Jan 07, 2022 / HVAC

We hear this all the time!

“I have the thermostat set to 70, but the upstairs is 78!”. This is a common issue in the winter when the temperatures drop, or in the summer when the temperatures go up. While there are a number of solutions, all of the solutions vary based on a number of factors. Your homes duct system layout, the type of heating and cooling equipment you have, or whether the system is zoned or not.

We will take you through each option and dispel some “quick fixes” that might actually damage your heating and cooling equipment.

Your Duct System Layout

In a perfect world, all homes would have ductwork in the floor for heating and ductwork in the ceiling for cooling. That isn’t the reality. 2-story homes have a variety of ductwork layouts, especially here in Indiana. Some have all the vents on the main level and second level in the floor, some have all the vents in the ceiling. Others have the main level vents in the floor and the second level in the ceiling. Is there a perfect setup? No. However, from an HVAC standpoint, we can typically work with the third option the best. Having vents in the floor on the main level and in the ceiling on the second level means that we can, more than likely, add a zone system to the heating system to allow to close a damper for the upstairs vents if the space starts to “overheat” in the winter. The same goes for the summer, it can close the damper on the main level and force air upstairs to cool down the space while maintaining the temperatures on the main level. This is done by adding a thermostat upstairs and connecting it to a zone control board and dampers. For more information on a zone system, please contact us.

Type of Heating & Cooling Equipment

We mentioned a zone system above. Zone systems work best with specific types of heating & cooling equipment. Primarily 2-stage or modulating furnaces/air conditioners or heat pumps. Basically, most heating and cooling equipment that is installed when a home is built is what’s referred to as “single-stage”, meaning, it’s either ON or OFF. 2-stage equipment has the ability to run at 60-70% of it’s capacity when one of the zones isn’t calling. 2-stage equipment also has the ability to run at 60-70% of its capacity on mild days. So, on a 40 degree fall day in Indiana, your 2-stage furnace can run at a lower capacity and provide more even heating. Consequently, a 2-stage air conditioner can run at 60-70% capacity on a 70-degree spring/summer night and help dehumidify the space.  This helps with more even heating/cooling as well as prevents the frequent starting and stopping that a single-stage unit. A modulating performs similarly to a 2-stage unit, but has anywhere from 3 to 65 stages of heating or cooling versus only 2. Lastly, simply putting a 2-stage or modulating furnace in without zoning, can help, but it is recommended to zone the duct system if you can. Particularly if the home is more than 1-story or has multiple levels.

Is zoning an option?

While zoning is a great option in most homes. The question becomes, can you zone my home. It’s hard to answer without visiting the home. We have to determine the duct system layout, home layout, ability to get a thermostat upstairs, etc. In most cases, it is possible. Especially in newer 2-story homes where the furnace is in the basement, the ductwork for the main level is in the floor, and the ductwork for the second story is in the ceiling. We know our chances are good to be able to zone those homes. However, some older homes may require a supplemental heating or cooling system for the upstairs due to the poor duct design. Most older homes with ductwork in the floor on the first and second floor may require some supplemental heating or cooling for the upstairs. Whether it’s by way of a ductless heating and cooling system, or a conventional heating and cooling system.

Will closing my vents force more air to other parts of the home?

No. This is a common misconception. Closing the registers or “vents” does not force the air elsewhere. The air still has to travel down the entire length of the run and then the air just dies at the end. Zoning is different because you are blocking the air at the source (close to the furnace). Closing the vents can cause bigger issues with your heating and cooling equipment. Now, if you close a couple of vents, it’s not going to technically hurt anything. However, if you close too many, you can put strain on your heating and cooling equipment. If too many vents are closed, it can cause your fan (aka blower) to work harder to move air through the duct system. This can mimic the symptoms of a dirty filter, which as we all know, is terrible for your heating and cooling system. Lack of air flow can cause your furnace to overheat and over time can cause damage to the furnace resulting in a cracked heat exchanger. In heat pump systems or with air conditioning systems, it can cause the system to ice up. If the system ices up, the blower can’t breathe and can damage more components such as the coil and/or the compressor. All of these things are costly to repair when out of warranty. So, if you want to close a couple of vents (2 or 3) you shouldn’t run in to many issues, but be mindful of them. The more open they are, the more the system can breathe.

Will running my fan in the “ON” position help?

This question is relevant to a number of things. Are you heating or cooling? How is your duct layout? Do you have a zone system? In some cases, this can help tremendously. In others, depending on the duct system layout, it won’t make much of a difference. Going back to what we said about the different types of equipment, a single-stage furnace typically has a single-stage fan/blower that pushes air at 100% of it’s capacity and, to some people, this may feel drafty. But, it will certainly circulate the air. The 2-stage and modulating furnaces typically have a variable speed fan/blower that can slow down to just a trickle and will help move air constantly through the space and maintain a more even temperature, without feeling drafty. At Control Tech, we do recommend running your fan in the ON position during heating months and AUTO during cooling months. The reason for AUTO during cooling months is due to humidity. Some homes are more humid than others. When your air conditioner runs in the cooling months, it heat and moisture are removed from the home. This moisture accumulates on the indoor coil. After the cooling system shuts down, there is still moisture on the indoor coil. If the fan continues to run, it can push that moisture off of the indoor coil and back in to the home, basically defeating the purpose of dehumidifying the home. If the fan is set to AUTO, it will shut off after the cooling cycle is complete and the moisture is able to wick off of the coil and dry out.

How much is this going to cost to fix?

Just like the answers above, it all depends on what you need. We always recommend a free estimate by one of our Design Techs to ensure that we are giving you the best solution possible. We never want to assume that a zone system or a new heating/cooling system is the fix before we lay eyes on your setup. As of January 2022, if you need a manual damper (one that can be controlled by hand) these can run from $250+ (each) installed. However, a zone system can be a better investment. Zone systems, in the Indianapolis market, can range from $2500+ depending on what is needed. Keeping in mind, installing a standard zone system with 2 wired zone dampers, 1 zone control board, and a new thermostat can take 2 technicians 4-8 hours to complete. It’s not just the equipment that you’re investing in, it’s the installation and dedication from our technicians.

Other factors

Don’t forget, there could be other factors causing issues with uneven temperatures. Lack of insulation, leaking windows and other forms of infiltration, undersized ductwork, not enough window shade, single pane glass versus double pane, etc. Never rule these things out. Having a blower door test can be recommended as well.

If you have any questions or would like more information, please contact us or call us at 317-873-3737!

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Control Tech is a residential & commercial heating, air conditioning, geothermal, and plumbing contractor located in Zionsville, Indiana. Since 1983, Control Tech has been a leader in the HVAC & Plumbing industry, and proudly serving customers in Indianapolis and all surrounding communities.

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