Retrozone F.A.Q

Frequently Asked Questions

01 - How does HVAC zoning work?
02 - What is included in a HVAC zoning system?
03 - What equipment do I need for a zoning system?
04 - How do I know what type HVAC equipment I have?
05 - What is multi stage or multi speed HVAC equipment?
06 - How do I determine what dampers are needed in my zoning system?
07 - I am a home owner, can I install a zoning system on my own?

08 - Where can I find comprehensive information on how to install

a zoning system?

09 - Can I save on energy costs with an HVAC Zoning system?

10 - How much energy will I save with a HVAC zoning system?

11 - Can I get more comfort AND save energy costs?

12 - You sell many types of dampers. How do I determine which damper to use?

13 - What if I have several ducts per zone?
14 - What is the Flexdamper System?
15 - How does the Flexdamper System work?
16 - How do I determine the size of my rectangular damper?
17 - What size rectangular dampers do you sell?
18 - How are the rectangular dampers installed?

01 A - How does HVAC zoning work?

HVAC zoning systems use motorized dampers or flex dampers to move forced air (heat and cool) to the occupied areas or to areas of your home or office where you have a temperature problem (i.e. upstairs or the west side of a home). An example would be in the winter time, you can heat the living area after work until time to go to bed. Then at bedtime you can close down the dampers in the living areas and send the conditioned air to the bedrooms. Therefore, you will not be wasting energy dollars heating areas that are not being used. Another prime example is in two story homes. Most of the heat moves upstairs so it is a challenge keeping the upstairs cool and the downstairs warm. A RetroZone system will eliminate this issue as well.

02 A - What is included in a HVAC Zoning system?

Generally, each zoning system will include flexible or mechanical dampers (at least one in each zone), thermostats for each zone, control panel for control of dampers and HVAC equipment plus a bypass equipment if needed. See our Zoning Packages (under Catalog tab) for examples of systems.

There are generally three types of zoning systems, Complete HVAC Zoning Systems, Slave Zones and a combination of a Slave / Complete Zoning System.

Slave Zones are HVAC zones where a thermostat or a switch directly controls the damper to simply close off airflow to an area, without controlling the HVAC system. This zone type is used in rooms/areas where exact temperature is not vital (i.e. in seldom used basements).

A Complete HVAC zoning system allows you to control temperature in each area/room that is it’s own independent zone. This requires a Control Panel, thermostats for each zone and at least one flexible or mechanical damper per zone.

You could also have a combination of both the Slave and Complete HVAC Zoning systems.

03 A - What equipment do I need for a HVAC zoning system?

You would need a thermostat for each zone (you can use your exiting thermostat or get matching thermostats), a control panel, the dampers or damper system, a 24Vac transformer and possibly a by-pass damper. You would need a damper on every duct coming off your plenum (the box at the end of your furnace with all the ducts coming out) and/or a damper going to all the ducts in all the separate zones.

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04 A - How do I know what type of HVAC equipment I have?

You can do this by checking your thermostat to see what wires are HOOKED UP. Simply take the cover off your thermostat so you will see the soldering, circuitry and terminal hookups. You want to look at the terminal hookups. If yours is like most you will have R, C or X, G, Y or Y1, W or W1. If you have a heat pump you would also have either the O or B hooked up (NOTE: these letters are abbreviations for the colored wire used, i.e. R = red, G = green, Y = yellow, W = white, B = brown or blue, O = Orange, C is different it is common) . If you have a multi stage unit you would have W2 and Y2 as well. There are others, but that is basically it. You should also know what size HVAC unit you have. It is measured in tonnage (AC) or BTUs (heat).

05 A - What is multi stage or multi speed HVAC equipment?

Some HVAC units have multiple speeds to help satisfy heat/cool demand faster. Multi speed units can go to a higher fan speed depending on how long an area takes to reach the desired temperature or based on the outdoor temperature. Retrozone carries all equipment needed for multi stage equipment zoning.

06 A - How do I determine what dampers are needed in my zoning system?

You need to know how your ducts are laid out. Best case scenario would be you have one main duct leading to all the other ducts for the area that you want to be zone 1 (downstairs), then the same for zone 2 (upstairs), etc. This is usually not the case, but if you do, you would only need 2 dampers, one for each zone. If you do not have this set up it is not a problem as our Air zone/Flexdamper system often has 5 to 10 dampers per zone.

If you do have several ducts serving any one zone, you should search out what ducts go where and what size they are. You either have round or rectangular ductwork, if round, measure the diameter, if rectangular, measure W x H. This needs to be measured directly on the ductwork, under the insulation. You should draw out a plan of your ductwork, noting the sizes along the way and showing the rooms they go to.

Find the furthest “upstream” you can go on the ductwork and still get all the ducts you must have in one particular zone area (i.e. You may be able to get several of the bedroom ducts on one damper, assuming you are going to make all the bedrooms one zone). Mark all these areas on your plan. This will tell you what dampers are needed to complete your zoning as desired.

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07 A - I am a home owner, can I install a zoning system on my own?

We would always recommend using a State Certified HVAC Technician, however we have sold thousands of systems to DIYers. Our systems all use low voltage electricity and come with very readable installation directions. Those installation directions are available on this site under the "Technical Support" tab.

08 A - Where can I find comprehensive information on how to install a zoning system?

It is a challenge to find HVAC zoning info on the internet, but the installation guide we send with the award winning Flexdamper System is complete. You can find this manual on our web site under the "Technical Support" tab.

09 A - Can I save on energy costs with an HVAC Zoning system?

A zoning system is traditionally sold to increase comfort in a home or office. However, by heating/cooling a smaller portion of your home, at any given time, you will save on energy costs. Zoning systems will allow you to heat/cool only the parts of your home that are occupied at any given time of the night or day. Plus the zoned areas have a faster temperature recovery time, as all conditioned air is going to that zone. It very well could be significant energy savings without giving up comfort.

10 A - How much energy will I save with a HVAC zoning system?

It depends on if you use the HVAC zoning system for energy savings or comfort. If used for energy savings only, then you could save 20-40% of energy costs.

11 A - Can I get more comfort AND save energy costs?

This is one of the best benefits of a zoning system. You get the comfortable air where you need it AND cut down on your energy bill. Compare it to other utilities that are zoned in your home: Lights – you only turn on where needed, not the whole house. Water – again, only where you need it. And Heating and Cooling is a much larger portion of your energy bill each month. By closing off the areas that are not used and putting more of that once wasted air in usable areas, you are satisfying your comfort needs and cutting the unit off quicker, saving more energy costs. More comfort at a lower energy cost.

12 A - You sell many types of dampers. How do I determine which damper to use?

If you have one duct per zone, you could do either the mechanical dampers (spring return or power open/power close) or the Flexdamper System. If the ducts are easily accessed, the motorized damper would be the more economical choice.

13 A - What if I have several ducts per zone?

You would want to go with the Flexdamper System.

14 A - What is the Flexdamper System?

The Flexdamper System is the ORIGINAL RETROFIT and award winning solution to zoning existing homes and smaller commercial applications. Anything you can do with a mechanical/motorized damper you can do with the Flexdamper System. The advantage of the Flexdamper System is it can easily be installed in very hard to get to locations. You can install directly through the register or through the plenum - and there is no need for the perfect cut required on metal dampers. The Flexdamper System is also much more economical when it is necessary to install several dampers per zone.

15 A - How does the Flexdamper System work?

Flexdampers insert into your existing ducts, from the register, plenum, or inline in the duct. Since they are freestanding in the duct, they may be maneuvered around corners or into tight spots. Flexdampers are connected to a solenoid panel and pumping unit. When a solenoid is de-energized, the solenoid switches to pressure, causing inflation, and shutting off airflow in the duct. Flexdampers are connected to vacuum, causing positive deflation with little or no restriction to airflow in the duct. Therefore, the Flexdamper acts the same as a Power Close / Spring Open damper. The bladders are made of military grade, non-expandable (not like a balloon) urethane. These bladders actually can outperform mechanical dampers.

16 A - How do I determine the size of my rectangular damper?

Remove any insulation then measure the outside of the duct’s width and height. You would order by these two dimensions. For example: If duct measured 14” wide and 10” tall, your duct would be 14x10. The stated order of each dimension is important – it should always be W x H. Rectangular Flexdampers (RFD) are ordered in 5 different sizes then field adjusted to custom fit the dampers. RFD sizes go from 6x6 to 24x12. See the Rectangular Flex Duct sizing chart in the Airzone Installation manual.

17 A - What size rectangular dampers do you sell?

We can make virtually any size damper. Call the Factory for unlisted sizes.

18 A - How are the rectangular dampers installed?

If accessible, very easily. You cut a slot in the side of the duct the height of the damper from 2” to 3” wide (depending on type of damper ordered). Slide the damper in the slot. Secure with some sort of weather stripping (if necessary). Screw in 4 sheet metal screws. Wire it up.

Rectangular Flexdampers (RFD) are field cut to size (as detailed in Airzone Installation Manual - available in our Technical Support section) mounted to the ductwork and attached to the plenum rated tubing.