Umulig Engineering provides water heating solutions in combination with our Aquatherm Green and Aquatherm Blue PPR Piping systems. Umulig Engineering supplies and installs air to heat, domestic, commercial and industrial heat pumps for water heating applications.


What is a heat pump?

Heat pumps use the energy stored in air to transfer heat from the outside ambient air to water storage tank/vessel using a suitable refrigerant. A heat pump works on a refrigeration cycle. It extracts heat from a suitable lower temperature source, such as air, ground or water to deliver it to a higher temperature sink. The vapour compression heat pump cycle has four main components:

  • EvaporatorThe low pressure, low temperature refrigerant vapour from the throttle valve enters the evaporator where the refrigerant extracts heat from air (source).
  • CompressorThe low temperature and low pressure vapour enters the compressor where it is compressed to a high temperature and high pressure vapour.
  • CondenserThe compressed refrigerant vapour then travels to the condenser, where the heat is transferred to the water.
  • Expansion ValveThe high pressure, high temperature refrigerant liquid from the condenser then travels to the expansion valve, which controls the flow of the refrigerant. The cooled refrigerant now experiences a pressure drop. The low temperature, low pressure liquid refrigerant then travels to the evaporator and the cycle begins again as shown in the figure below.

Domestic Range


The domestic heat pump range is developed to be integrated into your current existing geyser. This means, there is no need to replace your current hot water system when switching over to a heat pump. Our heat pump range can meet the same hot water demands of any domestic geyser but using a fraction of energy when compared to a geyser. Our domestic heat pump range is designed and manufactured locally for inland and coastal conditions. Our domestic heat pump can be installed within hours and offer you many years of saving. All our units come with intelligent LCD control panels that can be installed inside or outside the house for convenience. Contact us today to start saving.
Umulig Engineering is currently running a special on the 3kW heat pump (ERHP‐SU08E‐MS) for only R9999*(T&Cs apply).
Get a quote: heatpump@umulig.co.za

Commercial and Industrial Heat Pumps


Our commercial heat pump range has a heating capacity of 12 kW to 70 kW and is designed for supplying hot water for the following applications:

  • Commercial hot water systems such as schools, hospitals, hotels, hostels, universities and lodges.
  • Industrial hot water systems such as change houses, green houses and space heating.

The EH-MT range are also equipped with water regulating valves to ensure a constant outlet temperature of at least 55°C. Purchasing a commercial heat pump should be always viewed as an investment. A commercial heat will reduce your business’s electricity bill from the moment it starts working, but the return on investment is achieved over a 2-4-year period depending on the hot water usage. This means you will recover your initial capital investment on a monthly basis in the reduction of operating costs till the sum total of your monthly savings from using a heat pump = the initial capital investment. Contact us so we can design a suitable low maintenance, high reliability, high energy efficient hot water system to reduce your monthly operating costs. The units are also equipped with automatic defrosting which is excellent for self-protection during colder periods of the year.

Organisations that are using our heat pumps:

Swimming Pool Heat Pumps

Umulig Engineering supplies and installs heat pumps for residential or commercial swimming pools.


Residential Swimming Pool Heat Pumps

The EIP series swimming pool heat pumps have a unique fibre reinforced resin casing that makes them more corrosion resistant when installed outdoors. The heating capacity ranges from 6kW to 18 kW. The control logic of the EIP-series also encompasses an ECO-function which ensures that the heat pump only operates when ambient temperatures are above 10°C, thus optimising efficiency. These units are also equipped with an automatic defrosting function which is excellent for self-protection when the units need to operate during the cooler moths of the year.

Commercial Swimming Heat Pool Heat Pumps

The Enerflow EIP-MTC series were developed for 400V/3-phase/50Hz applications, with heating ranging between 50 kW and 150 kW. Multiple units can be installed together thus catering for any client’s needs. These units are ideally suitable for supplying warm water, at temperatures up to 40°C, for the following applications:

  • Commercial agricultural purposes
  • Olympic size swimming pools
  • Spa’s