ᐅ Wood log heating in a highly insulated house. How to implement?
Created on: 3 Nov 2017 12:38
S
SpeckiHello everyone,
I believe this post will spark some discussions 😉
First, about the project.
I will probably build a house in about 8 years, if everything goes according to plan... I know that’s a long way off, but I really enjoy the topic, so I’m already dealing with it now.
I’m assuming the house will have pretty good insulation (anything else doesn’t really make sense).
A major topic is the heating system.
I’m clearly leaning towards a wood log heating system.
Either as a wood gasification boiler in the basement or as a wood stove or wood-burning range with a water jacket.
Why wood?
- More ecological
- Cheaper
- More independence
I can usually get wood quite cheaply. I pay between 29 and 35€ per cubic meter (about 29 to 35€ per 1.3 cubic yards) on average. I know it means work, but that’s not a problem. Currently, we also use about 5 cubic meters (about 6.5 cubic yards) of wood per year for our wood stove in the kitchen. When you get older, you can always replace the wood heating system with a pellet heating system, heat pump, or something else.
My biggest question at the moment is the following:
Any wood log heating system (regardless of type) produces quite a high temperature.
How should I best design the heating system? Radiators aren’t really ideal in a well-insulated house, there are better options. For example, underfloor heating. But that requires a lower temperature. What ideas, comments, or suggestions do you have on this?
I want to brainstorm here because I’m currently stuck mentally.
Regarding hot water, I would also install a solar thermal system on the roof. It would supply the house with hot water in summer, and in winter the wood heating system would take over.
I’m also aware that I need a large buffer storage tank. I’m thinking around 3 cubic meters (about 4 cubic yards), ideally.
If I’m away for a few days in winter, an electric heating element can kick in and maintain the heating water temperature. This is expensive, but should rarely happen.
So, I hope I’ve conveyed all my thoughts so far and look forward to your input.
It probably won’t change much, but here is a note anyway:
Please don’t discuss the pros or cons of wood log heating systems here, but rather how and whether this can be implemented sensibly. 🙂
Best regards,
Specki
I believe this post will spark some discussions 😉
First, about the project.
I will probably build a house in about 8 years, if everything goes according to plan... I know that’s a long way off, but I really enjoy the topic, so I’m already dealing with it now.
I’m assuming the house will have pretty good insulation (anything else doesn’t really make sense).
A major topic is the heating system.
I’m clearly leaning towards a wood log heating system.
Either as a wood gasification boiler in the basement or as a wood stove or wood-burning range with a water jacket.
Why wood?
- More ecological
- Cheaper
- More independence
I can usually get wood quite cheaply. I pay between 29 and 35€ per cubic meter (about 29 to 35€ per 1.3 cubic yards) on average. I know it means work, but that’s not a problem. Currently, we also use about 5 cubic meters (about 6.5 cubic yards) of wood per year for our wood stove in the kitchen. When you get older, you can always replace the wood heating system with a pellet heating system, heat pump, or something else.
My biggest question at the moment is the following:
Any wood log heating system (regardless of type) produces quite a high temperature.
How should I best design the heating system? Radiators aren’t really ideal in a well-insulated house, there are better options. For example, underfloor heating. But that requires a lower temperature. What ideas, comments, or suggestions do you have on this?
I want to brainstorm here because I’m currently stuck mentally.
Regarding hot water, I would also install a solar thermal system on the roof. It would supply the house with hot water in summer, and in winter the wood heating system would take over.
I’m also aware that I need a large buffer storage tank. I’m thinking around 3 cubic meters (about 4 cubic yards), ideally.
If I’m away for a few days in winter, an electric heating element can kick in and maintain the heating water temperature. This is expensive, but should rarely happen.
So, I hope I’ve conveyed all my thoughts so far and look forward to your input.
It probably won’t change much, but here is a note anyway:
Please don’t discuss the pros or cons of wood log heating systems here, but rather how and whether this can be implemented sensibly. 🙂
Best regards,
Specki
From today’s perspective, these heating systems in new buildings only make sense if the fuel is cheap or free. Otherwise, the investment is not worthwhile.
In general, I believe that “burning” in new construction is becoming outdated. Insulation requirements are increasing, and heating demands are decreasing. So, “making a fire” doesn’t really make sense anymore, not to mention the comfort aspect.
Starting in 2021, only “nearly zero-energy buildings” have been eligible for approval. Thanks to the EU. This basically translates to passive houses. And you are already looking four years beyond that point. I think if wood heating is still used then, it will be automated pellet heating systems that can last a whole winter with just a few bags of pellets. Firewood is hard to regulate since a more continuous, smaller energy supply is needed.
In general, I believe that “burning” in new construction is becoming outdated. Insulation requirements are increasing, and heating demands are decreasing. So, “making a fire” doesn’t really make sense anymore, not to mention the comfort aspect.
Starting in 2021, only “nearly zero-energy buildings” have been eligible for approval. Thanks to the EU. This basically translates to passive houses. And you are already looking four years beyond that point. I think if wood heating is still used then, it will be automated pellet heating systems that can last a whole winter with just a few bags of pellets. Firewood is hard to regulate since a more continuous, smaller energy supply is needed.
Or with Brunner. However, you need a skilled heating engineer who is knowledgeable, still familiar with older “iron beasts,” and doesn’t just follow a standard template. Why is this necessary? The hydraulics must fit well to very well. Regarding the investment:
A well-planned heat pump is already significantly cheaper in terms of investment today and, when properly designed and configured, offers very good performance figures. The investment for any wood-based solution is inherently higher today: buffer tank, mixing valve, chimney, air supply, return flow temperature increase, additional domestic hot water tank or fresh water station, hydraulics that are not just standard.
Everything depends on the long-term fuel costs and the ideology of the future user.
A well-planned heat pump is already significantly cheaper in terms of investment today and, when properly designed and configured, offers very good performance figures. The investment for any wood-based solution is inherently higher today: buffer tank, mixing valve, chimney, air supply, return flow temperature increase, additional domestic hot water tank or fresh water station, hydraulics that are not just standard.
Everything depends on the long-term fuel costs and the ideology of the future user.
berny schrieb:
Check jenni.ch, you can find something there. Well planned, something like this can definitely make sense.Good example. The firewood boilers shown there start at 18 kW (about 60,000 BTU) heating capacity. That’s roughly three times too much. From 2021 onward, it’s about eight to nine times too high.
Even the solution with a stove in the living area starts at 8 kW (about 27,000 BTU). Burning one piece of wood simply releases way too much energy. You have to buffer a lot to balance it out, which isn’t worth it. Even today, only if you can (almost) ignore the cost of wood. The rest is idealism.
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