Then, you should subtract the return air temperature from the supply air temperature. You will find a recommended temperature rise range typically about 35-65 degrees)on the label plate for the furnace. Compare the value you measured with the label plate. If the temperature rise you measured is below the minimum range for your furnace, the blower heating speed can normally be reduced. If the temperature rise you measured is above the high range for your furnace, the blower heating speed can be increased.
Weather Lowdown. December in Istanbul sees the start of winter, with cold temperatures and wet weather. The average temperature is just 8C, with highs of 10C and overnight lows of 6C or below.
Turkey's largest city of Istanbul (known as Constantinople until 1930), with a population of over 9 million is located on both the east and west sides of the Bosporus strait so it straddles both what are traditionally considered Europe and Asia.