ᐅ District heating versus air-to-water heat pump for KfW 40 Plus standard
Created on: 18 Oct 2016 14:51
S
skybiker2000
Hello everyone,
we are currently planning our single-family house (about 160 m² (1720 sq ft)). It will be built using a timber frame construction method with a basement. The prefab house supplier offers a standard KfW 55 house. The rooms will be heated with underfloor heating.
In the building area, connection to the local district heating network is mandatory unless you build a KfW 40 plus house.
I have compared the possible costs.
District heating:
District heating connection including transfer station €8,948.80 (offer)
Additional costs for an extra heating circuit for underfloor heating €952.00 (offer)
Hot water storage tank €1,000.00 (estimate)
Connection costs for “heating” €3,000.00 (estimate)
Base price per year: approx. €350
Price per kWh: 10 cents gross
Total €13,900.80
Upgrading to KfW 40 plus:
Additional wall insulation €5,590.00 (offer)
Photovoltaic system €5,590.00 (offer)
Battery storage €7,990.00 (offer)
Air-to-water heat pump €3,000.00 → offset against current planning (estimate)
Additional basement insulation: €2,000.00 (estimate)
Total €24,170.00
Minus KfW 40 plus subsidy €10,000
Adjusted total €14,170
I have to admit the consultation with the energy advisor is still pending. They will probably be able to say exactly which measures are necessary to reach the KfW 40 plus standard.
Would you continue pursuing this option, or is KfW 40 plus with a basement unattainable? Starting with the existing district heating and then switching later in about 10 years probably doesn’t make sense either?
Thank you very much for your feedback!
Best regards,
Björn
we are currently planning our single-family house (about 160 m² (1720 sq ft)). It will be built using a timber frame construction method with a basement. The prefab house supplier offers a standard KfW 55 house. The rooms will be heated with underfloor heating.
In the building area, connection to the local district heating network is mandatory unless you build a KfW 40 plus house.
I have compared the possible costs.
District heating:
District heating connection including transfer station €8,948.80 (offer)
Additional costs for an extra heating circuit for underfloor heating €952.00 (offer)
Hot water storage tank €1,000.00 (estimate)
Connection costs for “heating” €3,000.00 (estimate)
Base price per year: approx. €350
Price per kWh: 10 cents gross
Total €13,900.80
Upgrading to KfW 40 plus:
Additional wall insulation €5,590.00 (offer)
Photovoltaic system €5,590.00 (offer)
Battery storage €7,990.00 (offer)
Air-to-water heat pump €3,000.00 → offset against current planning (estimate)
Additional basement insulation: €2,000.00 (estimate)
Total €24,170.00
Minus KfW 40 plus subsidy €10,000
Adjusted total €14,170
I have to admit the consultation with the energy advisor is still pending. They will probably be able to say exactly which measures are necessary to reach the KfW 40 plus standard.
Would you continue pursuing this option, or is KfW 40 plus with a basement unattainable? Starting with the existing district heating and then switching later in about 10 years probably doesn’t make sense either?
Thank you very much for your feedback!
Best regards,
Björn
S
skybiker200012 Nov 2016 11:13I have gathered the raw numbers – costs.
District heating vs. KfW 40 Plus (Only with a KfW 40 Plus house can I be exempted from mandatory connection to district heating)
District heating:
District heating connection – €8,948.80
Hot water storage tank – €1,000
Connection costs for "heating" – €3,000
Total: €13,900.80
The upgrade from KfW 55 to KfW 40 Plus (prefabricated house with basement)
+ Air-to-water heat pump
+ Additional insulation in basement from 14 cm (5.5 inches) to 16 cm (6.3 inches)
+ Insulation under the slab foundation
+ Connection of all basement rooms to the ventilation system
+ Photovoltaic system
+ Battery storage
+ Improved insulation on the exterior walls
Total: €47,659.00
minus €10,000 repayment subsidy (difference between KfW 55 and KfW 40 Plus)
Total: €37,659
Difference: €23,758.20
Can I justify this?
The additional costs are quite significant. I would need to save €100 per month for it to pay off in 20 years. The battery storage probably won’t last that long. Maintenance and replacement parts also need to be taken into account.
Maintenance and replacement of defective parts would at least be included with district heating.
Do you have any opinions on this?
Thanks!
Best regards,
Björn
District heating vs. KfW 40 Plus (Only with a KfW 40 Plus house can I be exempted from mandatory connection to district heating)
District heating:
District heating connection – €8,948.80
Hot water storage tank – €1,000
Connection costs for "heating" – €3,000
Total: €13,900.80
The upgrade from KfW 55 to KfW 40 Plus (prefabricated house with basement)
+ Air-to-water heat pump
+ Additional insulation in basement from 14 cm (5.5 inches) to 16 cm (6.3 inches)
+ Insulation under the slab foundation
+ Connection of all basement rooms to the ventilation system
+ Photovoltaic system
+ Battery storage
+ Improved insulation on the exterior walls
Total: €47,659.00
minus €10,000 repayment subsidy (difference between KfW 55 and KfW 40 Plus)
Total: €37,659
Difference: €23,758.20
Can I justify this?
The additional costs are quite significant. I would need to save €100 per month for it to pay off in 20 years. The battery storage probably won’t last that long. Maintenance and replacement parts also need to be taken into account.
Maintenance and replacement of defective parts would at least be included with district heating.
Do you have any opinions on this?
Thanks!
Best regards,
Björn
skybiker2000 schrieb:
Can I convince myself of this?No.
The calculation isn’t entirely complete, for example, the VAT on the photovoltaic system and battery may still be reimbursed (assuming there are separate invoices and it’s not already included in the total house construction cost). On the other hand, at KFW 40 level the heating load is reduced, which lowers consumption and might allow for a smaller heat generator (probably not in your case). For a planned ground-source heat pump, the drilling depth can also be reduced...
On the other side, there are costs associated with operating the photovoltaic system (tax issues, maintenance, risks), but also income through feed-in tariffs or savings through self-consumption. Whether the photovoltaic system is properly sized to match the battery is also questionable. There is a lot of faulty work being done in this area.
I believe you don’t even need to try this kind of calculation with a general contractor or construction company, since factors like “upgrades” and “don’t want/can’t” usually ruin any chance of profitability. In most cases, you don’t have control over the individual components. It might be different when building with an architect, but that’s just my impression.
One should ask who was involved behind the scenes to anchor this local heat nonsense there. It really bothers me. On paper, however, it is certainly marketed as especially “green.”
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