurizing the ducts for that zone.  It’s sending a high velocity of air through the registers of that one zone. This is generally putting a big strain on the entire system, with the exception of the unused zone.

High Blood-Pressure Isn’t Good, Right?

This strain is similar to 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 into this too much as I have several YouTube videos for customers 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 Unit, 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.

When it comes to heating and air zoning , my rule for our technicians is to size the system a half-ton larger than the largest zone in the house.  In this case it’s 2.5 tons, so we will size the whole system at 3 tons. This is a full ton smaller than the original one installed, which surprises some prospective buyers.  But it’s correct. 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 to the new system over time, especially if some bleed off dampers like the new Honeywell ARD dampers are installed. This allows the correct amount of air to get to the small zone and any extra bleed-off to the other zone in very small amounts.

Proper Heating and Air Zoning

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 home, but an experienced installer will know what is right and what’s not when it comes to zoning your house.

For a deeper dive, you may want to view our videos:  What Temperature Should I Set the Thermostat in My House? and What’s the Best Way to Cool My Two-Story House?  Both have a lot of good information you may not have known about your AC system, so I hope you enjoy them.

When Two Zones Don’t Make Sense

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 kids’ 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 degrees 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 Heating and Air 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 7 pm. 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 won’t quickly warm up and make it uncomfortable for you.  Set the downstairs to be 82 degrees, where no one needs the AC running. 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 down your second story as quickly as possible.

Saving Money with a Smaller System

You can set it up however you’d like 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 reason for having two thermostats is simple.  The system is not sized big enough to cool the whole house at once.  Because it’s designed to cool one floor, or one zone at a time, your home’s two-thermostat AC system is designed a little smaller.  We save money with smaller systems.  Efficiency is a huge concern for lots of people around the Sacramento Valley.  The smaller the system, the less we pay for the electricity used to run the AC.  When we don’t try to cool the entire house at once, we also save money and energy.

Summary

I hope this helps explain a little more about heating and air zoning, and how to use it properly. The intent 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.  It will satisfy one or the other zone first, and then give the full system to the lagging zone.

Thanks so much for stopping by and we’ll see you on the next blog post.

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HVAC Zoning: What You Should Know Before Retrofitting Your Home

Are you dissatisfied with the level of comfort provided by the HVAC system in your Sacramento home or business premises? Read on and discover some helpful information from Fox Family Heating and Air which will enable you to decide whether HVAC zoning would fix the problem.

What Is HVAC Zoning?

HVAC zoning refers to the creation of different sections/zones within a building so that the settings of the HVAC system can be customized for each of those zones. For example, you can divide your home into three zones. Each of those zones can have different heating or cooling settings from the other zones even if the entire building is served by one HVAC system.

Think about zoning as the installation of different light switches for each room in the home. You don’t have to switch on the lights in the entire house because you want to read late at night. Similarly, you don’t have to lower the temperature of the entire house just because your bedroom is too hot for your liking.

What Are the Required Zoning Components?

The zone control panel.

This is the “brain” of the entire zoned HVAC system. This control panel receives the requests made by the different thermostats and triggers the execution of those requests.

For example, the thermostat in the kitchen may call for extra cooling as someone is cooking. The zone control panel receives that request and opens the damper to that kitchen wider so that more conditioned air can be directed to that part of the building. The zone control panel is like a choir director who ensures that everything is working seamlessly.

Thermostats.

You will need as many thermostats as there are zones in the building. The thermostat in a given space allows the occupants of that space to select the desirable temperature settings.

Zone Dampers.

Think of zone dampers as “valves” which regulate the flow of conditioned air and heating into a zone/room. The damper executes the instructions sent by the zone control panel after getting information from the thermostat in a given zone/room. For example, the damper will close and reduce the flow of conditioned air if the room/zone has reached the desired temperature.

The dampers can be placed inside the ducts (in-line dampers) or they can be placed on the air registers. In-line dampers are usually preferred in case a new HVAC system is being installed. The dampers are usually placed on the air registers during retrofit applications in which access to the ductwork is difficult or expensive.

By-pass damper.

A by-pass damper is a special kind of damper which is used to get rid of the excess pressure in the HVAC system. This happens during when most zones have signaled (through the thermostat) that no heating or cooling is currently needed. The conditioned air of the HVAC system would overstrain the remaining zones which still require heating or cooling. The by-pass damper deals with that excess pressure/conditioned air by channeling it to the return air register or directing it to a common section of the building, such as a hallway.

Is HVAC Zoning Recommended for All Sacramento Buildings?

HVAC zone control isn’t a requirement for all buildings even if every building can attain benefits from this upgrade. The situations below represent examples of those who would reap the greatest benefits from HVAC zoning.

Buildings with extensions. HVAC zoning can be helpful if an extension, such as an additional bedroom or finished basement, was added and has unique heating, cooling and air conditioning requirements. For example, a room added above the garage may be hotter than other bedrooms in a home. Zoning addresses the unique needs of such an extra room.

Multiple levels. Buildings with multiple levels need HVAC zoning since each of those levels is unlikely to have the same HVAC needs. For instance, the ground floor may be cooler than an upper floor during the summer.

Different occupancy levels. Buildings with sections that are rarely used can benefit from HVAC zoning. This is because the areas which aren’t used a lot can have their air conditioning turned off. Rooms with lots of occupants can also have their HVAC settings adjusted to address the needs of that larger number of people who may feel hotter than those who are in a room with fewer occupants.

Single-level homes may not require zoning unless a Sacramento HVAC professional inspects the building and recommends that zoning is necessary.

How Can HVAC Zoning Be Done?

The way in which HVAC zoning is done in Sacramento depends on two key factors. First, what zoning system have you selected? Secondly, when is the zoning being done?

HVAC zoning can be done by installing different HVAC systems for the different “zones” created in the building. Zoning can also be done by redesigning an existing system so that different rooms/zones can be controlled independently from other zones. Ductless air conditioning systems can also be used to zone a building.

The timing of the project also impacts on how it can be done. For example, a new building can have the zones designed prior to the selection of an HVAC system. In such a case, the ductwork will be installed with the zones in mind. However, retrofit situations may dictate that the least intrusive method. Such as installing dampers on air registers instead of inside ducts. Your heating and air conditioning professional in Sacramento can assess your specific situation and advise on how zoning should be done.

HVAC zoning can deliver numerous benefits, such as increased equipment life and lower energy bills, to homeowners in Sacramento. Discuss your needs with an HVAC replacement technician so that the best approach can be designed to zone the system in your home.

When Should a Technician Recommend a Leak Search on my HVAC System?

how does an hvac unit work

Every spring and early summer we get what’s called the “first wave” of worried homeowners and rental tenants who realize there is something wrong with their AC system. Sometimes it’s a mechanical part like a capacitor or a motor, but other times it’s a refrigerant issue. This week we’re going to talk about refrigerant leaks, what the laws are and moral obligations you and your technician may have when it comes to refilling your HVAC system with refrigerant year after year.

As a technician who goes to hundreds of homes every summer in the hot Sacramento valley, I go out on these calls all time. Sometimes customers will call into the office and tell us another company told them they have to get a new system because they’re not allowed to fix older systems anymore. Other excuses I hear is, they don’t make R-22 anymore so there is no refrigerant to add back into their system. Unsuspecting homeowners will believe these technicians and fall for their unethical tactics. Other homeowners will call Fox Family Heating, Air Conditioning and Solar where we will offer a free second opinion to come out and verify a leak that supposedly exists and give them proper solutions to remedy the leaky system.
Let’s talk about the obligations we as decent human beings have to this great planet we live on. The government regulates and monitors our usage and consumption of refrigerant in this country. In other parts of the world, not so much! It’s crazy to think of the irresponsibility technicians in other parts of the world have when it comes to just pouring pounds and pounds of damaging refrigerant to earth’s ozone layer. You see, the refrigerant in our older systems now is R-22, a mix of chemicals that contains chlorine which degrades the ozone layer quickly if it were to get out into the open. The systems in our homes hold anywhere from 3 to 20 lbs. of refrigerant. Just two lbs. of refrigerant leaking into the atmosphere causes as much environmental damage as a van driving 10,000 miles down the road. The damaging result is global warming and accelerated environmental weather extremes.

You know the stories. You’ve seen it on TV. Al Gore told you this crazy weather is because of an accumulation of damaging practices we have as humans to this giant world. Refrigerant loss from our home HVAC systems don’t even have a definite requirement yet as to when we HAVE to perform a repair on the leak. The government right now, just says if the system holds over 50 lbs of refrigerant, then we have to fix the leak. Not only do we have to fix the leak on those systems but we have to come back and verify that leak is taken care of bi-annually until the EPA requirements for follow-up are satisfied. We as technicians are now responsible for logging any refrigerant coming in and out of any given system, not just commercial and industrial machines, but residential too.

how does an hvac unit work
When I get out on these calls with low refrigerant suspected, I will attach my gauges to the air conditioner outside and fire it up. The system will start but doesn’t sound normal. A light clanking noise quickly repeating itself in its own rhythm. After a few minutes of running, the gauges show me there is indeed very little refrigerant left in the system.

What does this mean? The HVAC system is separated into three lines for your refrigerant to stay in. The evaporator coil at your furnace, the condenser coil on the outside unit, and the copper line set that runs between the two coils. When the system was installed, these three sections were brazed together by the technician out at your house.

During the call, and at the very least, a technician should volunteer to visually go around and check all the brazed points in your lines. There are at least two points at the evaporator coil and two at the outdoor condenser coil that the installing technicians brazed together to complete your HVAC system’s refrigerant lines. The technician should be looking for oil around these connections. Why? Because the refrigerant in the system carries oil with it to lubricate the components inside the system, like the compressor. This means if the furnace and evaporator coil are up in the attic, the technician needs to get their ladder out and go up there to do this visual check. While they are up there, they should check the P-trap for oil in the condensate lines. A good technician knows that the majority of leaks happen at the evaporator coil or the condenser coil and very rarely at the line set that runs in between the two. If the evaporator coil is leaking badly enough, oil will drop down into the evaporator coil drain pan that the water usually goes down into. It then starts its way down the condensate drain line until the oil fills up in the P-trap. These are very easy checks the technician should include on the original diagnosis charge.

If they don’t see anything there and are sure they have checked all the easier points of access to the refrigerant lines at the evaporator coil, the tech should check the outdoor coil looking inside the top off the unit and all around it looking for darker stains of oil. Also, are the schrader cores where the gauges attach too loose or not sitting correctly within the service valve? If the tech is satisfied the leaks are not there, then he/she should start an investigation of sorts.

“Is there a history of leaking with this system?” is a question the technician should ask. The homeowner has some obligation to tell the truth here. If the owner deceives the tech, then we’re really not getting anywhere are we? I can say there have been very few owners that I didn’t believe when they told me, “No, never any leaks before,” or “Well we just moved in here two months ago.” At this point RIGHT HERE a technician should offer a strategy to the homeowner to help determine if it’s a leak and if so what will we do to try to find the hole and repair the system so it doesn’t leak anymore.
Our technicians at Fox Family ask if there is a history of leaking for this HVAC system because it helps us establish a base point for the rate in which this system is leaking. We want to know if there has been refrigerant added to this system before, and if so, when?

The main reason why I wrote this blog. If this is the first time the system has been “topped-off” to get you cooling again, then we should get you cooling and use this as a starting point to determine if this system is leaking and if so, how much and how often?

If the refrigerant was admittedly, “topped-off” last year, then I think it is a good time to introduce the idea of looking for the leak. This is mentioned whole heartedly in the best interest of the planet and its survival. We want to avoid being unethical here now that we know the system is being topped off every so often to maintain it’s cool air. R-22 has chlorine and R410 still has massive global warming potential. We need to stop that from getting out to the ozone! If we can find the leak then we can get the system back to factory specs.

When I want to introduce the leak search, I tell my customer, let’s get you back cooling today so your family is comfortable. The we should go ahead and start the leak search process which includes us going to the different parts of the AC system with our electronic sniffer looking for the leak. The majority of the time I can find the leak with this method. That cost $X amount and is good for the first hour of searching for the leak. If we can’t find the leak after the first hour, we bump it up a level to $X amount. This level of leak search includes us adding a fluorescent dye to the system so we can let it circulate in the system for a couple of weeks (while you are still staying cool). Then we come back out and look for the dye. If there is indeed a hole somewhere in that copper or aluminum line, the oil and the dye inside the lines will spew out of the hole and splash onto anything around it like the aluminum fins on the coil or the condensate drain pan and into the P-trap. We’ll take the dye kit which comes with some yellow glasses and a UV flashlight. When we shine the light onto the dye which has come out of the leak and we have our yellow glasses on we can plainly see the leak is coming from there. We shouldn’t stop looking though! Just because there is one leak doesn’t mean there aren’t two or more holes.

If the leak is in the fins of the evaporator or condenser coil, we can’t get in there to fix the leak without compromising the standards of the manufacturer. It’s possible yes but, the possibility of the repair causing a restriction or other repair if the brazing compound didn’t settle properly on the under side of the repair spot. Also, the copper or aluminum is a lot thinner on the coils than the copper line set that runs in between. This means when the leak is in the evaporator or condenser coil, and it’s not on a u-bend or other easily accessible spot, we’ll recommend you getting another coil from the manufacturer. We’ll get it ordered and replaced for you in no time.

No matter where the leak is, the money you have paid for the leak search will go toward the cost of repair. Some of these repairs can be upwards of $2000 to replace parts, so it’s nice to know we can find the leak, and then put that money towards the cost of repair.

Our clients always appreciate knowing exactly what to expect during the leak search process. Simply explaining the repair in common terms that aren’t too “techie” for the customer are also appreciated. A leak search is not always needed just because you went out to a house for the first time and it has a leak. There is proper way of establishing knowledge and data about this particular unit. Starting at that first time out there and getting the customer cool is the most important thing. Next year if we have to add refrigerant again, then we should establish a plan for finding the leak. It’s our moral obligation as techs and as homeowners to find the leak and repair it. If there is a history of leaking refrigerant from your system, it’s on you as homeowners to let us know. I realize it’s going to cost some money to make the repair, but once it’s fixed, you won’t have to keep paying for refrigerant that just keeps getting more and more expensive every year.

Thanks for checking out this blog on leak search recommendations. If you are a homeowner and are concerned that what the other technician said doesn’t match I’m saying here, you might want to call a trusted HVAC company that will set you straight and actually give you options other than “You need to replace your system!”