5 Rules of Zoning

It's not hard to design a zoning system, but you do have to keep a few things in mind. Here are the five rules we use to make sure those zoning systems really make your customers comfortable.

Transcript:

So here’s five rules of designing a zoning system. These are not complicated. These are very easy. Zoning is not complicated. We don’t want you to be intimidated by it. But if you follow these five steps, you can pretty much guarantee that you will not get yourself into trouble. You won’t be on the phone with tech support, and you’ll have a good, properly designed system.

So zoning, considerations: load calculations, grouping similar rooms with similar conditioning requirements. So, you don’t want to group rooms that have, you know, this room is totally comfortable, but this room is so warm during the summer. Maybe not consider pairing those two rooms together in your design. Right? What other rooms on this level are similar to this room? Well, you know, these other rooms over here on this east side of the home are very similar. Group those rooms together.

Never take rooms from different floors. You know, first and second floor. You don’t ever want to do a east west design. Don’t ever do first and second floor west, first and second floor east, and expect it to be great. You’re still going to have comfort issues up on the second floor. And a variance in temperature.

Don’t micro zone or over zone. Don’t go into zoning design assuming you have to put a thermostat in every single room. You don’t need that kind of depth. You don’t need that kind of control.

Be mindful of large glass, large loads, you know, great rooms. Great rooms are perfect example. A lot of them were built on the back of somebody’s house. They have three outside walls. People like them to be filled with tons of glass. A lot of them have big, high cathedral vaulted ceilings. Totally different environment than the rest of the house. So, you know, that room probably deserves its own dedicated thermostat.

And then be mindful of east and west load shift. Sun moves around. Where is it beating on this house? Where’s the load out at any given particular part of the day?

Number one rule or first rule, I should have called number one. First rule: get the homeowners input. This, hands down, should not be a skipped step. Don’t be that salesman that can eyeball the house from the curb, know the tonnage and BTU, and also identify how many zones they need. You need to go through and have that customer tell you, how do you use your house? Do you still have kids in the house? Or, you know, empty nester, do they come back from college? Do you have an in-law? Do you have a workout room?

Gather all of this information from the customer that lives there, that knows where every single one of those issues and pain points are. You know, where are your over conditioning rooms, where are your under conditioning rooms? Get all of that information so that you can apply it to your design.

I’ll give you an example of probably one of the last houses that I zoned before coming to work here, and how I applied all of the five rules that we’re we’re going to talk about here.

Second rule: load calculations. Now, I never suggested to do zoning, you need to whip out a computer and do a load calc on the house. You don’t need to do manual J or that kind of thing. What you do need to look for are a couple of things. One: Does the room have enough supplies to handle the load?

I have this room here. I have four supplies. I have a return back in the corner. If I go up top, I’ll see that these are, I think, 7s or 8s. That would tell me that I probably have enough supply for this room, to keep it comfortable. Now, I’ve seen attic spaces that were built out to be a bonus area, and the contractor could only get one register because everything’s finished downstairs. He couldn’t run ductwork, and he put one register that blasts into the room. And then he applies zoning to it, assuming that, my one supply, but I put zoning on it, give it a thermostat, I’ll be fine. No. You’re overestimating the power. You still need to have the right amount of ductwork into a space.

If you have a home that you guys built and put the system in and you have a history, or you’ve done the change out and you know, historically, this system works great, they just suffer from physics. Warm air rises. Cold air falls. First floor is great because that’s where the thermostat is at. And the thermostat doesn’t know it’s getting too warm on the second floor. Apply zoning to it.

If you’re walking into a customer’s house for the first time and they say, you know what? This house is terrible. It’s horrible to try and heat in the winter. It’s horrible to try to cool in the summer. And you know nothing about it. At least evaluate the system. Does it look sized right? Do I have three tons of air conditioning and only two tons of ductwork? Do I have rooms without enough supplies? Are there inherent design issues? Some of that for some of you guys that have been doing it long enough, you can probably get a pretty good feel for that by just eyeballing.

If you don’t have that kind of experience, maybe just measure the ductwork. Get your duct-a-lator out, see if you have enough, you know, does it match my equipment tonnage? Just do some basic evaluation. Look at the rooms. Is there enough supplies? Those kind of things.

So again, I don’t want you to think that, like, “Wow, to do zoning, I have to do a full manual J calculation, like I would the size of a furnace and air conditioning.” You may only want to do that if you’re walking in blind. And you’re you have some speculation about the system that’s been installed in that house.

Otherwise, if you have that history and you, you guys put it in and it’s been great, it’s just, you know, uncomfortable second floor or that room, like the great room. You know, put zoning on it, you should be pretty set.

Third rule, put the thermostats within the zone that it is controlling. Where do you think the most common place – somebody installed zoning in somebody’s house and they did this first floor, second floor. Where do you think the most common place that we see a second floor thermostat get installed?

Hallway.

Hallway. How close is the bedrooms on the second floor to the hallway temperature? Probably not very close. You have rooms like – you may have a room that’s above an unconditioned garage. You may have a room that has three outside walls. It definitely has windows and glass. Right? Does a hallway? It may not. It may not have any exterior walls. It may not have any windows. It is not the same climate as a room with the sun beating on it. Right?

So what would a solution be? You could put remote sensors on there and do an averaging of 2 or 3 rooms on your second floor, and have it in the hallway. That’s fine. This rule kind of plays into the fourth rule, that we think every master bedroom should have its own dedicated thermostat.

Who’s paying for the job? If that customer, every night when they go home or go to bed, the thermostat, you know, they go to bed at 10:00. At 9:00 that thermostat comes out of setback, cools their bedroom off to 72 degrees, and when they come upstairs at 10:00, that room is spot on, 72 degrees every night when they want to go to bed. How happy are they going to be? If the thermostat’s residing in the hallway and now the bedroom’s more comfortable, but it’s not really a set point, how happy are they going to be with their big investment that they made in zoning? Not as happy right?

So either make sure it’s sensing and averaging rooms. Make sure that you know, if the second floor is only getting one thermostat, put it in that bedroom. That bedroom deserves to be spot on every night when they go to bed. You’re basically putting the control where they sleep. And those are the happiest customers.

Now your fifth rule: create appropriately sized zones. This gets into: don’t micro zone. Don’t try to put a thermostat in every single room. What we’re talking about here is minimum zone size, percentage of the total CFM. So if you have a five-ton system, you have how many CFM? 2000, right? If you have a two-ton system, you have 800. The more you cut a pie up into pieces, the smaller and smaller those slices get. The more zones you try to put on an HVAC system, the smaller and smaller your zones get. They become problematic.

If you have a, PSC permanent split capacitor blower drive, an old system, and you’re going to put zoning on it, you can easily go down to about a third of the ductwork, 33%, and know that you’re not going to have a problem job. You’re not going to have to deal with a bunch of noise. You’re not going to have to have some crazy bypass on it, or you may not have to have one at all. You most likely won’t. We’ll talk about bypass design. But you can easily get down to that small of a segment of your duct system on that zoning system, and know that I’m not going to have to call Arzel because I have some nightmare job going on because I did some crazy design.

You can go smaller than this. It’s just going to mean that you’re probably going to eventually get to a point where you may have some static pressure issues, and when I say that, maybe just air noise, the air delivery in that zone may be greater than the customer likes. And for that reason we may have to put on a bypass.

Bypasses are not like the ultimate sin. You know, for a while, California was trying to ban them on zoning systems. They went full circle and said, okay, you can go ahead and use bypasses on systems. The problem with bypassing has typically always been they either get oversized and/or overly adjusted to open too much when the system is running. Stealing valuable static pressure. Taking a load off the equipment. Other things that we’ll talk about in bypass design.

But if you have a variable speed ECM, constant torque, whatever style motor, most every, or all equipment now is produced with those. You can get down to 25% of the ductwork, or less, with little or no bypass, when you use it with our HeatPumPro and our zone weighting. The panel basically gives you the control to tell the panel this zone is too small to go to second stage W2 heating, or Y2 airflow for cooling. We lock it in the low stage so that we prevent it from over staticking.

If we get multiple zones or large zones calling, we can tell it that you’re allowed to go to second stage. But because we never tried to put all four ton into that small zone, if we lock it in the low stage, we may only try to put three tons of airflow through there or whatever your equipment low stage capacity is.

And then bottom line, don’t over zone or micro zone. Don’t try and put a thermostat in every room. That HeatPumPro, if you look at the output, this would be your equipment connection where all your equipment ties on. We’ve actually given you two Y1 Y2 outputs, one dedicated for your air handler, whether it be a furnace or air handler, to control CFM blower staging, and a separate Y1 Y2 condenser output that goes to your heat pump or air conditioning, to control the actual BTU content of your equipment. And then we can, through that zone weighting, control when it gets Y2 output for air flow, and when it’s held back in the first stage. That gives you greater control of your equipment.

Other small zone alternatives, wild runs or dump zones. Always probably a better alternative to putting a bypass in. When you put a bypass in, you’re basically taking not only the excess static pressure and leaving it into the return. You’re also grabbing a lot of those BTUs and putting them into the return, which takes the load off of the equipment. If you can do a couple of wild runs or dump zone, putting it into some place that can handle that additional conditioning, that’s always a better alternative than a bypass.

Our AloneZone, or what we call our smart slave zone board, gives you control of a zone or dampers with the thermostat, but it can’t turn on the equipment. It’s an accessory that can be added to any one of our zone panels. So if you’ve identified, “Hey, I’ve got this tiny little zone here, I need to give it thermostatic and damper control, but I never want to allow this zone to turn on the equipment.” Then you would use that accessory.

And then last but not least, if you have to use a bypass, that’s fine. Just to make sure that it’s sized correctly and adjusted correctly.

So let’s take those five rules and the things that we just went through. I told you there was a house I zoned before coming to work here. I’m going to try and tie all those rules and, together the best I can.

Does anyone remember what that first rule was?

Homeowner’s input?

Homeowner’s input. So I get to the customer’s house, ring the doorbell, she comes and answers the door. What’s the first question I ask her? Where are your comfort issues? And the first thing she told me was, you’re like, you’re standing at it. I mean, I literally just walked in his customer’s house.

I’m literally just two foot steps into the house and she says, this is it. This is the worst part of the house. The house that I’m talking about is just outside of Chagrin Falls. It faces kind of southwest, and the whole front area of that part of the house is all glass, top to bottom. You know, it looks like something should be in the hills of California, not necessarily nestled in Chagrin Falls.

Very cool house, but, she said, you’re standing in the worst part of my house. All winter long, this is the coldest, draftiest, worst part of the house. All summer, this is just warm and kind of muggy and stuffy and it’s just terrible. All right. Great. Duly noted.

Takes me through the rest of the house. Here’s some areas. This is okay. This is whatever. She leads me around full circle on the first floor, and she says, oh, by the way, this is my husband’s office. He says he’s not getting the zoning unless he gets a thermostat in his office. Like, really? Like, okay.

Now that office had westerly exposure, had a fair amount of glass in it as well. I wasn’t sure using the slave zone was going to be a great answer, because you can’t turn on your equipment. It wasn’t going to be a small over-conditioning area. It’s a small under-conditioning area. I need to be able to provide BTUs there. How am I going to do this?

I thought then, full circle, coming into the customer’s home, this is the worst area of my house. It’s terrible all winter. It’s terrible all summer. That particular area of the house, and I’m going off memory, I think it had, like, two sevens up high and two sevens down low. We never dampered them. We left them as wild runs. What we created was, any time the AC called over here, that front foyer and all that glass got air conditioning. When it called over there, the front foyer got heating. It got a blast of heating to take that load off.

More importantly, when the husband went into his office. Which, by the way, I believe the first-floor system was four tons and there was only one six-inch run in his office. Wasn’t a very big office. I could give him a calling thermostat that could give him heat on demand, cooling on demand, because my smallest zone was not one six inch run on a four ton system.

It was one six inch run with two sevens up high and two sevens down low. My smallest zone wasn’t any longer too small.

You see what I did there? So you can do things like that. And it prevented me from ever having to even put a bypass on the system. And according to that customer, you know, the one time I had contact with them after putting in the zoning, you know, she claimed like, problem solved. It’s great in here during the summer. I don’t know about winter, but at least during the summer, you know, it solved the problem. Because every time the AC ran, that front foyer got conditioned.

And then, you know, the other rules, of course, there was a separate system on the second floor. We zoned that as well. Put a thermostat in the master bedroom suite. And in that particular case, they had four bedrooms, like three, I think, for their boys. And one guest bedroom. Put a thermostat on that one. And I did sensors, and we did averaging for all of those rooms.

So, that’s how you can kind of tie all those rules together. More importantly, I also had that background on that system. I knew that, you know, the equipment was sized well, the duct work was good. It was just, you know, they had lots of glass and a lot of diversity and things of that nature.

How do you know if you’re right? Most importantly, your customer’s going to be satisfied.

One thing that I liked about zoning, probably over most other products that I put in, the results were almost immediate. There were humidifiers I put in, but I’d have to tell the customer, “Give it a few days, get your humidity up in the house where it should be, you’ll start to feel the comfort.” I had salesmen go in before me, you know, quote and sell the highest end air conditioner and furnace that we offered.

And that customer was left with the impression that, “My new system is so efficient, the utility company is going to be paying me money to heat and cool my house.” And I would go back to that customer’s house, you know, and eventually they’d have all the bills on the counter and be like, am I saving the money that I should have been? Because I thought, honestly, when the salesman told me how efficient this thing was, I thought I’d have almost no bill. Like, we’re still going to use gas, still going to use electricity. You’re going to have something. Plus, your utilities went up, plus it was a hotter summer last year. I have no idea if you’re saving the money you should or not.

I could put in zoning and they knew that night when they went to bed that it did exactly what they wanted it to do. It could be 94 out when I pulled out of the driveway at 5:00, and that night when they go to bed and their bedroom’s 72 degrees, and they never over conditioned the whole rest of the house, they knew right then and there: “Uh-huh. Now I know what I bought. Now I know what this stuff does.” And there was no waiting period. So I really enjoyed that.

You’re going to maximize the effectiveness of the system. Like I said, most cases, there’s going to be considerable energy savings involved. The only time we don’t see that is, you know, somebody abuses it. “Hey, now I can set this thermostat to 65,” you know.

Or, we also saw another customer that said “I can turn all the rest of my house off, and I’m only going to put air conditioning into my living room when I’m in my living room.” Well, while the rest of the house is going up to 83, 84 degrees and building up humidity and load and everything else, returns are still pulling air from an 83, 84 degree house that’s unconditioned. And you’re trying to, you know, “I’m going to insta-freeze just my living room.” Well, it’s not going to perform well, and it’s probably not going to save you money because it’s going to struggle. It’s just going to have to run and run and run. Any cooling you put in there, it’s going to try and just find its way into the rest of the house.

And then, you know, just bottom line, better comfort throughout their home or building.

Follow those rules and you should have zero problem, zero issues with, you know, customer HVAC systems or complaints. I mean, those are pretty simple. Should be not intimidating.