Ideal Temperature at Home in Winter: Comfort, Health and Savings

With the arrival of the cold, the eternal dilemma arises: At how many degrees do I set the heating? Too much heat dries out the environment and shoots up the bill; too much cold affects well-being. The key is to find the balance, and windows play a more important role than you imagine.

What is the recommended temperature?

According to the Institute for Diversification and Energy Saving (IDAE), the recommended temperatures are:

The key fact: for every degree you raise the heating above the recommended level, energy consumption increases between 5% and 10%.. Going from 21 to 23 degrees can mean 20% more on the bill.

Why does heat escape from your house?

In an average home, heat loss is distributed as follows:

• Windows and glazed enclosures: 25-30%
• Facades: 25-30%
• Roof: 25-30%
• Floor: 5-10%
• Ventilation and infiltration: 10-15%

Windows are one of the main points of heat leakage. An old aluminum window without a thermal break can have a transmittance of 5-6 W/m²K, while a Kömmerling PVC window with double glazing drops to 1.0-1.3 W/m²K, and with triple glazing to 0.80 W/m²K.

How windows influence the comfort temperature

Efficient windows not only prevent heat from escaping: they eliminate cold drafts, the feeling of a "cold wall" near windows and condensation on the glass. This means you can keep the thermostat at 20 ºC and feel true comfort, instead of turning up to 23 ºC to compensate for the losses.

Comparison of systems

Practical tips for the winter

1. Ventilate for 10 minutes in the morning: Open windows wide to renew the air, but close quickly. 10 minutes with open windows is better than 1 hour with windows ajar.
2. Take advantage of the sun: On sunny days, open blinds and curtains on the south and east facades to capture free solar heat.
3. Close blinds at night: A blind with an insulated box like the VariNova (from 0,74 W/m²K) creates an additional air chamber that reduces night losses.



4. Do not cover the radiators: Long curtains or furniture in front of the radiator prevent heat circulation.
5. Regulate by rooms: Not all rooms need the same temperature.

The most profitable investment

Changing windows is one of the energy improvements with the highest return. On the Costa Blanca, where we use both heating in winter and air conditioning in summer, efficient windows work in both directions: they keep the heat inside in winter and outside in summer.

If you notice that your house does not maintain the temperature, that the crystals drip due to condensation or that the energy bill is excessive, the solution is probably in your windows. Consult us without obligation and we help you choose the best option for your home.

Recommended Temperatures by Room

The Role of Windows in Thermal Comfort

Good windows are essential to maintain the ideal temperature without wasting energy:

• Every degree counts: Raising the thermostat 1°C increases energy consumption by 7%. With efficient windows (U<1,3 W/m²K), you can maintain 21°C with half the energy than with old windows at 19°C.
• Cold wall effect: With low-quality windows, the interior surface of the glass can be at 8-10°C when it is 5°C outside, generating an uncomfortable feeling of radiant cold. With a low-emissivity double glazing, that temperature rises to 17-18°C, eliminating the discomfort.
• No drafts: Windows with class 4 air permeability eliminate cold drafts, allowing you to sit next to the window without discomfort.

Ecological Data

Heating represents 47% of energy consumption of an average Spanish household (IDAE). Improving glazing can reduce this item between 30% and 50%, which means a saving of 1-2 tons of CO₂ per year. In addition, the WHO recommends maintaining temperatures between 18-21°C for health: it is not necessary to have the house at 25°C if the windows insulate correctly.