Thermal Comfort  

What is the optimum temperature for each room in the home?

In the UK, the World Health Organization recognizes 18°C as the basic level of warmth required for a comfortable and safe home. Homes are, on average, heated for 8 hours per day and during the winter this usually increases to 10 hours.

Good insulation is paramount for heat transfer, and knowledge of how heat moves in and out of the home is essential for heating the buildings effectively. Heat transfer is the process of thermal energy being exchanged between systems dissipating the heat throughout the home. This occurs via conduction (heat transfer via the collision of molecules), radiation (the generation of heat from the emission of electromagnetic waves) and convention (when thermal energy moves away from the source).

Various temperatures have different effects on a building and its residents. If the interior temperature was reduced to 7-8°C, the building would only absorb 50% of moisture within it, leading to condensation and mould growth. On the other hand, if the temperature was too high this would cause inhabitants to feel lethargic.

Different parts of the home should be heated differently depending on inhabitants’ schedules, which is important for comfort, health, and well-being. The temperature should alter throughout the day not only for peak optimization, and energy conservation but also productivity. The key is to create a warm environment within a budget, creating comfortable spaces that people will get the most out of while minimizing costs when they are away or asleep.

Kitchen

People usually spend the most time in the kitchen and the optimum temperature is 21°C. Here, individuals are usually moving around the space whilst cooking, and therefore kitchens benefit from underfloor heating which provides a constant warmth throughout the room. This heating system provides optimum comfort for visitors; a constant level of thermal comfort throughout the space. This is best established via an air-to-water heat pump, which keeps the costs of heating the whole kitchen lower as lower water temperatures are required to heat a larger surface area. Here, heat rises throughout the home via convention and as kitchens usually take up a large part of the building’s space downstairs, the heat from this room increases the overall building’s temperature. On a hot day, for example, the warmth from the kitchen floor will transfer to the upper parts of the house, consequently heating the bedroom and bathroom.

Lounge

The living space and dining room should be similar in temperature to the kitchen, set at 21°C. Rather than underfloor heating, the best method to heat the lounge is a radiator, allowing heat to radiate around the space, taking into consideration that in this room, inhabitants’ are most commonly sat down, or sedentary and not exerting large amounts of energy.

The radiators should be unobstructed, facing into the room to allow furniture warmth to radiate into the space.

Windows are a passive source of heat generation, and should be in clear view of the sun’s rays to absorb as much natural heat as possible -- the reason why south facing rooms are considered more desirable. 

Bathroom

We spend the least amount of time in our bathrooms and these smaller spaces need to remain cooler in order to conserve energy, particularly as most of the heat needed in a bathroom is from hot water. Bathrooms should preferably be located in sunnier parts of the house to soak up the solar rays via radiation.

Bedroom

The bedroom should be one of the coolest parts of the house and should be a lower temperature in the hours before and during sleep. Low temperatures are vital for rest as temperatures above 23°C and below 12°C are proven to disrupt people’s sleeping patterns. Before we fall asleep, our body temperature drops significantly which promotes deep, continuous sleep.

The optimum temperature for bedrooms is 18°C. This can be achieved by proper ventilation and low-level heat radiating from a radiator facing the bed, allowing the body to fall asleep quicker, resulting in healthier sleeping patterns and overall feelings of wellbeing.