Thermia Diplomat Inverter

    • Reduce your energy consumption by up to 80%
    • Inverter technology adjusts precisely to real-time demand
    • New control system and newly designed color touchscreen
    • Optimum technology for higher annual efficiency
    • Superb hot water production (TWS and HGW technology)
    • Flexibility – for new-builds or renovations
    • One solution – heating, domestic hot water and cooling
    • Online – control your heat pump from anywhere
Thermia Diplomat Inverter

Energy class when the heat pump is part of an integrated system


Energy class when the heat pump is the sole heat generator Energy class according to Eco-design Directive 811/2013



  • Efficient performance in all seasons

    Efficient performance in all seasons

    The Thermia Diplomat Inverter is a ground-source heat pump with inverter technology that offers you superior performance thanks to its unique technical solutions. With an impressive seasonal coefficient of performance (SCOP) of 5.6 (Inverter M at 35°C floor heating according to EN14825), the Diplomat Inverter enables you to reduce energy consumption by up to 80%.

    SCOP is a measure that describes how efficiently a heat pump works over a full year, including warm and cold periods. It indicates the relationship between the amount of energy produced and the amount consumed. The higher the value, the better the system.

  • Inverter technology

    Inverter technology

    Continuously adjusting the heat pump’s output to current demand, inverter technology means that the heat pump can supply 100% of your energy requirements. This in turn means that there is no need for the user to pay for any auxiliary heating.

  • Heating


    Most common European heating systems are water-based, with heat being distributed via radiators or hydronic floor heating. The output temperature of the water distribution system is usually 30-35°C for floor heating and 45-55°C for radiators. Thermia heat pumps offer a low-carbon alternative to traditional boilers in modern buildings, whether for new-builds or refurbishments and regardless of the temperature required in the heating system.

  • Cool in the summer

    Cool in the summer

    The heat pump provides heat during the winter while in the summer the process can be simply reversed. The heat pump collects heat from the house and deposits it into the ground borehole to provide cooling. That is more cost-efficient than traditional air conditioning. The Diplomat Inverter with an optional accessory can also provide efficient cooling for your home during the summer.

  • Exceptional hot water production

    Exceptional hot water production

    With HGW (Hot Gas Water heater), Thermia has developed a unique patent-pending method for producing hot water. At the same time as water is being heated for distribution through the house’s heating system, hot water is produced at very high temperature through an extra de-superheater. This means that during the part of the year when the house is heated, you get lots of hot water at a very low cost. Thermia heat pumps equipped with HGW technology and a built-in 180-liter hot water tank can produce 419 liters of hot water (40°C) on tap, giving you the freedom for up to nine people to take showers at once.

  • More hot water, faster

    More hot water, faster

    The hot water tank is fitted with our TWS (Tap Water Stratification) technology, which means that hot water is produced faster and at higher temperatures than with traditional technology. Because the hot water is diluted to tap water temperature, the volume of usable hot water is considerably higher due to the high temperature.

    Thermia versus other brands in terms of hot water production:

    Thermia with TWS technology Typical traditional water heater
    • Recharging from 40°C to full load for a water heater using TWS technology: just 21 mins.
    •  Recharging from 40°C to full load for traditional water heater: 50 mins.
    • Time to fully recharge tank after peak consumption: 21 mins.
    •  Time to fully recharge tank after peak consumption: 50 min.


  • Touchscreen controller

    Touchscreen controller

    The new controller in the inverter heat pump boasts a color touchscreen display and user-friendly icons that are easy to understand.

  • New intelligent control system

    New intelligent control system

    The controller coordinates and controls the heating system. Thermia heat pumps work with complete precision to give your home the best possible indoor climate at the lowest possible cost. Our controller is very easy to use.

    The system uses an algorithm that ensures the lowest possible running cost while maintaining the desired indoor temperature.

    New features:

    • Color touchscreen and intuitive menu
    • Full overview of temperatures and curves
    • Plug-and-play software update via USB slot
    • Interface to BMS (Building Management System) – for the Smart House
  • Optimum technology

    Optimum technology

    Optimum Technology is a technology that constantly monitors your system and adjusts the pump’s performance accordingly. Speed-controlled Class-A circulation pumps guarantee that daily operation is always adjusted according to the user’s requirements and conditions. That means you can be sure your heat pump is always running at its most efficient level.

  • Flexibility


    The Thermia Diplomat Inverter is available in two output sizes: Inverter M 3-12kW and Inverter L 5-17 kW. Inverter M is available in both three-phase (400V) and single-phase versions (230V), Inverter L is available in three-phase (400V). The Diplomat Inverter has built-in 180-liter hot water tank. The Diplomat Duo Inverter is a version without hot water tank and ready to work with Thermia MBH and a separate hot water tank of 200 or 300 liters, or any other hot water tank. With a wide range of accessories, the Diplomat Inverter can also provide cooling, heat a pool and work in combination with solar thermal panels or additional heat sources.

  • Thermia Online

    Thermia Online

    The Thermia Online app enables you to check that your heating system is working properly, reduce the temperature when you are on holiday, or receive a notification if anything unexpected comes up. Our online system provides installers with comprehensive diagnostics data and also enables them to respond promptly to notifications or access a live feed on system performance. The Thermia Online app is available for both Android and iPhone.

  • Pool heating

    Pool heating

    The Diplomat Inverter can easily be supplemented to heat your pool, all year round. In this way, you can enjoy your pool in all seasons while substantially reducing the cost of heating it.

  • The essence of Scandinavian design and durability

    The essence of Scandinavian design and durability

    Thermia heat pumps are designed, tested and manufactured in one of the harshest climates in Europe. Swedish winters can be extreme. February is usually the coldest month, with temperatures dropping as low as -30°C or even lower in the north and heating is essential from September to May. The Thermia Diplomat Inverter is built on 40 years of experience in developing and supplying heat pumps. Today, it is the most advanced and latest domestic ground-source heat pump in Thermia’s product portfolio.

Incredible, but true…

Incredible, but true…

The comfort you want. The savings you’ll love.

Thermia heat pumps provide up to 80% energy savings,
50-75% savings on running costs
and can reduce your carbon footprint around 75%.

Thermia heat pump patented Hot Gas Water technology

How can Hot Gas Water technology improve comfort and convenience for your family?

Thermia ground source heat pumps feature Hot Gas Water (HGW) technology

Benefits of Hot Gas Water technology:

  • heats your home and produces domestic hot water simultaneously
  • lower energy bills
  • higher volume of hot water
  • increased water temperature
  • up to 20 percent higher annual efficiency in hot water production
  • provides your power shower hot tub and more with a constant supply of low-cost hot water

HGW technology is available in Thermia Inverter and Thermia Diplomat Optimum G3 models.


If you have any questions please contact us

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