ᐅ Roof suddenly too small for mechanical ventilation system!

Created on: 24 Feb 2019 08:51
M
M4rvin
Hi everyone,
we are building a small solid house with a general contractor. Originally, the plan was to have a gas boiler with a controlled ventilation system.
Now that we finally have an installer assigned, he told us there is no space for controlled ventilation!
This is quite short notice since the excavator is already on site, and digging for the foundation will probably start on Monday.

The general contractor has presented us with the following options:

Option 1:
- Gas condensing boiler with solar thermal system
(Photovoltaic system does not make sense here!)

Requirements:
o Flue pipe (either on the exterior wall or in the cloakroom niche)
o Buffer tank
o Expansion vessel
o Condensing boiler
o Piping for solar system up to the roof

Requires a lot of space

Option 2:
- Gas condensing boiler with ventilation (just sufficient for energy saving regulation calculations)
(Photovoltaic system does not make sense here!)

Requirements:
o Flue pipe (either on the exterior wall or in the cloakroom niche)
o Buffer tank
o Expansion vessel
o Condensing boiler
o Ventilation system (ceiling-mounted)

Basically no space available

Option 3:
- Air-to-water heat pump with ventilation
(Photovoltaic system can be added later – empty conduit to the roof)

Requirements:

o Buffer tank
o Expansion vessel
o Outdoor unit for air-to-water heat pump
o Ventilation system (ceiling-mounted)
o 10cm (4 inches) build-up in the sloped roof area needed for ventilation ducts

Option 4:
- Air-to-water heat pump without ventilation
(Energy saving regulation compliance is technically not a problem, but mechanical ventilation should possibly be ensured by e.g. window frame ventilation)
(Photovoltaic system can be added later – empty conduit to the roof)

Requirements:

o Buffer tank
o Expansion vessel
o Outdoor unit for air-to-water heat pump

Unfortunately, the additional costs for these options have not been communicated to us.
We are currently leaning towards option 4, but we are quite uncertain about these window frame ventilation solutions...

Have a nice Sunday
Marvin
M4rvin24 Feb 2019 12:06
Do you mean the proposed controlled residential ventilation system when you say unknown building technology?
D
Domski
24 Feb 2019 12:12
Yes. General contractors have a hard time with system technology from manufacturers that are not part of their standard range.
M4rvin24 Feb 2019 12:13
Ok, so I would need to ask the installer who was assigned a few days ago. He definitely seems to be an Elco installer!
ares8324 Feb 2019 12:20
Domski schrieb:
General contractors and unfamiliar/new system technology can be risky.
It doesn’t necessarily have to be unfamiliar. Some manufacturers offer different designs. If there is a wall-mounted unit involved, that’s actually good.
M4rvin schrieb:
Okay, so I’d need to ask the installer assigned a few days ago.
He definitely seems to install elco systems!
I wasn’t familiar with the name before, but there is a picture of a wall-mounted unit on their website. If it can be installed a bit higher, you could probably fit the washer and dryer underneath.
M4rvin24 Feb 2019 12:55
Regarding the heating, the contract states:
*According to the scope of work description, including towel radiators. A circulation pipe is already included as standard. A air-to-water heat pump from Duplex, ELCO, or Viessmann will be installed.
*A credit amount (-3927.45€) for omitting the air-to-water heat pump and installing a gas condensing boiler along with a solar system with 2 flat plate collectors from, for example, Buderus.
Installation includes underfloor heating.

Regarding ventilation:
*Not included in the scope of work and can be commissioned additionally upon request.
*Installation of a central ventilation system with heat recovery on the ground floor and attic floor. Ventilation outlets for supply and exhaust air will be installed in the respective ceiling above the floor to be ventilated.
A central ventilation unit with heat recovery from Pluggit, Maico, Dimplex, or the aforementioned manufacturers will be used.
Z
Zaba12
24 Feb 2019 15:21
Where is the floor plan so we can assess whether the mechanical ventilation system can fit? It’s not just about the size of the unit; you also need a continuous wall where you can run the ductwork, whether from the basement to the upper floor or from the ground floor to the upper floor.

Was the mechanical ventilation system included in the scope of work for ventilation planning and location planning? It doesn’t really sound like it.

If it had been included, the ceiling elements would already need to have openings for the ventilation panel. These should actually already be planned and ordered if construction is about to start.

Sounds like it was overlooked on both sides!

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