Wärmepumpe - too expensive, aren't they?

[Gambatte 791]

We will soon build our own house and I was/am cntemplating about heating via a thermal pump vs gas boiler. But purchase and installation of heat pumps are very expensive: our Bauunternehmer says to have a water-water heat pump would cost us 13keur more than conventional gas heating

At the moment we live in a house that has probably very similar energy consumtpion to what we will have later. And we are paying only 55eur/month for gas (for the record: we also pay another 55/month for electric).

Fazit: although more energy efficient, heat pumps are too expensive!

 

Do you have first hand knowledge? Experiences? Anything?

Thanks 

[Uncle Jamal 132]

I think you are talking about the pump type which draws water from 10m down right? If so, then these are the more expensive to install of these pumps. You could also look at an air water pump - these cost far less, but are less efficient. A good option these days though is to combine one of these with solar panels - increases your costs of course, but could make you almost free of costs after 10 -15 years or so.

[Gambatte 791]

Apologies the title was wrong, just edited.

No, 13k was/is the cost for Luftwasserpumpe (the lesser efficient type), Erdwarmepumpe would cost even more (but yes you are right, it's more efficient).

 

Still, even if you were from costs free after say15yr, it seems to me the initial cost is so high that make this option not very good.

 

You guys have experience with either type of theat pump?

[jeba 4,234]

What would be the cost of conventional heating? How long would it take to recover the cost of the difference between the two systems? Have you asked for quotes from other companies as well? Sometimes the differences are surprising.

[AnswerToLife42 2,491]

No personnel experience, only from a German forum: https://www.haustechnikdialog.de/Forum/30/Waermepumpen

7kW heat pump 8000€

As a collector you throw approx. 1000m 30mm plastic tube into a 80m long (around your lot) 1.8m deep ditch.

The tube will cost you approx. 1500€.

You only need an excavator and some friends to throw the tube in bunches into the ditch. search for "Grabenkollektor" in that forum.

Here is a picture, how they did it: https://www.google.de/search?q=erdw%C3%A4rme+forumskollektor&tbm=isch&source=iu&ictx=1&fir=5lsuE8pXGLYbqM%253A%252CcxQHiSclP5ttIM%252C_&usg=__NHPCrq9X8G26DXXt0Czk9LRU_9k%3D&sa=X&ved=0ahUKEwi8847B-JPcAhVGfywKHXXVCn0Q9QEIUTAJ#imgrc=uph6Ynx2NwmKhM:

 

Bauunternehmer don't like it because they can't earn much money with it.

 

[Gambatte 791]

24 minutes ago, jeba said:

What would be the cost of conventional heating? How long would it take to recover the cost of the difference between the two systems? Have you asked for quotes from other companies as well? Sometimes the differences are surprising.

 

But this I posted already earlier: costs of building the house with conventional gas-heating = X, cost of building the house with heat pum rather than normal gas heating = X + 13k.

Time to recover the cost of heat pump, if running the heat pump costs 0.5*720eur/yr, half as much as gas = 13k / (0.5*720)  = 36yr (ok, this ignore few things: energy inflation, servicing the loan, bla bla...)

 

No, asking other companies sounds like inviting trouble. Who does what? Who coordinates? Whom to speak to? Who is responsible when anything goes wrong... ? (they would be blaming each other, of course) 

 

I'd rather have only one end to speak to.

[Gambatte 791]

13 minutes ago, AnswerToLife42 said:

Bauunternehmer don't like it because they can't earn much money with it.

 

I disagree. How can this be in line with the fundamental laws of economics?

If they prefer not to sell stuff because they don't earn much money from it, they should either not sell it, or offer it at a higher cost.

 

No, I don't want "some friends" to build the heating of my house, as I already have a construction company (a very good one) building the whole house!

[El Jeffo 41,974]

Does your figure include the subsidies you can apply for - up to €10k - and the low-interest loans you might get from the KfW?

 

Friends of ours did this in Dresden. After some initial difficulties, which forced them to heat with electricity for several months (the contractor ended up covering their extra costs), their system has been up and running without a hitch for 9 years now. They figure their electricity bill is an extra €5/month due to the recirculating water pumps, but they save over €100/month in heating costs.

 

I don't think you'd get away with heating a house for €55/month, so your break-even should come sooner than 35 years. The higher energy efficiency value would increase the resale value of your home, too. Plus you'd have the peace of mind of being independent of fossil fuels and would be doing something for the environment.

[Gambatte 791]

2 minutes ago, El Jeffo said:

Does your figure include the subsidies you can apply for - up to €10k - and the low-interest loans you might get from the KfW?

Good point. No, it doesn't.  

 

2 minutes ago, El Jeffo said:

I don't think you'd get away with heating a house for €55/month, so your break-even should come sooner than 35 years. 

This has been our average during the last 4yr. I know it's less than average for similar household. We live in a 10yr old DHH, similar size to the EFH we are to build.

 

2 minutes ago, El Jeffo said:

The higher energy efficiency value would increase the resale value of your home, too. Plus you'd have the peace of mind of being independent of fossil fuels and would be doing something for the environment.

Yes, this is very attractive.

[Guest]

12 minutes ago, Gambatte said:

 

I disagree. How can this be in line with the fundamental laws of economics?

 

 

Please Explain...(and bear in mind which country you are refering to...)

[AnswerToLife42 2,491]

Concerning the monthly costs: We need approx. 8000kWh for heating. To produce this a heating pump should need 2000kWh of electrical energy. (an air heat pump may/will need more)

Assuming 30cents/kWh makes 50€/month.

Your estimation looks reasonable.

[Gambatte 791]

13 minutes ago, AnswerToLife42 said:

Concerning the monthly costs: We need approx. 8000kWh for heating. To produce this a heating pump should need 2000kWh of electrical energy. (an air heat pump may/will need more)

Assuming 30cents/kWh makes 50€/month.

Your estimation looks reasonable.

 

Actually 55eur/month was/is a measurement, not an estimate. It's our gas consumption averaged over the last 4yr. 

[jeba 4,234]

11 hours ago, Gambatte said:

No, asking other companies sounds like inviting trouble. Who does what?

Everybody does it. At least everybody I know. How else can you compare prices?

 

11 hours ago, Gambatte said:

Who coordinates? Whom to speak to

Your architekt. That´s a big part of what he is paid for.

 

[scook17 196]

On 10/07/2018, 08:53:22, AnswerToLife42 said:

No personnel experience, only from a German forum: https://www.haustechnikdialog.de/Forum/30/Waermepumpen

7kW heat pump 8000€

As a collector you throw approx. 1000m 30mm plastic tube into a 80m long (around your lot) 1.8m deep ditch.

The tube will cost you approx. 1500€.

You only need an excavator and some friends to throw the tube in bunches into the ditch. search for "Grabenkollektor" in that forum.

Here is a picture, how they did it: https://www.google.de/search?q=erdw%C3%A4rme+forumskollektor&tbm=isch&source=iu&ictx=1&fir=5lsuE8pXGLYbqM%253A%252CcxQHiSclP5ttIM%252C_&usg=__NHPCrq9X8G26DXXt0Czk9LRU_9k%3D&sa=X&ved=0ahUKEwi8847B-JPcAhVGfywKHXXVCn0Q9QEIUTAJ#imgrc=uph6Ynx2NwmKhM:

 

Bauunternehmer don't like it because they can't earn much money with it.

 

 

Lets say I was ok with digging up the lawn and putting this in

 

https://www.google.de/imgres?imgurl=http%3A%2F%2Fwww.erdwaerme-forum.de%2FThemen%2FBilder%2FTKEinbaufertig.jpg&imgrefurl=http%3A%2F%2Fwww.erdwaerme-forum.de%2F&tbnid=er1_XNvhbuax5M&vet=12ahUKEwjN68Kkhbn3AhUoM-wKHVrGBBgQMygDegUIARDAAQ..i&docid=QNtxKci29WgNLM&w=1200&h=1428&q=erdw%C3%A4rme%20forumskollektor&ved=2ahUKEwjN68Kkhbn3AhUoM-wKHVrGBBgQMygDegUIARDAAQ

 

Now you connect this to a ground source heat pump. What is the typical heat output per m2 of ground space?

What depth would you need to bury the pipe work? For me the photo seems very shallow:

 

https://www.erdwaermeplus.de/images/content/erdwaermekollektoren_flaeche.jpg

 

In winter time the ground is completely frozen, so is it that much warmer just a little way down?

[jeba 4,234]

6 hours ago, scook17 said:

What is the typical heat output per m2 of ground space?

That depends a lot on the structure and water content of the ground, not only it´s temperature. You need moisture to transfer the heat to your tubes. If it´s too dry (often the case  in sandy soil), efficacy goes down. That´s why our architect advised us against a heat pump at the time.

[AnswerToLife42 2,491]

My very late answer: if the ground is not too sandy you can extract approx. 80W/m if you use the "Ringgrabenkollektor" from "haustechnikdialog.de"

So, if the ditch is 100m long you should be able to extract 8kW. + 2kW from the grid (the heat pump needs energy) you get 10kW which should be enough for a modern 150m² house at -15°C. If you have extracted to much energy from the soil end of winter, the water around the tube will freeze, however, freezing will release even more energy. In spring you will have a block of ice under you lawn, but over the summer it will melt. The guys who recommended this type of collected said the "6 feet under" is optimal, meaning, you have too make sure that no ancient grave yard is under your plot of land.