Use Of Air Conditioning Research Articles

Effect of Roof Tile Colour on Heat Conduction Transfer, Roof-Top Surface Temperature and Cooling Load in Modern Residential Buildings under the Tropical Climate of Malaysia

Modern residential roofs in Malaysia mainly employ red and brown roof tiles due to aesthetic factors and the ability of the roof surface to reflect or retard heat transfer is typically not considered the main priority. The present article reveals the findings of a study on the effect of roof tile colour on heat conduction transfer through roof tiles and ceiling boards, roof-top surface temperature and cooling load. Findings suggest that the selection of white roof tiles significantly reduces the peaks of heat conduction transfer and roof-top surface temperature as well as the values of heat conduction transfer and roof-top surface temperature throughout diurnal profiles, which consequently reduces hours of indoor thermal discomfort and use of air-conditioners in indoor spaces. A decline in peak roof-top surface temperature of up to 16.00 °C that results in annual energy savings of up to 13.14% can be achieved when the roof tile colour is changed from red to white. Further research on the development of solar-reflective paint or coating products that can significantly increase the solar reflectance values of non-white roof tiles are essential to overcome issues related to maintenance difficulties and lack of preference among house buyers towards white roof tiles.

Better light spectral quality and thermal amplitude inside the greenhouse stimulate growth and improve acclimatization of in vitro–grown Cattleya warneri T. Moore

Growth and photosynthetic capacity of Cattleya warneri T. Moore seedlings cultivated in vitro were evaluated in two environments: (1) growth room (GR) with constant light, humidity, and temperature; and (2) greenhouse (GH) with variable humidity, temperature, and light intensity and quality. In both environments, two different tissue culture vessel lids were used: transparent plastic lids (TCVplastic) and non-transparent metal lids (TCVmetal). After 11 months of in vitro cultivation, five seedlings from each tissue culture vessel were evaluated for growth and photosynthetic capacity, while the other five seedlings of each tissue culture vessel were transferred to a greenhouse for acclimatization. Increased biomass production in vitro was observed in GH and GR (GH>GR). However, the photosynthetic capacity was not altered by the GH environment, since the net photosynthetic rate at 300 μmol m−2 s−1 (NPR300) was low in the final of period in all treatments. Therefore, the increase in biomass production in C. warneri was mostly dependent on the exogenous carbon source through the addition of sucrose to the culture medium. The use of TCVplastic in vitro improved seedlings’ growth in both GR and GH, showing an advantage in relation to TCVmetal. GH environment with quality light spectrum and thermal amplitude, and use of TCVplastic, increased biomass production in vitro and improved the acclimatization process of C. warneri seedlings, which also reduced electricity costs since the use of artificial light and air conditioning is not required.

Evaluating the Effect of Framing Energy Consumption in Terms of Losses versus Gains on Air-Conditioner Use: A Field Experiment in a Student Dormitory in Japan

Promoting energy conservation in university dormitories is challenging because student residents are typically charged a flat utility fee. One possibility to curb excessive energy use in the absence of monetary incentives is to highlight the environmental consequences of energy use. However, it is still largely unknown how these consequences should be communicated to effectively change people’s behavior. In the present study, we analyzed the effect of framing the environmental consequences of energy use in terms of losses versus gains on the air-conditioner use of student residents of a Japanese university dormitory. A total of 330 students were provided with stickers to attach to the air-conditioner remote control in their dormitory room during the winter term. The stickers conveyed that increasing the temperature will hurt the environment (loss frame), that reducing the temperature will protect the environment (gain frame), or that changing the temperature will affect the environment (neutral frame). Day-to-day variations in objective air-conditioner use data were analyzed as a function of experimental condition to examine the effect of message framing. The change in air-conditioner use from pre-intervention to intervention period did not differ between experimental groups and neither did the change from pre-intervention period to a period after the intervention.

Impact of temperature on obstructive sleep apnoea in three different climate zones of Europe: Data from the European Sleep Apnoea Database (ESADA).

Recent studies indicate that ambient temperature may modulate obstructive sleep apnoea (OSA) severity. However, study results are contradictory warranting more investigation in this field. We analysed 19,293 patients of the European Sleep Apnoea Database (ESADA) cohort with restriction to the three predominant climate zones according to the Köppen-Geiger climate classification: Cfb (warm temperature, fully humid, warm summer), Csa (warm temperature, summer dry, hot summer), and Dfb (snow, fully humid, warm summer). Average outside temperature values were obtained and several hierarchical regression analyses were performed to investigate the impact of temperature on the apnea-hypopnea index (AHI), oxygen desaturation index (ODI), time of oxygen saturation <90% (T90) and minimum oxygen saturation (MinSpO2 ) after controlling for confounders including age, body mass index, gender, and air conditioning (A/C) use. AHI and ODI increased with higher temperatures with a standardised coefficient beta (β) of 0.28 for AHI and 0.25 for ODI, while MinSpO2 decreased with a β of -0.13 (all results p<.001). When adjusting for climate zones, the temperature effect was only significant in Cfb (AHI: β=0.11) and Dfb (AHI: β=0.08) (Model 1: p<.001). The presence of A/C (3.9% and 69.3% in Cfab and Csa, respectively) demonstrated only a minor increase in the prediction of the variation (Cfb: AHI, R2 +0.003; and Csa: AHI, R2 +0.007; both p<.001). Our present study indicates a limited but consistent influence of environmental temperature on OSA severity and this effect is modulated by climate zones.

Energy Efficiency Improvement of the Split Air Conditioner Through Condensate Assisted Evaporative Cooling

The overwhelming evidence of global warming caused by human activities documents both contemporary impacts on human life but also extraordinary future risks are also assisted with it. Accretion of global temperatures engenders the extensive use of air conditioning devices to make the surrounding livable in the summer season. Energy consumption for air conditioning is also palpable by the evidence that this industry is the 2nd largest power-consuming sector in the consumer field. High temperatures also affect the performance of the air conditioning system by decreasing their energy efficiency ratio (EER) and cooling capacity (QC). Modifications are made in such a way to lower down the temperature of the surrounding by the use of a honeycomb wet pad which uses evaporative cooling with condensate of the indoor side. Experiments were made to observe the difference in performance efficiency, with modification and sans modification, by operating separately at 40–50 °C temperatures. Results were evident that condensate assisted evaporative cooling shows improvement in cooling capacity by 19% and a reduction in power consumption (P) by 13% as compare to the conventional system. A huge increase in the energy efficiency ratio of 36% was observed with the use of the modified system. The things used for the modification are cheaper and easily available in the market.

Percentage of reducing heat of coco fiber material as a potential isolation of building walls

This paper was purposed to determine the percentage of coco fibers ability in reducing heat as a potential for insulation building walls with different coco fiber thickness. For the fulfillment of thermal comfort in buildings requires engineering, knowledge and skills and innovation. One way to reduce hot air in the room can be done through walls, thereby reducing the use of air conditioning. The walls need protection and solar heat absorbers which can make the room inside the building have thermal comfort. Based on this, research needs to be done on natural ingredients that can function to reduce heat. Tests carried out on coconut fiber and fiber-free materials. Material without fiber and coco fiber thickness are 1 centimeter, 2 centimeter and 3 centimeter. This coco fiber material is coated with a mixture of cement which also functions as a fiber adhesive. In this case testing by applying heat of 35 Celsius degree to one side of the fiber and measuring the temperature that occurs on the other side of the fiber. The test results found that there was a significant difference between the heat temperature supplied and the heat temperature measured on coco fiber. The thicker the coco fiber material, the greater the percentage of heat that can be reduced. This shows that the coco fiber material has the potential to reduce heat as a wall covering against solar radiation.

Investigation of pipe materials and thermal conductivity of soil on the performance of ground heat exchanger operating under Malaysia climate

In nature, renewable energy is inherently free and must be implemented. The use of air conditioning and refrigerants that affect global warming is a serious issue. In building applications, renewable energy from the geothermal source, namely ground heat exchanger (GHE), has great potential. The main concept of GHE is utilizing the ground as an infinite thermal reservoir for cooling and heating to the fluid medium. In the GHE system, the air is used as a fluid medium of work. Because of the temperature difference between the air and underground temperature, the air cools in summer and gets heated in winter. In this present work, a study has been conducted to investigate the effect of pipe materials and thermal conductivity of soil on the performance of the GHE. The study acknowledges that the pipe materials do not give a significant effect on the performance of the GHE. Therefore, the lower thermal conductivity of pipe materials with low cost can be used in GHE implementation. The study also revealed that the range of thermal conductivity of soil which gives good ground heat exchanger performance is between 1.5 to 5 W/m·K. Besides, the length of the pipe was reduced from 25 to 10 meters.

Thermal Radiant Cooling System Using Recycled Water from Swimming Pool

Global warming has an impact on the high room temperature, that can cause excessive use of air conditioning (energy). This directly give contribution not only on the high electricity usage but also energy consumption which is related to the decreasing environmental quality (greenhouse gases emission). In this study, the main concern is to see the potential in maximizing the role of recycled water as air conditioning elements for cooling system. The recycled water referred to this study is the used water originating from the swimming pool area, in which the pool itself acts as a part of the recirculating water system. The system consists of pipe grids in different lengths and widths in suspended ceilings or concealed has possibility to adjust the heat radiation from tempered walls directly to the room. The pipe grids itself serves as a cooling agent. This research was conducted adopting basic equations for radiant heat transfer, the equations makes it easier when application in the field so it can be used to determine the cooling effect produced. Calculation method conducts analysis to the surface of the panel which was exposed to the radiation load which would then be transfered by recycled water from swimming pool. The calculation method obtained through this study is expected to be used as a reference in recycled water for the cooling system to the room. An assumption calculation is done to see the potential of the radiant panels surface cooling efficiency, particularly by looking from the pipe type variable aspect that showed Copper with a surface cooling efficiency value of 3,080 should be used as pipe type for future research with purpose to achieve a higher surface cooling efficiency without cost limitation. This research was carried out by adopting various methods that can overcome ecological problems so that the results will not only provides comfort for the user of the room, but also as a reference for environmentally friendly building designs.

The meanings of energy: a case study of student air conditioning activity

There has been much work on interventions aimed at changing consumer energy consumption behaviour, but the progress on emissions reductions is limited. We argue that further gains can be made through new examinations and developments of the theory that informs interventions, offering a critique of two major areas of theory in energy reduction: behaviour change and social practice theory (SPT). Behaviour change focusses on the individual consumer, but powerful social influences on energy consumption are often neglected, and results can be ambiguous. In contrast, SPT, while strong on explaining social influences, can sometimes leave ambiguous how interventions can be designed with and for individuals. We address this problem by focussing on a study of student use of air conditioning in Southeast Asia informed by the behaviour change approach. We then move to a discussion of how SPT could be used to conceptualise and design interventions for the same setting in a very different way. In working through the differences, we draw out two themes. The first is how far and in what ways we can meaningfully work with individuals to bring about social change on energy consumption. The second concerns the conflict between the abstract meaning of energy as an ecological threat, which many realise and care about, and its practical meaning as fuel for activities, for example, space cooling or commuting, which incur energy use as an unavoidable part of everyday life. We discuss ways of working with students to bring about greater consonance between the abstract and practical meanings of energy, by reconfiguring aspects of existing student practice to produce new means for individuals to act.

How Cool Pavements and Green Roof Affect Building Energy Performances

The urban heat island effect amplifies the global warming phenomenon with sensible aftermaths on the building energy consumptions. The absence of green areas, open water channels as well as the lack of free unsurfaced spaces creates a sort of urban cap and a heat reflection effect, from the bottom upwards, which persists in the early hours of the night. This heating effect exacerbates the use of air conditioners which, if on one hand helps to cool houses, on the other hand rejects outside hot air hindering the cooling effect of nighttime air. The aim of this study is to analyze the effects of urban heat island mitigation techniques on the building energy performances, such as cool pavements and green roofs. Measured temperatures were used to calibrate a model of a densely populated district in Rome by means of ENVI-met software. It was subsequently carried out an energy analysis through the use of TRNSYS in order to study the energy behavior of a reference building in its urban context in function of the variation of the boundary conditions.

Building Retrofit and Energy Conservation/Efficiency Review: A Techno-Environ-Economic Assessment of Heat Pump System Retrofit in Housing Stock

The world has not been able to achieve minimum greenhouse gas emissions in buildings’ energy consumptions because the energy and emissions optimization techniques have not been fully utilized. Thermal comfort is one of the most important issues for both residential and commercial buildings. Out of the 40% of global energy consumed by buildings, a large fraction is used to maintain their thermal comfort. In this study, a comprehensive review of the recent advancements in building energy conservation and efficiency application is presented based on existing high-quality research papers. Additionally, the retrofit of the heating/cooling and hot water system for an entire community in Cyprus is presented. This study aims to analyze the technical and environmental benefits of replacing existing electric heaters for hot water with heat pump water heating systems and the use of heat pump air conditioners for thermal comfort in place of the existing ordinary air conditioners for space heating and cooling. One administrative building, 86 apartments (including residential and commercial) buildings, and a restaurant building is retrofitted, and the feasibility of the project is determined based on three economic indicators, namely; simple payback period (SPP), internal rate of return (IRR), and net present value (NPV). The electrical energy required by the hot water systems and the heating/cooling system is reduced by 263,564 kWh/yr and 144,825 kWh/yr, respectively. Additionally, the retrofit project will reduce Cyprus’ CO2 emission by 121,592.8 kg yearly. The SPP, IRR, and NPV for the project show that the retrofit is economically feasible.

Can reversible room air-conditioner be used for combined space and domestic hot water heating in subtropical dwellings? Techno-economic evidence from Hong Kong

Residential buildings represent a predominant source of energy consumption in most subtropical cities. To enhance the energy performance of this sector, the use of reversible room air-conditioners (RRACs) for combined space heating and domestic hot water (DHW) production is proposed. The idea arises from the fact that in subtropical regions RRACs sized for cooling always have excessive heating capacities to allow a parallel production of DHW. In order to assess the techno-economic feasibility of the proposed initiative, a representative housing estate in Hong Kong consisting of 12,800 residential units was selected for an extensive simulation study. Results confirmed the technical viability of the proposed system. It was found that a wide adoption of the technology has the potential to reduce 7.7% of Hong Kong residential energy consumption and 744,192 t of CO2e emissions. The tolerable capital cost (TCC) approach was adopted for yearly economic viability analysis. The average TCC for individual residential units was found ranging from HK$2,241 to HK$26,286 depending on the household size, electricity price, and economic settings. This study provides preliminary evidence to confirm the viability of the proposed technology and opens a new way for residential energy savings in Hong Kong and elsewhere in the subtropical.

How the coldest local thermal sensation affects overall thermal sensation after turning on the air conditioning—Evidence from chamber experiments

To explore how the coldest local thermal sensation (LTS) affects the overall thermal sensation (OTS) after initiating air conditioner, three experimental scenarios (29 → 23 °C, 29 → 25 °C and 29 → 27 °C) were created to simulate the real circumstances in buildings with split air conditioner (SAC). 29 young students were recruited. The skin temperature of 10 body segments along with the LTS of 6 body segments and OTS were measured continuously. Results showed that the foot demonstrated the coldest sensation and the largest skin temperature change, and it exerted stronger influence on the OTS than other body segments. However, the dominance of the LTS of the foot over the OTS showed great dependence on air conditioner set point temperature and air conditioning duration. Moreover, the two aspects of air-conditioner use behavior interacted with each other when affecting the approaching degree of the OTS toward the LTS of the foot. Based on developing and validating models, differences in the approaching degree change trend over air conditioning duration under different set point temperatures were observed, and then the turning point for the set point temperature between the two change trends was identified. When tset<26°C, the OTS quickly approached the LTS of the foot and surpassed it over time. When tset≥26°C, the approaching speed significantly reduced. The time-varying and temperature-varying characteristics of the relationship between the OTS and the LTS of the foot provided new insight for understanding air-conditioner use behavior in SAC buildings.

Extreme Environmental Temperatures and Motorcycle Crashes: A Time-Series Analysis

Background: Available studies evaluating the impacts of extreme temperatures on the risk of traffic crashes have mainly focused on car crashes, overlooking the potential differences in ambient and vehicle indoor temperatures due to the use of air conditioners. One way to overcome this limitation is to focus on motorcyclists who are directly exposed to ambient temperature. The aim of this study, therefore, was to evaluate the effect of exposure to extreme cold and hot temperatures on seeking medical attention due to motorcycle crashes in Iran. Methods: The time-series study was conducted in Sabzevar City located in the northeastern part of Iran. Daily counts of medical attendance for motorcycle crashes from March 2011 to June 2017 were collected through emergency departments of all four hospitals of the city and the pre-hospital emergency systems. Data on daily minimum, mean and maximum temperature (°C), relative humidity (%), wind velocity (km/hr.), and precipitation (mm/day) were collected from the Sabzevar meteorological station. We developed semi-parametric generalized additive models following a quasi-Poisson distribution with the distributed nonlinear lag model to estimate the immediate and lagged (0-3 days) associations of indicators of daily thermal stress (one at a time) on daily counts of medical attendance for the motorcycle crash, controlled for the relevant covariates. Results: We found an increased risk of medical attendance for motorcycle crashes at both extremely cold (1 st percentile) and hot (99 th percentile) temperatures and also hot (75 th percentile) temperatures, mainly during lags 0 to 2 days. The risk estimates for extremely hot temperatures were larger than hot and extremely cold temperatures. We also found an increased frequency of medical attendance for motorcycle crashes during heatwave days compared to non-heatwave days. Around 10-11% of the medical attendance for motorcycle crashes was estimated to be attributable to non-optimal temperature. Interpretation : We observed an increased frequency of medical attendance for motorcycle crashes in association with short-term exposure to hot and cold ambient temperature in Sabzevar, a city in a middle-income country. Our findings, if confirmed by future studies, will have important implications for public health messaging, given the considerable burden associated with road traffic injury, particularly in low- and middle-income countries. Funding: This Project mainly was funded by the Shahid Sadoughi University of Medical sciences as a master thesis of Mr. D. Mohammadi. Dr. Gasparrini was supported by the Medical Research Council-UK (Grant ID: MR/M022625/1) and the Natural Environment Research Council-UK (Grant ID: NE/R009384/1). Payam Dadvand is funded by a Ramon y Cajal fellowship (RYC- 2012-10995) awarded by the Spanish Ministry of Economy and Finance and Mark Stevenson is funded by a National Health and Medical Research Council fellowship (ID1136250) Declaration of Interest: None to declare. Ethical Approval: The study was approved by the Ethics Committee of the Shahid Sadoughi University of Medical Sciences (Ethics Committee approval number: IR.SSU.SPH.REC.1396.121).

Modern Methods of Preservation and Conservation of Mutilated Health Records

Medical records are the document that explains all detail about the patient’s history, clinical findings, diagnostic test results, pre and post-operative care, patient’s progress and medication. If written correctly, notes will support the doctor about the correctness of treatment. Preservation of medical histories record is very crucial to patients’ healthcare quality since when preservation is not being discharged properly; medical histories records are either inaccessible or difficult to access, which has a detrimental effect on the healthcare services provided to patients. This study is on the Modern Methods of Preservation and Conservation of Mutilated Health Records. Most hospital preserve patient health records, However, most of these records both print and non-print were affected by dust and particulate matters, high temperature, air pollution, bad storage, overcrowdings, wear and tear due to excessive filing and retrieval, oxidation and excessive light. Measures were taken to curtail the mutilation, but this was not enough as some of the health records continue to deteriorate. Many hospital give little room for records preservation. The preservation and conservation activities in hospitals are not fully and appropriately carried out. In view of this a number of recommendations were made, some of which are: the use of air conditioning for 24 hours in the health records library and storage rooms and to ensure regular and frequent repairs, cleaning and dusting of the environments, Hospitals should fully engage in electronic preservation in order to meet up with the required standard of service in the 21st century and they should also exploit other sources of funding through advocacy, solicitation, endowment, consultancy, organizing seminars and workshops etc.

Prevalence of and risk factors for respiratory symptoms in an adult urban population.

OBJECTIVE: To determine prevalence of and risk factors for respiratory symptoms in an adult urban Pakistani population.METHODS: We conducted a multi-stage, community-based, cross-sectional survey from May 2014 to August 2015, comprising 1629 adults from 75 random clusters in Karachi using questionnaire-based interviews.RESULTS: Around 60% of participants were females and 43% belonged to the >37 years age group. At least one respiratory symptom was reported by 37.5% of participants. Breathlessness was the most common symptom (25.2%, 95%CI 23.1-27.3), followed by acute wheeze (10.1%, 95%CI 8.7-11.7). Multivariable models revealed that males and those aged >37 years were more likely to report acute and chronic phlegm and bronchitis, and breathlessness. Participants with a higher level of education were less likely to report acute and chronic cough. Participants with >5 years pack-years of smoking were more likely to report acute and chronic cough and breathlessness. Other risk factors included passive smoking, regular use of air conditioning and mosquito coils, wet spots and mould in the house, and exposure to dusty jobs.CONCLUSION: We found breathlessness to be the most prevalent respiratory symptom and identified various risk factors for respiratory symptoms.

Energy Consumption Pattern of Residential Buildings: Case Study of Residential Area in Batu Pahat, Johor

According to the National Energy Balance report released by the Energy Commission of Malaysia in 2016, the residential sector uses 21.6% of the total energy in Malaysia. Residents waste energy through inefficient energy consumption and a lack of awareness. Building occupants are considered the main factor that influences energy consumption in buildings, and to change energy consumption on an overall scale, it is crucial to change individual behaviour. Therefore, this study focused on analysing the energy consumption pattern and the behaviour of consumers towards energy consumption in their homes in the residential area of Batu Pahat, Johor. A self-administrated questionnaire approach was employed in this study. The findings of this study showed that the excessive use of air conditioners was a significant factor in the increasing electricity bills of homeowners as well as the inefficient use of electrical appliances. Also, this study determined the effect of awareness on consumer behaviour. This study recommends ways to help minimise energy consumption in the residential area.

Eco-Driving and Its Impacts on Fuel Efficiency: An Overview of Technologies and Data-Driven Methods

Eco-driving is a multidimensional concept that includes driving behavior, route selection and all other choices or behaviors related to the vehicles’ fuel consumption (e.g., the use of quality fuel, the use of air conditioning, driving at peak hours, etc.). The scope of this paper is to present an overview of recent literature referring to eco-driving and developed models for calculating fuel consumption, as well as the most important factors affecting it. Recent literature contains a large number of models that estimate fuel consumption, based on naturalistic driving data, which are collected using smartphones and OBDs. In this work, the existing literature is critically assessed in relation to conceptual, methodological and data related aspects. The analyses result to a set of limitations and challenges that are further discussed in the framework of system wide implementations for deriving policies that increase drivers’ awareness, but also improve system performance.

Experimental Investigation of a Direct Evaporative Cooling System for Year-Round Thermal Management with Solar-Assisted Dryer

Building cooling is achieved by the extensive use of air conditioners. These mechanically driven devices provide thermal comfort by deteriorating the environment with increased energy consumption. To alleviate environmental degradation, the need for energy-efficient and eco-friendly systems for building cooling becomes essential. Evaporative cooling, a typical passive cooling technique, could meet the energy demand and global climatic issues. In conventional direct evaporative cooling, the sensible cooling of air is achieved by continuous water circulation over the cooling pad. Despite its simple operation, the problem of the pad material and water stagnation in the sump limits its usage. Moreover, the continuous pump operation increases the electrical energy consumption. In the present work, a porous material is used as the water storage medium eliminating the pump and sump. An experimental investigation is performed on the developed setup, and experiments are conducted for three different RH conditions (low, medium, and high) to assess the porous material’s ability as a cooling medium. Cooling capacity, effectiveness, and water evaporation rate are determined to evaluate the direct evaporative cooling system’s performance. The material that replaces the pump and sump is vermicompost due to its excellent water retention characteristics. There is no necessity to change material each time. However, the vermicompost is regenerated at the end of the experiment using a solar dryer. The passing of hot air over the vermicompost also avoids mould spores’ transmission, if any, present through the air. The results show that vermicompost produces an average temperature drop of 9.5°C during low RH conditions. Besides, vermicompost helps with the energy savings of 21.7% by eliminating the pump. Hence, vermicompost could be an alternate energy-efficient material to replace the pad-pump-sump of the conventional evaporative cooling system. Further, if this direct evaporative cooling system is integrated with solar-assisted drying of vermicompost, it is possible to provide a clean and sustainable indoor environment. This system could pave the way for year-round thermal management of building cooling applications with environmental safety.

A field investigation of the thermal environment and adaptive thermal behavior in bedrooms in different climate regions in China.

Sleep thermal environments substantially impact sleep quality. To study the sleep thermal environment and thermal comfort in China, this study carried out on-site monitoring of thermal environmental parameters in peoples' homes, including 166 households in five climate zones, for one year. A questionnaire survey on sleep thermal comfort and adaptive behavior was also conducted. The results showed that the indoor temperature for sleep in northern China was more than 4°C higher than that in southern China in winter, while the indoor temperatures for sleep were similar in summer. Furthermore, 70% of people were satisfied with their sleep thermal environment. Due to the use of air conditioning and window opening in various areas in summer, people were satisfied with their sleep thermal environments. Due to the lack of central heating in the southern region in winter, people feel cold and their sleep thermal environment needs further improvement. The bedding insulation in summer and winter in northern China was 1.83clo and 2.67clo, respectively, and in southern China was 2.21clo and 3.17clo, respectively. Both northern China and southern China used air conditioning only in summer. People in southern China opened their windows all year, while those in northern China opened their windows during the summer and transitional periods.