About
FROSTI (the Financially Responsive Open-Source Thermostat Initiative) is a Raspberry Pi-based thermostat that monitors the local spot market for power and changes temperature targets to minimize power usage during periods of high prices.
Features
- Real-time monitoring of local power-price
- Web-based configuration
- 2.9” e-paper display clearly visible from a distance
- LED indicators for mode changes
- Full RESTful API for monitoring status and controlling from remote
Today, FROSTI works with GoGriddy, but can be extended in the future for other power markets.
Motivation
I love the idea of having electricity priced based on supply/demand. It wasn’t long after a few friends told me about GoGriddy that I signed up. Starting in January of 2019, I was easily saving 20% or so relative to available electricy plans. Everything was going according to plan.
Then in August of 2019, Houston (where I live) experienced record heat combined with electricity generation capacity shortages, causing massive spikes in prices. There were several times that month where prices got to $9/kW*h, costing me around $100 in a single hour.
My motivation is very simple. Air conditioning is by far my biggest source of power consumption. If I can curtail usage during periods of high prices, I get the benefits of cheap power 99.95% of the time and de-risk the other 0.05%, and I come out a winner.
Future Work
FROSTI is about far more than just lowering your power bills. The data that comes from FROSTI is valuable for things like:
- Sizing a next A/C system (e.g. how many ‘tons’)
- Knowing whether your A/C system is short-cycling
- Knowing how changing your temperature targets affects HVAC usage
Also, with the addition of remote sensors, we could do things like:
- Balance HVAC for additional rooms
- Monitor the temperature of air coming out of the ducts, potentially catching problems
- Monitor the air speed at the ducts, potentially notifying the homeowner that airflow is impeded (e.g. filter needs changed)