ᐅ Wood log heating in a highly insulated house. How to implement?
Created on: 3 Nov 2017 12:38
S
Specki
Hello 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
First of all, thank you for your responses.
As I mentioned, I can get the fuel quite cheaply. I did a comparison with gas. To achieve the same heat output, the cost with wood is only a third of what it is with gas.
Thanks, I’ll take a look.
So, as it seems, in terms of initial costs an air-to-water heat pump is now really better, as you can save a lot.
I am generally convinced that a heat pump offers many advantages for a well to very well insulated house. What bothers me a lot, however, is the dependence on electricity and electricity prices. And a photovoltaic system doesn’t help much if there is hardly any sun in winter or snow is covering the panels....
Best regards
Specki
Alex85 schrieb:
Even today, these heating systems only make sense in new builds if the fuel is cheap or free.
As I mentioned, I can get the fuel quite cheaply. I did a comparison with gas. To achieve the same heat output, the cost with wood is only a third of what it is with gas.
berny schrieb:
Check out jenni.ch, you can find something there
Thanks, I’ll take a look.
So, as it seems, in terms of initial costs an air-to-water heat pump is now really better, as you can save a lot.
I am generally convinced that a heat pump offers many advantages for a well to very well insulated house. What bothers me a lot, however, is the dependence on electricity and electricity prices. And a photovoltaic system doesn’t help much if there is hardly any sun in winter or snow is covering the panels....
Best regards
Specki
Specki schrieb:
What really bothers me a lot is the dependence on electricity and electricity prices.
Personal opinion: this issue is being blown way out of proportion.
1. In the long run, energy sources tend to rise in cost roughly in sync, meaning any significant imbalance will always be corrected through market mechanisms ("Electricity is too expensive, so I’ll heat with tiny peppercorns!" => the neighbor thinks the same way => What happens to the price of peppercorns now?).
2. Electricity even has the advantage of being so fundamentally essential to the functioning of our economy and society that politicians will make sure it does not become prohibitively expensive.
Yes, personal opinion. Others may, of course, see this differently.
Best regards
K
kkk2727296 Nov 2017 07:48I have a wood gasifier installed in my newly built house, with a gas boiler as backup.
Currently, there is a 2000-liter (530-gallon) buffer tank installed, but there is space for an additional 1000 liters (265 gallons). It is important to note that the heating room naturally needs to be somewhat larger, and the wood also needs to be stored somewhere.
For houses around 130 m² (1400 ft²), which only consume about 40 euros of gas per month, it probably isn’t worthwhile. When you factor in the effort and everything around it, it is likely not much cheaper than other heating systems.
It’s a matter of personal preference.
Currently, there is a 2000-liter (530-gallon) buffer tank installed, but there is space for an additional 1000 liters (265 gallons). It is important to note that the heating room naturally needs to be somewhat larger, and the wood also needs to be stored somewhere.
For houses around 130 m² (1400 ft²), which only consume about 40 euros of gas per month, it probably isn’t worthwhile. When you factor in the effort and everything around it, it is likely not much cheaper than other heating systems.
It’s a matter of personal preference.
Hello @kkk272729,
thank you for your brief report.
The large buffer tank confirms my thoughts. What type of heating water distribution do you use? Underfloor heating, radiators, wall heating?
What supply temperature do you operate with?
How well insulated is your house? Is it up to KfW standard?
Why did you choose gas as a backup system? My plan would be to use electricity as a backup since I currently assume it will hardly ever be needed.
How often do you heat the stove?
I would appreciate a few more details from you 🙂
Yes, that is certainly true. But my approach is leaning in that direction... now I just want to find out how practical it actually is 🙂
Best regards
Specki
thank you for your brief report.
The large buffer tank confirms my thoughts. What type of heating water distribution do you use? Underfloor heating, radiators, wall heating?
What supply temperature do you operate with?
How well insulated is your house? Is it up to KfW standard?
Why did you choose gas as a backup system? My plan would be to use electricity as a backup since I currently assume it will hardly ever be needed.
How often do you heat the stove?
I would appreciate a few more details from you 🙂
kkk272729 schrieb:
It’s a matter of settings.
Yes, that is certainly true. But my approach is leaning in that direction... now I just want to find out how practical it actually is 🙂
Best regards
Specki
K
kkk2727296 Nov 2017 08:32Also gas as a backup for when you’re on vacation, sick, or on a business trip—whatever the case. Also to avoid being a slave to the heating system. If you don’t feel like firing up the burner, then you simply don’t have to.
I have three heating circuits: underfloor heating on the ground floor, underfloor heating on the upper floor, and radiators.
The underfloor heating covers about 350 m² (3,767 sq ft).
I only have radiators in the bathrooms and one in the hallway. This is a separate heating circuit because I sometimes want to run them a bit warmer.
The supply temperature depends on the outdoor temperature.
For domestic hot water, I use an instantaneous water heater (fresh water station).
I can’t share any long-term experience yet because I am already heating but not yet living there.
Regarding KfW standards—I have no idea. Construction consists of 24 cm (9.5 inches) aerated concrete, 2 layers of 6 cm (2.4 inches) insulation, a 4 cm (1.6 inches) air gap, and brick cladding.
I have three heating circuits: underfloor heating on the ground floor, underfloor heating on the upper floor, and radiators.
The underfloor heating covers about 350 m² (3,767 sq ft).
I only have radiators in the bathrooms and one in the hallway. This is a separate heating circuit because I sometimes want to run them a bit warmer.
The supply temperature depends on the outdoor temperature.
For domestic hot water, I use an instantaneous water heater (fresh water station).
I can’t share any long-term experience yet because I am already heating but not yet living there.
Regarding KfW standards—I have no idea. Construction consists of 24 cm (9.5 inches) aerated concrete, 2 layers of 6 cm (2.4 inches) insulation, a 4 cm (1.6 inches) air gap, and brick cladding.
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