Single-family house, Energy Saving Ordinance 2016, developer recommends additional insulation - is it sensible?

Good morning,

my assumptions I had stated before my calculation: 42cm monolithic vs. 17.5 bricks + 16 cm EPS

I had referred to 36.5; reading should help

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

For that I had written that the corresponding calculations are needed to specify the possible saving effect; I do not possess a functioning crystal ball.

Rhineland regards

Hello building expert,
the 42cm originally did not come from me either. Manu1976 brought up the 42cm block because she wanted to suggest monolithic AND with brick (according to the Energy Saving Ordinance 2016). With Ytong & Co, 36.5 would have been enough for my building project as well. I have read your posts here about this material. It would certainly have been an option for me.

oh yes, too bad you don’t have a crystal ball. I don’t have one either and also no calculation.....

no one here will be able to tell you without an exact calculation (these take longer...) what you approximately save with additional insulation.

Hello Thorsten - I just wanted to know it roughly. And the post from Andreas together with your line of thinking already helped me. Whoever pays 50,- per month has at best a savings potential of 600,- annually. And no initial investment is financed, and there is no showering either....

Sure, now we could assume that energy prices increase by 10% p.a. adjusted for inflation...

By the way, my heating installer told me exactly the same about the condensing boilers. He also assumes based on experience a lifespan of about +/- 12 years. But this only applies to the currently installed systems. The ones installed now should last a bit longer than 12 years because we rarely run our heating systems at full load and the system is off anyway for half a year because of the solar.

Regards
Michael

Hi Michael,

great that I was able to help you move forward a bit in your considerations.

The 2016 KFW100 corresponds in large parts roughly 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 very small mistake.
Yes: The systems are off about 35% of the year (approximately). Even in summer, it sometimes rains for days and you need hot water. The coverage rate of the thermal solar system with 5 sqm at my place is below 50%.....(the capital costs for the TSA are not included in the above 50,-, there I only listed the direct costs of the energy carrier without auxiliary energy (pumps)).

When the boiler is needed for heating in winter: it often runs (at my place) with about 3kW output. That means part-load operation, the lower limit. Even last winter at -10 degrees the device (the smallest in the manufacturer's program) operated at 23-30 % base load range occasionally, the place gets cozy warm at 22 degrees. Part-load operation is not optimal for the device. But it still works.

Downside: Systems tend to cycle quite a bit in a Kfw 70, these houses no longer have a large energy demand and actually everything on the market is already oversized for such a small house like mine with 135 sqm usable area. The cycling puts a great strain on the lifespan of a gas condensing boiler. Additionally, no heating engineer takes the time to optimize the system for weeks so that the cycling lands in a somewhat “healthy range” (approx. << 10 burner starts per hour of runtime). I started with 60 starts/burner hour.....Weeks later I had programmed the system so that it was usable, I think I now know the manual of the heating system by heart.....

I definitely expect to have to buy a new gas condensing boiler in 12, at the latest 15 years. Given the bargain price of the devices....bearable.

However: An air-water heat pump also needs to be optimized......that is a lot of work too.

Best regards
Thorsten

Hi Michael,

That's exactly what it's about - I just want to avoid the 9500. Unless that would be completely nonsensical economically.

No drilling / water protection area. Brine doesn’t make sense - better to insulate more.


Viessmann still builds with stainless steel. The others don’t - says my heating guy. The Rotex I assumed has aluminum. Viessmann costs twice as much.
I’d like to lose the case of beer - and in case I win, even share it
But if you assume a gas condensing boiler for 2500-3000, then you also have to take a Panasonic air-water heat pump for under 7000. And who knows what heat pumps will be worth in 10 years - maybe a replacement pays off anyway one way or another.

You calculate your solar thermal yield at 1000-1500 kWh. How many m² do you have installed - 10 m²? Heating support? If yes, what do you do with the input in summer - swimming pool, laundry or similar - then it pays off.
I also have 10 m² collector included with my gas alternative, but I also calculate with at best 1500 kWh actually usable yield.

That's how it looks..... And our eco-friendly folks will definitely “invent” cross-financing for the expensive grid expansion at constant low gas prices. I’ll also bet a case of beer...

Regards
Michael

you won’t be able to avoid the additional costs at all, it’s only about what you spend the money on, not whether you spend it.

Whether the other boilers have no stainless steel chambers, I don’t know, but what I do know is that the 2500 to 3000 I assumed already refer to a Viessmann. You can get the Viessmann Vitodens 300 delivered to your place for 2500-3000 euros and that is their high-end product. The simpler ones you can get easily for under 2000. Yes, someone still has to connect it, that’s true, but then again, so does the air-water heat pump.

We currently have 5 sqm of solar thermal installed. The heating system has a display showing how much solar energy it collects per day. These are only estimates anyway, but it gets up to max 11 kWh per day in summer on sunny days. We just don’t consume more heat then. So let that be maybe 1000 kWh per year, with a lot of luck 1500 kWh. From early May to October we use almost no gas, maybe 100 kWh in these good 5+ months. Hot water then runs completely on the solar system.

Regards,

Andreas

We had a summer to run away from here locally in 2015. If it wasn’t cold, it rained. Otherwise, it was cold + rained. Unbelievable, considering that in some parts of Germany the summer was good. I myself also emigrated to my homeland Bavaria for a few weeks, where it was 20 degrees and more warmer and the sun was shining.... Every low-pressure system that came over the Atlantic in 2015 had the order to say hello in Velbert. Great.

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

Yield TSA: You can forget about it with me in 2015.... and almost calculate it as 0. It was not even 200 kWh. No wonder, it only rained here. We rarely saw blue sky....

When the sun shines: record 14 kWh. But on such days no one needs hot water... only cold.

Gas consumption 130 cubic meters from 01.04.15 - 30.09.15.

PS: After x storms of high quality in recent weeks, which once again tore everything to pieces (by now I have already secured everything here), we have storm warnings again today and I am afraid in the gusts that it will rip the trees out of the ground. A wind turbine: I could really use one here, it would spin itself to death. A TSA? Rather not useful here.