I live in an apt building in the 60's. I always notice that the room is always warmer than the outside in the winter time(even with no heating). This stays true in the summer time where it would be 65 outside at night and somehow the room can stay in the low 80's(if I leave A/C and ventilation off).

Does this indicate a well insulated apt?

It is really easy to warm up my apt with a cheap $20 electric heater in the winter. I would go from low 40's to 70's with the heater on full.

However, in the summertime, my window A/C unit struggles to even get the room to the low 80's. Granted, I am on the 2nd floor and have windows facing the sun most of the day.

Is it just a weak A/C, lack of airflow?

  • What is the exposure of the outside wall(s)? North, south, east, west.. Is it on the top floor and if so a) what color is the roof and b) is it often covered with snow? Commented Aug 16, 2017 at 22:46
  • @Harper, one wall faces west. Most of the sun comes from that side. Roof is a light beige. Never snow. It is on the 2nd floor of a 2 story apt. stairs are outside.
    – mugetsu
    Commented Aug 17, 2017 at 6:30

1 Answer 1


Meet solar load

When the sun beats on your house, it warms it up - winter or summer. (more in the summer). There's 1000 watts of solar heat per square meter that's square-on with the sun, and only a limited ability of your roof to shed that heat - eventually some of it pushes through the insulation.

This is a lot of heat, and you get the brunt of it being on the top floor.

Needless to say, this is your friend in the winter and your enemy in the summer. And it's a big enemy in the summer.

Part of the value of solar panels is it essentially puts parts of your roof in shade, reducing/eliminating that solar load (depending on how well air circulates around the panels). Having the panels racked a foot or two off your roof helps with this.

As a renter, you have basically zero options to deal with this, unless you can sway the landlord somehow.

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