Hello everyone,
Since we are interested in building with Weberhaus, we are currently looking into different heating technologies. Weberhaus offers all houses with an air-to-air heat pump as standard directly from the factory. This is their standard system and is already included in the price. Weberhaus calls this the so-called "comfort heating technology."
What bothers me about this is that it is basically an electric heating system. The heat pump electrically heats the water and also the rooms via air ducts. These air ducts also have heating wires that can be activated if the recovered heat is not sufficient.
I wonder if this is the right technology for us. Here are some disadvantages that come to mind without having experienced the air-to-air heat pump in winter:
1. Air is a poor heat carrier. It cools down too quickly and hardly stores any heat energy. Water is better in this regard.
2. I imagine the air being very dry in winter?
3. Because of the air movement, I imagine there could be increased dust buildup despite filters?
4. The system seems to rely on, or even require, that I do not ventilate myself but leave it to the system? However, occasional airing out (through shock ventilation) is a comfort factor for me (bathroom, bedroom, kitchen, etc.).
5. Electricity prices have only risen over the years (which makes no sense, since we have enough electricity). If electric vehicles become widespread and the government raises electricity taxes similar to fuel taxes, that could be the end of electric heating.
6. Thinking about people who relied on storage heaters in the 70s and now cannot sell their homes, I get uneasy about electric heating...
7. Retrofitting the heating system later, for example to gas or water-based heating, seems likely to be very expensive since everything would need to be gutted.
8. The air outlet vents somewhat spoil the walls for me. Especially with patterned tile wallpaper, I imagine this looks unattractive.
The clear advantage is the price! It seems to be excellent. No other heating technology is available so cheaply.
What else comes to your mind? Do you have any suggestions for me? Of course, I am also interested in experiences from owners of such heating systems.
Good luck
laurooon
Since we are interested in building with Weberhaus, we are currently looking into different heating technologies. Weberhaus offers all houses with an air-to-air heat pump as standard directly from the factory. This is their standard system and is already included in the price. Weberhaus calls this the so-called "comfort heating technology."
What bothers me about this is that it is basically an electric heating system. The heat pump electrically heats the water and also the rooms via air ducts. These air ducts also have heating wires that can be activated if the recovered heat is not sufficient.
I wonder if this is the right technology for us. Here are some disadvantages that come to mind without having experienced the air-to-air heat pump in winter:
1. Air is a poor heat carrier. It cools down too quickly and hardly stores any heat energy. Water is better in this regard.
2. I imagine the air being very dry in winter?
3. Because of the air movement, I imagine there could be increased dust buildup despite filters?
4. The system seems to rely on, or even require, that I do not ventilate myself but leave it to the system? However, occasional airing out (through shock ventilation) is a comfort factor for me (bathroom, bedroom, kitchen, etc.).
5. Electricity prices have only risen over the years (which makes no sense, since we have enough electricity). If electric vehicles become widespread and the government raises electricity taxes similar to fuel taxes, that could be the end of electric heating.
6. Thinking about people who relied on storage heaters in the 70s and now cannot sell their homes, I get uneasy about electric heating...
7. Retrofitting the heating system later, for example to gas or water-based heating, seems likely to be very expensive since everything would need to be gutted.
8. The air outlet vents somewhat spoil the walls for me. Especially with patterned tile wallpaper, I imagine this looks unattractive.
The clear advantage is the price! It seems to be excellent. No other heating technology is available so cheaply.
What else comes to your mind? Do you have any suggestions for me? Of course, I am also interested in experiences from owners of such heating systems.
Good luck
laurooon
However, you should always consider the actual consumption costs, not just theoretical values on paper. The air-to-air heat pump performs well on paper but not in reality (at least in my latitude in North Rhine-Westphalia). A neighbor has a KfW 55 standard house (I only have KfW 70 according to the old energy saving ordinance), but with his air-to-air heat pump, he has significantly higher costs (despite a smaller area) than I do with my ground-source heat pump. I chose the ground-source heat pump because there is no gas connection available, and it is one of the few options that can compete with gas in terms of running costs.
Besides that, most of the electricity used here is generated by burning fuel to heat water, which then evaporates, drives a turbine (which is huge, heavy, and spins at 3,000 rpm), and afterwards, the electricity is stepped up and down through several transformers, transmitted over many kilometers of cables, until it powers an electric motor that compresses gas. The resulting heat is then transferred to the water in your heating system via a heat exchanger.
Given this, I find it reasonable to ignite a flame and heat water at home with high efficiency. By the way, it generally applies that the greater the temperature difference, the higher the efficiency—at least when the goal is simply to transfer heat energy (or convert it into other forms of energy).
Besides that, most of the electricity used here is generated by burning fuel to heat water, which then evaporates, drives a turbine (which is huge, heavy, and spins at 3,000 rpm), and afterwards, the electricity is stepped up and down through several transformers, transmitted over many kilometers of cables, until it powers an electric motor that compresses gas. The resulting heat is then transferred to the water in your heating system via a heat exchanger.
Given this, I find it reasonable to ignite a flame and heat water at home with high efficiency. By the way, it generally applies that the greater the temperature difference, the higher the efficiency—at least when the goal is simply to transfer heat energy (or convert it into other forms of energy).
B
Bieber081524 Jan 2017 21:59Saruss schrieb:
A neighbor has a KFW55 house (I only have KFW70 according to the previous energy saving regulations), but with his air-to-air heat pump, his costs are many times (!) higher (with less area) than mine with my ground-source heat pump.Are investment costs taken into account in this statement (with what depreciation period) or only the monthly operating costs?For now, only the monthly consumption. Since his investment costs are "hidden" (all-inclusive price for the house), a direct comparison is not possible.
However, the ground loop drilling usually lasts for the lifetime of the house, and in addition, with underfloor heating, I am ultimately more flexible in choosing the heat source (if a better option becomes available) in the future compared to an air-to-air heat pump. Assuming his heating system cost the same as mine, excluding the drilling, then we are roughly at the point where I have paid off my loan, and the total costs are equal.
However, the ground loop drilling usually lasts for the lifetime of the house, and in addition, with underfloor heating, I am ultimately more flexible in choosing the heat source (if a better option becomes available) in the future compared to an air-to-air heat pump. Assuming his heating system cost the same as mine, excluding the drilling, then we are roughly at the point where I have paid off my loan, and the total costs are equal.
Hmm, but if gas is already connected, what do I choose then? For a ground source heat pump, I would have to drill, which costs a lot of money. Besides, geothermal energy needs to be available in the first place, which isn’t practical everywhere. Basically, my options are to use gas or simply electricity. To be honest, I haven’t looked into ground source heat pumps much yet.
markus270325 Jan 2017 07:28laurooon schrieb:
This whole setup costs €15,000 (about $16,000) and turns the house into a KFW 40+ bunker, which in turn is subsidized with €15,000 (about $16,000). This probably makes sense for the air-to-air heat pump, but for gas?From what I’ve read here, you personally seem to lean more towards gas. You wrote earlier that the costs basically cancel out with the subsidy, plus you get added value in the house from the thicker walls and the electric storage heater plus photovoltaics.
So for me, the situation would be clear then.
You’re right. But KfW 40+ applies if I use an air-to-air heat pump. If I use gas instead, as far as I understand, I can forget about KfW 40+ and would fall back to something like KfW 55. But I’ll look into that again! I have an appointment with the advisor this Friday.
I fully agree that a thicker building envelope is an advantage, and personally, I don’t see any downsides to it. What about you? I lose about 2m² (22 sq ft) of living space because with thicker walls, the house doesn’t become larger from the outside but smaller on the inside. Unfortunately.
Regarding photovoltaics, the question for me right now is whether it really makes sense. The appealing calculations for photovoltaics are based on the following assumptions:
1. The modules are new and remain new (which is not realistic)
2. The modules are perfectly clean. Any bird droppings or dirt film would reduce performance.
3. Generous hours of sunlight are assumed.
4. The storage battery maintains at least 80% of its nominal capacity for over 20 years. Practically no memory effect. Is that realistic?
So the question for me is whether it makes sense now or if photovoltaic technology, especially batteries, still needs a few more years of development. But I’m really interested in your opinions—or even better, your experiences.
Best regards,
laurooon
I fully agree that a thicker building envelope is an advantage, and personally, I don’t see any downsides to it. What about you? I lose about 2m² (22 sq ft) of living space because with thicker walls, the house doesn’t become larger from the outside but smaller on the inside. Unfortunately.
Regarding photovoltaics, the question for me right now is whether it really makes sense. The appealing calculations for photovoltaics are based on the following assumptions:
1. The modules are new and remain new (which is not realistic)
2. The modules are perfectly clean. Any bird droppings or dirt film would reduce performance.
3. Generous hours of sunlight are assumed.
4. The storage battery maintains at least 80% of its nominal capacity for over 20 years. Practically no memory effect. Is that realistic?
So the question for me is whether it makes sense now or if photovoltaic technology, especially batteries, still needs a few more years of development. But I’m really interested in your opinions—or even better, your experiences.
Best regards,
laurooon
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