Build a single-family house as KfW55 or Efficiency House 70?

2019-12-28 14:16:09

For my timber frame house, the improvement from 70 to 55 would only have been about 5,000 EUR more expensive.

2019-12-29 17:28:39

The subsidy for KfW55 is relatively low and as such not a particularly desirable goal. The question is how good or bad the insulation is in the standard without KfW already, and what payback period is acceptable for you.

If you find out the H't value for both variants, you can calculate with it and roughly estimate the amortization. The value describes the insulation quality without influence from technology or other cosmetic adjustments. Alternatively, look at which components are exactly improved and what the insulation values are for each.

Photovoltaics usually always pay off; the covered area should be as large as possible to increase the profit. Homebuilders are not necessarily the best partners for photovoltaic systems; I would plan and install that separately. Provide an empty conduit to the roof. Installing an only just sufficiently sized system for the sake of a subsidy would be a mistake.

Yes, we already plan to utilize as much area as possible for photovoltaics. We also want to organize it ourselves and not through the general contractor. We will definitely have an empty conduit installed.

2019-12-29 17:39:24

How do you come up with these additional costs?! In 2016, we had about €4,500 extra for the whole house going from KfW70 to KfW55 (a bit more insulation and better insulation under the floor slab). Plus, subtracting the €5,000 subsidy, so a good calculation.

Our basement is almost entirely underground (rock), and only the hallway/entrance has underfloor heating, but all rooms have controlled residential ventilation. However, the values were so good that KfW55 was easily achieved.

The entire consultation the day before yesterday was more than poor! She immediately rolled her eyes when we mentioned air heat pump and KFW and said why we want to spend so much money unnecessarily. During the calculation came the sentence "I knew it, nearly €20,000 more just for the insulation you need." I then asked more precisely, and it was said the house is built stone by stone and then plastered; insulation will not be applied at all. The difference would amount to €20,000.

But as I said, the whole consultation was very questionable in some respects.

2019-12-29 17:43:27

The subsidy for KfW55 is relatively low and as such not a particularly desirable goal. The question is how good or bad the insulation in the standard without KfW already is and what payback period is acceptable for you.

If you find out the H't value for both variants, you can calculate with it and roughly estimate the payback period. The value describes the insulation quality without influence from technology or other accounting tricks. Alternatively, look at which components are exactly improved and what the insulation values are for each.

According to the consultant, the insulation in an energy-efficient house would basically just be the brickwork and then the plaster. Nothing else would be insulated at all and since all the insulation material could be saved here, we would have savings of around €20,000. That was never an option for us anyway, so we will stick with KfW55, but she ranted so extremely against KfW55 and also against the air-to-water heat pump that it seemed strange to us anyway.

2019-12-29 18:16:37

According to the advisor, the insulation in an energy-efficient house would just be the brickwork and then the plaster. Nothing else would be insulated at all, and since all the insulation material could be saved here, we would save about €20,000. It wasn't an option for us anyway, so we will stick with KfW55, but she ranted so extremely against KfW55 and also against the air-water heat pump that it seemed strange to us.

I wouldn't know how you could save €20k from that. The woman would seem suspicious to me.

2019-12-29 18:24:19

I wouldn't know how to save 20k€ with that. The woman would seem suspicious to me.

I strongly suspect that the KfW-70 house is planned monolithically, i.e. without external thermal insulation composite system (ETICS). To reach KfW-55 level, the general contractor can now only offer an insulation facade. So not just a few centimeters more, but wrapping the entire facade specifically for this purpose. That 20k€ is gone very quickly....

Are there also KfW-70 offers with ETICS? The surcharge should rather be 5 to 10k€.

Air-to-water heat pumps are generally more worthwhile the lower the heat demand is.

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Build a single-family house as KfW55 or Efficiency House 70?

User0815

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Sternchen31

Sternchen31

michert

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