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

  • Erstellt am 2015-12-17 22:22:17

ölschlamm

2015-12-21 13:49:56
  • #1


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



Man Bauexperte – it’s great that you help people here, but have you also read what I wrote: The insulation IS mandatory with gas and the Energy Saving Ordinance 2016. But how much it saves additionally – that was the question.



First of all, thanks a lot for your long answer, but I haven’t given myself the answer. If I calculate with 10000 kWh, burning at least 2 cubic meters of wood in the wood stove (which is well below my long-term average), then I get to 7000 kWh. With an annual performance factor of 2.1 and an electricity price of 0.25 € per kWh, that is 840 euros. I would have estimated the gas costs significantly lower than you did. At the end of the day, I still come to additional costs of 500 euros per year with my calculation. Against that stand additional costs of 9500 euros for gas + solar + insulation + tank + etc.

Do you think an aluminum condensing boiler lasts 20 years?
And 9500 over 20 years with 1.5% interest amounts to over 12500 euros. I can pay a lot more electricity for quite a long time with that.

And two answers: Yes, it is the Energy Saving Ordinance 2016 – the building application will be submitted in spring. Therefore: gas only with additional insulation (wall + roof or floor slab). And I don’t want XPS beneath the floor slab. I also believe that will work well – but a residual risk remains. And my house stands on it.



No, I want to keep the initial investment low. The house will probably be sold in 10+ years.

Greetings to you all
Michael
 

nordanney

2015-12-21 13:59:09
  • #2

Couldn’t that possibly backfire then?
 

Musketier

2015-12-21 13:59:14
  • #3


Doesn't that contradict all your posts here?
If you first spend an extra €9,000 on gas, the investment is not low but initially higher.
But for this additional investment, you could probably already get almost a geothermal drilling (if feasible in the mountains), which is certainly more efficient than gas and presumably easier to sell in 10 years than a house with gas.
 

andimann

2015-12-21 14:37:10
  • #4
Hi Ölschlamm,





I don’t know what you mean by an aluminum condensing boiler?!? A modern gas condensing boiler has a stainless steel combustion chamber, you would have to buy really cheap junk for that.
Does it last 20 years? No idea, but if you want to sell the house anyway in 10 years, you don’t have to worry about that.
But I’d almost bet a case of beer that it will last longer than a normal air-water heat pump under your operating conditions. And in case something happens, you get a new gas boiler for 2,500–3,000 €, an air-water heat pump will cost you more.

If a heat pump, you will probably really have to go with a geothermal probe. How that compares price-wise I can’t judge.

Since you already fall under the 2016 version of the new eco-madness regulation, you now have an economic problem. You can turn and twist it as you want, you will have to throw several thousand euros out the window anyway. You can only choose in which direction you throw the money...

Best regards,
Andreas
 

ölschlamm

2015-12-21 16:39:56
  • #5

That's exactly the point - I just want to avoid the €9500. Unless that would be complete nonsense economically.

The borehole is not in a water protection area. Brine doesn't pay off – better to insulate more.


Viessmann still builds with stainless steel. The others don’t – says my heating engineer. The Rotex I assumed has aluminum. Viessmann costs twice as much.
I would gladly lose the crate of beer – and if I profit, 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 the heat pumps will be worth in 10 years – maybe an exchange pays off either way.

You calculate the yield of your solar thermal system at 1000-1500 kWh. How many square meters have you installed – 10 m²? Supportive for heating? If yes, what do you do with the input in summer – pool, laundry, or similar, then it pays off.
With my gas alternative, I also have 10 m² collector forcibly included, but I also calculate with at best 1500 kWh actually usable yield.

That’s how it is..... And our eco people will surely "invent" cross-financing for the expensive grid expansion with a consistently low gas price. I’m also putting a crate of beer on it...

Regards
Michael
 

T21150

2015-12-21 16:47:17
  • #6


Well, this eco-madness regulation is really something!

Dear Ölschlamm,

No one here will be able to tell you without a precise calculation (these take longer...) how much you roughly save with additional insulation (or to what extent you further minimize transmission heat losses).

My KFW-70 house has 135 sqm of usable space and is heated with a gas condensing boiler + thermal solar (domestic hot water). The heating energy consumption "gas" is about 6,500 kWh/year, including meter fees this corresponds to costs averaging 50,- per month. This as a reference point.

The costs for the gas connection vary depending on the municipality. Roughly I think: 1500 - 3000. An air-to-water heat pump costs more, of course it does not require a connection. Thus, in terms of costs, you get into the same order of magnitude as a gas condensing boiler. An annual performance factor of about 2.5 should be achieved by the air-to-water heat pump though, otherwise you run the risk of slightly higher costs with it.

But with these houses, we are already in the region of: 45-65 Euros/month.
You can insulate, do this and that: maybe you save 10 or 20 per month.
You can offset the necessary investment and personally determine:
- Is it worth it to me?
- Does it bring me anything?
- Am I investing in ecology or purely optimizing my own business case.

Best regards and good luck with your decision-making.

By the way: From very knowledgeable sources, I know that a gas condensing boiler is designed for a service life of about 12 years. Also the ones from the manufacturer starting with V... Some last longer, others shorter, which you as a user can partly influence, but that’s another story. The relevant internal parts in the right places must be made of stainless steel, otherwise such a device would have no long service life at all. Those with V are definitely good. Yes. But others are good too. Often slightly cheaper though. My boiler from another brand manufacturer costs 1800 euros bare. It may also break after 12-15 years, then I screw in the successor because the installation grid will be kept by the company again.

The yield of your collector, unless it’s vacuum flat-tube, is exaggeratedly high. I would say, calculate with 1000 kWh, but a lot of that dissipates in summer when you don’t need it, and in winter you have nothing.

Thorsten
 

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