Hello everyone,
so far, I have been an advocate for a ventilation system with heat recovery (decentralized in the new build – a central system is too expensive for us in terms of purchase and maintenance).
Our general contractor (GC) is planning a simple exhaust ventilation system from Lunos. I had asked him to obtain quotes from two companies (Lunos and Seventilation) for a ventilation system with heat recovery. The price difference would be between 3,000 and 4,000 euros.
On Saturday, we had another discussion with the planning engineer from our GC.
He raised the question of how much savings a heat recovery system would actually provide and when it would likely pay off.
The geothermal heating system (after a startup phase of about 1 year with higher costs) is expected to have an annual electricity consumption of around 600 euros (I am cautiously estimating 700 euros).
The ventilation system is supposed to recover and return 80-90% of the waste heat (the airflow direction changes every 75 seconds). I don’t believe, for example, that this could save as much as 50% of the electricity costs for the geothermal system.
If around 100 euros are saved per year, the ventilation system with heat recovery would take about 30 years to pay off at current electricity prices (assuming everything lasts and no additional costs arise).
This does not yet include the electricity consumption of the ventilation system itself or possible regular additional maintenance.
On the other hand, I am not under the illusion that electricity prices will remain the same.
What are your thoughts on this?
f-pNo
so far, I have been an advocate for a ventilation system with heat recovery (decentralized in the new build – a central system is too expensive for us in terms of purchase and maintenance).
Our general contractor (GC) is planning a simple exhaust ventilation system from Lunos. I had asked him to obtain quotes from two companies (Lunos and Seventilation) for a ventilation system with heat recovery. The price difference would be between 3,000 and 4,000 euros.
On Saturday, we had another discussion with the planning engineer from our GC.
He raised the question of how much savings a heat recovery system would actually provide and when it would likely pay off.
The geothermal heating system (after a startup phase of about 1 year with higher costs) is expected to have an annual electricity consumption of around 600 euros (I am cautiously estimating 700 euros).
The ventilation system is supposed to recover and return 80-90% of the waste heat (the airflow direction changes every 75 seconds). I don’t believe, for example, that this could save as much as 50% of the electricity costs for the geothermal system.
If around 100 euros are saved per year, the ventilation system with heat recovery would take about 30 years to pay off at current electricity prices (assuming everything lasts and no additional costs arise).
This does not yet include the electricity consumption of the ventilation system itself or possible regular additional maintenance.
On the other hand, I am not under the illusion that electricity prices will remain the same.
What are your thoughts on this?
f-pNo
I do not deny that aerated concrete also has its advantages and that other materials have their drawbacks.
However, it is obvious to me that an aerated concrete house takes longer to dry than a house made of hollow clay bricks plus external thermal insulation composite system (ETICS).
Simply because the block itself provides the insulation, there is a significant temperature gradient within the block, whereas the hollow clay brick is fully warmed through.
In fact, it can take years in practice to achieve the same U-value as calculated (if at all) because the residual moisture in the block increases the thermal conductivity.
These disadvantages apply to varying degrees, of course, also to insulating bricks made from Poroton.
However, it is obvious to me that an aerated concrete house takes longer to dry than a house made of hollow clay bricks plus external thermal insulation composite system (ETICS).
Simply because the block itself provides the insulation, there is a significant temperature gradient within the block, whereas the hollow clay brick is fully warmed through.
In fact, it can take years in practice to achieve the same U-value as calculated (if at all) because the residual moisture in the block increases the thermal conductivity.
These disadvantages apply to varying degrees, of course, also to insulating bricks made from Poroton.