San Gabriel Valley, California
The house, the system, the power behind it.
JoyfulHouse is Kofen Chang on real estate and Bryan Li on smart home, energy, and engineering. We sell the house, wire it, and power it — and we build the technology we install.
12+ years
Real estate experience
CalRE# 01951860
Licensed agent
EG4 certified
Solar + storage installer
17
Open source projects
Real estate
San Marino · South Pasadena · Arcadia · Alhambra
Homes we actually know.
Our real estate practice is led by Kofen Chang, whose intimate knowledge of the San Gabriel Valley has guided families through some of the most significant transactions of their lives. With a consultative approach grounded in market insight and personal attention, we help clients buy, sell, and invest with clarity and confidence.
- Buyer representation with personalized home search
- Seller services with professional staging and marketing
- Investment property analysis and portfolio guidance
- Deep knowledge of San Marino, South Pasadena, Arcadia, and Alhambra
Smart home
Home Assistant · open source
A house that runs itself.
Bryan Li designs intelligent living environments using Home Assistant and open-source automation. From lighting scenes and climate control to security systems and energy dashboards, every installation is tailored to how you actually live — not a one-size-fits-all package.
- Home Assistant setup, configuration, and optimization
- Custom automation and sensor integration
- Energy monitoring and smart dashboard design
- Open-source integrations: Moogo, Spintouch, IntelliCenter
Energy
EG4 certified · SolarEdge · Enphase
Power from your own roof.
We design and install solar panel systems and battery storage that meaningfully reduce utility costs and increase your home's energy independence. Our expertise spans EG4 battery systems, SolarEdge inverters, and Enphase microinverters — matched precisely to your property and consumption patterns.
- EG4 certified installer — hybrid inverters and battery storage
- SolarEdge and Enphase certified installations
- Custom system design for your energy needs and budget
- Backup power and off-grid solutions
Open source
Home Assistant · Python · ESPHome
The tools we build
The tools we build for our own installations — and maintain in the open. They are the same technology we run in clients' homes.
Home Assistant integrations
Local Modbus + cloud monitoring and control for EG4 / Luxpower inverters, GridBOSS, and batteries.
Home Assistant integrations
Local MQTT bridge turning Brilliant in-wall panels into Home Assistant entities — no cloud.
Home Assistant integrations
Weather-aware control for Moogo mosquito misting systems.
Home Assistant integrations
Zone control and cartridge monitoring for Thermacell LIV mosquito repellent.
Home Assistant integrations
Lab-grade pool and spa water chemistry from the LaMotte WaterLink SpinTouch, in Home Assistant.
Home Assistant integrations
Water chemistry analysis and dosing recommendations for pools and spas.
Home Assistant integrations
Local 433 MHz RF control of AOK / Zemismart roller blinds — MQTT, no cloud.
Home Assistant integrations
Full pool and spa automation for Pentair IntelliCenter (maintained).
Home Assistant integrations
Tankless water heater control and monitoring for Rinnai Control-R (maintained).
Python libraries
Python client for Thermacell IoT devices over the ESP RainMaker API.
ESPHome firmware
ESPHome firmware controlling QuietCool attic and whole-house fans over their native 433 MHz link.
ESPHome firmware
ESPHome MQTT beacon for the Sonoff RF Bridge R2 — scheduled 433 MHz transmission.
Contact
San Gabriel Valley, California
Ready when you are.
Let's start a conversation. Whether you're buying, selling, or exploring smart home solutions, we're here to help.
Get in touch