Periodic Blower (Fan only) Cycle
Answered
I have my ecobee set to run the fan a minimum of 5 minutes every hour. This really helps get 'stale' air moving and prevent odors from accumulating in any room.
This seems to be an unanticipated challenge for Flair. Regardless of my Home / Away status, I want all my vents open when the blower kicks on (without A/C or heat).
In it's current state, however, this isn't possible. When a room meets/exceeds it's setpoint or if AWAY, the vent closes, meaning the blower cannot vent that room.
Ideally, I need Flair to integrate into ecobee (and other thermostats) to watch for anytime the AC/Heat is NOT running and open all the vents.
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Most systems use the fan to circulate conditioned air as an efficiency measure after the heat/AC cycle.
The feature you refer to is called 'Heat/Cool Dissipation' in ecobee. When that setting is 'Auto', the HVAC system, there is no call for FAN outside of the call for HEAT/COOL. However, you can manually set the value to X seconds, and the thermostat will issue a call for FAN after the HEAT/COOL call is released. I admit there may be some difficulty in differentiating between that brief period and a FAN ONLY period. If that ends up being a problem, just make sure to outline the limitations in the documentation for the new feature.
Aside from ecobee’s min fan setting, do you know how often your fan runs in a typical day?
I don't understand your question. I've told my ecobee to run the fan X minutes each hour using the 'Fan Minimum On Time' setting. Outside that, it runs anytime I have a call for HEAT/COOL, but that is driven by the HVAC, not the thermostat.
Thus, for my situation, the logic can be as simple as 'open all vents during any call for FAN'
Others may have older thermostats that require FAN + HEAT/COOL when heating and cooling, but that's easily differentiated by watching for aux1heat, aux2heat, cool1, cool2, etc. in the ecobee API. The API returns Equipment Status:
- heatPump
- heatPump2
- heatPump3
- compCool1
- compCool2
- auxHeat1
- auxHeat2
- auxHeat3
- fan
- humidifier
- dehumidifier
- ventilator
- economizer
- compHotWater
- auxHotWater
You would just watch for 'fan' without any of the associated heating and cooling methods.
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I'm with Ken on this. My home tends to have big swings in heat/cool. My basement gets down to 65 degrees in summer and my office (south facing) gets upwards of 85 degrees at the same time. Both are usually occupied and it causes problems with flair and ecobee to work together well. With a call to the fan only from Flair and then using the vents to direct basement air back to the blower and send it upward to my office seems like an efficiency would be gained (not just for me but for everybody using flair). Seems quite limited to only have a fan call when heat/cool is also on. Also, a button within the flair controller for all open with a timer (15 minutes, 30 minutes...until I change it) would be a great addition for those of us who like to circulate air at certain times.
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Sam,
To your question of "how often your fan runs in a typical day?" here's an example: our fan runs nearly 90% of the time. Here's an example ecobee report from the last 7 days showing the number of seconds the fan is on and the number of seconds the heat is on. You'll notice that the fan is blowing a lot, even when the heat is not on. https://www.icloud.com/iclouddrive/0rAaIN0Sg_aKYKD3sIQWKP4Ww#tstat-report2021-02-01-to-2021-02-08 This is primarily to support air filtration. It'd be great if the flair vents could recognize when the fan is on in fan only mode and open the vents to facilitate that air circulation for filtering purposes.
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This is a long thread that has been going on for over a year. Since the API calls are pretty straight forward, why can’t flag / option be added to “open vents during fan”. Done.
I am not understanding why this can’t be added in an afternoon by the devs vs me building my own calls. Let’s make it happen guys.
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Indeed - it looks like this thread has been around for a while. I am running into the issue described above as well. Let me describe my use case:
The house is equipped with both forced air cooling and heating. The climate is such that winter is all heating, summer is mostly cooling, and fall and spring you can have heat in the morning and cooling running in the afternoon. My objective is to even out temperature across 3 levels of the house. Before installing Flair this has been done by running furnace fan all the time at 40%. This gets the temperature within 1.5C between top and bottom of the house during the heating season and within 2.5 - 3C within the cooling season.
After installing Flair vent and puck in the coldest bedroom on the lowest level my temperature differential actually went up to ~4C. The reason for this is that when cooling kicks in during the day Flair vent shuts and does not open until a heating cycle happens - usually next morning. In the meantime the bedroom no longer gets the benefit of air circulation from the furnace since the vent is shut - despite the fact that the room temperature is 2 -3C below set point and that Duct Temperature is 1.5-2C higher than the room temperature.
In my use case, if Flair was to ignore all the thermostat input (other than the global setpoint) and simply opened the vent when room below or above the setpoint by, say 1C, and duct temperature is above or below room temperature - say by the same 1C. This way, if there is temperature difference between vent and room that can bring the room closer to setpoint open the vent; otherwise close it.
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To add another thought to the above: I would love to see a feature that allows me to configure each Flair Vent with the maximum percentage open setting. This way the vent is either closed, or when opened it is opened to the maximum setting. This allows for compensating for the shorter air duct runs closer to the furnace that notoriously get hotter air when heating and colder air when cooling and it is coming at a higher velocity due to the proximity to the furnace.
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I mean ideally it would work off of the ecobee sensors/pucks. For example:
Set temp 72
Room 1: 71
Room 2: 65
Room 3: 78
Room 4: 73
Room 5: 72
room 6: 62
Room 7: 79
In this sense the average is approx 71.5 which will not initiate a call to ecobee, however, if flair was able to see that the rooms with largest delta to open and start the fan it could balance them out. In this example it would be room 2,3,6,7. Ecobee could just turn on the fan and redistribute the air to these rooms. This seems like a simple coding exercise. Does Flair have anyting like this in the works?
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As you contemplate those options, please also consider how Flair knows if a fan-only cycle or in-use/not in-use is currently happening.
- When Flair controls everything, it's obvious is Flair is calling for fan or something else or nothing.
- When Ecobee (or another connected thermostat) is controlling, the integration can determine what is going on.
- When some other thermostat with no integration is controlling equipment, it's obviously more difficult.
Something like a duct temperature delta combined with the settings above might be enough. A heat or cool cycle both produce a much larger duct temperature difference that just the fan running. Using that combined with the settings above could achieve similar result.
In my current setup without a connected thermostat and Flair set to Mode Auto Heat/Cool, when a fan only cycle runs, the Flair system seems to assume the house is heating. This opens up the cold basement vents, as the vent air is slightly warmer than the room. It keeps the few upstairs vents closed, as those rooms don't need heating. But, it's not entirely clear why Fair assumes the house is in heating mode. It would be more accurate to assume it's in a fan mode and neither heating nor cooling and then take action based on that.
I have 3 pucks. With 1 in the cold basement and 2 upstairs. But, 7 vents in the cold basement and 2 upstairs. The vent temp is above all the room temps, but only by a few degrees. When an actual heating or cooling cycle runs, the vent temp is significantly more than 15, probably more then 20 degrees different from the room temps, larger difference when heating but still substantial for cooling.
This unconnected configuration does mean my cold basement vents open and allow air exchange with the warmer upstairs rooms when the fan only cycle runs. At least for the upstairs rooms that don't have Flair vents. I replaced exactly 1/3 of my vents with Flair, so they can all close if needed.
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There may be two distinct scenarios based on Flair capability to make call for heat / cooling / fan. Assuming that Flair is in passive mode - it can detect whether thermostat calls for heat / cooling / fan, but cannot request it, the setup when Flair compares the air temperature at the vent with room temperature and decides to open the vent if the delta moves the room temperature towards the setpoint may be the safest option. If Flair can actively request heating or cooling from the thermostat this opens additional possibilities for setups (like mine) where there furnace fan is in always-on mode recirculating air and in auto mode heating or cooling depending on the need; in this scenario Flair could actively even out temperature by calling for heat with only the vents in cold places open or calling for cooling with only vents in the warm room opened.
Note, that in my observation Flair switches from heat to cool mode depending on the last call from the thermostat. This means that after a heat or cooling call the vents that were closed remain closed and the ones that were open remain open. However, the furnace keeps circulating air afterwards and this arrangement misses the opportunity to even out the temperature across the house.
I would love to test the experimental feature mentioned above: "we're testing where your Smart Vent can look at the air temperature coming from the fan and measure this against the temperature seen in the room". It sounds like it would take care of my issues around equalizing the temperature across the house. If the trigger points are implemented the right way the system should be able to open the vents for ventilation when the temperature has equalized.
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I have 14 Flair vents installed out of 18 registers. Still my basement is consistently 3 degrees colder than the rest of the house because of stratification (and probably an insufficient air return in the basement?) I appreciate that I am now not freezing in my office while my partner is sweltering in his (he gets the sun in the morning). But if the basements vents opened when the air is recirculating I think this would help curb the stratification, and possibly save on energy by forcing more cold air to be recirculated through the house.
Flair can and should be smarter (and greener)
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Another EcoBee example here.
Our bedrooms are configured with Flair vents and pucks.
Last year we changed out the old heat only system for a full heat pump based HVAC. The system has UV and ozone filtration.
We have the blower configured to be on 50 to 55 out of 60 minutes. This is great for the rest of the house, but the bedrooms are more often than not, failing to circulate air thanks to remaining closed. This recirculation concept seems like something that would be fairly important to address with a feature update.
Finding this thread is more than 2 years old, does not inspire confidence. Taking recent pandemic delays into account… it's still overdue guys.
Folks here, have taken the time to detail this pretty thoroughly, and I'm a bit surprised there's no (apparent) impetus to move on this important efficiency update. The system is essentially defeating the health benefits of the filtration system for these rooms.
Our installer recommended removing the vents, since they do not seem to support the recirculation recommended by the HVAC manufacturer. We kept them, but now that we've had about a year with the HVAC changes, I'm leaning towards removal and would not recommend. This is solely based on the missing fan only recirculation feature discussed here. If this were to be implemented, this would again be a "complete solution." As it is, it has only really been helpful for us when we had an overpowered heat only system.
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Hi Chris Traeger,
Thanks for reporting. This has been fixed and should be working now.
All the best,
Finn
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I'm thrilled to learn about this new setting! I'll experiment with Active Vents vs All Vents and will try to remember to report back what I learn to this post. A question I have is, "Will it work for both fan-only and my humidifier?". I have a whole-home-humidifier that, of course, operates independently of any fan-only settings. I look forward to seeing if closed vents open when the fan or humidifier activates and there's no other call for the vents to open, such as for heat or cool.
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Cullen Ponte, if I understand the feature correctly, Enhanced Circulation will open either all vents or active vents (depending on the selected mode) when Heating or Cooling is not actively running on the thermostat. Any 3rd party integrations, such as a humidifier connected directly to your plenum's fan controls, would continue to operate as they did previously. If the heat/cool cycle is in process then the humidifier would apply to air already running through the plenum. If heat/cool is inactive, the all vents would open and the humidifier would operate through all the vents.
A slight caveat here - the opening and closing of vents isn't instantaneous. There can be a few minutes of delay between when the heat/cool cycle ends, flair sees that it ended, Flair issues a signal to the vents to open, and the vents actually open. I don't see that as a dealbreaker however. There will still be open vents from the previous heat/cool cycle while the remaining vents a queueing up to open.
EDIT: I'm second guessing myself here. Maybe Flair Customer Support can weigh in and verify what I said is correct or counter it with the correct functionality? Do vents open when not heating/cooling or was is strictly when 'fan only' was in use? If the latter... I don't think that will work well for humidifiers/dehumidifiers.
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