Seat Batten Guide: Which Material Gets Hottest in Summer?

Timber? Aluminium? The answer may surprise you.

Comfort sitting outdoors can depend on many factors: position, view, shelter, microclimate, social comfort and more – see our Gehl cheatsheet on how to place seats in the city.

The temperature of the seat under you can also contribute.

Metal, for example, is commonly thought to be hottest in summer and coldest in winter. Street Furniture Australia’s inhouse engineers ran a study, dubbed the Goldilocks Batten Project, to get to the truth.

Access the full Goldilocks Report (730KB).

They tested anodised, powdercoated and woodgrain aluminium, and oiled hardwood (Jarrah) battens. For comparison, they also looked at raw aluminium – a material we do not use in seats.

The battens were placed in the sun, and the temperature recorded regularly. The engineers noted how long it took the material to heat up or cool down, in full sun and with clouds.

Which Seat Batten Gets Hottest, and Which Feels Hottest?

The batten that feels hottest in a blind test is NOT the batten with the highest recorded temperature on a sunny day.

• Anodised aluminium was 10°C cooler than oiled timber. There is a common misperception is that anodised is hot in summer. It is actually cooler than oiled hardwood, making it great for coastal locations but should be avoided for colder climates.

• Oiled hardwood battens reach the highest temperature, as oil causes the material to store heat. Regular oiling is recommended for seats as it improves durability.

• Aluminium still FEELS hotter than wood, as metal has higher conductivity to skin. Raw aluminium gets hotter than anodised.

• Woodgrain and powdercoated aluminium reached higher temperatures than anodised aluminium: the extra layer insulates the material. A thick powdercoat can provide conductivity levels similar to timber: so it will feel cooler than raw aluminium.

• Applying white powdercoat or white paint will raise emissivity: light-coloured materials do not store as much heat.

What Makes Battens Hot?

Three main factors determine how responsive battens are to heat:

• Thermal Mass – how much heat energy and time it takes to change temperature. High mass is best for battens – we want them to heat and cool slowly.

• Radiation Emissivity – how much energy absorbed from the sun is emitted out or stored within. Battens that store heat feel hot, so higher is better.

• Conductivity – how fast heat is transferred from the surface of the metal to skin.

Hardwood battens have the highest thermal mass of materials tested – they change temperature most slowly. They are solid, while the aluminium are hollow extrusions, so perhaps this is not surprising.

In tests where wind blew across aluminium extrusions, the metal quickly cooled.

Our Experience of Battens is Not Rational

Our team – with more than 30 years of experience supplying furniture to public spaces – notes that the comfort people experience from different kinds of battens on seats is also affected by psychological factors.

• Looks matter. Timber and woodgrain aluminium tend to look warmer and more inviting to travellers waiting for the train, or relaxing in a park.

• Your choice of colour may help overcome perceptions – for example, using warmer colours for psychological effect if cold is a concern.

• The shinier a material is, the hotter or colder it looks.

• People dress for the weather. Bare skin does not usually come in contact with a bench in winter.

So which batten should you choose? If heat is a concern, anodised aluminium does not get as hot, and will cool more quickly with cloud cover, wind or moving shade.

When designing for colder climates, timber and colourful palettes can make environments more inviting.

Street Furniture Australia materials and finishes are suitable for all-weather conditions, however certain selections empower you to optimise comfort.