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Payback in 5 years when replacing
90s air handling unit

EcoCooler cooling unit
Envistar Flex

Kvarteret Skomakaren Office Building | Växjö, Sweden

By replacing an old air handling unit, the property owner lowered energy use by 85,000 kWh/year – a saving equal to 50 kWh/m2/year. In this article, you will learn more about how it happened.

Watch the video to learn how the property owner saved 85,000 kWh/year by replacing an air handling unit from the 90s.


New ventilation solution saves energy

The property owner Emilshus carried out an energy efficiency project at Kvarteret Skomakaren, a 1,700 square metre office building in Växjö, Sweden. The old air handling unit from the 90s was replaced by a new and more energy-efficient unit.

“In addition to the tenants getting a better indoor climate, we have calculated that the new air handling unit will reduce energy use by approximately 85,000 kWh/year”, says Marcus Arhov, Technical Manager at the property owner Emilshus.

Marcus Arhov, Emilshus

This energy saving increases the property owner’s net operating income, which also leads to the property rising in value.


Quick action with big effect

Anton Andersson, Ventilation Installer at Cretec, participated in the installation of the new air handling unit.

“We are replacing an old air handling unit from 1991. The SFP value is around 3 and the unit has a heat recovery between 40 and 50%”, says Anton.

Demolishing the roof, lifting out the old unit, and bringing in the new unit only took three days. The new air handling unit from the Envistar Flex range is equipped with the integrated cooling unit EcoCooler, which means that the old outdoor cooling installation could be removed.

Anton Andersson, Cretec Installation

“The high heat recovery that comes with the new unit means that we reduce the additional heat from the district heating by around 80%. The electricity use for the fans drops by an estimated 50%”, says Anton Andersson.


A project with several winners

The property owner Emilshus quickly received an estimate of the payback time for replacing the air handling unit in this office property. The calculated saving of 85,000 kWh/year made it an easy decision to invest.

On top of saving energy, the new air handling unit also creates a better indoor climate for the tenants.

Such a significant energy saving also leads to a reduction of the negative climate footprint for all parties involved, which contributes to a more sustainable future.

Replacing a 90s air handling unit resulted in a big energy saving for office building

The old air handling unit from the 90s was removed and the new one was brought in. The replacement took three days and resulted in an energy saving of 85,000 kWh/year for this 1,700 square metre office building.

Property floor surface 1,700 m2
Operating time, ventilation 3,500 h/year
Energy use,
old air handling unit*
113,000 kWh/year
Energy use,
new air handling unit*
28,000 kWh/year
Total energy saving 85,000 kWh/year
Energy saving
per square metre
50 kWh/m2/year
Time for AHU replacement 3 days
Payback** 5 years

*The air handling unit’s energy use for electricity and district heating.

**This is an office property. Another type property type, for example a block of flats, with longer operating times would result in an even shorter payback time.


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More about the products in this project

Thanks to




EQ Building | Bristol
Kvarteret Skomakaren Office Building | Växjö, Sweden

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