Previously we were finding a lot of HAVEN Monitors were seeing pretty crazy swings in their relative humidity and temperature data whenever the air handler would turn on or off.

  1. When turning on, the RH and temps would start high and then come down to what seemed like reasonable interior levels.

  2. When turning off, the RH and temps would rise up very quickly back to these seemingly hot and sticky levels.

Before - RH & T - Horizontal.png

Initially, we thought this was due to the air being stagnant in the duct: logically, without airflow, humidity and temperatures could be rising in the return. Especially in places that are experiencing higher outdoor temperatures than ever before.

HOWEVER. This year we did some more digging and found that there was actually another factor at play! The Monitor itself! It actually has some self-heating tendencies that have affected the sensor readings in homes where the air handler cycles on and off. It wasn’t affecting homes that have continuous airflow, because this is what was cooling the Monitor.

GOOD NEWS #1. We have only ever used the data when airflow is ACTIVE to control equipment. This is good to know because IF THIS WASN’T THE CASE, we’d have been activating dehumidifiers based on higher than accurate RH and T, which would have caused them to run basically as soon as the air handler cycles off… so a lot.

GOOD NEWS #2. We have now characterized the self-heating of the Monitor, which will now be compensated in the readings. Compared to reference devices when fan is both on AND off, our new advanced algorithms achieve:

  • an average temperature reading accuracy of 1.5ºC

  • an average relative humidity reading accuracy within 3%

After - RH & T - Horizontal.png

That pretty much meets the accuracies of what your trusted psychrometers promise. Of course, you’ll still have the option to calibrate the sensors during installation, and we’re even in the process of developing new post-install workflows that will allow you to take new measurements when you’re in the home for other maintenance purposes.

What to expect in the readings going forward…

You’ll notice a teeny bump when the air handler cycles on and off, but nothing that should cause an alarm. This will hopefully reduce any nuisance calls you may have gotten from your customers.

We recommend the next time you are at your customers' homes to take a measurement and see for yourselves how the new compensation is being applied. There may be a couple tweaks needed in certain cases for previously installed devices. For new installations, you should see the magic right away, set it and forget it.

Hope this gives you enough insight into the work we’ve done to make sure our products meet your high quality and reliability standards. We’re a small team, and we care a lot about you.

Happy monitoring and controlling!


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