ᐅ KfW 70 or Home Ownership Program – Which Is More Cost-Effective?

Hello everyone,

My partner and I want to build a turnkey solid house but are still somewhat undecided about the home technology and its financing.

Several acquaintances recommended a local builder who constructed their houses. We actually felt fairly advised by the contact person at this company, and we also received the most affordable offer from them. Two other providers were significantly more expensive even in the basic package, and we got the impression they were trying hard to sell us a ground-source heat pump.

The house from the preferred provider is expected to cost around €161,000 (approximately $174,000) in the basic package (“energy-saving house” with 150 sqm (1,615 sqft) of living space and facing brickwork). Additional possible costs would be:
- Single-flue chimney (for the fireplace we want) for €3,500 (approximately $3,800)
- Triple-glazed windows with a five-chamber system for €1,800 (approximately $1,950) (extra charge compared to double glazing)
- Controlled residential ventilation with heat recovery for €8,500 (approximately $9,200)
- Solar system with 4.5 sqm (48 sqft) collector area and 300-liter (79-gallon) water storage tank for €5,500 (approximately $6,000)

Included in the base price are a gas condensing boiler with weather-compensated control and night setback, as well as flat panel radiators.

We are now wondering: KFW70 or home ownership program? This decision will certainly be influenced by the expected effectiveness of the solar system. The roof slopes will face east and west, which is less than ideal for solar collectors. In addition, about 20 meters (66 feet) west of the house there are tall oak trees providing a lot of shade.

Roughly calculated, the KFW70 loan would be about €7,000 (approximately $7,600) cheaper in the first ten years (until repayment via a home savings contract) than the loan from the home ownership program. This would cover the extra cost of materials and installation for the solar system. But what additional costs should we expect to realize the building project as a KFW70 energy-efficient house? “Organizational efforts” and costs for system maintenance are hard for me to estimate.

In the providers’ brochures, ground-source heat pumps sound appealing: independence from fossil fuels and long service life. However, based on what I have read from independent guides, rising electricity costs and difficult-to-assess efficiency put ground-source heat systems in a very different light. For cost reasons, we have also distanced ourselves from such a solution.

Are there other economical options to take advantage of the attractive conditions of the KFW70 loan without relying on solar energy or ground-source heat?

I would appreciate your independent opinions and experiences on this topic.

Best regards,
Dennis

Hello,

mad-zero schrieb:
...... However, based on what I have read in independent guides, rising electricity costs and the difficulty of accurately estimating efficiency put geothermal systems in a very different light.

The costs of all energy sources will increase significantly. The efficiency of heat pump systems can be well assessed, provided that precise planning and sizing are performed.

mad-zero schrieb:
...... Are there other economical options, ...

Certainly, but this requires knowledge of the actual demand (power, energy) for heating and domestic hot water.

Best regards

mad-zero schrieb:

For us, the question now is: KFW70 or Homeownership Program? This decision will certainly also be influenced by the expected efficiency of the solar system. The house’s roof slopes will face east or west, which is probably unsuitable for solar collectors. In addition, there are tall oak trees about 20 meters (65 feet) west of the house, casting a lot of shade.

Hello Dennis,

You seem to assume that KFW70 has something to do with solar thermal (ST)... Unfortunately, this is often suggested, but it is still incorrect...

Actually, you already give yourself the answer: an east-west facing roof with heavy shading. The economic benefit of solar thermal is already borderline when it comes to an unshaded south-facing roof... In your case, in my opinion, you can even skip the calculations suggested by Euro and just use a bit of common sense 🙄

The question about KFW70 is completely different. Whether it is worthwhile for you, I cannot judge. Better ask your builder how big the cost difference is between the energy saving regulation and KFW70. Then you might be able to answer this question yourself...
My advice (this is what I did): building envelope to KFW70 standard. I wanted controlled ventilation anyway – for reasons of indoor comfort. Then I checked what extra effort it would take to really meet KFW70. After my builder recalculated, it came down to an additional 4 cm (1.5 inches) of insulation in the roof... I didn’t need to think twice about that...
But this is a consideration independent of the financing through the KFW bank. What makes sense for you or not, I can’t assess...

Regards,
Micha 😎

What’s stopping you from combining both loans? In my opinion, they don’t necessarily exclude each other...

And how exactly did you calculate that the KfW 70 loan saves €7,000 in the first 10 years compared to the homeownership program???

Micha&Dany schrieb:
....In my opinion, with you, one could even skip the calculations accurately suggested by Euro and just use a bit of common sense...

This apparently common sense has caused many costly failures! Self-proclaimed hobby experts, who offer no guarantees or warranties for their statements or posts, often see things quite differently, as is frequently the case here! 😉

Best regards

€uro schrieb:
This apparently common sense has caused many money pits!!
Self-proclaimed hobby experts, without any guarantee or liability for their statements/posts, often see things very differently here! 😉

Best regards.

Oh Euro,
the "self-proclaimed hobby experts" argument is getting a bit worn out, don’t you think?
I probably know much more about solar energy and solar radiation than you do.
Just because I have no experience with solar thermal systems doesn’t mean I don’t know that an east-facing roof receives 20-25% less solar radiation than the same roof facing south (of course, roof pitch also plays a role). And if that east roof is heavily shaded...
If you don’t believe me, feel free to look up “solar radiation chart” on good old Google. Sorry Euro, but that chart is only useful for estimates, not precise calculations...
And if I also know that solar thermal isn’t always cost-effective even on a south-facing roof, then I don’t need to spend hundreds of dollars to have a calculation done whose result is very likely already clear beforehand.
And no, I’m not calculating the probability that I have the only east-facing, shaded roof where solar thermal makes sense—I’m just estimating that probability 😀

Even a photovoltaic system, which normally still yields a 6-8% return on investment, would never pay off on such a roof...

In this particular case, I would check the application of the 15% rule. If cost-effectiveness is given here, I wouldn’t waste a thought on solar thermal...

But that’s just the insignificant opinion of someone who (of course only as a hobby) has been planning photovoltaic power plants for years...

Best regards
Micha 😎