ᐅ Price difference for new construction: KfW 70 vs. KfW 55 energy standards

Good evening, dear forum members,

I am looking for a rough estimate of the additional costs involved in building a standard new house compared to a KfW 70 or KfW 55 energy standard. The low interest rates are very attractive, but is the extra expense for a KfW-certified house really worth it? Or would it make sense to implement only parts of the KfW standard? Perhaps a fireplace and a decent gas boiler would be sufficient.

Thank you for your help!

Regards,
Nils

Hi Nils,

The question is hard to answer because it depends on many factors, especially what you already plan to build. Many prefabricated houses seem to already meet the KfW 55 standard, or if you are planning to equip a solid construction house with a heat pump and ventilation anyway, the additional cost of going from 70 down to 55 might be quite small.

Tuning a house originally designed to KfW 70 standard up to KfW 55 will likely cost more than the interest savings you will gain.

In this forum, figures between 5,000 and 15,000 € have been mentioned, with some much higher outliers.

Others here may know more about the current legal situation, but so far it seems that just the required certification for KfW 55 alone consumes the interest savings.

You can forget about savings on heating costs in this context anyway. A modern house has heating costs in the range of 40-80 € per month. Saving 20% of that won’t make much difference for you.

Long story short, financially it will most likely not be worthwhile unless you are planning to build a house that barely misses the KfW 55 standard and can be brought over that threshold with little effort.

A gas boiler will only work with a relatively large solar system due to the new stricter environmental regulations in place now. This means there is little savings in upfront costs compared to an air-to-water heat pump. However, operational costs will be better with a gas condensing boiler.

Best regards,

Andreas

andimann schrieb:


Others may be more informed about the current legal situation, but so far it seems that the expert required for KfW 55 certification alone cancels out any savings from lower interest rates.

I would like to bring my question back to the table regarding this matter:

https://www.hausbau-forum.de/threads/kfw-baubegleitung-Nachweis-Abnahme.13877/page-2#post-108562

Thank you for your response.
How much more expensive would the necessary components be compared to the standard ones?
How do solid construction houses compare to prefabricated houses?
Many offers are advertised as an all-inclusive package.
Best regards, Nils

Hello Nils,

nils1985 schrieb:

I am looking for a rough estimate of the additional costs from a standard new build to KfW 70 and KfW 55. The low interest rates are very tempting, but is the extra cost for a KfW house worth it? Or should one perhaps only implement parts of the KfW standard?

That cannot be answered in general terms, as it depends on...

How large is the single-family house, with or without a basement, what kind of technology—especially a controlled mechanical ventilation system with heat recovery—is installed, and what is the wall construction?

nils1985 schrieb:

A fireplace and a decent gas boiler might be enough.

For those providers who have already offered KfW 70 as a standard last year, there will likely not be much change, as they mostly use air-to-water heat pumps. This means they meet the requirements of the current Energy Saving Ordinance 2016 without additional effort. This is due to the (positive) change in the primary energy factor for an air-to-water heat pump. Therefore, the step to KfW 55 is manageable.

If you want to build with a gas condensing boiler, it looks different. You will have more effort to meet the Energy Saving Ordinance requirements. More insulation and at least a solar system for domestic hot water heating are necessary. The monetary effort to comply with the Energy Saving Ordinance 2016—compared to an air-to-water heat pump—is higher.

A fireplace is purely for comfort; wood is quite expensive and only pays off if you can get it cheaply or for free. Apart from the fact that in modern single-family homes even the four candles of an Advent wreath generate plenty of warmth.

So, more specific details from you are needed to answer your question somewhat reliably.

Best regards, Bauexperte

Quick question: Is it possible to meet the 2014 Energy Saving Ordinance requirements using a gas condensing boiler and a mechanical ventilation system with heat recovery, without relying on solar energy?