Fervo Case Studies

Domestic property

Renovation Project

Location: Cheshire

Technologies used: Air Source Heat Pump, Solar PV, Under floor heating


Integrated Air Source Heat Pump and Solar PV installation for a large Cheshire renovation project.

Fervo Renewable Energy have completed the installation of a Stiebel Eltron WPL 25 air source heat pump and a 3.84kW solar PV installation.

With the original home being relatively poorly insulated by current building regulation standards, a traditional air source heat pump alone would struggle to meet the properties heat loses.  By combining the Stiebel Eltron WPL 25 with the client’s existing oil boiler in a bi-valent design allowed the client to maximise the efficiencies of the air source heat pump whilst ensuring their home always remains heated to the desired room temperatures, even during the coldest winter days.

The Stiebel Eltron WPL 25 is a sophisticated heat pump that controls the delivery of heat to the mixed underfloor/radiator circuits and the properties hot water system.

For the underfloor heating and hot water systems, the heat pump needs no assistance at all in meeting the demand from the home.  For the radiator circuits for most of the year, the heat pump will deliver heat up to a pre-determined ambient air temperature.  However, during colder periods the backup boiler can be called upon to raise the temperature further in the radiator circuits to a point appropriate to keep the house warm.

Cheshire farmhouse

Cheshire farmhouse

Such a system design brings a number of benefits: –

  • The air source heat pump is used to the maximum of its efficiencies meaning energy costs are kept to a minimum.
  • The backup boiler is used to a minimum, only raising the temperature of the water for the radiator circuits after the heat pump has already heated it.
  • There is no need to “over-size” radiators.
  • The system enables the property to be “future-proofed” against rising fuel cost prices by allowing the “cut-in temperature” to be varied as price fluctuations occur in electricity and fossil fuel prices.
  • The system qualified for the Domestic Renewable Heat Incentive, allowing the homeowner to receive index-linked tariff payments for seven years based on the amount of heat supplied by the air source heat pump.

In addition to the air source heat pump Fervo installed a 3.84kW solar PV array comprising 12 Seraphim 320Wp solar panels.  These provide free electricity to the house, offsetting some of the cost of running the heat pump and making the home even more sustainable.  The solar installation also allows the homeowner to benefit from payments under the Feed-in Tariff scheme for 20 years.

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