Hello everyone,
During the planning phase of building a house, you inevitably come across forums about home construction and topics related to energy standards. I have already read several books and browsed various websites on the subject. I should mention that I am not a professional in this field. What I have noticed is that the entire topic of "economic / ecological home construction" is heavily influenced by commercial interests. The so-called "smart" consumer is often misled by marketing terms and a government-led campaign for "CO2-efficient building." Books or websites dealing with this subject often do not provide clear, comprehensive assessments.
In the "better" literature, insulation materials are compared in terms of insulation value and whether they are expensive or affordable. However, I still cannot determine what makes the most sense for my individual case. I simply do not want to spend excessive amounts of money, especially on things that do not add value, such as polystyrene insulation. If additional costs for a particular heating system are reasonable over a feasible period, then yes.
Our current goal is to build a simple single-family home with about 130 - 140 sqm (1400 - 1500 sq ft). The house should cost around €200,000 (without outdoor landscaping, floor coverings, land, or additional construction-related costs; our expectations are modest).
I am interested in knowing, based on the current state of technology, what is the most energy-efficient and cost-effective building option?
Energy-saving regulation / building standards according to KfW, yes or no, and if yes, which level?
Solid construction or prefabricated house?
Condensing boiler technology or heat pump?
Thank you very much for your answers!
Best regards
During the planning phase of building a house, you inevitably come across forums about home construction and topics related to energy standards. I have already read several books and browsed various websites on the subject. I should mention that I am not a professional in this field. What I have noticed is that the entire topic of "economic / ecological home construction" is heavily influenced by commercial interests. The so-called "smart" consumer is often misled by marketing terms and a government-led campaign for "CO2-efficient building." Books or websites dealing with this subject often do not provide clear, comprehensive assessments.
In the "better" literature, insulation materials are compared in terms of insulation value and whether they are expensive or affordable. However, I still cannot determine what makes the most sense for my individual case. I simply do not want to spend excessive amounts of money, especially on things that do not add value, such as polystyrene insulation. If additional costs for a particular heating system are reasonable over a feasible period, then yes.
Our current goal is to build a simple single-family home with about 130 - 140 sqm (1400 - 1500 sq ft). The house should cost around €200,000 (without outdoor landscaping, floor coverings, land, or additional construction-related costs; our expectations are modest).
I am interested in knowing, based on the current state of technology, what is the most energy-efficient and cost-effective building option?
Energy-saving regulation / building standards according to KfW, yes or no, and if yes, which level?
Solid construction or prefabricated house?
Condensing boiler technology or heat pump?
Thank you very much for your answers!
Best regards
W
winnetou788 Aug 2017 09:18Nordlys schrieb:
The problem with any calculation is the assumptions you make. Please determine the following for your house: estimated gas consumption (I calculate 8,000 kWh for 110 sqm (1,184 sq ft)). Find out the annual cost for that from a typical provider, like EON or similar. Determine the electricity consumption. You can reasonably transfer your current usage to the new house. Calculate the additional cost of a heat pump. Find out the one-time gas connection fee and spread it over 15 years. Estimate the expected electricity consumption of your new build with the heat pump (gas will then be eliminated). Make one table covering only 15 years. Anything longer makes little sense, since the heating system—no matter which—will likely need replacement by then. Now do the calculation. My forecast: a heat pump only pays off if you assume sharply rising gas prices and moderately increasing electricity prices. In my opinion, that’s not realistic. Both will likely rise: gas because of scarcity, electricity because of electric vehicles.
Controlled mechanical ventilation with heat recovery is, in my view, more of a comfort feature than an energy saver.
A photovoltaic system on the roof to support the pump: in my opinion, it won’t make a big difference either, as the initial investment is simply too expensive.
My conclusion: if you have extra money, don’t spend it on building services technology, but on a nice garden fountain or something similar—that will bring you more joy.
One more thing: if you use KfW funding, you must provide proof that you’ve met the KfW standards. If you build to the basic Energy Saving Ordinance (EnEV or GEG), you can skip blower door tests and similar procedures.
My opinion: the current Energy Saving Ordinance is a green-ideological education scheme to promote certain industries under the label of CO2 reduction. No one calculates the CO2 needed for manufacturing all these things, etc. If you truly want to save CO2, take the train, walk, buy a gasoline car with 75 hp and a hybrid system, avoid a wood-burning stove, and above all, eat less meat—then no rainforest will be cleared for soybean plantations. KarstenThe difference between a heat pump and gas heating is not that big.
For me, underfloor heating with gas and solar was the standard.
The extra cost for the Vaillant geothermal system with a 100 m (330 ft) deep borehole was 6,460 EUR.
For the gas connection, I would have paid 1,280 EUR.
For the heat pump, I receive a subsidy from BAFA of 4,500 EUR.
Additionally, I had to pay for borehole insurance and apply to the local water authority.
In the end, the extra cost for a geothermal heat pump comes to 1,120 EUR.
That is actually quite negligible.
B
Bauherr20188 Aug 2017 09:18Nordlys schrieb:
The problem with any calculation is the assumptions you make. Please determine the following for your house: expected gas consumption (I calculate about 8000 kWh for 110 sqm (1184 sq ft)). Find out the annual price from a typical provider, like eon or similar. Determine the electricity consumption. You can fairly transfer your current usage to the new house. Calculate the additional cost of a heat pump. Determine the one-time cost of the gas connection. Spread that over 15 years. Estimate the expected electricity consumption of your new building with the heat pump, since gas will no longer be needed. Make one table. It should only cover 15 years. Anything beyond that doesn’t make sense since any heating system will need replacement by then. Now calculate. My forecast: a heat pump will only be worthwhile if you assume sharply rising gas prices and moderately rising electricity prices. In my opinion, that’s not realistic. Both will rise: gas due to scarcity, electricity due to electric vehicles.
In my view, controlled mechanical ventilation is more of a comfort feature than an energy saver.
A photovoltaic system on the roof to support the pump: in my opinion, that won’t make a significant difference either, the initial investment is simply too expensive.
My conclusion: if you have extra money, buy something nice like a garden fountain or similar instead of investing in building technology. You’ll enjoy that more.
One more thing: if you use KfW funding, you need proof that you have met KfW requirements. If you build to the basic Energy Saving Ordinance standard, you can avoid blower door tests and similar.
My opinion: the current Energy Saving Ordinance is a green-ideology-driven educational concept to promote certain industries under the label of CO2 reduction. No one calculates the CO2 needed for manufacturing all these things. If you really want to save CO2, take the train, walk, buy a petrol car with 75 hp (56 kW) plus a hybrid system, avoid a wood stove, and above all, eat less meat to prevent more rainforest being cleared for soybean plantations. KarstenThank you for your reply, Karsten. And that is exactly why I am questioning it.
W
winnetou788 Aug 2017 09:29At least I have to agree with that once.
Nordlys schrieb:
My opinion: The current energy-saving regulations are basically a green ideological initiative designed to promote certain industries under the label of CO2 reduction. No one calculates all the CO2 involved in the production processes, etc. If you really want to save CO2, take the train, walk, buy a 75 hp gasoline car with a hybrid system, avoid a wood-burning stove, and above all, eat less meat so that no more rainforest is cleared for soy plantations. KarstenLess meat—that’s coming from the hotdog eater. Education is, of course, important too—we’ve already discussed how most people try climate education instead of simply reducing birth rates.
But I don’t see it as that simple. Looking at my dad’s old house—nice, but an energy disaster. Heating costs over 3000 euros per year. Compared to that, I’m doing well with 750 euros for the same size. Where would we be if the KFW (state development bank) didn’t keep tightening the standards? Probably still in the Middle Ages.
D
daniels878 Aug 2017 09:36HilfeHilfe schrieb:
Air source heat pumps are apparently not reliable in cold regions because they are prone to failure.
We have one, and so do the neighboring houses. Our climate is rather mild, but then we had a harsh winter and four air source heat pumps broke down. Two have been replaced.
So what now? Was it the manufacturer, the general contractor, or Mother Nature?
Oh no, it was Merkel.
You’re asking strange questions that no one can answer.This often happens because savvy homeowners disable the electric backup heater to save a few dollars each month. As a result, the compressor overworks itself and causes significant noise emissions. During winter nights, we even activated the noise reduction mode (from 11 PM to 3 AM) and ended up with heating costs of about €60/month (~$65/month) in the first year. I think people often try to save money in the wrong places. Even if it costs €10 more per month (~$11), it’s really not a big deal.
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