When Target Temp and Current Temp is 73, Home Assistant shows 72.

[hollywoodscotty]

Setting Target Tempurature to 73* F in Home Assistant, the number shows 73 in red for a moment, goes white, then shows to 72. Current Temperature shows as 72. On AprilAire app, temp and target temp are indeed 73. It appears my temps are off by 1 degree. However, when I set the target temp to 76 in Home Assistant, it stays 76 in Home Assistant, and the app also shows 76, so this issue is inconsistent. Device is 8840M.

[chamberlain2007]

@hollywoodscotty Which version are you using?

[hollywoodscotty]

Owner

In HACS I see 0.7.0. Under device info I see Firmware: 3.03 and Hardware: Rev. H

[chamberlain2007]

@hollywoodscotty Thanks for this report. I was finally able to find the issue. Resolved in #30 which will be the 0.7.1 release. It is currently in testing and will be released in a few days when I am comfortable with it.

The problem here is with the conversion between Celcius and Fahrenheit that HA does and when it rounds. Basically:

• The thermostat is always Celsius. It reports the 73F as 22.5C
• We report the temperature as 22.5C to HA
• HA converts 22.5C to 72.5F and then rounds it to 72 (Python rounding is toward the even value, hence 72 not 73)
• HA displays it as 72F

To fix this (without trying to modify HA core):

• The thermostat is always Celsius. It reports the 73F as 22.5C
• We convert the 22.5C to 72.5F then add 0.01F to push it over. Then convert back to 22.51C
• HA converts 22.51C to 72.52F and then rounds it to 73
• HA displays it as 73F

It's hacky but it works.

Thanks again for the report.

[hollywoodscotty]

"python rounds to even" that's bananas, but excellent catch. Thank you!

[chamberlain2007]

According to the docs https://docs.python.org/3/library/stdtypes.html#numeric-types-int-float-complex

round(x[, n]) | x rounded to n digits, rounding half to even. If n is omitted, it defaults to 0.

In C# which is my day-to-day language, it also rounds to even by default, however it also has a parameter for specifying the midpoint rounding, eg

double temperature = 72.5;

Console.WriteLine(Math.Round(temperature)); // 72
Console.WriteLine(Math.Round(temperature, MidpointRounding.AwayFromZero)); // 73
Console.WriteLine(Math.Round(temperature, MidpointRounding.ToNegativeInfinity)); // 72
Console.WriteLine(Math.Round(temperature, MidpointRounding.ToPositiveInfinity)); // 73
Console.WriteLine(Math.Round(temperature, MidpointRounding.ToZero)); // 72