Heating systems

The composition of heating systems used in the building stock is the link from the computed energy need to energy use. Energy need states what the building requires in terms of space heating, non-substitutable electrical use and domestic hot water. The composition of heating systems in the building stock assigns specific heating technologies to meet the energy demand for space heating and domestic hot water. Various heating technologies have different efficiencies and energy products which then determines the energy use.

A combination of different heating systems can be assigned to each building category and each age group (building code). It is also possible to do this on an aggregated level, e.g. giving all non-residential area the same heating system. For instance, 5 % of the house area use only direct resistance heating to heat the home, while 56 % of the house area use a combination of direct resistance heating, an air-to-air heat pump and a wood stove. The composition of heating solutions can be changed over time in the forecast period and the initial heating systems share can be adjusted in the calibration process.

The input to EBM is the aggregated composition of heating systems houses, apartment blocks and non-residential buildings, in other words the share of e.g. the area in houses that use the different heating systems. The source of the initial composition is the Norwegian energy performance building database which has been processed outside of EBM and described under data assumptions NVE. As part of this processing, the use of different energy products in the different building categories is compared with the national energy balance to fine tune the distribution of the various heating technologies. The process is described under model functionality and data assumptions NVE and an overview is shown in the flowchart below.

Model functionality

Making changes to heating systems

The easiest way to change the initial shares of heating systems is through Kalibreringsark.xlsx as part of the calibration process described here Calibrating the model. The input file 🧾 heating_system_initial_shares.csv remains unchanged with this method. It is also possible to change the heating systems share in the input file. All combinations of building code and building category are given their own heating systems share. In the input file, the shares are indentical within the building groups of house, apartment block and non-residential building.

Making changes to the efficiency, energy product or load share factor can be done for each of the 12 combinations of heating systems in the input file 🧾 heating_system_efficiencies.csv. An overview of the heating system combinations can be found in the Tables and glossary subchapter.

Data assumptions NVE

Selecting certificates

The initial heating system shares are based on the Norwegian energy building performance database. The database contains information on the energy class of certified buildings. There are 1,2 million certificates in total spread out among the 13 building categories, however for some categories, especially non-residential buildings, the number of certificates are low. Some cleaning is done on the dataset to filter out misleading certificates and duplicates. The cleaning steps done are the following:

• Removed certificates that were missing building category, heated floor area or energy performance label.

• Removed certificates where calculated delivered energy per is above 1000 kWh/m ².

• If a certificate has been issued to the same address more than once, the most recent certificate is kept. This is done for all building categories except for apartment blocks or hospitals as one address can contain multiple buildings or apartments. For apartments the apartment number is often missing.

After these three steps there are about 1 million certificates remaining. The associated building code classification is added to the certificates based on the supplied. building year.

Determining heating systems

The certificates have a column for “heating system”. This column can vary from one or more energy products to a combination of various technologies. About 130 000 certificates do not have this information. For certificates missing this information an estimate is done based on the combination of “delivered energy”. For example, if the certificate has values for “bio” and “electricity” the heating system is set to “Electricity - Bio”. This results in 190 different heating systems which are aggregated to 12 categories shown in the table below, together with the corresponding technology for the different loads and domestic hot water. The abbreviations in the “Heating systems” column are explained in the table heating systems abbreviations under the Tables and glossary section.

Heating systems overview

Heating systems	Base load	Peak load	Tertiary load	Domestic hot water
Electric boiler	Electric boiler			Electric boiler
DH	DH			DH
Electricity	Electricity			Electricity
Gas	Gas			Gas
Electricity - Bio	Electricity	Bio		Electricity
DH - Bio	DH	Bio		DH
HP - Bio - Electricity	HP	Bio	Electricity	Electricity
HP - Electricity	HP	Electricity		Electricity
HP Central heating - Electric boiler	HP Central heating	Electric boiler		HP Central heating
HP Central heating - Gas	HP Central heating	Gas		HP Central heating
Electric boiler - Solar	Electric boiler	Solar		Electric boiler
HP Central heating - Bio	HP Central heating	Bio		HP Central heating

Calculating the heating system share

The useful area summed up per heating system, building category and building code is then divided by the total useful area of the given building category and building code to give the heating system shares. The useful area is part of the energy certificates. This can be written as:

\[\text{heating system share} = \frac{\sum^n_{area_{hs}}}{\sum^k_{area_{bc}}}\]

Where:

• area in this context is the useful area given by the energy performance certificates.

• \(area_{hs}\) is the useful area for a given group of heating system, building category and building code. For example: Electricity - Bio, House, TEK49

• \(area_{bc}\) is the useful area for a given group of building category and building code. For example: House, TEK49.

• \(n\) and \(k\) is the number of certificates in the respective group.

Manual tuning of heating systems

The process described above gives a good starting point for the distribution of heating systems, but manual tuning is needed. The manual tuning of heating systems is done to roughly hit the energy use from statistics before calibration. Manual tuning is done by shifting a percentage of one heating system to another on a per building and building code basis. An example is given below which shifts 45 % of the district heating technology share into Heat pump central heating and electric boilers for apartment blocks in TEK07, TEK10 and TEK17.

{
  "current_heating_system": "DH",
  "new_heating_system": "HP Central heating - Electric boiler",
  "share": 0.45,
  "list_buildings": ["Apartment block"],
  "list_TEK": ["TEK07", "TEK10", "TEK17"]
}

Aggregating the heating systems

🧾 heating_system_initial_shares.csv

The building energy performance database gives us information on heating systems across the various building codes and categories. However, for some building categories, especially for newer building codes, the number of certificates is too low to give a good representation of that particular building code and category. In addition, the energy balance statistics is reported on “residential” and “non-residential” buildings without any other details such as building code or specific building category. To get a good point of comparison we therefore aggregate the heating systems into three groups per building code based on the useful area in EBM:

• House

• Apartment block

• Non-residential buildings

For aggregation purposes it is assumed that all the area with the same combination of building category and building code have the same heating systems, regardless of the condition of the area. Finally, the share of heating systems is aggregated up to the three building groups. The new aggregated heating system shares are then determined for all the building codes in the three building groups. This means that a TEK69 house has the same composition of heating systems as a TEK17 house, and a TEK69 kindergarten has the same composition of heating systems as a TEK10 office. The resulting heating systems are then used as an input to EBM. An example of the aggregated composition of heating systems is given below for houses.

Aggregated heating systems - house

building_category	TEK	heating_systems	year	heating_system_share
house	PRE_TEK49	DH	2023	0.021
house	PRE_TEK49	DH - Bio	2023	0.007
house	PRE_TEK49	Electric boiler	2023	0.025
house	PRE_TEK49	Electric boiler - Solar	2023	0.0003
house	PRE_TEK49	Electricity	2023	0.052
house	PRE_TEK49	Electricity - Bio	2023	0.224
house	PRE_TEK49	HP - Bio - Electricity	2023	0.564
house	PRE_TEK49	HP - Electricity	2023	0.099
house	PRE_TEK49	HP Central heating - Electric boiler	2023	0.003

A final tuning of the heating systems is done in the calibration step of the model. For more information on calibration see Calibrating the model.

Heating systems efficiencies and load share

🧾 heating_system_efficiencies.csv

Each heating technology is either a base load, peak load, tertiary load or domestic hot water, making up the combined heating system. The different heating technologies have an associated efficiency factor, load share factor and energy product. The efficiency factor, together with the related energy product, is used to get energy use per energy product from energy need. For example, given that the energy need is only covered by the specific technology:

• Air-air heat pumps have an efficiency factor of 2,5 with electricity as an energy product. If the energy need for space heating is 1000 kWh, then the energy use is 400 kWh lectricity.

• Wood fired stoves have an efficiency factor of 0,65 with bio (fuelwood) as an energy product. If the energy need for space heating is 1000 kWh, then the energy use is 1538 kWh bio.

The load share factor decides how much of the heating need is covered by a specific technology. For example, an air-air heat pump can not provide heating to the whole building, it needs supplementation from another heating technology at extreme temperatures. The current efficiencies and coverage factors are assumptions made by NVE.

All the combinations can be found in the Tables and glossary subchapter.

Forecasting

🧾 heating_system_forecast.csv

Forecasting of heating systems towards 2050 are based on the following expected development:

• Natural gas is phased out as a heating system for buildings by 2030.

• Continued growth in use of air-air heat pumps in houses.

• Increase in use of water-borne heating in new apartment blocks and non-residential buildings due to building code requirements.

• Increase in use of electric boilers and central heating heat pumps due to more water-borne heating.

• District heating will increase in both non-residential buildings and in apartment blocks.

The current implementation of forecasting for energy systems is simplified, meaning it is not based on an economic optimization model such as TIMES.

Forecasting the use of heating systems

Forecasting the use of heating systems are necessary to go from energy need to energy use. The forecasting defines the change in one heating system to another heating system towards 2050. The change is done on a percentage basis compared with the start year and can be specified on building category and building code. To increase the share of one heating system, another must be decreased by the same amount. The percentage changes are given in the input file 🧾 heating_system_efficiencies.csv.

An illustration of the forecasting is given in the table below. The table has the same format as the input file 🧾 heating_system_efficiencies.csv, but with example numbers. The first row gives an example where all fossil gas is phased out in non-residential buildings in 2030. If the heating system share of “Gas” in non-residential buildings is 10 % in the start year, then the table states that 25 % of 10 % changes over to the combination “HP Central heating - Electric boiler” in 2025. That increases the overall share of “HP Central heating - Electric boiler” in 2025 by 2,5 % and decreases the share of “Gas” by 2,5 %.

In 2030 the table states that 1 or 100 % of of heating system “Gas” changes to “HP Central heating - Electric boiler”. The heating system share of “Gas” has not changed in the start year and is still 10 %. That increases the overall share of “HP Central heating - Electric boiler” in 2030 by 10 % and decreases the share of “Gas” by 10 % which results in the heating system “Gas” being phased out by 2030.

The second row of the forecasting illustration increases the share of the heating system “HP - Electricity - Bio” in houses by decreasing the share of “Electricity - Bio”. In this example the intial heating system share of “Electricity - Bio” is 20 %. In 2040 it states that 50 % of “Electricity - Bio” changes over to “HP - Electricity - Bio”. The intial share is 20 % so that means that 10 % in total (50 % of 20 %) changes over to the new heating system “HP - Electricity - Bio”. In 2050 100 % of the heating system “Electricity - Bio” has changed over to “HP - Electricity - Bio” and the overall heating system share of “HP - Electricity - Bio” for houses has been increased by 20 percentage points.

Heating systems forecasting illustration.

Building category	building code	Initial heating systems	Shares	New heating systems	2024	2025	2030	2040	2050
non_residential	default	Gas	0.10	HP Central heating - Electric boiler	0.10	0.25	1	1	1
house	default	Electricity - Bio	0.20	HP - Bio - Electricity	0.05	0.10	0.25	0.5	1

An example on how the forecasted share of heating systems can look are shown in the figure below. Here the share of air-air heatpumps is increased over time by shrinking the share of “Electricity - Bio” and increasing the share of “HP - Electricity - Bio”. With the same rates as in the table above.

Tables and glossary

Tables

The table below shows the abbrevations used for the various heating systems. The full terms are also explained in more detail under Heating systems glossary.

Heating systems abbreviations

Heating systems abbreviations	Full term
Electric boiler	Electric boiler
DH	District heating
Electricity	Electricity (direct resistance heating)
Gas	Gas
Electricity - Bio	Electricity - Bioenergy (fuelwood)
DH - Bio	District heating - Bioenergy (fuelwood).
HP - Electricity - Bio	Air-air heat pump - Electricity (direct resistance heating) - Bioenergy (fuelwood)
HP - Electricity	Air-air heat pump - Electricity (direct resistance heating)
HP Central heating - Electric boiler	Heat pump central heating - Electric boiler
HP Central heating - Gas	Heat pump central heating - Fossil natural gas
Electric boiler - Solar	Electric boiler - Solar heat collector
HP Central heating - Bio	Heat pump central heating - Bioenergy (fuelwood)

The tables below show the various combinations of heating systems and heating technologies.

Heating systems efficiency

Heating systems	Base load	Peak load	Tertiary load	Base load efficiency	Peak load efficiency	Tertiary load efficiency
Electric boiler	Electric boiler			0,98	1	1
DH	DH			0,99	1	1
Electricity	Electricity			1,00	1	1
Gas	Gas			0,96	0,96	1
Electricity - Bio	Electricity	Bio		1,00	0,65	1
DH - Bio	DH	Bio		0,99	0,65	1
HP - Electricity - Bio	HP	Electricity	Bio	2,50	1	0,65
HP - Electricity	HP	Electricity		2,50	1	1
HP Central heating - Electric boiler	HP Central heating	Electric boiler		3,00	0,99	1
HP Central heating - Gas	HP Central heating	Gas		3,00	0,96	1
Electric boiler - Solar	Electric boiler	Solar		0,98	0,7	1
HP Central heating - Bio	HP Central heating	Bio		3,00	0,65	1

Heating systems coverage

Heating systems	Base load	Peak load	Tertiary load	Base load share	Peak load share	Tertiary load share
Electric boiler	Electric boiler			1.0	0.0	0.0
DH	DH			1.0	0.0	0.0
Electricity	Electricity			1.0	0.0	0.0
Gas	Gas			1.0	0.0	0.0
Electricity - Bio	Electricity	Bio		0.7	0.3	0.0
DH - Bio	DH	Bio		0.95	0.05	0.0
HP - Electricity - Bio	HP	Electricity	Bio	0.5	0.4	0.1
HP - Electricity	HP	Electricity		0.5	0.5	0.0
HP Central heating - Electric boiler	HP Central heating	Electric boiler		0.85	0.15	0.0
HP Central heating - Gas	HP Central heating	Gas		0.85	0.15	0.0
Electric boiler - Solar	Electric boiler	Solar		0.85	0.15	0.0
HP Central heating - Bio	HP Central heating	Bio		0.85	0.15	0.0

Heating systems domestic hot water

Heating systems	Domestic hot water	Domestic hot water efficiency
Electric boiler	Electric boiler	0.98
DH	DH	0.99
Electricity	Electricity	0.98
Gas	Gas	0.96
Electricity - Bio	Electricity	0.98
DH - Bio	DH	0.99
HP - Bio - Electricity	Electricity	0.98
HP - Electricity	Electricity	0.98
HP Central heating - Electric boiler	HP Central heating	3.0
HP Central heating - Gas	HP Central heating	3.0
Electric boiler - Solar	Electric boiler	0.98
HP Central heating - Bio	HP Central heating	3.0

Heating systems glossary

Glossary of terms used in heating systems

English	Norwegian	Norwegian explanation	Explanation
Heating systems	Oppvarmingsløsninger	Kombinasjon av en eller flere oppvarmingsteknologier. Er en andel som summerer seg til 1 innenfor hver kombinasjon av TEK og bygningskategori.	Combination of one or more heating technologies. Fraction which adds up to 1 for each combination of building code and building category.
Base load	Grunnlast	Oppvarmingsteknologien som dekker majoriteten av oppvarmingsbehovet.	The heating technology that meets the majority of the heating need.
Peak load	Spisslast	Oppvarmingsteknologiensom dekker det resterende oppvarmingsbehovet.	The heating technology that meets the remaining heating need.
Tertiary load	Ekstralast	Oppvarmingsteknologien som dekker det resterende oppvarmingsbehovet etter grunnlast og spisslast.	The heating technology that meets the remaining heating need after base and peak load.
Base load energy product	Grunnlast energivare	Energivaren som brukes avgrunnlasten.	The energy product used by the base load.
Peak load energy product	Spisslast energivare	Energivaren som brukes av spisslasten.	The energy product used by the peak load.
Tertiary load energy product	Ekstralast energivare	Energivaren som brukes av ekstralasten.	The energy product used by the tertiary load.
Base load coverage	Grunnlast andel	Andelen av varmebehovet som dekkes av grunnlasten.	Share of the heating need covered by the base load.
Peak load coverage	Spisslast andel	Andelen av varmebehovet som dekkes av spisslasten.	Share of the heating need covered by the peak load.
Tertiary load coverage	Ekstralast andel	Andelen av varmebehovet som dekkes av ekstralasten.	Share of the heating need covered by the tertiary load.
Base load efficiency	Grunnlast virkningsgrad	Virkningsgrad, kan være over eller under 1.	Efficiency factor, can be smaller or larger than 1
Peak load efficiency	Spisslast virkningsgrad	Virkningsgrad, kan være over eller under 1.	Efficiency factor, can be smaller or larger than 1.
Tertiary load efficiency	Ekstralast virkningsgrad	Virkningsgrad, kan være over eller under 1.	Efficiency factor, can be smaller or larger than 1
Domestic hot water	Tappevann	Oppvarming av varmt vann til tappevannsbruk.	Heating of domestic hot water.
Domestic hot water energy product	Tappevann energivare	Hvilken energivare som brukes til å varme opp varmt tappevann.	Energy product used by the heating technology providing hot tap water.
Domestic hot water efficiency	Tappevann virkningsgrad	Virkningsgrad for teknologien som brukes til å varme opp varmt tappevann.	Efficiency factor for the technology providing hot tap water.
Cooling efficiency	Kjøling virkingsgrad	Virkningsgrad for kjølemaskin.	Efficiency factor for cooling unit.
Cooling	Kjøling	Kjølemaskin.	Cooling unit.
Direct resistance heating	Direktevirkende elektristiet.	Direktevirkende elektrisk oppvarming. For eksempel panelovn og vifteovn. Punktoppvarming.	Direct resistance heating. For example electric wall heater or convection ovens. Space heating.
Electric boiler	Elkjel	Elkjel. Vannbåren varme.	Electric boiler. Water borne heating.
District heating	Fjernvarme	Fjernvarme. Vannbåren varme.	District heating. Water borne heating.
Gas boiler	Gasskjel	Naturgasskjel. Vannbåren varme.	Natural gas boiler. Water borne heating.
Direct resistance heating – Wood stove	Direktevirkende elektristet - Vedovn	Direktevirkende elektrisitet og vedovn. Punktoppvarming.	Direct resistance heating and wood stove. Space heating.
District heating – Wood stove	Fjernvarme – Vedovn	Fjernvarme og vedovn. Vannbåren varme og punktoppvarming.	District heating and wood stove. Water borne heating and space heating.
Heat pump air air – direct resistance heating – wood stove	Luft luft varmepumpe – Direktevirkende elektrisitet – Vedovn	Luft luft varmepumpe, vedovn og panelovn (evt varmekabler). Punktoppvarming.	Heat pump air air, wood stove and direct resistance heating. Space heating.
Heat pump air air – Direct resistance heating	Luft luft varmepumpe – Direktevirkende elektrisitet	Luft luft varmepumpe og direktevirkende elektrisitet. Punktoppvarming.	Heat pump air air and direct resistance heating. Space heating
Heat pump central heating – Electric boiler	Vannbåren varmepumpe – Elkjel	Vannbåren varmepumpe (væske – vann eller luft – vann) og elkjel. Vannbåren varme.	Water borne heat pump and electric boiler. Water borne heating.
Heat pump central heating – Gas boiler	Vannbåren varmepumpe – Naturgasskjel	Vannbåren varmepumpe og fossilkjel. Vannbåren varme.	Water borne heat pump and fossil boiler. Water borne heating.
Electric boiler – Solar collector	Elkjel – Solfanger	Elkjel og solfanger. Vannbåren varme.	Electric boiler and solar collector. Water borne heating.
Heat pump central heating – Wood stove	Vannbåren varmepumpe - Vedovn	Vannbåren varmepumpe og vedovn. Vannbåren varme og punktoppvarming.	Water borne heat pump and wood stove. Water borne heating and space heating.
Heat pump central heating	Vannbåren varmepumpe	Samlebetegnelse for luft-vann, væske-vann (bergvarme, jordvarme eller sjøvarme) og ventilasjonsvarmepumpe.	Term for different types of heat pumps delivering hot water such as air-water, liquid-water (ground heat, ocean heat) and ventilation heat pumps.

Last Updated on 2025-11-06.

Version: 1.0.1.