MVHR systems

Cernunnos uses  the “ESP – Rega System”, the most comprehensive and efficient mechanical ventilation and heat recovery and ventilation (MVHR) system available.

The extremely versatile ESP-Rega System sets itself apart from all others through the integration of the ESP “Ecocent” to enable the system to deliver copious quantities of domestic hot water (DHW) at the same time as efficiently performing wider heat recovery and ventilation duties that are so critical in today’s house design. The system can also be used to provide hot water for towel rails and UFH in bathrooms and other areas. The ESP-Rega system achieves this through employing proprietary technology, developed by Regavent and ESP, that allows the MVHR system to use the Ecocent’s heat recovery capability fully integrated with the wider MVHR system capability. The technology is unique, robust, simple to install and fully automated to allow the Ecocent to draw heat-laden, stale recovered air at any time required to deliver large quantities of DHW. The ESP-Rega System delivers DHW 24 hours a day, 365 days a year through active heat recovery, the system also pays for itself through the savings that it delivers – The Ecocent delivers up to 70% savings on the cost of producing DHW and no other system on the market can achieve this.

The design of the ESP-Rega System also allows solar thermal to be fully incorporated as well as the unique ESP “Heat Squirrel” that recovers heat from waste water and uses that heat to produce DHW or to contribute to central heating requirements. So, even some of the heat that is normally thrown down the drain as waste water can be recovered and used effectively.

The ESP “REGA” Mechanical Ventilation Heat Recovery (MVHR) Systems

The central air unit is the heart of any whole house heat recovery ventilation system; it houses two fans, one extract and one supply and a heat exchanger. The extract fan removes stale moist air from the home and the supply fan brings fresh air in to replace extracted moist air.

Designed for loft or wall installation the ESP REGA central units are designed for continued ventilation of domestic dwellings and small commercial premises. The unit casings are manufactured from strong, corrosion resistant galvanised steel, this houses a long life plastic heat exchanger, thus the only wearing parts are the fan motors. Selected for durability and performance the fan motors are of external rotor design. With sealed for life ball bearings they are quiet running and completely maintenance free in operation. Experience has shown that under normal 24 hour operating conditions the expected motor life should exceed 10 years.


All central units are available with the option of volt DC motors offering reduced energy consumption. Although the initial cost of the DC motors is higher than AC, the energy savings can recover the intial outlay within six to eight years. DC motors convert two thirds of the power used into useful work compared to only a half for AC motors. Reduced electrical losses mean lower temperatures and less thermal stress giving even longer motor life and continued electrical savings many years into the future. Central air units with DC motors are supplied ready fitted and wired with the correct electronic power supply.

The heat exchanger is of counter flow design, a layout calculated to give the highest level of efficiency. In very cold conditions where high internal to external temperature differentials are experienced the heat exchanger can recover up to 90% of the of the heat from the extracted stale air. Under more normal operating temperatures with a differential of 15°C 75% of the available heat will be used to warm the incoming fresh air. The heat exchanger requires no routine maintenance but may be removed for cleaning if an exceptional build-up of grease or dust makes this necessary. Alternatively replacement units are avaIlable at low cost.

The central units incorporate filters for dust removal on both extract and fresh air supply. The washable filters protect the heat exchanger from the build-up of dust and from grease and other particles in the stale air. Frequency of cleaning of the filters is dependent on the level of contamination but typically would be an annual operation.

Any ventilation system must be unobtrusive in operation and low noise is thus of great importance, to this end ESP REGA central units are supplied complete with an acoustic/thermal insulation jacket. Manufactured from high density close cell neoprene foam the jackets not only prevents noise breakout from the unit but also reduces heat loss to maintain thermal efficiency. To further ensure quiet operation each unit comes mounting cradel incorporating rubber mounts, preventing noise trnasmission to the structure.

When the cool incoming air and the warm stale air pass across the heat exchanger the moisture in the stale air condenses. All ESP REGA Air Units are supplied with a drain connection and small diameter hose to allow this condense to be drained away from the unit.

Unit data

Unit 325 325-12 325-16 650 650DC
Air   Volume l/s 90 85 90 180 180
Duct   Connection mm 125 125 160 160 2x1602x160
Power ConsumptionBoost Operation 210 140 140 400 240
Power ConsumptionNormal Operation 110 70 70 210 100
Motor   Type AC DC DC AC DC

The Powerful motor in the ESP REGA units utilize forward curved impellors to quietly and efficiently move large volumes of air under high pressure to overcome the frictional resistance of duct systems.

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