Cost comparison
Cost comparison of window rebate vents
Three ventilation systems compared by operation and costs - ventilation does not have to be expensive
The total costs of three ventilation systems for one year are compared in the cost comparison below. The values refer to a project which has been implemented in practice. There is a significant difference in the acquisition cost and follow-up costs of the individual systems.
system 1
ventilation system with air intake/exhaust
air systems with heat recovery
system 2
exhaust air system with air intake via Regel-air® PLUS window vents
system 3
Regel-air® PLUS for free ventilation as cross ventilation
Background information
The Regel-air® PLUS system is a combination of the window rebate vents FFL which react automatically to wind pressure and the continuously adjustable, manually operated overlap vents OV.
It is important to save energy
Everyone agrees that it is necessary to save energy. Numerous new construction laws, standards and regulations prescribe that buildings should be constructed every more tightly from an energy perspective. As a consequence, the EnEV states that:
"Buildings to be erected shall be constructed in such a way that the minimum air exchange required for health and heating is ensured."
Sample object
The total costs of three ventilation systems for one year are compared in the cost comparison below. The values refer to a project which has been implemented in practice. There is a difference in the acquisition cost and follow-up costs of the individual systems.
The following factors have been taken into account
- acquisition costs
- capital costs (finance over 20 years)
- ventilation heat losses
- electricity costs
- maintenance costs
Basis for comparison
A house or apartment with a size of 60.12 m² forms the basis for the comparison. In accordance with DIN 1946-6, an air volume flow of 85 m³/h (fan-assisted ventilation) is required for systems 1 and 2. For system 3, which works without a fan and is intended for cross ventilation, the ventilation for moisture protection must be fulfilled in accordance with the standard. In order for the three systems to remain comparable because of the ventilation heat losses, the increased requirements are also generated in system 3 by manually opening the windows.
Overview of total costs for system 1:
House or apartment with motorised intake and exhaust air system with heat recovery
| 1 a.) | acquisition costs house or apartment 60.12 m² (complete with controller) |
€ 63.00/m² | (rounded) € 3,800.00 |
| 1 b.) | capital costs (financed over 20 years) • repayment 5% of € 3,800.00 • interest 2.5% incl. funds from KfW development bank (incl. interest rebate) |
€ 190.00/a € 50.00/a |
€ 240.00/a |
| 1 c.) | ventilation heat losses • at 77 m³/h and 80% heat recovery • through infiltration of 8 m³/h | € 28.00/a € 14.00/a |
€ 42.00/a |
| 1 d.) | maintenance costs • electricity for electrical drive (without heating unit!) • cleaning of heat exchanger, lines, condensate & filter, maintenance in accordance with VDI 6022 by qualified personnel |
€ 10.00/a € 200.00/a |
€ 210.00/a |
| grand total 1 b.) to 1 d.): | € 492.00/a | ||
Overview of total costs for system 2:
House or apartment with exhaust air system with Regel-air® PLUS window vents
| 2 a.) | acquisition costs house or apartment 60.12 m² (exhaust air technology complete with controller) air intake via 6 pairs of Regel-air® PLUS incl. installation |
€ 15.00 /m² € 85.00/pair |
(rounded) € 900.00 € 510.00 |
| 2 b.) | capital costs (financed over 20 years) • repayment 5% of € 1,410.00 • interest 2.5% incl. funds from KfW development bank (incl. interest rebate) |
€ 71.00/a € 18.00/a |
€ 89.00/a |
| 2 c.) | ventilation heat losses • 85 m³/h incl. infiltration via Regel-air® |
€ 152.00/a | € 152.00/a |
| 2 d.) | maintenance costs • electricity for electrical drive • filter change by inhabitants |
€ 50.00/a € 20.00/a |
€ 70.00/a |
| grand total 2 b). to 2 d.): | € 311.00/a | ||
Overview of total costs for system 3:
House or apartment with Regel-air® PLUS window vents for free ventilation
| 3 a.) | acquisition costs house or apartment 60.12 m² (6 pairs of Regel-air® PLUS incl. installation) | € 85.00/pair | (rounded) € 510.00 |
| 3 b.) | capital costs (financed over 20 years) | € 25.50/a € 6.50/a | € 32.00/a |
| 3 c.) | ventilation heat losses • user-independent moisture protection ventilation via Regel-air® and opening windows = 85 m³/h in total | € 152.00/a | € 152.00/a |
| 3 d.) | maintenance costs • maintenance and energy | – | – |
| grand total 3 b.) to 3 d.): | € 184.00/a | ||
Conclusion
It can be proven at any time that the heat recovery determined for a ventilation system with heat recovery must be paid for with a significantly higher acquisition or capital costs as well as electricity and maintenance costs.
€492.00 /a (system 1): €311.00 /a (system 2) = 1,58 x price
€492.00 /a (system 1): €184.00 /a (System 3) = 2,67 x price
Where is the sustainable economic efficiency in this?
(Rising energy costs and cost changes due to inflation were not taken into account in these calculations, as they are difficult to project.)
We will be happy to provide you with additional information on the cost comparison on request.