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Replacing AHUs: Calculate energy savings and payback

An older ventilation unit that appears to be in good condition may be unexpectedly profitable to replace. It is easy to calculate energy savings and payback period when replacing e.g. a unit from the 1990s. Given that it is over 20 years old, today’s units are significantly more efficient. To calculate the energy savings and payback period, an investment calculation is performed in IV Produkt Designer.

Energy efficiency

Bernd Hake shows how to calculate energy savings and payback before replacing an air handling unit.

mollier diagram

Comparison between old and new AHU

Older unit

  • Air flow: 20,000 m³/h (5.6 m³/s)
  • Belt driven fans, SFP value: 3.5 kW/m³/s
  • Heat recovery unit, approx. 40% recovery
  • Operating time: 3,500 hours/year

In the 1990s, plate heat exchangers and run-around coils were generally used as heat recovery units. On installation, the temperature efficiency was around 50% and after over 20 years of operation it may have fallen to about 40%.

New unit, Envistar Flex

  • Air flow: 20,000 m³/h (5.6 m³/s)
  • Rotary heat exchanger
  • Reversible heat pump ThermoCooler HP
  • Temperature efficiency: 87.8% (Heat pump + heat exchanger)
  • SFP value: 1.63 kW/m³/s
  • Energy price: 0.15€/kWh for electricity, 0.08€/kWh for heating
  • Installation cost: 115,000€
  • Reduced maintenance cost over 20 years: 1,500€ x 20 years = 30,000€
  • Energy savings: 137,000 kWh/year
  • Payback period: 5.9 years
  • Increase in property value: 166,000€ (An increased net operating income of approximately 13,300€ and required rate of return of 8%)

IV Produkt Cloud: How to add users

This instructional video shows how to add users in IV Produkt Cloud – the cloud service that enables remote control of IV Produkt’s air handling units.
Knowledge

Market Hall replaces air handling unit – saves 160,000 kWh/year

With a payback period of 3.7 years, the market hall’s new air handling unit is an investment that pays for itself quickly – a sustainable combination of energy efficiency and comfort.
Reference

Christmas wishes and opening hours 2025

HVAC Produkt of the Year – Ventilation, new partner in the Netherlands, grand opening of new production facilities, and a completely new website. Let’s look back at the year 2025!
News

IV Produkt wins Commercial HVAC Product of the Year – Ventilation

IV Produkt has won Commercial HVAC Product of the Year – Ventilation at the H&V News Awards 2025 in London. The award recognises the Envistar Flex ThermoCooler HP – a unique heat pump air handling unit developed specifically for markets where heating is a key priority.
News

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