ᐅ Controlled residential ventilation system or photovoltaic system? Looking for decision-making guidance, pros and cons
Created on: 8 Feb 2018 13:08
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cybergnom
Hello,
I have been thinking for a while about the following question:
New build single-family house, 220m² (2,370 sq ft) plus basement, not built to KFW standard, gas boiler plus solar thermal system.
The budget still allows for either a mechanical ventilation system with heat recovery or a photovoltaic system.
My current pros and cons are:
If I choose the mechanical ventilation system, I get better indoor air quality and save on heating costs in winter (but electricity costs will increase). I could retrofit the photovoltaic system later, but I don’t expect to do so (due to financing rates, saving around €10,000 just on the photovoltaic system is practically not feasible).
If I choose the photovoltaic system, I also save money in summer (when heating and mechanical ventilation are hardly needed anyway). However, in winter, manual ventilation (obviously without heat recovery) means higher heating costs. Retrofitting a mechanical ventilation system later would definitely not be possible.
At the moment, I see it like this: whatever I choose, it feels like the wrong decision.
Maybe someone can offer me a tip or advice...
Thanks and best regards
cybergnom
I have been thinking for a while about the following question:
New build single-family house, 220m² (2,370 sq ft) plus basement, not built to KFW standard, gas boiler plus solar thermal system.
The budget still allows for either a mechanical ventilation system with heat recovery or a photovoltaic system.
My current pros and cons are:
If I choose the mechanical ventilation system, I get better indoor air quality and save on heating costs in winter (but electricity costs will increase). I could retrofit the photovoltaic system later, but I don’t expect to do so (due to financing rates, saving around €10,000 just on the photovoltaic system is practically not feasible).
If I choose the photovoltaic system, I also save money in summer (when heating and mechanical ventilation are hardly needed anyway). However, in winter, manual ventilation (obviously without heat recovery) means higher heating costs. Retrofitting a mechanical ventilation system later would definitely not be possible.
At the moment, I see it like this: whatever I choose, it feels like the wrong decision.
Maybe someone can offer me a tip or advice...
Thanks and best regards
cybergnom
New houses are certainly being designed and built with decentralized ventilation systems.
Each option has its pros and cons, and everyone needs to decide what suits them best. Some people prefer fully automatic systems, while others want to have as much control and as many options as possible.
Mold growth is definitely a concern in modern airtight houses, but it is important to understand the available options before making a decision. Besides decentralized units, there are other ventilation concepts that do not require complete ductwork throughout the entire house: for example, installing exhaust fans in the kitchen and bathroom(s) and providing fresh air supply to other rooms without fans. This is known as an exhaust ventilation system, a third alternative alongside centralized and decentralized ventilation. In any case, I recommend that everyone thoroughly informs themselves and weighs the options before installation.
To return to the original question: regardless of the type, I would prioritize ventilation over photovoltaic systems.
Each option has its pros and cons, and everyone needs to decide what suits them best. Some people prefer fully automatic systems, while others want to have as much control and as many options as possible.
Mold growth is definitely a concern in modern airtight houses, but it is important to understand the available options before making a decision. Besides decentralized units, there are other ventilation concepts that do not require complete ductwork throughout the entire house: for example, installing exhaust fans in the kitchen and bathroom(s) and providing fresh air supply to other rooms without fans. This is known as an exhaust ventilation system, a third alternative alongside centralized and decentralized ventilation. In any case, I recommend that everyone thoroughly informs themselves and weighs the options before installation.
To return to the original question: regardless of the type, I would prioritize ventilation over photovoltaic systems.
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cybergnom9 Feb 2018 14:26Hello everyone,
Thank you for all the opinions.
Sometimes you just have to make a decision without thinking for days or weeks.
I had my plumber install a mechanical ventilation system with heat recovery. It will be a Zehnder Comfoair Q450 enthalpy model. The cost is around €14,000. Since the decentralized fans are no longer needed, the additional cost is about €11,000.
For me, there is even another big comfort gain:
With the mechanical ventilation system, I can run my Bora system as a recirculating system instead of an exhaust system and don’t have to keep a window open while cooking.
Regards,
cybergnom
Thank you for all the opinions.
Sometimes you just have to make a decision without thinking for days or weeks.
I had my plumber install a mechanical ventilation system with heat recovery. It will be a Zehnder Comfoair Q450 enthalpy model. The cost is around €14,000. Since the decentralized fans are no longer needed, the additional cost is about €11,000.
For me, there is even another big comfort gain:
With the mechanical ventilation system, I can run my Bora system as a recirculating system instead of an exhaust system and don’t have to keep a window open while cooking.
Regards,
cybergnom
cybergnom schrieb:
For me, there is even another major comfort gain:
With the controlled residential ventilation system, I can set up my Bora system as a recirculation instead of an exhaust system and don’t have to keep a window open while cooking all the time.
Best regards,
the gnomeI’m not entirely clear on the context.
What would have prevented you from using a recirculation hood without controlled residential ventilation?
Opening a window with an exhaust hood is usually only necessary if there is a combustion appliance dependent on indoor air (such as a gas boiler or wood stove) in use. This is for pressure equalization and to prevent exhaust gases from being drawn into the living space.
If you have a heat pump and no stove, opening a window is generally not necessary. It’s only required for proper operation of the exhaust hood itself.
Controlled residential ventilation plays only a secondary role here.
With controlled residential ventilation, when using an exhaust hood, an open window or wall vent is recommended to avoid shifting the pressure balance between indoors and outdoors and to ensure the proper function of the ventilation system. But this only applies while the exhaust hood is running.
Aside from that, your decision to go with controlled residential ventilation is absolutely right. We installed the Zehnder Q350. I would definitely recommend the version with the enthalpy exchanger. It costs €500-1000 more but offers significant benefits for indoor air quality, as it avoids the typical problems with overly dry air.
If needed, that feature can also be easily retrofitted on the unit.
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Baumfachmann9 Feb 2018 19:05The Zehnder Q450 is a very good choice
matte1987 schrieb:
Windows only need to be opened when using a vented extractor hood if there is a combustion appliance dependent on room air (such as a gas boiler or wood stove).In new construction, vented extractor hoods are always an interesting topic due to the airtightness of the building. Such a hood can exhaust a significant amount of air outside—where should that air come from? A chimney would obviously be problematic, but even without one, this remains an issue.
However, I still don’t quite understand why this is less of a problem with a controlled ventilation system. Controlled ventilation is not a substitute for a kitchen hood (though it can help with odors).
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