Hello,
we are currently planning the renovation of a masonry barn that has long been used as a wood storage and workshop, and earlier partly as a livestock stable and grain storage. With all the opinions from various building professionals around me, my head is starting to spin; so I hope to get some independent opinions here :-)
We have basically finalized the floor plan with our architect; but now the question came up as to why we are planning to place our wood stove in the living room with a flue pipe running outside along the house wall, instead of designing an internal flue pipe.
So far, I have only seen an advantage in having an external chimney because it supposedly prevents thermal bridges to the roof and is probably less expensive.
Am I missing something? Would an internal chimney flue actually be more advisable, even in our case? And if so – for what reasons?
The stove is basically meant to just make the living room cozier (visually and, of course, thermally in winter) and is not intended to heat the entire apartment in any way.
Here are some basic details about the building project in case relevant:
Floor area approximately 230 sqm (2,475 sq ft)
If you need more information beforehand, feel free to ask... Thanks in advance 🙂 🙂
we are currently planning the renovation of a masonry barn that has long been used as a wood storage and workshop, and earlier partly as a livestock stable and grain storage. With all the opinions from various building professionals around me, my head is starting to spin; so I hope to get some independent opinions here :-)
We have basically finalized the floor plan with our architect; but now the question came up as to why we are planning to place our wood stove in the living room with a flue pipe running outside along the house wall, instead of designing an internal flue pipe.
So far, I have only seen an advantage in having an external chimney because it supposedly prevents thermal bridges to the roof and is probably less expensive.
Am I missing something? Would an internal chimney flue actually be more advisable, even in our case? And if so – for what reasons?
The stove is basically meant to just make the living room cozier (visually and, of course, thermally in winter) and is not intended to heat the entire apartment in any way.
Here are some basic details about the building project in case relevant:
Floor area approximately 230 sqm (2,475 sq ft)
- 2 floors: ground floor = basement (already existing), living area on the 1st floor (slab already in place)
- Roof will be torn down and rebuilt, but without usable attic space, i.e. probably as a cold roof with nail-plated trusses and metal roofing; insulation will then be in the ceiling towards the living area. An alternative of a sandwich roof was also discussed. This will be clarified in the next few days.
- Heating: gas heating or heat pump (probably the latter), with solar thermal and photovoltaics
If you need more information beforehand, feel free to ask... Thanks in advance 🙂 🙂
K
Knallkörper15 Nov 2016 09:05Hello Knallfrosch,
I also don’t find exterior chimneys very attractive. When they are new, it might be acceptable. But over time, algae and moss tend to grow on the supports and they require maintenance and cleaning. The facade usually ends up with some stains as well.
Sealing an interior chimney at the roof is not complicated. Especially if you don’t have roof insulation (cold roof, thumbs up!), it’s no problem. If a leak ever occurs, it becomes visible quickly and can be fixed relatively easily. With rafter insulation, it’s a bit more challenging, but in my opinion still not critical.
The wall installation of an exterior chimney also needs to be sealed, and depending on the wall construction, this can be quite complex.
I also don’t find exterior chimneys very attractive. When they are new, it might be acceptable. But over time, algae and moss tend to grow on the supports and they require maintenance and cleaning. The facade usually ends up with some stains as well.
Sealing an interior chimney at the roof is not complicated. Especially if you don’t have roof insulation (cold roof, thumbs up!), it’s no problem. If a leak ever occurs, it becomes visible quickly and can be fixed relatively easily. With rafter insulation, it’s a bit more challenging, but in my opinion still not critical.
The wall installation of an exterior chimney also needs to be sealed, and depending on the wall construction, this can be quite complex.
Our chimney is installed on a straight wall, and the sealing didn’t seem to be an issue. In a corner of the house, the builder didn’t want to do it (hip roof / hipped roof), as it could cause significant problems. That was never an option for us anyway.
For the next build, I would place the chimney internally so that it isn’t visible in the living room but rather in the room behind it (meaning the living room wall would be flush). The utility room, for example, would be an ideal location for this. Another advantage of placing it next to the utility room is the simple drainage of water from the chimney (just connecting it to the utility room’s waste water system). Most people don’t do this; as a result, water can seep in and collect inside the chimney until the next time it’s lit.
For the next build, I would place the chimney internally so that it isn’t visible in the living room but rather in the room behind it (meaning the living room wall would be flush). The utility room, for example, would be an ideal location for this. Another advantage of placing it next to the utility room is the simple drainage of water from the chimney (just connecting it to the utility room’s waste water system). Most people don’t do this; as a result, water can seep in and collect inside the chimney until the next time it’s lit.
andimann schrieb:
Heating: No, currently there is no calculation that can realistically make a heat pump economical.
In recent years, gas prices have generally decreased while electricity prices have risen. Gas prices have remained relatively stable over the past few years, sometimes slightly declining. Electricity prices have also experienced similar trends.
A comparison largely depends on the local individual consumption costs (including fixed fees) as well as the investment costs. However, investment costs for gas are often somewhat oversimplified in calculations. While the burner may be cheaper, the connection is not free (though it’s a one-time fee), there is also a cost for the chimney, and ongoing maintenance and chimney sweeping must also be paid for continuously.
That’s why heat pumps are artificially favored in the energy-saving regulation calculations while gas heating systems are penalized. For a new build, you usually have to install a controlled ventilation system and/or considerable solar thermal to still be allowed to install a gas heating system. A renewable share is mandatory. The primary energy calculation is designed so that gas heating without a renewable share is no longer feasible. You mentioned controlled ventilation and solar thermal as possible solutions (connection to biogas would be another, if feasible). It’s not “considerable” solar thermal that’s required — most new builds I’ve seen have two solar thermal panels on the roof.
Heat pumps are not “artificially favored.” The primary energy factor was adjusted, yes, but the electricity mix in Germany has also changed, so that is understandable. Certainly, some subsidy might be included to promote this heating technology.
A photovoltaic system isn’t very useful for your heat pump at first. Heat pumps require 400 V / three-phase while photovoltaic systems deliver 240 V / two-phase. It doesn’t match... No offense, but that’s simply incorrect. Three-phase inverters are basically standard and mandatory for systems over 4.x kWp. Heat pumps and photovoltaic perfectly match each other.
And you need your heat pump in winter, so you can forget about the photovoltaic output then. Photovoltaic electricity alone is likely not enough to fully supply the heat pump (although this depends on system size and heating load).
However, it can also be argued that heat pumps and photovoltaic systems work well together in winter because the heat pump uses all the electricity generated on-site immediately for heating, which significantly increases self-consumption. The small amount of self-generated electricity is therefore especially cost-effective when considered in isolation.
If you want to put something on your roof these days, it should be solar panels. Small-scale photovoltaic systems are simply not worthwhile and much less profitable than solar thermal systems. The efficiency for generating electricity is significantly lower and decreases even more as temperatures rise (which is somewhat paradoxical, since it’s usually warmer when the sun is shining ^^). In the end, it’s all about calculations and a lot of debate, so you need to decide for yourself what you want.
Solar thermal is affordable and nowadays considered the standard if you want to add something to the roof of a single-family home. At least it can (but does not have to!) pay off eventually, although it does require some work and can cause issues.
As mentioned before, a ventilation system with heat recovery as a renewable energy component is also approved, and a ventilation system is always sensible today and provides real comfort. Whether you save 10€ less on heating costs is irrelevant, since heating costs in a new house are negligible compared to all other additional expenses. However, if you no longer need to ventilate (but can if you want to) and don’t have to worry about mold anymore (although it can’t compensate for roof leaks), that is a genuine comfort improvement.
Solar thermal is affordable and nowadays considered the standard if you want to add something to the roof of a single-family home. At least it can (but does not have to!) pay off eventually, although it does require some work and can cause issues.
As mentioned before, a ventilation system with heat recovery as a renewable energy component is also approved, and a ventilation system is always sensible today and provides real comfort. Whether you save 10€ less on heating costs is irrelevant, since heating costs in a new house are negligible compared to all other additional expenses. However, if you no longer need to ventilate (but can if you want to) and don’t have to worry about mold anymore (although it can’t compensate for roof leaks), that is a genuine comfort improvement.
Hi,
sorry, I didn’t mean to start the old "gas versus heat pumps" debate.
Yes, the electricity mix has changed. But it’s not constant throughout the year. In summer, there is indeed a very high share of renewable energy. In winter, and even more so on a winter night, the share is much lower. And that’s exactly when the heat pumps run! They end up using electricity from environmentally harmful lignite coal or the equally questionable nuclear power from France...
Best regards,
Andreas
sorry, I didn’t mean to start the old "gas versus heat pumps" debate.
Alex85 schrieb:
Heat pumps are not exactly “favorably calculated” either. The primary energy factor has been adjusted, yes, but the electricity mix in Germany has also changed, so that is understandable.
Yes, the electricity mix has changed. But it’s not constant throughout the year. In summer, there is indeed a very high share of renewable energy. In winter, and even more so on a winter night, the share is much lower. And that’s exactly when the heat pumps run! They end up using electricity from environmentally harmful lignite coal or the equally questionable nuclear power from France...
Best regards,
Andreas
B
Bauexperte16 Nov 2016 23:02andimann schrieb:
And then they merrily waste electricity from environmentally friendly lignite coal or the equally environmentally friendly nuclear power from France... And the pumps of the gas condensing boiler use exactly which electricity ...?Regards, Bauexperte
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