ᐅ Is it possible to have gas heating without solar panels in a new build?
Created on: 1 May 2022 16:22
D
derFriese
We are currently planning our new build and struggling with the heating system. The living area of the house is about 165 m² (1776 ft²) plus a heated basement that is rarely used. The house features KfW40-level insulation, controlled mechanical ventilation, and underfloor heating.
Originally, we wanted to install a heat pump, but the prices for heat pumps are outrageous. Even with rising gas prices (electricity prices have also increased), we wouldn’t be able to recoup the initial investment (the additional cost for an air heat pump compared to gas from various builders is around €15,000-20,000). Therefore, we are planning to go with gas heating, with the option to switch to a heat pump later on.
The KfW40 subsidy is no longer available, and I am wondering if it is possible to install a gas condensing boiler without solar thermal panels under the building energy law, given that we already have good insulation and controlled mechanical ventilation. The idea is to save costs and leave more room for photovoltaic panels in the future. Does anyone have experience with this?
Originally, we wanted to install a heat pump, but the prices for heat pumps are outrageous. Even with rising gas prices (electricity prices have also increased), we wouldn’t be able to recoup the initial investment (the additional cost for an air heat pump compared to gas from various builders is around €15,000-20,000). Therefore, we are planning to go with gas heating, with the option to switch to a heat pump later on.
The KfW40 subsidy is no longer available, and I am wondering if it is possible to install a gas condensing boiler without solar thermal panels under the building energy law, given that we already have good insulation and controlled mechanical ventilation. The idea is to save costs and leave more room for photovoltaic panels in the future. Does anyone have experience with this?
Hello,
…the key word here is "calculated" heating demand. This calculation is only slightly more realistic than fuel consumption figures for cars. Small everyday factors such as children going in and out every five minutes in winter, leaving the front door wide open for about 2 minutes each time, or the bathroom window being opened after a shower and then unfortunately left open for the next 3 hours because it was forgotten, or the fresh air enthusiast who insists on cross-ventilation despite having a controlled ventilation system, are not taken into account. In other words, reality is somewhat missing…
For real life, it’s reasonable to add 50% or more as a margin.
Best regards,
Andreas
WilderSueden schrieb:
A KfW40 house has a calculated heating demand of 25 kWh/sqm, which results in 4000 kWh.
…the key word here is "calculated" heating demand. This calculation is only slightly more realistic than fuel consumption figures for cars. Small everyday factors such as children going in and out every five minutes in winter, leaving the front door wide open for about 2 minutes each time, or the bathroom window being opened after a shower and then unfortunately left open for the next 3 hours because it was forgotten, or the fresh air enthusiast who insists on cross-ventilation despite having a controlled ventilation system, are not taken into account. In other words, reality is somewhat missing…
For real life, it’s reasonable to add 50% or more as a margin.
Best regards,
Andreas
N
Neubau20225 May 2022 08:51derFriese schrieb:
I had factored in the additional costs for controlled residential ventilation with gas.
Option 1
Air source heat pump + controlled residential ventilation: Tecalor THZ 504 + €36,800 (compared to gas)
Option 2
Gas: Wolf CSZ (included)
Controlled residential ventilation: Tecalor TVZ 180: + €17,600
Calculation (current prices from Check24 as of today):
- Heat demand = 12,000 kWh per year
- Gas: approximately €1,800 per year
- Electricity (annual performance factor: 4): 12,000 kWh / 4 = 3,000 kWh => €1,214
- Difference: €586 per year 1. Prices are unrealistic. It could be due to the general contractor. For another project we were involved with during the planning phase, a 4 kWp photovoltaic system and 4 kW battery storage would have also added €20,000.
2. You need to consider with photovoltaic installation that with a heat pump, at least part of the heating can be powered by the photovoltaic system. This is not possible with gas. Therefore, this is another point in favor of the heat pump.
andimann schrieb:
Hello,
...the key term here is the "calculated" heating demand. This calculation is only slightly more realistic than fuel consumption values given for cars. Little details like children who go in and out every 5 minutes during winter, leaving the front door wide open for 2 minutes each time, or the bathroom window that is opened after showering and unfortunately stays open for the next 3 hours because it was forgotten, or the fresh air enthusiast who insists on cross-ventilation despite having a controlled ventilation system—these are not taken into account. In other words, reality is somewhat missing...
For real life, it’s reasonable to add a 50% or higher margin.
Best regards,
Andreas That is precisely not the case in reality. Much more often, the actual heating load is lower than the calculated one. This starts with general allowances for thermal bridges and ends with internal heat gains. Large window areas also promote heating from low sun angles, and shutters have an effect as well. The better the insulation of the house, the greater these factors become. Cooking, TV, people, candles... all of these are internal heat gains that reduce the heating demand.
By the way, children can be taught to close doors properly—I know this because I have done it.
Warning, Off Topic…
Don’t overestimate the business idea: this thing doesn’t compete with a trailer, as it is far too large, heavy, and expensive. Those who can afford it probably already own a proper boat at their dock, have a waterfront property, or otherwise have money to spend. Investors are more likely to rent it out than move it around themselves.
08/27 … the date conflicts with the Caravan Salon in Düsseldorf 😳
Pinkiponk schrieb:
You can do everything with it, except fly ... not yet. ;-) I assume this caravan boat will replace the usual trailers and caravans. In my opinion, there is no reason to buy a trailer or caravan anymore if you can have a caravan boat.
Don’t overestimate the business idea: this thing doesn’t compete with a trailer, as it is far too large, heavy, and expensive. Those who can afford it probably already own a proper boat at their dock, have a waterfront property, or otherwise have money to spend. Investors are more likely to rent it out than move it around themselves.
08/27 … the date conflicts with the Caravan Salon in Düsseldorf 😳
W
WilderSueden5 May 2022 11:13andimann schrieb:
...the key term here is "calculated" heat demand. This calculation is only slightly more realistic than fuel consumption figures for cars.I am relatively close to the standard consumption and sometimes even below it. But of course, I also know people who constantly start their car for very short trips, which naturally leads to double-digit consumption and rapid wear and tear.The same applies to heating. In our heating cost statement, we always pay significantly more for the share of the square meters than for actual consumption, even though we have a second exterior wall and most neighbors only have one. For a detached house, I do expect that we will at least be within the range of the calculated demand. Besides the possibilities mentioned by @Joedreck, I also immediately think of the bedroom. We don’t need 22 degrees Celsius (72°F) there, so the heating demand is significantly lower in that room.
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Pinkiponk5 May 2022 17:04WilderSueden schrieb:
Are you referring to a floating caravan or a houseboat?Update: This is no longer relevant for us. My husband just told me that the price, which was around 99,000/100,000 € about 3-4 years ago, has now risen to 200,180 €. :-( Demand seems to be high; otherwise, I assume such price increases wouldn’t be possible.Similar topics