Heating your apartment/house

Wow that you manage to have an electricity bill under 5,000 yens in winter, even for a 1LDK, is impressive.

I do the same as you : living in my kitchen/living room during daytime since it gets warm when sunny. When it's too windy or cloudy it's cold tho.

At nights I use an electric blanket to keep me warm in bed. I only sleep with 2 other regular blankets and a futon. Our bedroom and that side of the apartment is very cold and more humid. Some mornings it's around 8°C.

I hate aircon so it's a no. We only have a removable one for cooling the bedroom in summer because my husband cannot sleep with the heat.

I've tried various heating systems such as aircon and oil heater (?) (in Japanese it's オイルヒーター, warm, not dry but heavy on the kWh). This year we're having an kerosene stove for the first time.

It's not electric but you have to buy the kerosene. I like it the best so far : nive warmth and I can place a pan on top so I cook on it which saves use of the electric IH.

I also use curtains in the living room at night, which might seem obvious but I don't have curtains in my apartment except for the bedroom.

I'd like to place a curtain at the entrance because I feel like most of the cold enter from the door but I haven't figured out a manageable system yet.

Oh btw even with switching heating to kerosene and not using the IH our electricity bill is still between 7,000 and 9,000 monthly for November and December.

PS: i too live in a apartment with single paned windows and poor isolation..it's really unbelievable from my perspective since in France they have a energy cost efficiency rating system for buildings and also house appliances. I've heard that in Hokkaido double paned windows are a standard and that some new houses even in warmer areas are built with double paned windows (even triple sometimes, Japaneses do or do not lmao).