I thought I'd try to put a little more analytics behind how much it costs me to have WeatherCat running with my out-of-the-ordinary usage case which only uses WeatherCat to collect data, display desktop gauges, and perform ad-hoc data inquiries upon occassion. I love that WeatherCat already retrieves history data from my Davis WeatherLink each time WeatherCat starts to bring my local database up-to-date. The net is, it isn't a lot of money each year, but with WeatherCat now preventing sleep on my iMac and my asking it to collect local data every 2 minutes, it does add approx 34% to the energy consumed when I'm not using my machine.
For those interested in a little more detail, here you go. It's not super-scientific, but IMHO beats the anecdotal guesses I (and I suspect others) tend to make about situations like this.
Environment:
- 27" 5K iMac, 4 GHz i7, 16GB, with SSD -- running macOS Sierra 10.12.3
- Davis VP2 Plus, WeatherLinkIP set to 1-minute logging
- I purchased a Kill-A-Watt to measure kWh used on my iMac in two 8-hour scenarios
-- 1) My normal apps (Mail, iMessage, etc) with macOS Energy Savings ON to wake on network access, turning the display off after 5 mins, and putting disk drives to sleep when not in use. WeatherCat was NOT running. I did not otherwise touch or interfere with macOS during this 8-hour period.
-- 2) Same environment as above, but with WeatherCat RUNNING. WeatherCat only collects data on 2-min intervals, and I allow it to collect more often if it determines the need. It also has 8 custom gauges displaying on my desktop, but otherwise, no other functions most users utilize (weather site uploads, banners, FTP, etc) were enabled.
- I generally have my iMac turned-on for ~15 hours/day, and while the time I'm sitting in front of it varies, for this purpose I estimated 3 hours of use/day/365-days per year when macOS would not otherwise be sleeping. I assumed WeatherCat would be running for the time I was using macOS.
- My electrical rates vary for 6 months of summer vs winter, and also by time-of-day, so I took that into considerations in the cost extrapolation.
Summary
With my setup, WeatherCat consumes approx 0.041 kWh additional energy for what I am asking it to do. Extrapolating for my varying costs of energy and without taxes and other tariffs, that's about $24.29/year of additional energy cost that really isn't necessary in my use case (because WeatherCat catches-up data recording from logger history upon startup).
While it seems perhaps ridiculous for less than $25/year savings, I have recently started to try and remember to manually shut WeatherCat down when I am leaving my iMac for an extended period. I already had WeatherCat automatically start when I login to macOS, so it will catch it's database up the next morning, or when I start it again manually during the day. My original thought with this request still stands ... while perhaps the die-hard WeatherCat users may not make use of this new functionality, some outliers like myself and perhaps a future set of users would, and we'd save a few ongoing pennies of energy at the same time.