iDM heat pumps

iDM Energiesysteme is an Austrian heat pump maker whose products and technical guidance are published from Austria, in German and English, for the DACH region of Germany, Austria and Switzerland. Its air source line is the AERO family, which includes the AERO ALM range, the ALM 10-50 MAX and the AL TWIN, alongside a connected platform called the iNTELLiGENTE heat pump with the NAVIGATOR controller¹. In the UK, heat pumps remain a minority heating choice: around 1% of homes have one installed³, while the Climate Change Committee estimates approximately 10% of existing UK homes will need to be heated by a heat pump by 2030⁴.

For a UK household, an iDM heat pump is an imported appliance. The engineering, documentation and support model are Austrian, and the maker's commissioning and environmental guidance is written for the DACH market, so UK building regulations, grant rules and grid context apply on top of it. What follows sets out what iDM publishes about its products, what the UK rules require, and where the two need to be read together.

An Austrian maker with a long heat pump history

iDM Energiesysteme GmbH is an Austrian manufacturer, and everything it publishes about its heat pumps is written from that base. Its guidance pages cover installation parameterisation, heat distribution, environmental impact and operating limits, and its product documentation is dated and updated through 2026, which indicates an actively maintained product line rather than a legacy catalogue¹. The company's connected platform, the iNTELLiGENTE heat pump, carries the NAVIGATOR control system with cascade management and connectivity, plus optional iON and iVIS add-ons².

What that means for a UK buyer is a specific set of dependencies. The appliance is engineered, documented and supported from Austria, so spare parts, firmware and technical guidance flow through a foreign manufacturer and its distribution chain. That is not unusual in the UK heat pump market, but it is a real dependence: a household choosing iDM ties its heating to a company whose documentation, warranty terms and support arrangements are written for the DACH region first. The physics of the heat pump is identical wherever it is installed; the regulatory and support context is not.

The iDM line-up: AERO, TERRA, iPump and MAX

iDM's air source line is the AERO family. The maker's AERO overview, dated 13 July 2026, presents the AERO ALM range, the ALM 10-50 MAX and the AL TWIN, with capacities, costs and efficiency guidance¹. A companion page on air as a heat source lists the output ranges for the AERO ALM, SLM, ALM 10-50 MAX and AL TWIN alongside siting rules and corrosion risks¹. The TERRA ground source line, the iPump and the MAX complete the family names in iDM's catalogue.

The connected end of the range is the iNTELLiGENTE heat pump, described on product pages dated 10 July 2026. Its feature set includes the NAVIGATOR controller, cascade management and connectivity, with optional iON and iVIS add-ons². Cascade management matters for larger properties: it lets multiple units run as one controlled system rather than as separate appliances.

iDM does not publish UK prices, so any cost figure for an iDM installation is installer-quoted. What the maker does publish is capacity and efficiency guidance for its own ranges¹, which is the material a UK installer would use when sizing a system against a heat loss calculation.

Earth, air or water: how the heat source works

Every heat pump, iDM's included, works on the same underlying process, known as the refrigerant cycle: it extracts energy from the air, ground or water and converts it into heat¹⁰. iDM publishes an explainer of the four-stage vapour-compression cycle, with the performance metrics used to describe it¹⁰. The source determines the family:

• Air source units take heat from the air outside¹¹. Air-to-water heat pumps source their heat from the air outside and distribute it around the home via the hot water system¹¹.
• Ground source units transfer energy from the natural heat stored in the earth to heat the home and domestic hot water¹².
• Water source units use the energy stored in ground water, surface water, or sea or sewage water¹³.

There are also thermally driven heat pumps, which use heat or an engine to drive the compression cycle instead of an electric compressor¹³, though these are not the domestic norm. For a household weighing independence, the source choice sets different dependencies: an air source unit needs only an outdoor location and electricity, while ground and water source systems need ground works, boreholes or a water source, which is more upfront work for a more stable source temperature.

One system for both warming and cooling

A heat pump is a versatile system capable of providing heating, cooling and hot water for homes, commercial buildings and industrial applications¹⁰. In UK guidance, air source heat pumps can give both heating and cooling, which makes them versatile across seasons¹⁴, and air-to-air units can be configured for cooling as well as heating¹⁵. Air-to-air systems usually have one unit outside and at least one unit inside, connected by pipes carrying refrigerant between them¹⁵.

For an iDM AERO air-to-water system, cooling depends on the emitters: a wet system of radiators or underfloor pipes can deliver cooling only where the pipework and controls are designed for it, and underfloor circuits are the more common route. The maker's heat distribution guidance covers emitters, buffers, domestic hot water systems and hydraulic controls for the AERO range¹⁶, which is where the cooling and hot water arrangements for a specific installation are set out.

The practical point for a UK household is that heating and cooling from one appliance replaces both a boiler and, potentially, separate summer cooling, with one electricity metering point and one service relationship rather than several.

Existing radiators and flow temperatures: which are suitable

The question most retrofit households ask is whether the existing radiators can stay. The independent guidance is that air-to-water heat pumps work well in combination with large radiators and underfloor pipes¹¹, so a full emitter replacement is not inevitable. What changes is the water temperature flowing through them.

UK records for heat pumps provide values at flow temperatures of 35, 45 and 55 degrees C⁵, which are the test points at which efficiency is measured. In practice, guidance for radiator-sized systems suggests setting the minimum heat pump flow temperature to around 30 degrees C and sizing the system so the maximum sits around 45 degrees C⁶. Lower flow temperatures mean the heat pump condenses heat from electricity more efficiently, so bigger emitters running cooler generally cost less to run.

iDM's own heat distribution guidance for the AERO range covers emitters, buffer vessels, domestic hot water systems and hydraulic controls¹⁶, which is the maker's equivalent material. It is written for the DACH region, so a UK installer would apply it alongside UK sizing rules: heat pumps should be selected to meet the full space heating requirement at the design condition chosen for heat loss calculations¹⁷.

The limits of iDM heat pump performance

iDM publishes two guidance pages on limits: one defining the technical, legal and economic operating limits for heat pump systems and the relevant European standards¹⁸, and one on operating boundaries and boundary categories¹⁹. These are the maker's own statements of where its products stop being the right answer, and they are worth reading before purchase rather than after.

UK rules add their own boundaries. Heat pumps up to a capacity of 45kW are in scope of the official deployment statistics⁷, which marks the edge of the domestic market. Medium-temperature heat pumps are defined by delivering their declared capacity for heating at an indoor heat exchanger outlet temperature of 55 degrees C²⁰, so a home needing sustained high flow temperatures is at the harder end of the retrofit range. There is also an operational limit in how heat pumps prioritise loads: where a heat pump provides space heating and hot water, it will not provide any space heating until water heating demand is satisfied²¹.

The electricity supply can be a limit too. Where a property's new Maximum Demand is 60A or less and other requirements are met, the installer notifies the distribution network operator via the heat pump connection form within 28 days of installation; where new Maximum Demand sits between 60A and 100A inclusive, an application must be made prior to installation using the same form²². A house with a small electrical supply may need supply work before a heat pump can be connected.

UK availability and what owning one means

iDM heat pumps are sold in the UK through installers rather than a domestic manufacturing base. UK support is available for installers and manufacturers to expand supply chains²³, which reflects a market still scaling: around 20,000 domestic heat pumps are installed every year⁶, around 1% of homes have one³, and approximately 10% of existing homes will need to be heated by a heat pump by 2030⁴.

The rules a UK household faces are these:

• Microgeneration Certification Scheme certification is a requirement for heat pump installations made under the Domestic Renewable Heat Incentive, the Green Homes Grant and the Clean Heat Grant²⁴, and MCS certification is the route to grant support.
• Boiler Upgrade Scheme eligibility covers urban and rural properties in England or Wales, on or off the gas grid, including eligible self-builds²⁵.
• Permitted development rights in England were amended to remove the rule that a heat pump must be installed at least 1 metre from the property boundary²⁶.
• The installer applies for the grant on the household's behalf through Ofgem, with quotes available via the MCS find a heat pump installer tool or through an energy supplier²⁷.

Owning one shifts the household's dependencies rather than removing them. A gas boiler ties a home to the gas grid and a gas supplier; a heat pump ties it to the electricity grid, a distribution network operator, an installer for servicing, and, for a connected iDM system, the manufacturer's software and servers. The home stops burning a fuel at the property and starts drawing on the grid's generation mix, which changes both the cost structure and the emissions picture.

Green credentials and how electricity is generated

The emissions case is the strongest argument for heat pumps in the UK, and it is structural. Heating our homes accounts for around 14% of the UK's total greenhouse gas emissions⁸, and heat pump retrofits would only deliver around an additional 0.1 MtCO2e of emissions savings in 2025²⁸, a figure that reflects how few are installed so far rather than how little each one saves.

iDM publishes its own environmental framework, distinguishing direct, indirect, embodied and avoided emissions for heat pumps and their regulatory context²⁹, and an electricity mix explainer covering primary energy factors and green electricity claims³⁰. The maker has also published a fact-check of 17 heat pump environmental myths, separating verifiable technical facts from assumptions about energy use, emissions, refrigerants, noise, cold weather operation and grid impact³¹. These pages are written for the DACH region, so the grid assumptions differ from the UK's, but the underlying physics carries over.

The honest position for a UK household is this: a heat pump has no direct emissions at the property, and its indirect emissions depend on the UK electricity mix, which continues to change. The appliance itself carries embodied emissions from manufacture, and an imported unit carries them from a longer supply chain. What a heat pump removes is the household's dependence on burning gas or oil at home, and what it adds is dependence on the grid's pace of decarbonisation. For a fuller treatment, see heat pumps and household energy independence and the pillar guide to heat pumps.