ᐅ Gas boiler without solar panels – from when is this allowed?
Created on: 19 Jan 2018 12:15
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Chilledkroete
Hello everyone,
we are currently building a new house with 220m² (2,368 sq ft) plus a 110m² (1,184 sq ft) basement, of which 80m² (861 sq ft) is heated. The project is being completed without KfW funding and currently without an energy consultant. The attic is not finished. The walls are made of 36.5 cm (14 inches) bricks with a U-value of 0.09 W/m²K, windows are triple-glazed, the roof is insulated with 60 mm (2.4 inches) wood fiberboard, and the collar beams are insulated with 35 cm (14 inches) of mineral wool, as is the roof slope.
The house has a mechanical ventilation system with heat recovery and a geothermal heat exchanger.
Up to now, we had planned a gas boiler combined with solar thermal, but this is not economical when comparing the additional costs for solar thermal with the gas price. Until now, we believed that gas heating was only allowed in combination with solar thermal. My question is: is this really the case?
Would it possibly be allowed, with a precise calculation, to install a gas boiler alone? My research so far suggests that, especially due to the mechanical ventilation system, this might be permitted. However, I would prefer not to hire an energy consultant who might conclude that it is not possible, and then we would have wasted the cost.
We are currently undecided between a standalone gas boiler (if allowed) or a fuel cell system because of government incentives. We have ruled out gas plus solar thermal.
Thank you very much and best regards
PS: No, there is no architect or general contractor managing this. Although it costs us a lot of time, it is working well at the moment.
we are currently building a new house with 220m² (2,368 sq ft) plus a 110m² (1,184 sq ft) basement, of which 80m² (861 sq ft) is heated. The project is being completed without KfW funding and currently without an energy consultant. The attic is not finished. The walls are made of 36.5 cm (14 inches) bricks with a U-value of 0.09 W/m²K, windows are triple-glazed, the roof is insulated with 60 mm (2.4 inches) wood fiberboard, and the collar beams are insulated with 35 cm (14 inches) of mineral wool, as is the roof slope.
The house has a mechanical ventilation system with heat recovery and a geothermal heat exchanger.
Up to now, we had planned a gas boiler combined with solar thermal, but this is not economical when comparing the additional costs for solar thermal with the gas price. Until now, we believed that gas heating was only allowed in combination with solar thermal. My question is: is this really the case?
Would it possibly be allowed, with a precise calculation, to install a gas boiler alone? My research so far suggests that, especially due to the mechanical ventilation system, this might be permitted. However, I would prefer not to hire an energy consultant who might conclude that it is not possible, and then we would have wasted the cost.
We are currently undecided between a standalone gas boiler (if allowed) or a fuel cell system because of government incentives. We have ruled out gas plus solar thermal.
Thank you very much and best regards
PS: No, there is no architect or general contractor managing this. Although it costs us a lot of time, it is working well at the moment.
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Baumfachmann22 Jan 2018 00:31Hello, I have 90sqm (970 sq ft) on the ground floor, 86sqm (925 sq ft) on the upper floor, with a 1-meter (3 ft) knee wall and a ceiling height of 4.60 meters (15 ft). Gas condensing boiler without solar, 100 cubic meters (3530 cubic feet) of water per year, so not very economical. Two people use 3200 kWh per year. Gas bill of €385 was not a problem for us. The house is built to passive house standards.
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Baumfachmann22 Jan 2018 00:32Controlled residential ventilation with heat recovery
That was not sufficient for us.
At that time, KfW 70 - which corresponds to today’s minimum requirement according to the Energy Saving Ordinance 2016.
We have a 5.4 sqm (58 sq ft) solar system combined with gas, plus controlled ventilation with heat recovery, and thicker roof insulation. The solar system is not a burden for us.
At that time, KfW 70 - which corresponds to today’s minimum requirement according to the Energy Saving Ordinance 2016.
We have a 5.4 sqm (58 sq ft) solar system combined with gas, plus controlled ventilation with heat recovery, and thicker roof insulation. The solar system is not a burden for us.
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Chilledkroete22 Jan 2018 13:50ypg schrieb:
For us, that was not enough.
Back then KfW 70 – which corresponds to today’s minimum requirement of the 2016 Energy Saving Ordinance.
We have a 5.4 sqm (58 sq ft) solar system with gas, plus a controlled mechanical ventilation system with heat recovery and thicker roof insulation. The solar system doesn’t cost us much.The University of Kassel offers a great Excel sheet that allows you to perform the calculations yourself.
Thanks to the 2016 Energy Saving Ordinance, it probably won’t be enough and the solar system is necessary.
However, not because of better efficiency, but only due to the legally required factor...
Baumfachmann schrieb:
Hello, I have 90m² (970 sq ft) on the ground floor, 86m² (925 sq ft) on the upper floor, with a 1-meter (3.3 ft) knee wall and a ceiling height of 4.60m (15 ft). Gas condensing boiler without solar, using 100 cubic meters of water per year, so not very economical. Two people consume 3200 kWh per year. Our gas bill was €385, which was not a problem. The house was built to passive house standard.No offense, but why incur the additional effort (and cost) of a passive house and then install a fossil fuel system? To me, it feels like stopping halfway without fully committing to the concept...
But I’m always open to learning more
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