ᐅ Single-Family Home Energy Saving Regulation 2016: Is Additional Insulation Recommended by Developers Worthwhile?

Good morning,

ölschlamm schrieb:

I had based my assumptions in my calculation: 42cm (17 inches) monolithic vs. 17.5 bricks + 16cm (6 inches) EPS

I referred to 36.5; reading should help.

ölschlamm schrieb:

But how much does it save additionally – that was the question.

I wrote that the relevant calculations are needed to specify the potential savings; I do not possess a working crystal ball.

Regards, Bauexperte

Hello building expert,
the 42cm (16.5 inches) dimension was originally not from me either. Manu1976 brought up the 42cm (16.5 inches) block because she wanted a monolithic AND brick solution (according to the 2016 Energy Saving Ordinance). For my construction project, 36.5cm (14.4 inches) with Ytong and similar materials would have been enough. I have read your posts here about this material. It definitely would have been an option for me.

Oh yes, it’s a pity you don’t have a crystal ball. I don’t have one either, and I also don’t have any calculations...

T21150 schrieb:
no one here will be able to tell you roughly what you save with additional insulation without a precise calculation (these are longer...) .

Hello Thorsten – I just wanted to have a rough idea. And Andreas’ post together with your approach did help me move forward. If you pay around $50 per month, the maximum annual savings potential is about $600. And that’s without considering any return on initial investment, and showers don’t get skipped either...

Of course, we could now assume that energy prices increase by 10 percentage points per year, adjusted for inflation...

By the way, my heating installer also told me exactly the same about condensing boilers. Based on experience, he assumes a service life of around 12 years. But this only applies to the systems currently installed. The units being installed now should last longer than 12 years, because we rarely run our heating systems at full capacity, and since we have solar, the system is off for about half the year anyway.

Best regards
Michael

Hi Michael,

Great if I was able to help you move forward a bit with your considerations.

The 2016 KFW100 standard roughly corresponds to the current KFW70. So you have a good calculation basis for your decisions (which heating system, which additional insulation).

With the gas condensing boiler, you are making a small misconception. Yes, the system is off for about 35% of the year. Even in summer, there can be several rainy days when you need hot water. The coverage rate of the thermal solar system with my 5 m² (54 sq ft) collector area is below 50%... (the capital costs for the solar thermal system are not included in the 50 euros mentioned above; I only listed the direct energy carrier costs excluding auxiliary energy like pumps).

When the boiler is needed for heating in winter, it often runs at around 3 kW output in my case. So it operates at part load, near the lower limit. Even last winter at -10°C (14°F), the smallest unit from the manufacturer ran intermittently at 23-30% basic load, and the house gets comfortably warm at 22°C (72°F). The part-load operation isn’t ideal for the unit but still works.

A downside: systems in KFW70 buildings often tend to cycle frequently because these houses have very low energy demand. Almost everything on the market for a small house like mine with 135 m² (1,453 sq ft) usable area is actually oversized. Frequent cycling significantly reduces the lifespan of a gas condensing boiler. Additionally, no heating engineer usually takes the time to optimize the system over weeks so the cycling stays within a reasonably "healthy range" (around << 10 burner starts per hour of runtime). I started with 60 starts per burner hour... Weeks later, I had programmed the system so it was acceptable—I think I now know the boiler’s manual by heart...

I definitely expect to have to buy a new gas condensing boiler in 12, at the latest 15 years. Considering the bargain price of the units, that’s manageable.

However: an air-to-water heat pump also needs to be optimized... that’s a lot of work too.

Best regards,
Thorsten

Hi Michael,

ölschlamm schrieb:
That’s exactly the point – I just want to avoid the 9500. Unless that would be complete nonsense economically.

The drilling is not allowed / water protection area. The geothermal option doesn’t pay off – better to insulate more.

@andimann
Viessmann still uses stainless steel. The others don’t – says my heating technician. The Rotex I assumed has aluminum. Viessmann costs twice as much.
I’d gladly take that crate of beer off your hands – and share it if I actually win
But if you assume a gas condensing boiler for 2500–3000, then you have to assume a Panasonic air-to-water heat pump for under 7000. And who knows what heat pumps will be worth in 10 years – maybe replacing them will pay off anyway.

You estimate your solar thermal yield at 1000–1500 kWh. How many square meters do you have installed – 10 m² (108 ft²)? Heating support? If yes, what do you do with the surplus in summer – pool, laundry, or something similar? Then it makes sense.
With my gas alternative, I also have 10 m² (108 ft²) of collector forced anyway, but I realistically estimate at best 1500 kWh usable yield.

That’s how it is… And our eco-friendly politicians will surely “invent” a cross-subsidy for the expensive grid expansion if gas prices stay low. I’m also betting a crate of beer…

Regards
Michael

You simply won’t be able to avoid the additional costs at all; it’s only a matter of what you spend the money on, not whether you spend it.

I don’t know if the other heating systems don’t have stainless steel chambers, but I do know that the 2500 to 3000 I assumed already refer to a Viessmann. You can get the Viessmann Vitodens 300 delivered to your home for 2500–3000 Euros (about 2700–3200 USD), and that’s their high-end product. The simpler ones are easily under 2000. Yes, someone still needs to install it, that’s true, but the same goes for the air-to-water heat pump.

We currently have 5 m² (54 ft²) of solar thermal installed. The heating system shows how much solar energy it collects each day. These are estimates anyway, but it reaches a maximum of 11 kWh per day in summer on sunny days. We just don’t consume more heat. So, for the entire year, let’s say maybe 1000 kWh, with a lot of luck 1500 kWh. From early May to October, we almost don’t use any gas, maybe around 100 kWh during these roughly five months. Domestic hot water is completely covered by the solar system.

Best regards,

Andreas

In 2015, we experienced a summer here that was just unbearable. If it wasn’t cold, it rained. Otherwise, it was cold and raining. It’s incredible, considering that in some parts of Germany the summer was actually good. I myself even spent a few weeks in my home region of Bavaria, where it was 20°C (68°F) or more warmer and the sun was shining....

Every low-pressure system that came across the Atlantic in 2015 seemed to have orders to stop in Velbert and say hello. Great.

I used more gas per day in April/May than I do now in December. And even in June, the heating had to run on some days.

Solar yield: You can pretty much forget about 2015 for me....almost zero. It was less than 200 kWh. No wonder, it was just raining here all the time. We rarely saw a clear blue sky....

When the sun did shine: record was 14 kWh. But on such days, no one needs hot water... only cold.

Gas consumption was 130 cubic meters from 01.04.15 to 30.09.15.

PS: After several severe storms in recent weeks that once again caused widespread damage (by now, I have everything properly secured here), we already have a storm warning today. With the gusts, I’m again worried that the trees will be uprooted.

A wind turbine: I could really use one here; it would be spinning nonstop. A TSA? Probably not practical in this location.