Hello, we are currently planning our single-family house of 165 m² (1,777 sq ft) in the Sauerland region.
We want to build using 36.5 or 42.5 cm (14.4 or 16.7 inches) hollow bricks without additional insulation, as we are not fans of external thermal insulation composite systems (ETICS). Underfloor heating is planned, probably no ventilation system, as it is too expensive.
Since the village is not connected to the natural gas network and we have no basement, therefore no space for, for example, pellet storage, we have to install a heat pump.
A ground source heat pump would cost €4,500 more after deducting the BAFa subsidy compared to an air source heat pump.
I have also often read that heat pumps do not make sense with monolithic construction.
What would you recommend?
We want to build using 36.5 or 42.5 cm (14.4 or 16.7 inches) hollow bricks without additional insulation, as we are not fans of external thermal insulation composite systems (ETICS). Underfloor heating is planned, probably no ventilation system, as it is too expensive.
Since the village is not connected to the natural gas network and we have no basement, therefore no space for, for example, pellet storage, we have to install a heat pump.
A ground source heat pump would cost €4,500 more after deducting the BAFa subsidy compared to an air source heat pump.
I have also often read that heat pumps do not make sense with monolithic construction.
What would you recommend?
boxandroof schrieb:
I didn’t expect any other answer Anything else would have been untruthful. I still believe it’s not cost-effective, especially since here you only get a subsidy of about €1100 (approx. $1200) for a complete system (photovoltaic and storage) under the 10,000 Houses Program since August 2019. There is no support for retrofitting later on.
I received an offer for the BYD high-voltage battery at €5700 (approx. $6200) in the standard 6.4 kW configuration. It can be easily upgraded yourself (plug and play) with 1.32 kW (approx. 1.8 hp) modules for €670 (approx. $730) each. This way, the storage will reach 9 kW. The problem is that the car doesn’t fully charge from the system in summer either (in spring and autumn, not at all, and in winter we don’t even need to discuss), because I only get home around 5 p.m. So the car can be fully charged using the battery storage, and there should still be 2–3 kW (approx. 2.7–4 hp) left for nighttime use.
That’s the theory!
G
goalkeeper5 Nov 2019 09:52Has anyone actually taken the time to calculate when the whole topic of photovoltaic systems, storage, etc. becomes cost-effective? Including the currently expensive purchase of an electric vehicle and the system?
It doesn’t pay off in a lifetime—or if it does, only at a time when the first cheap Chinese panels have already failed, right?
In our area, the general contractors advised against it back then—and usually, they’re happy to sell you anything.
It doesn’t pay off in a lifetime—or if it does, only at a time when the first cheap Chinese panels have already failed, right?
In our area, the general contractors advised against it back then—and usually, they’re happy to sell you anything.
goalkeeper schrieb:
Has anyone actually taken the time to calculate when the whole topic of photovoltaic systems, storage, etc., becomes cost-effective?There are plenty of calculations available for every desired outcome.goalkeeper schrieb:
Has anyone actually taken the time to calculate when the whole topic of photovoltaic systems, storage, etc. pays off? Including the currently expensive purchase of an electric car and the system?
It doesn’t seem to pay off in a lifetime—and if it does, then only by the time the first cheap Chinese panels fail, right?
In our region back then, every general contractor advised against it—and normally they are happy to sell you anything.The photovoltaic system should pay off in about 11 years without storage, assuming nothing breaks. Let’s say 16 years. The car costs me 77€ per month (insurance, electricity, maintenance included). Since I don’t pay battery leasing fees, the purchase should pay off after 9 years (compared to keeping my old diesel). And by “pay off,” I really mean that I have recovered the purchase costs. Of course, this doesn’t include setting aside money for a new vehicle. Three years and 40,000 km (25,000 miles) are already gone.Controlled residential ventilation and geothermal exchangers will probably never pay off. Insulation and better roller shutter boxes, windows, etc., for an energy efficiency standard like KfW 55 (after subsidies) will likely take an estimated 30 years.
B
boxandroof5 Nov 2019 10:06goalkeeper schrieb:
Has anyone actually taken the time to calculate when the whole topic of photovoltaics, storage, etc., becomes financially viable? Yes, many people have. Here is my current understanding:
Photovoltaic systems pay off on their own through feed-in tariffs. The larger the system, the more cost-effective it becomes. Four months ago, I installed a 10kWp photovoltaic system, as I don’t have more space available. It is expected to pay for itself in about 11–12 years, and after that, it will generate around €1000 (approx. $1100) profit per year until the support ends after 20 years. Self-consumption is just a bonus on top. The technology is robust and comes with long-term warranties.
Storage systems are simply not economical yet and also not environmentally sensible, since there is no surplus of “green” electricity in the grid. This means that the electricity stored with losses in the battery and then used personally could have been fed into the grid more efficiently for others to use.
Car: no idea, that’s to come. A new electric vehicle is definitely more expensive than its conventional counterpart.
Economy is always just one factor...
Ventilation system: Economically rarely viable, but it provides a huge increase in comfort.
Battery storage: Rarely economical, but there are cases where it makes sense (a friend of mine runs a farm now converted to selling organic meat with large refrigeration units operating 24/7... a prime use case).
Good insulation: Considering the increased value of the house, it can be economical up to a certain extent. However, the increased comfort should not be overlooked. Beyond a certain standard, though, there is hardly any additional comfort improvement (in my opinion), as long as there is a certain level of airtightness and the walls no longer get cold as is typical in older buildings. The added value (in my view) comes more from continuous controlled ventilation (with preheated air).
Electric car: I don’t have one but am thinking about it. I can charge for free at work (+ photovoltaic system at home on the roof), so the conditions are ideal... whether it is economical is secondary, electric cars are just cool.
Otherwise, as Mycraft says, you can always run calculations in any direction with various assumptions if you need a justification for yourself.
Ventilation system: Economically rarely viable, but it provides a huge increase in comfort.
Battery storage: Rarely economical, but there are cases where it makes sense (a friend of mine runs a farm now converted to selling organic meat with large refrigeration units operating 24/7... a prime use case).
Good insulation: Considering the increased value of the house, it can be economical up to a certain extent. However, the increased comfort should not be overlooked. Beyond a certain standard, though, there is hardly any additional comfort improvement (in my opinion), as long as there is a certain level of airtightness and the walls no longer get cold as is typical in older buildings. The added value (in my view) comes more from continuous controlled ventilation (with preheated air).
Electric car: I don’t have one but am thinking about it. I can charge for free at work (+ photovoltaic system at home on the roof), so the conditions are ideal... whether it is economical is secondary, electric cars are just cool.
Otherwise, as Mycraft says, you can always run calculations in any direction with various assumptions if you need a justification for yourself.
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