Heating Degree Days Research Articles

Relative Comparison of Benefits of Floor Slab Insulation Methods, Using Polyiso and Extruded Polystyrene Materials in South Africa, Subject to the New National Building Energy Efficiency Standards

This article aims to assess the benefits of floor slab insulation measures using extruded polystyrene (XPS) and polyisocyanurate (also referred to as polyiso or PIR) insulation materials at various levels of insulation thicknesses for a detached residential building. An EnergyPlus simulation analysis was carried out within the seven energy zones (represented by eight locations) of South Africa in accordance with the South African national code for building energy efficiency (SANS10400-XA). The energy savings and payback periods related to the use of the insulation over a lifecycle period of 50 years were assessed. Cape Town (zone 4) behaved differently from other locations and hardly benefited from the application of floor slab insulation measures. Generally, polyiso (PIR) insulation performed better than XPS for vertical gap insulation, and lower insulation thicknesses required higher insulation depths to maximize energy savings. Similarly, lower insulation thicknesses (25 mm and 50 mm) required higher perimeter insulation widths to maximize energy savings for horizontal perimeter insulation, especially in Sutherland (zone 6) and Cape Town. The maximization of energy savings was also achieved at low insulation thickness for the full floor slab insulation method, except for Sutherland and Fraserburg (zone 7). The locations that benefitted most from the floor slab insulation methods were Pretoria (zone 5), Thohoyandou (zone 3), Sutherland (zone 6), Fraserburg (zone 7), Welkom (zone 1), Ixopo (zone 5H), Witbank (zone 2), and Cape Town (zone 4), in that order. Generally, higher net energy savings are achieved in areas with lower humidity levels and areas with greater annual sums of both cooling and heating degree days.

Determination of optimum insulation thickness of building walls according to four main directions by accounting for solar radiation: A case study of Erzincan, Türkiye

Reducing heat transfer from the building will reduce the energy cost required to heat the building. Significant energy savings of 25 % to 50 % can be achieved when the appropriate thickness of thermal insulation is applied to the building walls. In this study, calculations were made to determine the optimum insulation thickness of some thermal insulation materials used to reduce the heat transfer from buildings in Erzincan, located in Türkiye's fourth climate zone. The optimum thickness of the thermal insulation to be applied to the external walls was determined using the heating degree day method, taking into account the effect of solar radiation according to the four main directions. Optimum insulation thicknesses and payback periods were calculated for combinations of two building materials (pumice and bricks), four fuels (fuel oil, LPG, natural gas, and coal), and three insulation materials (XPS, EPS, and Rock wool). The numbers of heating degree days were calculated as 2229 in the north, 1425 in the east and west, and 1118 in the south direction for the four main wall directions. The lowest optimum insulation thickness for these heating degree day values, which minimizes the total heating cost, was obtained for pumice/XPS/natural gas combination. The optimum insulation thicknesses for this combination were calculated as 0.037 m in the north, 0.025 m in the east and west, and 0.02 m in the south direction. The calculated payback periods for all combinations range from 0.9 to 4 years and the payback period of Pumice/XPS/Natural Gas combination is 4 years.

Effect of Elevated Air Temperature on the Growth and Yield of Paddy Rice

Rice is one of the major food crops, particularly in Asia. However, it is vulnerable to high temperature and has high yield fluctuations. Monitoring crop growth and physiological responses to high temperatures can help us better understand the agricultural impacts of global warming. The aim of this study is to monitor growth, development, and physiological responses to high temperature conditions on paddy rice and to assess their combined effects on yield. In this study, changes to growth, maturity, and senescence in paddy rice throughout the growing season were identified under elevated air temperature conditions created by a temperature gradient field chamber (TGFC). That facility provides a gradient from the ambient air temperature (AT) to 3 °C above AT (AT + 3 °C). To represent crop physiology and productivity, we measured the plant height, chlorophyll, normalized difference vegetation index (NDVI), and maximum photosynthetic rate (Amax) to assess growth and physiological processes, and heat stress effects on four yield measurements were assessed using the heating degree day index. Rice height increased more rapidly in the AT + 3 °C treatment from the early growth stage to heading, while SPAD and NDVI decreased more rapidly at AT after heading. The Amax of AT and AT + 3 °C was not significantly different in the tillering stage. However, it was higher at AT in the booting stage but higher at AT + 3 °C in the grain filling stage. These results indicate that paddy rice was not affected by heat stress at the tillering stage, but a cumulative effect emerged by the booting stage. Further, photosynthetic capacity was maintained much later into the grain filling stage at AT + 3 °C. These results will be useful for understanding the growth and physiological responses of paddy rice to global warming.

Field study of energy and environmental performance of ground source heat pumps retrofitted in a cluster of UK social housing dwellings

This paper uses an empirical field based approach to examine seasonal variation in heat pump electricity use and indoor temperatures across a cluster of 50 social housing dwellings retrofitted with ground source heat pumps (GSHP). The case study dwellings were co-located in a socially deprived housing estate in Oxford (UK). Time series monitoring data was collected on indoor, outdoor and target temperatures, heat pump electricity use (kWh), space heating and hot water operation status (on/off) in non-heating and heating seasons. Contextual data about the dwellings were gathered through heat pump surveys and energy performance certificates. Results showed 60% rise in electricity use during the heating season with statistically significant correlation observed between indoor and target temperatures, energy efficiency rating and monthly electricity use. When electricity use was normalised for outdoor temperature, lower electricity use per heating degree day (HDD) was observed in the heating season in the majority of dwellings, confirming the efficient running of the heat pumps. Mean daily indoor temperatures were found to be stable across majority of dwellings, with peak electricity use largely happening outside of the national evening peak period of 4pm-7pm. Despite there being a ‘Timer’ mode in relation to outside weather, most of the residents used the ‘Manual’ mode of operation to adjust target temperatures, possibly to overcome the low output temperatures of heat pumps. While resident training will help to enhance understanding of heating controls, smarter operation of heat pumps through automation based on optimisation of indoor and outdoor temperature, occupancy patterns, heating preferences and electricity price signals could result in further energy savings.

Skilful sub‐seasonal forecasts of aggregated temperature over Europe

AbstractSubseasonal‐to‐seasonal (S2S) forecasts span the prediction range of weeks to 2–3 months ahead, bridging the gap between medium‐range and seasonal weather forecasts. There has been growing interest in S2S forecasts in recent years, largely because of the many potential uses of forecasts spanning these timescales. However, the skill of S2S forecasts beyond the first 2 weeks or so is poor, potentially limiting the usability of these forecasts. We show in this study that when considering accumulated temperatures, there is in fact good forecasting skill over Europe for accumulation periods up to 30 days ahead. Using a set of S2S hindcasts, we show using both a deterministic and a probabilistic measure of skill that the accumulated 2‐metre temperature forecasts out to 30 days are skilful over most of Europe. In summer, South West Europe has highest skill, while in winter North East Europe has highest skill. As an example application of such forecasts, we also evaluate the skill for summer cooling degree‐days (CDD) and winter heating degree‐days (HDD). For 30‐day winter HDD, there is good skill in all four European regions; for 30‐day summer CDD, the skill is limited in North West Europe, but still good in other regions.

BEM to BIM in the early design phase: A comparison between static and dynamic heating energy predictions

Due to climate change and increasing pressures on resources, the demand for more energy-efficient buildings is increasing globally. Building information modeling (BIM) and building energy modeling (BEM) are two essential tools to make the necessary transition to net-zero energy buildings (NZEB). This article presents two case studies aiming to automate information from the BIM model to predict annual heating energy use at the early design phase (EDP) using static energy calculations. This article presents a comparison between results obtained with the static and dynamic energy calculations with the building energy simulation (BES) package IDA-ICE. The goal of the static calculations is to allow working directly in the BIM model in real time to obtain annual energy use based on building surfaces, heated floor area, heated volume, and other inputs related to the heating degree-day (HDD) method. This article shows that the static method provides results that differ by ±25% from results of the dynamic method, which is sufficiently precise at an early design phase to provide guidance to the architects, who make key decisions affecting building energy performance.

Application of Silica-Aerogel-Fibre-Based Thermal Renders for Retrofits in Building Walls: A Comparative Assessment with Benchmark Solutions.

The current climate change context raises the demand for reducing energy and environmental impacts while keeping an economic balance and building users' comfort. Thermal insulation solutions are potential allies in ensuring the adequacy of existing buildings for challenging sustainability requirements. In this scenario, silica-aerogel-fibre-based thermal renders are innovative solutions for which integrated approaches still lack information, and they should be compared with benchmark multilayer solutions, such as those based on expanded polystyrene (EPS), extruded polystyrene (XPS), mineral wool (MW), and insulated corkboard (ICB), to evidence their prospective economic, environmental, and energy benefits. This paper quantifies the optimum insulation thicknesses, life cycle savings, payback periods, and environmental impacts of innovative thermal renders compared to conventional thermal insulation materials when applied as a retrofit in existing facade walls. The results show that cost-optimised thermal renders with sisal fibres led to the best overall performance. Higher heating needs led to higher optimum render thicknesses and life cycle savings. With a 0.02 m thickness, aerogel-fibre-based thermal renders outperformed other materials in terms of heating-degree days (HDD) from 1000 °C·day onwards; they can save approximately EUR 60∙m-2, 1000 MJ∙m-2, and 100 kg CO2 eq∙m-2 while presenting a U-value 13% lower throughout their 30-year lifetime when compared with the second-best multilayer solution with XPS.

Driving factors of energy related CO2 emissions at a regional level in the residential sector of Iran

Iran has increased its CO2 emissions significantly during the past few decades. The household sector in Iran contributes one of the largest sectors of CO2 emissions. Despite this significant contribution, the existing policies have predominantly concentrated on large-scale initiatives while overlooking the regional role in shaping and implementing these plans. Therefore, this study investigates the relationship between CO2 emissions and the efficient factors in three major groups including energy, climate, and household socio-economic factors. This study aims to address regional carbon emissions and develop CO2 reduction policies tailored to each region's specific circumstances. It focuses on planning strategies at the regional level to effectively tackle CO2 emissions. Household panel data of 28 provinces of Iran are employed by using both static and dynamic panel models for the years 2001 to 2019. Static estimation includes Fixed Effect (FE), Random Effect (RE) and pooled Partial least squares (PLS), Dynamic estimation includes difference Generalized Method of Moments (GMM) and system Generalized Method of Moments (GMM). The empirical result of the static method showed positive dependence of household CO2 emissions on Heating Degree Days (HDD), Cooling Degree Days (CDD), precipitation level, oil consumption, gas consumption, household income, size of household, and also building stocks. In more detail, educational rate, dummy variable (removal of energy subsidy), and oil price reveal the greatest negative impact on the emissions with elasticities of − 0.428, − 0.31, and − 0.15; It represents 1% increase causes − 0.428, − 0.31, − 0.15, decrease CO2 emissions, respectively. however, household size, gas consumption, and oil consumption show the most significant positive effects on CO2 emissions with 1 percent increase causes CO2 emissions increases by 0.1, 0.044, and 0.026, respectively. Regarding the impact of climate factors, a 1% increase in Heating Degree Days, Cooling Degree Days, and precipitation level causes CO2 emissions increase by 0.024%, 0.004%, and 0.011% respectively, due to an increase in fossil energy demand. Results of the dynamic method of the system Generalized Method of Moments are similar to the static estimation results, except for that household size and urbanization are not significant. Also, removing the energy subsidy for fossil fuels due to substantial subsidy in fossil fuels in Iran or implementing a re-pricing energy policy can be a beneficial way to control carbon emissions from households within the provinces of the country. However, it is important to consider that this shift could potentially transfer subsidies to investments in the private sector for renewable energies.

Energy Audits and Energy Modeling as a Tool towards Reducing Energy Consumption in Buildings: The Cases of Two Multi-Unit Residential Buildings (MURBs) in Toronto

This research is based on an energy audit of two multi-unit residential buildings (MURBs) located in Toronto, Canada. Energy consumption (gas and electricity) data were extracted from the energy bills of the two buildings for a consecutive period of three years. The data were then normalized to account for variations in weather conditions. Conclusions were drawn from correlation analyses between kWh, cooling degree days (CDDs), and heating degree days (HDDs), which were then compared to the energy consumption benchmarks of MURBs within the GTA. An energy simulation using e-Quest v.3.64 was performed, utilizing the advantages of the e-Quest building modeling tool to create a virtual 3D model of the audited buildings. A baseline model was constructed to reflect the actual buildings and was used to simulate the outcomes and calculate the projected energy savings from window replacements with a higher energy efficiency than the existing ones. The simulation results revealed that triple low-E glazing outperformed single- and double-glass windows, achieving reductions of 38% and 34% in gas consumption, respectively. The building envelope simulations showed that enhancing insulation reduced gas consumption by 4%, while an insulation upgrade demonstrated no discernible savings. Reducing the window area by 20% (north/south sides) led to a 6% decrease in gas consumption, while a 30% reduction resulted in approximately 9% of energy savings.

A fuzzy cognitive map-based algorithm for predicting water consumption in Spanish healthcare centres

The management of water consumption in healthcare centres can have positive impacts on both the environmental performance and profitability of health systems. Computational tools assist in the decision-making process of managing the operation and maintenance of healthcare centres. This research aimed to integrate the empirical knowledge of experts in Healthcare Engineering and the historical data from 66 healthcare centres in a Fuzzy Cognitive Map. The outputs of the predictive model included water consumption, water cost, and CO2 emissions in healthcare facilities, along with eleven variables to discover the causes and consequences of water consumption in healthcare centres. A healthcare centre with about 12 350 users, located in a city that experiences an average of 1100 heating degree days, whose facilities be moderately energy-efficient contributing over 50% with renewable energies is expected to consume 8.4 dam3 of water with 32.1 k€ of cost, and contribute realising 30.8 ton CO2eq emissions. The use of Fuzzy Cognitive Maps for prediction can provide a high level of effectiveness in identifying the factors that contribute to water consumption and in designing key performance indicators to manage the environmental performance of healthcare buildings. This tool is extremely effective in enhancing the performance of the management division of health systems.

Ericoid shrub encroachment shifts aboveground-belowground linkages in three peatlands across Europe and Western Siberia.

In northern peatlands, reduction of Sphagnum dominance in favour of vascular vegetation is likely to influence biogeochemical processes. Such vegetation changes occur as the water table lowers and temperatures rise. To test which of these factors has a significant influence on peatland vegetation, we conducted a 3-year manipulative field experiment in Linje mire (northern Poland). We manipulated the peatland water table level (wet, intermediate and dry; on average the depth of the water table was 17.4, 21.2 and 25.3 cm respectively), and we used open-top chambers (OTCs) to create warmer conditions (on average increase of 1.2°C in OTC plots compared to control plots). Peat drying through water table lowering at this local scale had a larger effect than OTC warming treatment per see on Sphagnum mosses and vascular plants. In particular, ericoid shrubs increased with a lower water table level, while Sphagnum decreased. Microclimatic measurements at the plot scale indicated that both water-level and temperature, represented by heating degree days (HDDs), can have significant effects on the vegetation. In a large-scale complementary vegetation gradient survey replicated in three peatlands positioned along a transitional oceanic-continental and temperate-boreal (subarctic) gradient (France-Poland-Western Siberia), an increase in ericoid shrubs was marked by an increase in phenols in peat pore water, resulting from higher phenol concentrations in vascular plant biomass. Our results suggest a shift in functioning from a mineral-N-driven to a fungi-mediated organic-N nutrient acquisition with shrub encroachment. Both ericoid shrub encroachment and higher mean annual temperature in the three sites triggered greater vascular plant biomass and consequently the dominance of decomposers (especially fungi), which led to a feeding community dominated by nematodes. This contributed to lower enzymatic multifunctionality. Our findings illustrate mechanisms by which plants influence ecosystem responses to climate change, through their effect on microbial trophic interactions.

Predicting Building Energy Demand and Retrofit Potentials Using New Climatic Stress Indices and Curves

Building energy requalification in Italy and Europe has been much discussed in recent years due to the high percentage of existing buildings with poor energy performance. In this context, it is useful to obtain a user-friendly and fast tool to predict the thermal energy demand (TED) for space conditioning and the related primary energy consumption (PEC) as a function of climatic stress. In this study, the SLABE methodology (simulation-based large-scale uncertainty/sensitivity analysis of building energy performance) is used to simulate representative Italian buildings, varying parameters such as geometry, envelope and HVAC (heating, ventilating and space conditioning) systems. MATLAB® in combination with EnergyPlus is used to analyze 200 buildings belonging to two structural types (multi-family buildings and apartment blocks) built in 1961–1975. Nine scenarios (as-built scenarios and eight retrofit ones) are investigated in 63 climatic locations. A regression analysis shows that the classical HDDs (heating degree days) approach cannot give an accurate prediction of TED because solar radiation is not accounted for. Thus, new climatic indices are developed alongside solar radiation, including the heating stress index (HSI), the cooling stress index (CSI) and the yearly climatic stress index (YCSI). The purpose of our work is to obtain climatic stress curves for the prediction of TED and PEC. Testing of this novel approach is performed by comparison with another building energy simulation tool, showing a low discrepancy, i.e., the coefficient of variation of the root mean square error is between 12% and 28%, which confirms certain reliability of the approach here proposed.

Spatiotemporal trend analysis of climate indices for the European continent

Abstract The objective of this study is to analyze and visualize the spatial distribution of trends for 74 climate indices on a monthly time-scale in direction, magnitude, and significance level at a resolution of 0.1° during the period of 1950–2021 over the European region. The Mann–Kendall and Sen's slope estimators reveal that growing degree days with mean air temperature >4 °C (gd4) and heating degree days with mean air temperature <17 °C (hd17) show the largest increase (0.93 °C August) and decrease (1.03 °C July), respectively. The universal thermal climate index (utci), relative humidity (rh), wind chill index (wci), global radiation (bio20), and potential evapotranspiration (pet) are of significant importance due to higher correlation and magnitude of change. Country-specific zoning shows the highest warmer days during August experienced by Bosnia and Herzegovina (southeastern Europe) and lower colder days during January by Belarus (eastern Europe). High wind and high utci were experienced by Liechtenstein (southeastern Europe) region during July. The highest wci was experienced by San Marino (southern Europe) in June and Portugal (southern Europe) in March. Bio20 and rh decline were experienced by Russia (eastern Europe) and Moldova (southeastern Europe) in May and September, respectively. Results are useful to mitigate the risk associated with each of the climate indices for specific European regions.

Distribution range contractions and identification of conservation priority areas for canids in Sichuan Province, China

Canids are among the numerous taxonomic groups that have recently experienced significant population declines. The reconstruction of distribution range changes using long-term ecological data can reveal processes underlying spatial contractions that short-term studies may not detect. We integrated ecological niche modeling with long-term ecological records to estimate the magnitude of canid range contractions in Sichuan Province over the last 50 years. Our findings indicate that canid distributions underwent sharp contractions between the 1970 s and 2010 s (contraction rates: gray wolf Canis lupus 24.62%, dhole Cuon alpinus 75.65%, red fox Vulpes vulpes 48.63%, Tibetan fox V. ferrilata 26.88%, and raccoon dog Nyctereutes procyonoides 30.84%). Concerning environmental variables, our results suggest that altitude, dd＜18 (degree-days below 18 °C, heating degree-days), LUCC (land use), and human population density contributed the most to patterns of canid distribution between the 1970s and 2010s. Canid contraction rates in nature reserves were significantly lower than in other types of protected and non-protected areas. For all study species, 47% of the canid conservation priority areas on average have been protected in Sichuan Province. The Chinese government has recently upgraded canid species’ protection level and established more national parks. However, it is critical to invest in the surveillance of anthropogenic disturbance, compensation schemes for human–wildlife conflict, and public wildlife conservation education.

A Facility’s Energy Demand Analysis for Different Building Functions

A more accurate determination of energy demands for buildings is of utmost importance for estimating future energy demands. This article presents two novel ideas that have the potential to contribute to a more precise determination of expected energy demands. The first idea involves accounting for a building’s function more thoroughly, which enables the determination of different energy demands for two or more identical buildings, depending on their respective usage functions. According to a case study, the heating energy demand can be up to twice as high in a commercial facility compared with a residential building. Similarly, the cooling energy requirement can also differ. The second idea concerns determining the heating degree day (HDD) and cooling degree day (CDD) values from the daily minimum and maximum temperatures. This idea may be relevant when few instantaneous values are available for the daily mean temperature. According to the case study, the calculated values from the daily minimum and maximum temperatures follow the HDD and CDD values specified from the daily mean temperature. However, the difference is less than 2% for the heating season and higher for the cooling season. Therefore, further research is required to refine the constants in the cooling equation.

The heat stress during anthesis and the grain-filling period of spring maize in Northeast China is projected to increase toward the mid-21st century.

Against the background of global warming, heat stress has become more frequent, which adversely affects the growth and development of spring maize plants in Northeast China. To adapt the regional maize production to climate change, it is imperative to understand the spatio-temporal characteristics of heat stress. In the present study, we analyzed three of the indices for heat stress, including the number of heat stress days, heating degree days (HDD, the total heat degree-days during critical stages), and the percentage of stations with heat stress. From 1981 to 2019, the number of heat stress days varied greatly among the study years, ranging from 0 to 14 and 27 days, respectively. The average HDD was 7.8 and 5.0 °C day from 1981 to 2000, respectively, and the main hot-spots of heat stress occurred in the southwest regions. Moreover, compared with 1981-2000, the region of HDD during anthesis higher than 10 °C day in 2041-2060 under the SSP1-2.6 and SSP5-8.5 climate scenarios increased by 9.1-50.1% and 0.1-28.6%. The average HDD during the critical stages from 2041 to 2060 increased under the SSP5-8.5 climate scenario, being 1.5 times higher than that during 1981-2000. HDD during maize anthesis and the grain-filling period showed an overall increasing trend with years. About 19% and 58% of the study locations showed heat stress during the past 39 years, respectively. Heat stress during anthesis and the grain-filling period for spring maize in Northeast China is projected to increase toward the mid-21st century. © 2023 Society of Chemical Industry.

Evaluation of the Primary Energy and Carbon Dioxide Emissions of a Passive Ventilation System with a Solar Air Heater

Improvements in envelope performance have reduced heat loss from insulation, and the ratio of heat loss through ventilation load has become relatively large. In recent years, the use of heat recovery ventilation systems (HRV) has particularly increased. However, ventilation generates not only ventilation load but also air conveying fan power, such that conserving energy for both is important. Therefore, this paper focuses on a passive ventilation system with a solar air heater (PVSAH), which is a passive ventilation system that does not use air conveying fan power and uses a solar air heater that uses solar energy. The total energy consumption of the PVSAH, the widely used mechanical exhaust ventilation system (EV), and the HRV, which has high energy efficiency, was compared with the ventilation load plus air conveying fan power. The primary energy evaluation and carbon dioxide (CO2) emissions were compared by region, and the optimal system was proposed according to regional characteristics. In warmer zones, the PVSAH saved the most energy, while the HRV increased energy consumption. The comparison of CO2 emissions by ventilation systems when using heat pumps for cooling and heating showed that PVSAH > MEV > HRV for Heating Degree-Day (HDD) 1500 and below, PVSAH > HRV > MEV for HDD 1500 to 2750, and HRV > PVSAH > MEV for HDD 2750 and above. MEV were favored in that order. As the CO2 emission factor decreases, the difference in CO2 emissions between systems decreases. If the difference in emissions becomes smaller, then considering the initial and running costs and the risk of failure of the system is crucial. A simple system configuration with low risks of failure and maintenance, such as PVSAH, may prove advantageous in the future.

The Distribution of Energy Efficiency and Regional Inequality

This paper uses data on heating bills to study the distribution of energy efficiency outcomes in the German multi-apartment residential building stock. To uncover the underlying energy efficiency of buildings, we estimate the causal response of heat energy demand to variability in heating degree days. We examine the heterogeneity in temperature response using both fixed effects regressions and causal forests, and pay close attention to the regional socioeconomic distribution. Our results suggest that the distribution of energy efficiency is not equitable in the West of Germany. We show that although the newer and more energy-efficient buildings are located in the South of Germany, the older building stock in less prosperous East regions of Germany are surprisingly energy efficient, likely as a result of large investments in renovations post-reunification. Finally, we show that the regional distribution of energy efficiency reflects, in part, differences in heating needs – thus, the poorer energy standards of buildings in the North-West should be weighed against the warmer climatic zone.

Analysis of heating degree-days (HDD) data using machine learning and conventional time series methods

Analysis of heating degree-days (HDD) data using machine learning and conventional time series methods

Energy Analyses of Multi-Family Residential Buildings in Various Locations in Poland and Their Impact on the Number of Heating Degree Days

Reducing energy demand and greenhouse gas emissions in the construction industry is one of the daunting challenges to be addressed in the context of global warming. The purpose of these analyses was to examine how the energy class of a multi-family residential building regarding thermal insulation and type of ventilation affects the usable energy demand for heating and ventilation purposes, the length of the heating season, and the amount of demand for energy consumed by auxiliary devices. This article presents the energy analyses of multi-family residential buildings with identical technical parameters located in different locations in Poland. For research purposes, a total of 354 energy balances were compiled, covering 59 meteorological stations, 3 types of ventilation systems, and 2 building insulation standards. This article presents the ways in which the location and energy class of buildings affect the length of the heating season and the demand for energy required for heating and ventilation purposes. The results of the analyses carried out in this article show that the location and the energy class of the building have a significant impact on the demand for primary energy (EP). As a result, it was concluded that when designating a reference building for the energy rating system, its location should be taken into account and reference buildings should be designated considering climate zones.