Is It Actually More Efficient to Heat the Entire Apartment?

If it’s a small apartment?

Ugh, my apartment wall looks gross in close-up.

If there’s one thing I thought I knew about dealing with heat when you had to pay for it yourself, it’s that you should only heat the rooms you’re in. Right?

So that’s how I’ve been doing it. I’ve been carefully turning my electric heating units on and off as I move between my bedroom and my living room, closing all of the doors in between. Right now, an unheated room naturally settles to a temperature of about 58 degrees, so I’d let one room (and the hallway and bathroom) chill out while I turned the other room’s thermostat up to 65.

My apartment layout. Not to scale.

But then I did a bunch of laundry, and I had all of these sweaters that needed to dry flat, so I spread them out among the flat surfaces of my apartment, set the heat at 65 degrees in both my bedroom and my living room, and opened all of the doors.

It was like being in an entirely different apartment.

First of all, it was significantly warmer. That should theoretically come as no surprise; two heaters equals twice as warm, right?

Except the heaters aren’t running as often, and I’ve even turned the thermostats down a few degrees.

In this case—and this is just my uneducated, I only took one science class in college guess—keeping both rooms warm seems to take less energy than keeping one room warm while everything else stays cold. With the “only heat one room” method, the warm air wants to escape under the door into the hallway, the cold air wants to get in, and the entire apartment is constantly adjusting its concept of room temperature. With the “heat both rooms” method, room temperature stays constant.

Which is probably why setting one room to 65 degrees meant me wearing a sweater and a scarf and a blanket while holding a cup of tea to keep my hands warm, and setting both rooms to 60 or 62 degrees means me wearing a sweater. (I also no longer need to jack my heat up to 70 degrees for the ten minutes before bed in a vain attempt to get my bedroom just a little bit warmer before I hide under two duvets and hope the little breathing hole I made for myself lasts all night.)

I’ll have to wait two months to get the electricity bill, but I swear this has to be better than only heating one room at a time.