窓の効用

室内の温熱環境を考えていると窓に振り回られる。窓が無いと日射が入らないので暗いし寒いし、しかし、窓が有るとそこから熱が逃げる。これはあくまでも冬の場合で、夏は逆に窓が有ると日射が入り暑くなり、窓が無いと影になり暑さがやわらぐが風が入らない。全館空調を１日中行えば、窓の存在に左右されないが省エネでは無い。

今の冬の時期の晴天の昼間に窓際が寒いのは、窓の断熱性が脆弱だからである。南面以外の窓は断熱性の高いサッシと室内側に断熱性の高い付属部材を設置しないと、ブラインドやレースカーテンでは不十分、窓際にストーブを置いても熱は外に逃げる。ところが、今の時期、晴天だと南面の窓には電気ストーブ1台分の熱量があるので、レースカーテンも開けて熱を室内に取り入れたい。

ただ、このような簡単なことがわかっている専門家が実は少ない。

"The utility of windows"

When thinking about the thermal environment in the room, it is swung around by the window. Without windows, it's dark and cold because sunlight doesn't enter, but with windows, heat escapes from there. This is only the case of winter, and on the contrary, in summer, if there is a window, sunlight enters and it becomes hot, and if there is no window, it becomes a shadow and the heat softens, but the wind does not enter. If the entire building is air-conditioned all day long, it will not be energy-saving, although it does not depend on the presence of windows.

The reason why the windows are cold during the sunny day of this winter is that the heat insulation of the windows is weak. For windows other than the south side, blinds and lace curtains are not enough unless a highly heat-insulating sash and highly heat-insulating accessories are installed inside the room, and even if a stove is placed near the window, heat escapes to the outside. However, at this time of year, when the weather is fine, the window on the south side has the amount of heat for one electric stove, so I would like to open the lace curtain to take in the heat indoors.

However, there are actually few experts who know such a simple thing.