ᐅ Older Building with Natural Ventilation and "Cooling"?

Hello everyone,

I will be taking over my parents’ old house next year.

- Built in the early 1900s, 2 full floors, 160cm (63 inches) of usable living space
- Insulation, windows, etc. are from the early 2000s
- Plumbing and electrical systems date back to 1981
- Currently using liquid propane gas for heating and water, but this will be removed (above-ground tank is taking up space)

Since we plan to renovate all the walls and floors anyway, we would also like to install a central mechanical ventilation system with heat recovery, including air conditioning.

I have read here several times that heat pumps with passive cooling don’t provide much benefit.

My current idea is:
- Heat pump for hot water and heating
- Central mechanical ventilation system supplying all rooms (ducts in walls/ceilings)
- Central air conditioning integrated into the ventilation system for effective cooling
- Supported by photovoltaic panels or solar thermal system (flat roof garage with 50mm (2 inches) insulation, perfectly oriented)

The air conditioning can be debated, but for health reasons it is necessary.

- Is this a practical and effective solution, and are there ready-made systems available?
- Photovoltaic or solar thermal – which is more suitable for this setup?

Thanks for your help,
Regards,
ruediger42

Is there already underfloor heating installed, or will it be newly installed? Otherwise, I’m not sure if a heat pump makes sense.
Did I understand correctly that a mechanical ventilation system with heat recovery (controlled ventilation) is planned? Unfortunately, this cannot be used for cooling; an air conditioning system would need to be installed separately.

Hi,

There is no underfloor heating.

Unfortunately, you cannot cool with that; an air conditioning system would have to be installed separately.

The question is: Can this be combined through the piping? Or do I really need, depending on the room, one controlled mechanical ventilation supply, one controlled mechanical ventilation exhaust, and also one air conditioning unit?

Pinky0301 schrieb:

...
Did I understand correctly that a mechanical ventilation system with heat recovery is to be installed? Unfortunately, such a system cannot provide cooling; an air conditioning system would have to be installed separately.

That is not entirely correct. Cooling coils in the mechanical ventilation system with heat recovery can enable cooling, although there are several potential issues to consider (condensation, etc.).

My nephew is currently installing such a system (Helios); I can share an update in a few weeks on how it works out.

An air-to-air heat pump is inefficient for passive cooling, while a brine-to-water heat pump is somewhat better suited. Both are generally only sensible with underfloor heating systems, as only these allow for low supply temperatures.

A combination of traditional radiators and solar thermal systems (both “high-temperature technology”) or alternatively a heat pump paired with underfloor heating or thermally activated building systems is recommended.

ruediger42 schrieb:

Hi,
There is no underfloor heating.
The question is: Can this be combined using the same pipes? Or do I really need, depending on the room, one supply air unit for the controlled residential ventilation, one exhaust air unit for the controlled residential ventilation, and an additional air conditioning unit?

Exhaust air goes to the bathroom and (living) kitchen, supply air to the living room (or two supply air units in the living kitchen depending on size) and to all other rooms.
This is calculated by the heating engineer or, for the heating engineer, by the manufacturer of the controlled residential ventilation system.

In a controlled residential ventilation system, it is common to work with overflow areas. @superzapp has already explained this. This means that not every room has supply and exhaust air.

If you want cooling, use an air conditioning system in addition. You don’t need it in every room either.

Cooling via the controlled residential ventilation system (not to be confused with controlled residential ventilation!) is possible, but complex and less easy to control. The variant described by @superzapp is still a "last resort" (but a good one). The air exchange rate would need to be much higher (5-10 times per hour), and a proper air conditioning unit should be installed upstream. It also makes sense to avoid overflow areas in this case (otherwise there are no different temperature zones). We use a similar system.

A more practical solution for you would be a classic controlled residential ventilation system combined with a central air conditioning unit connected to indoor units (for example, in the bedrooms and living room).