Effects of quilts on comfortable indoor temperatures and human thermal responses during sleep

Abstract

Quilts play a vital role in the thermal comfort of sleeping people. This study aims to investigate the comfortable indoor temperatures and thermal responses when people sleep in different quilts. The experiment tested three kinds of quilts (down, silk, and polyester), and each kind of quilt involved six filling weights. Sixteen participants (eight males and eight females) conducted whole-night sleeping trials to acquire skin temperatures, bedding temperatures, and thermal perceptual responses. The lower and upper limits of air temperatures ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>lower</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{lower} $$</mml:annotation></mml:semantics> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>upper</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{upper} $$</mml:annotation></mml:semantics> </mml:math> ) for comfortable sleeping were obtained. The results indicated that thermal sensation votes were in the range from 0.1 (close to "neutral") to 1.3 (close to "slightly warm") when participants felt comfortable and preferred "no change" in thermal preference. The corresponding comfortable mean skin and bedding temperatures were 34.6 ~ 35.2°C and 31.2 ~ 32.7°C, respectively. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>lower</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{lower} $$</mml:annotation></mml:semantics> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>upper</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{upper} $$</mml:annotation></mml:semantics> </mml:math> had good linear correlations with bedding insulations. For the same bedding insulation, the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>lower</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{lower} $$</mml:annotation></mml:semantics> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>T</mml:mi> <mml:mtext>upper</mml:mtext></mml:msub> </mml:mrow> <mml:annotation>$$ {T}_{upper} $$</mml:annotation></mml:semantics> </mml:math> were highest for using silk quilts, followed by down and polyester quilts. The comfort ranges of air temperatures and quilt insulations were finally determined. The findings may benefit understanding the thermal requirement of quilts and help people select and design quilts to achieve thermal comfort.