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  4. Internal windows to make your home more comfortable



eco-friendly house - 燃費の良い住まい

Internal windows to make your home more comfortable

If your house is too cold to heat in the middle of winter, or if you use oil or gas heaters but condensation causes mould, this can be reduced by renovating the building insulation.

If you want to insulate your home, you need to find out which parts of your home – floors, walls, ceilings, front doors, windows, etc. – are poorly insulated. Then, depending on the situation, the insulation method is decided. Depending on the renovation budget, we may prioritise the areas with the least insulation.

For example, the aluminium sashes that are commonly used in the windows of a house are often a weak point for thermal insulation in winter, as aluminium has a tendency to conduct heat very easily, allowing the heat of the heated room to escape very quickly.

In one of our renovations of a reinforced concrete apartment building, the existing aluminium sashes were retained, but in addition, plastic internal windows were installed.

One day in the middle of winter, we checked the insulation effect and measured the following temperatures:

The windows faced the west wall, and it was cloudy, so there was not much room temperature increase due to solar radiation. The temperature was measured at around 15.00 pm.
At this time, the room temperature was 21.3°C with one air conditioning unit running. First of all, the surface temperature of the outer wall was measured from the road, and it was about 4°C.

The left-hand side of the image above was taken using a thermal imaging camera. The warm areas are shown in white or yellow and the cooler areas in dark purple to give an idea of the temperature distribution in terms of colour. The picture on the right shows an actual image of the same area. The circles in the middle and the temperature indicator in the upper left-hand corner indicate that the temperature of the wall in the middle of this image is 4.1 °C or 5.0 °C.

We then photographed the windows from the inside in two different conditions: with the plastic window open and with the plastic window closed.

In the top left image above, with the plastic inner window open, the temperature of the outer aluminium sash surface is measured. We can see that the lowest temperature is 7.3°C. (The dark purple area indicates the aluminium part.) In the centre, the glass is marked with a circle and the temperature is 10.0°C.

On the other hand, in the image below left, with the plastic window closed, the temperature of the surface of the plastic window is measured, and it can be seen that the lowest temperature is 15.0°C. (This is the dark blue area. The lowest temperature is 15.0°C. (This is the dark purple area.) In the centre of the window, the glass is marked with a circle and the temperature is 18.9°C.

In summary

Indoor surface temperature of external aluminium sash 7.3~10°C 15.0-18.9°C for plastic internal windows

The results show that.

For a person in the immediate vicinity of this window, there is a significant difference in the degree of comfort between a room that is cooled at 7.3-10°C and one that is cooled at 15.0-18.9°C. It has been suggested that a room temperature of 19°C or more is desirable as a guideline to avoid harmful effects on human health. It is true that a room temperature of around 19°C is comfortable without the need for extremely heavy clothing.

It is advisable to use a variety of methods to determine the contents of the insulation work, such as the use of software to simulate utility costs and the measurement of airtightness, etc. In this way, it is possible to confirm the current situation with numerical values.

In this case, it can be seen that the plastic window protects the interior from the cold outside and prevents the interior surface temperature of the window from dropping by 8-9°C.

If your home is cold and difficult to live in, or if you suffer from condensation, then this insulation renovation could make your home more comfortable. If you have the opportunity to renovate your home, we recommend that you also consider insulation renovation.