Hello and thanks in advance for any replies!
We have been living for a few years in a bungalow from the 1970s. Okay, it’s not located in Africa, but in northern Germany, although we do have warm summers here and the number of hot days is increasing rather than decreasing.
Inside the house, temperatures can reach 26–27°C (79–81°F) on really hot summer days, and it’s quite difficult to sleep at night. The house is actually in decent condition, the roof and windows were replaced less than 10 years ago, so I’m hesitant to upgrade everything to passive house standard. Besides, we don’t really have the budget for that.
During the day, we already do everything we can to keep the sun out—roller shutters (not everywhere), blinds, etc. At night, I only want to open the windows partially because, being a bungalow, all windows are easily accessible from outside.
I’m considering what would be the most sensible solution but feel a bit overwhelmed by the many options. I understand I will need professional advice at some point. But is there anyone who can objectively compare all solutions rather than just promoting one?
So I ask you: What are your opinions and experiences?
Climate split system (two indoor units)
Decentralized ventilation
In theory, a centralized ventilation system could also be an option to cover most areas
What do you think about ventilation with an earth tube (ground heat exchanger)? Sounds quite interesting.
All options are available with or without heat recovery, with or without a heat pump.
Oh, and if the system is also more economical for heating in winter than our low-temperature oil heating, that would be great as well.
We have a fireplace—what about the risk of negative pressure with that?
The living area is 165 m² (1776 sq ft). Cooling would primarily be needed in the bedroom and two children’s rooms. Maybe through the hallway, and then it spreads into the rooms?
So overall, I find this topic complicated because of the many possible solutions. Decentralized ventilation seems most interesting to me if it can also cool and be cheaper than oil heating. It’s also appealing because I can keep the windows closed, which significantly reduces burglary risk.
Thank you very much to everyone who read this long message and shares their opinion. I hope the text is clear.
Greetings from the north (Africa)
We have been living for a few years in a bungalow from the 1970s. Okay, it’s not located in Africa, but in northern Germany, although we do have warm summers here and the number of hot days is increasing rather than decreasing.
Inside the house, temperatures can reach 26–27°C (79–81°F) on really hot summer days, and it’s quite difficult to sleep at night. The house is actually in decent condition, the roof and windows were replaced less than 10 years ago, so I’m hesitant to upgrade everything to passive house standard. Besides, we don’t really have the budget for that.
During the day, we already do everything we can to keep the sun out—roller shutters (not everywhere), blinds, etc. At night, I only want to open the windows partially because, being a bungalow, all windows are easily accessible from outside.
I’m considering what would be the most sensible solution but feel a bit overwhelmed by the many options. I understand I will need professional advice at some point. But is there anyone who can objectively compare all solutions rather than just promoting one?
So I ask you: What are your opinions and experiences?
Climate split system (two indoor units)
Decentralized ventilation
In theory, a centralized ventilation system could also be an option to cover most areas
What do you think about ventilation with an earth tube (ground heat exchanger)? Sounds quite interesting.
All options are available with or without heat recovery, with or without a heat pump.
Oh, and if the system is also more economical for heating in winter than our low-temperature oil heating, that would be great as well.
We have a fireplace—what about the risk of negative pressure with that?
The living area is 165 m² (1776 sq ft). Cooling would primarily be needed in the bedroom and two children’s rooms. Maybe through the hallway, and then it spreads into the rooms?
So overall, I find this topic complicated because of the many possible solutions. Decentralized ventilation seems most interesting to me if it can also cool and be cheaper than oil heating. It’s also appealing because I can keep the windows closed, which significantly reduces burglary risk.
Thank you very much to everyone who read this long message and shares their opinion. I hope the text is clear.
Greetings from the north (Africa)
Benutzer19 schrieb:
A ventilation system could bring cooler air into the house at night.As a basic principle: ventilation does not cool.
And an air conditioning unit does not ventilate.
Whether combined units exist, I do not know and do not want to debate that.
B
boxandroof22 Jun 2019 10:25Benutzer19 schrieb:
How much does a photovoltaic system cost? Approximately 1000 to 1400 per kWp. You usually break even after 14 to 15 years. The subsidy lasts for 20 years. It almost always pays off. The larger the system, the better in every way: less shading impact, higher absolute and relative returns, and more electricity produced in winter for self-consumption compared to smaller systems. You can find lots of information online. If needed, consider taking out a loan to build a larger system.
H
hampshire22 Jun 2019 10:30boxandroof schrieb:
There are some reports online that confirm the effect.A study by Creaton states otherwise. Nowadays, you can easily find confirmations for almost any theory.Benutzer19 schrieb:
There can be no issues with the roof’s tightness during construction or afterward?Yes, there can be – a Norwegian system from Sun-Net avoids damaging the roof covering.Benutzer19 schrieb:
How much does such a photovoltaic system cost? I know, probably a very general question.Roughly estimate €1000 - 1500 per 1 kWh (kilowatt peak) – this is also very approximate.Benutzer19 schrieb:
Are subsidies available for this?KfW provides loans for the system and grants for storage units.Benutzer19 schrieb:
When does it become cost-effective?With proper sizing, over 10 years (again, very approximate).Benutzer19 schrieb:
Oh, and I read something about small business status starting at a certain photovoltaic system size?Small business status applies from 10 kWp (kilowatt peak) upwards – from this threshold, you would also need to pay the energy levy.Questions that can help you further:
How much electricity do I use in each month?
What is the typical load distribution over 24 hours? (you could measure this a few days)
What is the household’s “base load” — which devices run constantly and what is their power consumption, for example, refrigerator, air conditioning in summer?
From this, you can get a fairly good idea of the appropriate system size, whether to use single-phase or three-phase, and if storage is needed.
You have enough roof space.
The standard modules are high-voltage systems. I wouldn’t install these directly over rooms you spend a lot of time in. Online sources will support all sorts of opinions — I mark this as a personal view rather than a scientifically established concern.
One more thing: The house will hardly be any cooler with modules on the roof. That was the intention, right?
B
Benutzer1922 Jun 2019 11:27Ok, thanks for the information!! The high-voltage aspect does put me off a bit at first. The idea of photovoltaics being cost-effective and helping to reduce electricity costs for an air conditioning system sounded interesting initially. So, I think I’ll focus on just one air conditioning unit for now. It will probably be expensive enough...
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