# DIY Controller for radiator fans **URL:** \ **Category:** Hardware\ **Created:** [9 October 2024 11:13 UTC](https://community.openenergymonitor.org/t/diy-controller-for-radiator-fans/26865 "2024-10-09T11:13:04Z")\ **Posts on this page:** 1\ **Showing post:** 22
**Author:** ![Timbones](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/timbones/32/20308_2.png) [@Timbones](https://community.openenergymonitor.org/u/Timbones)\ **Post date:** [14 October 2024 17:28 UTC](https://community.openenergymonitor.org/t/diy-controller-for-radiator-fans/26865/22 "2024-10-14T17:28:02Z")
Nice experiment. Another method would be to use the feature in My Heatpump app to estimate emitter size with and without the fans. I reckon my fans increase output by about 1kW. > [@Infer radiator spec and system volume using the MyHeatpump app](https://community.openenergymonitor.org/t/infer-radiator-spec-and-system-volume-using-the-myheatpump-app/24798/5): > > Very interesting, Trystan. I’ve been playing with this all week and it seems to match [my system](https://heatpumpmonitor.org/system/view?id=1) quite well. I calculate I have a total radiator output of 16,655 W, and the app gives me figures around there. Some of my radiators have fans fitted to them, and I estimate they increase output by 25% on those radiators, taking the total output to 18,000 W. This morning started with 2 of the radiator fans not running (17,000W), and switched on at 6am. You can maybe see the effect they had on [this h…](https://emon.cryosphere.co.uk/app/view?name=AirSourceHeatPump&readkey=bb72ba957b02fecf8fb85fb1d2868782&mode=power&start=1700106950&end=1700119570) --- _[View the full topic](https://community.openenergymonitor.org/t/diy-controller-for-radiator-fans/26865)._