ᐅ Build a Single-Family Home to KfW55 or Efficiency House 70 Standards?
Created on: 27 Dec 2019 20:24
S
Sternchen31
Hello everyone,
we hope you can help us a bit. We have purchased a plot of land, the notarization appointment has already taken place, and now we are waiting for the payment deadline. Meanwhile, we are already in contact with several solid construction companies that we have shortlisted and have received two offers so far; the third meeting was today.
So far, it was clear to us that we would build a KfW 55 single-family house (about 125 m² (1350 sq ft) living space on the ground floor and first floor) with a full basement (30 m² (320 sq ft) basement possibly used as living space with underfloor heating), a photovoltaic system, heat pump, and underfloor heating with individual room control.
Today, for the first time, we were asked why we actually want to build to KfW 55 standards. An efficiency house 70 would be around €20,000 - 30,000 cheaper, plus approximately €15,000 for the photovoltaic system. According to this, it would take about 15–20 years for the additional costs of building to KfW 55 with a photovoltaic system to be recovered through energy savings. The subsidies, except for the €5,000 from KfW, are no longer as favorable as they used to be and may not be cost-effective.
We have already received two offers from construction companies where this question about not building to KfW 70 did not come up at all.
We are now a bit confused and would like to exchange some thoughts on this.
Many thanks in advance.
we hope you can help us a bit. We have purchased a plot of land, the notarization appointment has already taken place, and now we are waiting for the payment deadline. Meanwhile, we are already in contact with several solid construction companies that we have shortlisted and have received two offers so far; the third meeting was today.
So far, it was clear to us that we would build a KfW 55 single-family house (about 125 m² (1350 sq ft) living space on the ground floor and first floor) with a full basement (30 m² (320 sq ft) basement possibly used as living space with underfloor heating), a photovoltaic system, heat pump, and underfloor heating with individual room control.
Today, for the first time, we were asked why we actually want to build to KfW 55 standards. An efficiency house 70 would be around €20,000 - 30,000 cheaper, plus approximately €15,000 for the photovoltaic system. According to this, it would take about 15–20 years for the additional costs of building to KfW 55 with a photovoltaic system to be recovered through energy savings. The subsidies, except for the €5,000 from KfW, are no longer as favorable as they used to be and may not be cost-effective.
We have already received two offers from construction companies where this question about not building to KfW 70 did not come up at all.
We are now a bit confused and would like to exchange some thoughts on this.
Many thanks in advance.
S
Sternchen3129 Dec 2019 17:28boxandroof schrieb:
The subsidy for KfW55 is relatively low and therefore not a particularly attractive goal. The question is how good or bad the insulation is in the standard version without KfW, and what payback period is acceptable for you.
If you find out the H't value for both options, you can calculate and roughly estimate the payback. This value describes the insulation quality without influence from technology or other adjustments. Alternatively, check which building components are specifically improved and their insulation values.
Photovoltaic systems generally pay off; the installed area should be as large as possible to increase the profit. Homebuilders are not necessarily the best partners for photovoltaic systems, so I would plan and install them separately. Make sure to include a conduit for the roof. Installing a system just barely large enough to qualify for a subsidy would be a mistake. Yes, we definitely plan to use as much area as possible for the photovoltaic system. We also want to organize it ourselves, not through the general contractor. We will definitely have the conduit installed during construction.
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Sternchen3129 Dec 2019 17:39blackm88 schrieb:
How do you come up with these additional costs?! In 2016, upgrading from KfW70 to KfW55 only cost us about €4,500 (roughly $4,800) for the entire house (a bit more insulation and better insulation under the foundation slab). After deducting the subsidy of €5,000 (about $5,300), it was a pretty good deal.
Our basement is almost completely underground (rock), and only the hallway/entrance area has underfloor heating, but all rooms have controlled ventilation. The values were good enough to easily meet KfW55 standards.The whole consultation the day before yesterday was very poor! She immediately rolled her eyes when we mentioned air-source heat pumps and KfW and asked why we would want to spend so much money unnecessarily. During the cost calculation, she said, "I knew it, almost €20,000 (about $21,300) more just for the extra insulation you need." When I asked for more details, she said the house will be built brick by brick and then plastered, so no additional insulation would be applied. That would make the difference €20,000.
But as I said, the whole consultation was questionable in many ways.
S
Sternchen3129 Dec 2019 17:43boxandroof schrieb:
The subsidy for KfW55 is relatively low and, as such, not a very desirable goal. The question is how good or bad the insulation is with the standard without KfW support, and what payback period is acceptable for you.
If you find the H't value for both options, you can calculate and roughly estimate the payback period. This value describes the insulation quality without influence from technology or other optimistic assumptions. Alternatively, check which building components are improved exactly and what their insulation values are in each case.
According to the consultant, the insulation in the energy house would only be in the brickwork and then the plaster. Nothing else would be insulated, and since all the insulation material could be saved here, we would save about €20,000 (approximately $22,000). In any case, this option was not suitable for us, so we will stick with KfW55, but she was extremely critical of the KfW55 standard and also of the air-to-water heat pump, which made us find her comments quite odd.
Sternchen31 schrieb:
According to the consultant, the insulation in an energy-efficient house would basically just be the brickwork and then the plaster. There wouldn’t be any additional insulation at all, so by saving on all the insulation materials, we would save around €20,000. That wasn’t an option for us anyway, so we will stick with KfW55, but she was extremely negative about KfW55 and also about the air-to-water heat pump, which seemed strange to us. I don’t see how you could save 20,000 euros that way. That woman seems suspicious to me.
michert schrieb:
I don’t see how you could save 20,000 euros that way. I would be suspicious of that woman.I strongly suspect that the KfW-70 house is planned as monolithic, meaning without external thermal insulation composite system (ETICS). To reach KfW-55 standard, the general contractor can then only offer an insulated facade. So it’s not just a few extra centimeters of insulation, but the entire facade would need to be wrapped. That easily adds up to 20,000 euros...Are there also KfW-70 offers with ETICS? In that case, the additional cost should be more like 5,000 to 10,000 euros.
An air-to-water heat pump usually becomes more economical the lower the heating demand is.
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