Just check coupons out (with price alert and history). Best price?
Aliexpress
There’re some similar (or not) items on Aliexpress
Click here to search by yourself. Here are coupons that you can use.
Latest coupon and price update (UTC):
Power: 2000W, Voltage: 220V
Price history and price alert
Price history (for all/most countries) for Xiaomi Smartmi Electric Heater is here.
Price records source(s): Gearbest
Click on image to enlarge.
You can set price alert (for Banggood and Aliexpress (only if product name will be the same as on Banggood and I will post it on social media though, so it’s more like Banggood price alert)).