ᐅ New Construction Gas Heating – How to Design Underfloor Heating for a Heat Pump?

I am a bit confused; the lifespan and reliability of ground source heat pumps can be clearly understood. The technology is actually quite old and has recently become more popular due to significant improvements in efficiency. I have done a lot of reading and sought advice. In my opinion, the bigger question is what will happen with gas and electricity prices in the future. Otherwise, as far as I know, maintenance costs are much lower, and it’s generally calculated that a ground source heat pump pays off after about 12 to 15 years.

I don’t want to speak badly about gas, because to operate a gas stove alone, I know plenty of people who only have gas in their homes. Generally, I also faced the budget issue—gas or ground source heat pump. I decided we should go with the ground source heat pump now instead of potentially paying twice in the long run. Gas will definitely not be installed in the house (no connection will be laid), with the hope and expectation that the ground source heat pump will pay off as soon as possible, depending on electricity prices...

Well, prices are rising, whether it’s electricity, gas, or oil, so I don’t think any of these energy sources will get cheaper... and I also don’t believe that gas will become significantly more expensive than electricity.
But all of this is just a guess; that much is clear.

What’s easier to calculate is the amount of savings I need to achieve for a heat pump system to be worthwhile...
With an additional investment of 13,000 euros, I would need to save 866 euros per year to break even in 15 years. I’d like to see someone convince me otherwise. Even if I generously account for savings on connection fees and maintenance, I’d still need to save around 60 euros per month on energy costs for a geothermal heat pump system to pay off after 15 years.

For the gas heating system, I have budgeted monthly costs of 80 euros (approximately 88 USD) for our household... meaning a heat pump should cost me around 20 euros (about 22 USD) per month in operating expenses for me to consider it worthwhile 😉

I am now getting a quote for an external air-source heat pump... let’s see where the price will land. But since there apparently are no subsidies anymore, I think this topic will be put on the back burner for now.

Hello,

Vega82 schrieb:

We are building to KfW70 standard, which we achieve even without solar panels by using a mechanical ventilation system with heat recovery (Helios), which is required by the local building regulations anyway.

You have found a very good provider for mechanical ventilation from the Swiss company. Take a look at their other product offerings; I could almost wish to win the lottery, although prices have become more affordable now. Heliobus has had a branch in Germany for about 2 or 3 years, so customs fees no longer apply.

Vega82 schrieb:

Our budget is 180k, which we have already slightly exceeded. All extras are included in that. (130 m² (1,399 ft²) floor area, gable roof, rectangular shape)

Surely some extras are already included in the 180k for the house?

Vega82 schrieb:

As described, I think there are pros and cons to everything... if money weren’t an issue, I would go for a ground source heat pump... but with the uncertainties about service life and reliability, I currently see no reason to pay the extra cost. Also because we have a gas connection directly on the property, so connection costs remain low (which are also partially subsidized by the local energy provider).

Either it’s covered by subsidies or district heating is mandatory; somehow the basic suppliers have to recoup their costs 😉

Regards, Bauexperte

Well, no one can guarantee how fast the payback period will be. You might also be unlucky and have a heat pump fail early... I’m not claiming that a ground source heat pump is a perfect solution or anything like that; in my opinion, gas is a reliable option for clear cost calculation. You know in advance that maintenance costs, chimney sweeping, etc., will be incurred. Everything else really depends on personal preference, like how warm you want your home to be. For me, 19°C (66°F) is enough... But if I want it warmer, say 22–24°C (72–75°F)... that’s when the calculations get more complicated! What bothered me personally about gas was that in consultations, the additional costs were often downplayed. On average, you’ll hear about around 300 EUR, sometimes more, sometimes less. From what I read, the lifespan of a gas boiler is about 15 years. I think that with my relatively low heating demand, a ground source heat pump makes sense. I’m also open to being convinced otherwise ;-) Basically, my point was just that there are uncertainties regarding lifespan and reliability. The lifespan of any heating system can unfortunately be only a few months if you’re unlucky, but generally, we’re talking about 20 years or more. For gas, I’ve seen information that the average lifespan is about 15 years. There are plenty of pros and cons for both systems, but in one aspect, gas heating has an advantage: it is easier to calculate costs accurately, despite higher expenses!

When it comes to additional costs, please don’t forget the loan.
If it costs 5,000 € more, in the end it will certainly not be just 5,000 € more. … you have to pay interest on the loan if the extra cost is not paid in cash, which makes it even more expensive.

I have been living in my 124 m² (1,335 sq ft) newly built home for a year now (KfW70, three people). During the last mild winter, I used about 800 cubic meters (28,250 cubic feet) of gas. However, I have two solar collectors for hot water on the roof. I turned off the heating from May to October (using only solar for hot water), but it still doesn’t pay off financially. For hot water, you need significantly less than one cubic meter (35 cubic feet) of gas per day. For the annual inspection, the heating technicians charge 100–180 € (approximately 110–200 USD) per year (cleaning and new gasket).

Of course, the financing effort must also be taken into account. However, please don’t forget to spread the cost of the probe(s) for the ground-source heat pump over the expected lifespan of the house.
When I calculate the solar collectors that are often installed with gas systems to achieve KfW70 standards, it seems even more questionable to me, as these never really pay off.