[Paper Review] Estimating country-specific space heating threshold temperatures from national consumption data

Smail Kozarcanin, Gorm Bruun Andresen+1 more|arXiv (Cornell University)|Mar 27, 2019

Building Energy and Comfort Optimization33 references4 citations

TL;DR

This study proposes a method to estimate country-specific space heating threshold temperatures using publicly available national electricity and gas consumption data combined with weather data. By applying Akaike's Information Criterion (AIC) to identify the summer season when heating is not required, it finds that gas-heated countries average 15.0 ± 1.7 °C thresholds, while electrically heated countries average 13.4 ± 2.4 °C, with no evidence of heating in June–August despite positive heating degree-days.

ABSTRACT

Space heating in buildings is becoming a key element of sector-coupled energy system research. Data availability limits efforts to model the buildings sector, because heat consumption is not directly metered in most countries. Space heating is often related to weather through the proxy of heating degree-days using a specific heating threshold temperature, but methods vary between studies. This study estimates country-specific heating threshold temperatures using widely and publicly available consumption and weather data. This allows for national climate and culture-specific human behaviour to be captured in energy systems modelling. National electricity and gas consumption data are related to degree-days through linear models, and Akaike's Information Criteria is used to define the summer season in each country, when space heating is not required. We find that the heating threshold temperatures computed using daily, weekly and monthly aggregated consumption data are statistically indifferent. In general, threshold temperatures for gas heating centre around 15.0 +/- 1.7 degree C (daily averaged temperature), while heating by electricity averages to 13.4 +/- 2.4 degree C. We find no evidence of space heating during June, July and August, even if heating degree-days are present.

Motivation & Objective

• To improve accuracy in energy systems modeling by estimating country-specific space heating threshold temperatures.
• To address the lack of high-resolution heat consumption data by leveraging widely available electricity and gas consumption data.
• To identify the summer season—when space heating is not required—using statistical model selection (AIC) on heating degree-days.
• To demonstrate that aggregated consumption data (daily, weekly, monthly) yields statistically indistinguishable threshold estimates.
• To challenge the common practice of using uniform threshold temperatures (e.g., 16°C or 18°C) across multiple countries.

Proposed method

• Uses national electricity and gas consumption data aggregated at daily, weekly, and monthly resolutions.
• Calculates heating degree-days (HDD) using outdoor temperature data and varying threshold temperatures.
• Applies linear regression to model the relationship between HDD and energy consumption.
• Employs Akaike’s Information Criterion (AIC) to identify the optimal summer season (i.e., months with no heating demand) for each country.
• Tests the robustness of results across different data aggregation levels (daily, weekly, monthly).
• Classifies the summer season as the period with the lowest AIC value, indicating the best fit for no heating demand.

Experimental results

Research questions

• RQ1 What is the optimal country-specific heating threshold temperature for space heating using national consumption and weather data?
• RQ2 How does the choice of data aggregation (daily, weekly, monthly) affect the estimation of heating threshold temperatures?
• RQ3 Does the summer season—when space heating is not required—vary significantly across European countries, and can it be reliably identified using AIC?
• RQ4 To what extent do current assumptions of uniform threshold temperatures (e.g., 16°C or 18°C) misrepresent actual national heating demand patterns?
• RQ5 How do gas and electric heating systems differ in their threshold temperature profiles across countries?

Key findings

• Gas-heated countries exhibit a mean heating threshold temperature of 15.0 ± 1.7 °C, while electrically heated countries average 13.4 ± 2.4 °C.
• There is no statistically significant difference in threshold temperature estimates when using daily, weekly, or monthly aggregated consumption data.
• No evidence of space heating demand is found during June, July, and August in any of the studied countries, despite positive heating degree-days.
• The summer season—defined as the period with no heating demand—varies significantly across countries, with southern European nations (e.g., Portugal) having summer periods up to 9 months long.
• The study suggests that current national energy demand estimates for space heating in Great Britain may be overestimated by up to 93% if non-optimized threshold temperatures are used.
• Threshold temperatures vary significantly even among neighboring European countries, indicating that blanket assumptions (e.g., 16°C or 18°C) are not representative of national realities.