ᐅ Which heating system would you choose for our planned new build?
Created on: 24 Jan 2016 11:25
F
Frenzi
Hello everyone,
I have already read a lot in this great forum, but somehow I’m not making any progress.
Maybe you can help me...
We (a couple in our mid-50s) are planning, possibly, to sell our semi-detached house (prefabricated house with about 115 sqm (1235 sq ft) built in 1999) and build a detached single-family home.
Here are the basic details of the house:
- Prefabricated house with panel construction, approx. 125 sqm (1345 sq ft) on a slab foundation without a basement, exterior wall U-value about 0.14
- 2 people (kids have moved out)
- South-facing plot
- Fully developed new residential area (gas available)
- Targeting KfW 55 standard to potentially qualify for subsidies (but not mandatory)
We have spent several weeks researching and have some non-binding offers. According to these, such a house will cost us turnkey around 230,000 with a standard heating system.
We don’t want to spend too much, even though our current house is mortgage-free. But we’re not getting any younger. When selling our current home, we will have about two-thirds equity available, so we would need to take out a loan for at least one-third.
That’s why I’m paying particular attention to the cost-effectiveness of the heating system. Because what good are the claimed top values of different heating types if the extra costs only pay off after 25 years and I’m already six feet under on the plot?
So, here are the options I’m currently considering:
1. Standard gas boiler (condensing) with underfloor heating (cost about 2,500 in gas connection fees for the house)
2. Nibe exhaust air heat pump F730 at no extra cost (so saving the gas connection)
3. Air-to-water heat pump Elco S05 (COP value 4.0) surcharge 7,000 (net 4,500 after deducting no gas connection)
4. Stiebel Eltron LWZ 304 integral system surcharge 11,500 (net 9,000)
5. Ground-source heat pump Vaillant flexoCompact surcharge 10,900 (net 8,400)
For options 1, 3, and 5, we would like to use a controlled ventilation system with heat recovery (Zehnder 350D), which would cost us about 2,000 due to a promotion. For options 2 and 4, this would not be necessary. A solar system for domestic hot water for option 1 would cost about 3,500.
Some home builders recommend the Proxon system (Proxon Zimmermann ventilation). However, I quickly ruled this out after some research. I also have concerns about the Nibe system that I might end up paying more because I may need to use electric backup heating in winter.
Currently, our gas bill for two people in our house is about 70 per month (condensing boiler and underfloor heating).
I would prefer to avoid a gas connection to reduce dependence on one energy source. Photovoltaics interest me, but I think they are still too expensive right now. I would have a conduit installed for future preparation. A pellet heating system is not an option due to lack of storage space.
My current conclusion:
I’m leaning either toward
1. Gas boiler without solar hot water plus ventilation system (total additional cost with gas connection about 4,500) or
2. Elco air-to-water heat pump plus ventilation system (total cost about 6,500).
I am very unsure about option 2 (Nibe exhaust air pump), although the architect says it is sufficient and economical. It would cost us no extra money and no gas connection for the house.
Which type of heating would you choose?
What makes sense and what doesn’t? (Not considering environmental factors)
Thank you in advance for your opinions!
Regards,
Frenzi
I have already read a lot in this great forum, but somehow I’m not making any progress.
Maybe you can help me...
We (a couple in our mid-50s) are planning, possibly, to sell our semi-detached house (prefabricated house with about 115 sqm (1235 sq ft) built in 1999) and build a detached single-family home.
Here are the basic details of the house:
- Prefabricated house with panel construction, approx. 125 sqm (1345 sq ft) on a slab foundation without a basement, exterior wall U-value about 0.14
- 2 people (kids have moved out)
- South-facing plot
- Fully developed new residential area (gas available)
- Targeting KfW 55 standard to potentially qualify for subsidies (but not mandatory)
We have spent several weeks researching and have some non-binding offers. According to these, such a house will cost us turnkey around 230,000 with a standard heating system.
We don’t want to spend too much, even though our current house is mortgage-free. But we’re not getting any younger. When selling our current home, we will have about two-thirds equity available, so we would need to take out a loan for at least one-third.
That’s why I’m paying particular attention to the cost-effectiveness of the heating system. Because what good are the claimed top values of different heating types if the extra costs only pay off after 25 years and I’m already six feet under on the plot?
So, here are the options I’m currently considering:
1. Standard gas boiler (condensing) with underfloor heating (cost about 2,500 in gas connection fees for the house)
2. Nibe exhaust air heat pump F730 at no extra cost (so saving the gas connection)
3. Air-to-water heat pump Elco S05 (COP value 4.0) surcharge 7,000 (net 4,500 after deducting no gas connection)
4. Stiebel Eltron LWZ 304 integral system surcharge 11,500 (net 9,000)
5. Ground-source heat pump Vaillant flexoCompact surcharge 10,900 (net 8,400)
For options 1, 3, and 5, we would like to use a controlled ventilation system with heat recovery (Zehnder 350D), which would cost us about 2,000 due to a promotion. For options 2 and 4, this would not be necessary. A solar system for domestic hot water for option 1 would cost about 3,500.
Some home builders recommend the Proxon system (Proxon Zimmermann ventilation). However, I quickly ruled this out after some research. I also have concerns about the Nibe system that I might end up paying more because I may need to use electric backup heating in winter.
Currently, our gas bill for two people in our house is about 70 per month (condensing boiler and underfloor heating).
I would prefer to avoid a gas connection to reduce dependence on one energy source. Photovoltaics interest me, but I think they are still too expensive right now. I would have a conduit installed for future preparation. A pellet heating system is not an option due to lack of storage space.
My current conclusion:
I’m leaning either toward
1. Gas boiler without solar hot water plus ventilation system (total additional cost with gas connection about 4,500) or
2. Elco air-to-water heat pump plus ventilation system (total cost about 6,500).
I am very unsure about option 2 (Nibe exhaust air pump), although the architect says it is sufficient and economical. It would cost us no extra money and no gas connection for the house.
Which type of heating would you choose?
What makes sense and what doesn’t? (Not considering environmental factors)
Thank you in advance for your opinions!
Regards,
Frenzi
That’s right, Thorsten, but he should have stated that from the beginning instead of approaching it indirectly with an additional charge on top of the promotional price (without knowing whether controlled residential ventilation would be sufficient).
Apart from that, regarding the values (assuming that the U-value refers to the entire wall and not just the stud space), the rest should be appropriate. Then we would have a heating load of around 3-4 kW somewhere. So it’s perfect for a heat pump. And then let’s start calculating: plus gas plus controlled residential ventilation plus possibly solar if it really isn’t enough, and the ventilation and heat recovery unit at a reasonable price. An extra 11,500 is absolutely absurd as a surcharge...
Apart from that, regarding the values (assuming that the U-value refers to the entire wall and not just the stud space), the rest should be appropriate. Then we would have a heating load of around 3-4 kW somewhere. So it’s perfect for a heat pump. And then let’s start calculating: plus gas plus controlled residential ventilation plus possibly solar if it really isn’t enough, and the ventilation and heat recovery unit at a reasonable price. An extra 11,500 is absolutely absurd as a surcharge...
Rübe1 schrieb:
Exactly, Thorsten, but then he needs to say that upfront and not sneak in an extra charge on top of the promotional price (without knowing if the controlled residential ventilation system is even sufficient).
By the way, regarding the values (assuming that the U-value refers to the entire wall and not just the cavity!!), the rest should correspond accordingly. Then we’re looking at a heating load of around 3-4 kW. Perfect for a heat pump. And then let’s start calculating: plus gas, plus controlled residential ventilation, plus possibly solar if it really isn’t enough, and the ventilation and heat recovery unit at a reasonable price. An extra 11,500 is absolutely absurd as an additional charge....Absolutely right! Especially that extra charge is “the killer.”
Heating load assumption of 3-4 kW: I agree with that as well.
The original poster should have everything calculated as a full cost calculation and then decide.
I would leave out the controlled residential ventilation here: it’s a comfort feature that is controversial. You either like it or you don’t. I like it. It’s excellent.
Best regards,
Thorsten
The gas connection costs EUR 2,500, the ST EUR 3,500, and there is a EUR 4,000 subsidy from BAFA for the ground source heat pump. The additional EUR 900, which makes it more expensive, is worth it to me...
Personally, I also assume that even during your 'shorter' usage period, heating with electricity (to operate a ground source heat pump) will be more cost-effective than gas.
Personally, I also assume that even during your 'shorter' usage period, heating with electricity (to operate a ground source heat pump) will be more cost-effective than gas.
I argue that with the insulation and size, the heating load should actually be even lower than you suggest. If you don’t need the KfW 55 subsidy and 70 is sufficient, you can still build a house to the KfW 55 insulation standard and save on heating costs without adding too much complexity to the system.
Otherwise, as I already mentioned: the lower the demand, the less important the choice of heat generator becomes. At around €50 per month and 10% savings, that’s a difference of €60 per year—you will never recover the higher cost of an expensive system. I would also separate ventilation and heating, not use combined systems.
For gas heating, you definitely need a boiler that can modulate down very, very low.
Also, the statement that a heat pump is ideal at a heating load of 4 kW is nonsense. There are heat pumps with outputs of 15 kW that can operate below zero degrees Celsius (32°F) without a backup electric heater.
Otherwise, as I already mentioned: the lower the demand, the less important the choice of heat generator becomes. At around €50 per month and 10% savings, that’s a difference of €60 per year—you will never recover the higher cost of an expensive system. I would also separate ventilation and heating, not use combined systems.
For gas heating, you definitely need a boiler that can modulate down very, very low.
Also, the statement that a heat pump is ideal at a heating load of 4 kW is nonsense. There are heat pumps with outputs of 15 kW that can operate below zero degrees Celsius (32°F) without a backup electric heater.
Hello everyone,
First of all, thank you for the many replies and the ongoing discussion.
The more I talk to prefab house sellers, the more I get the impression that they deliberately offer deals like a Proxon unit at the same price as a condensing boiler (Proxon, Zimmermann ventilation) and “birthday gifts” like a free exhaust air heat pump to avoid the installation effort of a flue system for the boiler and/or because the systems with electric heating rods are heavily subsidized by the manufacturers.
After signing the contract, the seller doesn’t seem to care if I end up with double the heating bills.
So far, I haven’t met a single “advisor” at the showrooms who didn’t mislead you in some way.
By now, I’m so confused that I don’t know what to do anymore.... :-(
First of all, thank you for the many replies and the ongoing discussion.
The more I talk to prefab house sellers, the more I get the impression that they deliberately offer deals like a Proxon unit at the same price as a condensing boiler (Proxon, Zimmermann ventilation) and “birthday gifts” like a free exhaust air heat pump to avoid the installation effort of a flue system for the boiler and/or because the systems with electric heating rods are heavily subsidized by the manufacturers.
After signing the contract, the seller doesn’t seem to care if I end up with double the heating bills.
So far, I haven’t met a single “advisor” at the showrooms who didn’t mislead you in some way.
By now, I’m so confused that I don’t know what to do anymore.... :-(
Frenzi, just take your time to think it through calmly.
No one is giving anything away for free. If someone wants to "give something away," they actually want something in return. It’s the fancy last-minute bargain offer valid only until the end of the week. Forget it. Sellers have to deliver results, it’s as simple as that. And especially buyers with a high proportion of cash are making things difficult—well, better I stay quiet. Sellers sell what they’re supposed to. And anything considered luxury is particularly expensive. Very expensive. The more expensive, the higher the commission. For example, the heat recovery ventilation system is being offered online for 11,500 euros (about 12,900 US dollars). So, was there no heating system installed before?
A house nowadays, especially in terms of technology, is more than just four walls and a roof. It’s about concepts and systems, especially in the energy-efficient house sector. But do the sellers even know that?
No one is giving anything away for free. If someone wants to "give something away," they actually want something in return. It’s the fancy last-minute bargain offer valid only until the end of the week. Forget it. Sellers have to deliver results, it’s as simple as that. And especially buyers with a high proportion of cash are making things difficult—well, better I stay quiet. Sellers sell what they’re supposed to. And anything considered luxury is particularly expensive. Very expensive. The more expensive, the higher the commission. For example, the heat recovery ventilation system is being offered online for 11,500 euros (about 12,900 US dollars). So, was there no heating system installed before?
A house nowadays, especially in terms of technology, is more than just four walls and a roof. It’s about concepts and systems, especially in the energy-efficient house sector. But do the sellers even know that?
Similar topics