ᐅ Gas boiler without solar panels – from when is this allowed?
Created on: 19 Jan 2018 12:15
C
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.
It’s important to understand the principle, and it doesn’t hurt to look up and read the energy saving regulation. It requires the mandatory use of renewable energy in new buildings. This doesn’t have to be solar energy. Heat recovery through a heat exchanger is also an option. However, the more renewable energy you use, the less strict your insulation requirements can be. Gas, as a fossil fuel that produces CO2 without absorbing any, is penalized under the energy saving regulation. Pellets, for example, also release CO2 into the air, but since they come from wood, they absorbed CO2 while growing. Pellets are therefore rated more favorably. Whether that makes sense is another question. That’s just how it is. I still chose gas, for various reasons. So I had to compensate with solar panels and high-quality windows and well-designed wall construction. By the way, this solar system was the sole provider of hot water until early November and can take over again from mid-March. It’s not that bad. What options are there for gas instead of solar? As mentioned, controlled mechanical ventilation combined with excellent insulation might work. Gas plus a photovoltaic (PV) system—that would be more expensive and not very practical. You won’t avoid having an engineer run the calculations, but only once your building concept is finalized. Then you’ll see whether it’s feasible or not. An experienced engineer can often tell at a rough glance whether it might work or is hopeless. Some tips to enable it during planning: don’t use overly large glazing, especially in the north. Karsten
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