Automated HVAC Vents

Ok, really, truly my last post on this topic.
Good luck with whichever path you choose!

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Yes please! Badly needed. Better yet if these could be connected / controlled based on rules for the temperature sensors per room and or the thermostat.

One solution that may make something like this more viable is the pressure sensor in the vent - not to dump air like most people are suggesting, but to not allow you to close the vent if the pressure is too high. It can work with the thermostat, temperature sensors, and airflow sensors (some installed in the ducts) to allow you to adjust airflow to where itā€™s needed, but not allow you to make adjustments that can cause damage. Iā€™m aware of the maybe-later label, I just wanted to give my input if something like this ever enters the pipeline.

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A product that has been gaining a lot of popularity lately is HVAC zone control. While popular, it is expensive, and the retrofit options are expensive and limited. Plus, many startup companies seem to have disappeared in the last yearā€¦ Iā€™d love to see and purchase a Wyze product that opens and closes room air vents, as needed.

The upstairs of my home is always warmer, as warm air rises. My main level and basement are much cool, with the basement being the coolest level. Although my office is upstairs, it is rarely occupied during the day, so there is less need to cool the whole upstairs, just the main level, and my office. During the night, we like the cooler temps in our room, but there is no need to cool the main floor. In the morning, the main level is much cooler than the upstairs. The option to open and close vents on a schedule would absolutely lower my energy bills. Electric for AC in the summer, and Gas for the furnace in the winter. In Michigan, Spring and Fall would be good times to better utilize the blower fan, rather than using extra gas or electric. This seems like it could qualify for local, state and federal tax rebates. If so possibly bundle in vents, hubs, thermostat, temp sensors in one package, to push more product?

As far as the product goes, a vent cover that can replace existing vents, would be ideal. Battery options are nice, but having to charge them, I see that being a painā€¦ A low profile usb cable might be the best option. Maybe a magnetic wireless battery charger for ceiling vents? Easy to put up at night with an extended stick type thing, then pull down in the morning? Controlling the vents should easily tie into current systems with temp/humidity control and the thermostat. An option could also include a sensor that measures air quality? Or an option like vehicle oil change, where youā€™re notified when to change your furnace filter, which doesnā€™t actually require a sensor.

A downside to this would be possible liability with existing furnace blower systems? It might depend which type of furnace or furnace blower that you have, such as variable speed. Closing too many vents could hurt the furnace. So possible HVAC systems from year XXXX and up are OK? Models _____ are good to use this with? Too many different vent sizes could make manufacturing expensive?

The pressure issue is something that keeps getting mentioned, and rightly so, but most of the current vents Iā€™ve researched mention their vents all monitor the pressure . This monitoring prevents the vents from over pressurizing the HVAC system and causing damage. So this feature request should have a built in pressure monitor and limit/prevent homeowner from closing to many vents .

Hereā€™s a FAQ answer Flair on how they deal with this:

Flairā€™s Back Pressure Protection limits the number of Smart Vents that can be closed at one time. Flair will never close more than 1/3 of the total vents in a system - this is based on the total number of vents in your home, not just Smart Vents. This has shown to be safe by a Lawrence Berkeley National Labs study. To go further, we used a 100% safety margin over their conclusions.

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Basically, they need to replace Keen which is what I have. I use Keenā€™s app and EcoBee thermostat app as well as Samsung Smart Things. Until Wyze came along, I kept all my devices compatible with SmartThings so I could use one app. Now, I prefer to use Google Home and Wyze. So, a good venting solution might be worth it, but I have not installed Wyze Thermostat yet, since it does not have linked sensors for temperature to be place remotely. I currently use the sensors to balance throughout the house when to turn on and off the HVAC.

Iā€™d love for yā€™all to produce a line of HVAC smart vent to enhance your thermostat. Any plans? If I ask very nicely maybe?

A person should really understand the application and also understand the HVAC a lot more than the average homeowner does. Pretty easy to frost up a cooling coil or overheat a gas burner by not doing this exactly right. Most home furnaces arenā€™t designed for variable volume.

@BillG-MN
I did that exact thing before I educated myself more on the topic. I closed off vents in rooms i didnā€™t use, however this caused not enough air being pushed through and the heater would shut down. Opened some vents and it ran fine.

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Exactly. It gets rough on equipment. Wait until someone closes the vent for the room that the thermostat is in, and listen for the complaint about the thermostat not working. LOL

Would like to see you integrate your temp sensors and thermostat controls with powered vents to control where the air flows in the house based on the temp sensors.

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So I would also really appreciate a product (system of products) that could help with this problem. After reading some comments about solutions possibly worse than the problem I now understand that the solution would have to be, not smart, but very, very clever. Withe the right family of products itā€™s still doable, but thereā€™s more to it that just sensing a room temp and opening and closing ā€˜smart ventsā€™. There would also need to be a way for the clever system to sense furnace temp to open more vents to void heat as necessary? The same might be true to an extent to keep compressors from freezing up? Deep HVAC question, does or can the thermostat receive that data from heat/cool units? If not, a way for the central units to communicate with clever vents would have to be created. Iā€™m assuming the installation of those sensors is beyond even above average DIYers.

There are smart vents (Smart Vents | Flair). I need to do more reading on that site to see if they address those issues. Obviously if you have a room that gets a bit too cool in summer or warm in winter, a single smart vent works. If the opposite is true, thatā€™s when the central unit issues arise, right?

I might vote for Wyze to enter that arena, with caveat: that an entire system is engineered to address issues, and/or huge, giant big fat warnings on the product page, packaging and installation instructions.

If the system came to fruition, I would strongly suggest that the vents be rechargeable. The port would need to be on the face so that I just have to plug it into the nearest wall socket.

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I would also recommend that the vents can be hard wired for power from a power brick or from the HVAC system directly.

As fas as Iā€™m aware, thermostats are just fancy switches from the HVACā€™s perspective, and donā€™t receive any information from it. That said, I believe they are able to work with installed temperature sensors, if wired to the thermostat.

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If you look at some of the big players in smart thermostats they already integrate with smart vents. I donā€™t think you do every vent in the house but maybe i want to reduce flow in one room for sleepingā€¦

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Iā€™d like to make a few general comments about this type of system. As a professional control system engineer for 40 years or so before I retired, I designed systems like this on a daily basis. Many commercial buildings have this type of system, where the thermostat controls air volume delivery into a room, based on the cooling or heating demand. A system like this has a name. It is called a VAV (variable air volume) system.

VAV systems are not terribly complicated, but there are some important design things that must be done right for them to work. Just putting a damper on a duct probably wonā€™t solve perceived problems, but might make them worse. Pinching off a few ducts increases the pressure in the ductwork. This does not make the system more quiet. It makes it louder, and might even make some rooms whistle. Partially reducing the air flow to one room reduces the air velocity coming from a diffuser. As a result, the air is not thrown across the room as designed, but rather, spills out of a ceiling register straight down in a thin air stream. If this is onto your bed or desk, you will be less comfortable, not more comfortable. If the register is in the floor, the cool air might just pool around the register instead of being distributed around the room. At least your feet will be cold. If your furnace can deliver both heat and cool, be aware that when heating, the damper opens on a call for heat and closes otherwise. When the furnace is delivering cooling, it is just the opposite. The thermostat has to know what the furnace is doing.

When zones start to close, pressure builds up in the duct, which is not desirable. In commercial buildings, mostly, the pressure in the duct is measured, and the fan speed is adjusted to maintain the correct pressure. In some ā€œel cheapoā€ systems, a bypass damper between the supply and return is installed to control duct pressure. The first design reduces energy consumption. The second does not.

There has been plenty of discussion about reduced volume causing the cooling coil to frost over. There has been little discussion about reducing volume to a condensing type burner, which can cause serious damage to the PVC flue, by exhausting too hot of combustion products.

All of these considerations and others are routinely dealt with in a professional design. But you should see the abortions put together by heating and cooling contractors who think they know what they are doing. Iā€™m not sure that it is a good idea for a person to hack one of these together without knowing the full deal.

For what it is worthā€¦

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Here is an idea. On Amazon, you can find vents that have fans built in them. They pull the air from the vent which doesnā€™t have as much hot or cold air coming out of it pulling the desired air into the room.

AC Infinity AIRTAP T4, Quiet Register Booster Fan with Thermostat Control. Heating Cooling AC Vent. Fits 4ā€ x 10ā€ Register Holes. https://www.amazon.com/dp/B0792QR5YT/ref=cm_sw_r_apan_glt_fabc_RB5E78NDEYFCVV28TRHD

thank you for your professional insights! I do have a question about the duct work and itā€™s efficiency. While doing some research on Aeroseal, a duct sealant that is injected into the duct work to seal up gaps, and read numerous articles about how if your HVAC was installed mid '80ā€™s, or older, that your system is at best 40% efficient. The claims are that most of this duct work has leaks that prevent the system from operating optimally.

If the duct work is leaky, would this offset any potential pressure issues when using smart vents? I know I found some sizable holes in my system and used aluminum duct tape to seal as best as possible.

Thanks!

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@thecasesā€¦ I think the 40% number that you are quoting is somewhat creative on the part of the duct sealing company. The furnace is probably in the 80% range. In most cases, heat lost by leaky ductwork is still heat gained by the house, even if it doesnā€™t go where you want it to. The exception would be duct leakage into a space like an unheated, vented attic, which is a real possibility with some of the plastic flex duct I that I have seen in such spaces.

Big leaks can be a problem, preventing the pressure from building high enough to distribute air down some branches. But if they are leaking into the house, it is not really inefficiency because it is still heating the house. Big leaks to the outside go to heat the outside, not the house, and would be considered inefficiency.

If the ā€œsmartventsā€ close off some of the registers in the house, as you have mentioned, pressure will build in the ductwork, and the leaks will leak more, including any attic leaks. I donā€™t think the fan in a typical residential furnace can build up enough pressure to cause damage, but it sure can cause whistling noise, which will reduce your comfort.

For what it is worthā€¦

So maybe not having the fans, but open and close control based on using the hub/sensors to maintain temp in each room. Sensors by themselves donā€™t really provide anything but a snapshot of temp. But if integrated into a ā€œautoā€ open/close vents, helps control rooms temps (cheaper development than fans). Just a 2 AA batt motor.

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