ᐅ What to replace an oil heating system from 1989 in an old, characterful house with?
Created on: 9 Jan 2021 14:19
M
meowmeow
Hello dear forum,
we have an old timber-framed house in the Alpine foreland. Built around 1910 with an extension from the 1960s, the original building has a basement, the extension does not. The insulation is rather poor, and the windows are either double-glazed or old. A hailstorm completely destroyed our roof, so a new roof with good insulation has now been installed.
Currently, we have a Viessmann oil heating system from 1989 with a 2000l (528 gallons) oil tank in the basement, which has caused no major problems so far. The hot water is also centrally supplied by this system. With the old roof, we used about 1900-2500l (502-660 gallons) of oil in winter, depending on the season. With the new roof, we don’t have experience yet, but I expect some improvement. The house has about 115m2 (1238 square feet) of living space, heated by radiators.
Since the heating system is getting old and there are currently larger subsidy programs, we are considering modernization. From my research so far, a heat pump seems to be out of the question because we would need a better-insulated house and underfloor heating? Other types of electric heating seem even less economical?
The least invasive option would probably be a new condensing oil boiler, but these are not subsidized, so I could just wait until the old one breaks down?
A pellet heating system seems too complicated to operate? My mother will soon be 70 and often lives alone in the house. In her old age, I don’t want to put too much strain on her. We frequently visit with our child for several days, but mostly in summer. Also, the long transition phase with low heating loads appears to speak against a pellet system.
I can’t really estimate the costs for gas. A gas connection might be possible with the local supplier if the neighbors join in. We would need about 60-70m (197-230 feet) of gas pipeline on our own property. What costs should I roughly expect? Alternatively, a tank could be buried in the garden, but we are not very enthusiastic about that idea. We are somewhat confused by current politics: on the one hand, fossil fuels are supposed to become much more expensive to promote renewable energy, but on the other hand, gas condensing boilers are heavily subsidized?
For sentimental reasons, we could imagine installing a water-bearing wood stove in the living room. We already have a wood-burning stove in the kitchen where we occasionally cook, and which also provides some heating in winter.
However, it would have to connect to the same chimney currently used by the oil heating system – or the future gas heating system – and from what I understand, this is not allowed, so I might have to give up that dream, right?
We are considering a photovoltaic system on the roof, but we plan to remove the attic floor and renovate the upstairs room within about 5-10 years to get higher ceilings. This would also include adding a few skylights. I should probably wait for these renovation measures first.
What would you recommend? How should the new heating system be sized – I assume this can be calculated quite well based on previous energy consumption?
Thank you very much for your time and help!
we have an old timber-framed house in the Alpine foreland. Built around 1910 with an extension from the 1960s, the original building has a basement, the extension does not. The insulation is rather poor, and the windows are either double-glazed or old. A hailstorm completely destroyed our roof, so a new roof with good insulation has now been installed.
Currently, we have a Viessmann oil heating system from 1989 with a 2000l (528 gallons) oil tank in the basement, which has caused no major problems so far. The hot water is also centrally supplied by this system. With the old roof, we used about 1900-2500l (502-660 gallons) of oil in winter, depending on the season. With the new roof, we don’t have experience yet, but I expect some improvement. The house has about 115m2 (1238 square feet) of living space, heated by radiators.
Since the heating system is getting old and there are currently larger subsidy programs, we are considering modernization. From my research so far, a heat pump seems to be out of the question because we would need a better-insulated house and underfloor heating? Other types of electric heating seem even less economical?
The least invasive option would probably be a new condensing oil boiler, but these are not subsidized, so I could just wait until the old one breaks down?
A pellet heating system seems too complicated to operate? My mother will soon be 70 and often lives alone in the house. In her old age, I don’t want to put too much strain on her. We frequently visit with our child for several days, but mostly in summer. Also, the long transition phase with low heating loads appears to speak against a pellet system.
I can’t really estimate the costs for gas. A gas connection might be possible with the local supplier if the neighbors join in. We would need about 60-70m (197-230 feet) of gas pipeline on our own property. What costs should I roughly expect? Alternatively, a tank could be buried in the garden, but we are not very enthusiastic about that idea. We are somewhat confused by current politics: on the one hand, fossil fuels are supposed to become much more expensive to promote renewable energy, but on the other hand, gas condensing boilers are heavily subsidized?
For sentimental reasons, we could imagine installing a water-bearing wood stove in the living room. We already have a wood-burning stove in the kitchen where we occasionally cook, and which also provides some heating in winter.
However, it would have to connect to the same chimney currently used by the oil heating system – or the future gas heating system – and from what I understand, this is not allowed, so I might have to give up that dream, right?
We are considering a photovoltaic system on the roof, but we plan to remove the attic floor and renovate the upstairs room within about 5-10 years to get higher ceilings. This would also include adding a few skylights. I should probably wait for these renovation measures first.
What would you recommend? How should the new heating system be sized – I assume this can be calculated quite well based on previous energy consumption?
Thank you very much for your time and help!
M
Myrna_Loy5 Jun 2021 07:28I would also schedule an appointment with a structural engineer. In timber-frame houses, the floor ceilings serve a bracing function. They hold the exterior walls together in tension through the beams, preventing them from bowing outward due to the roof's lateral thrust. The floor area acts like a diaphragm, stiffening the house against wind loads on the roof. Raising this structure is usually only possible with significant effort and very high costs. Based on my experience, complete removal is out of the question.
The floor beams should remain inside; only the floorboards in between should be removed.
Today was finally the appointment with the energy consultant, who encouraged me to continue pursuing the topic of heat pumps.
So far, I have contacted five heating installers; four categorically reject heat pumps in older buildings. One has been trying to schedule a visit for 8 weeks now :/
If anyone here has a recommendation for a heating installer in the Ammersee / LL area, I would be very grateful.
Maybe there is also someone whose heat pump in an older building I could visit (Bavaria area)?
I would really like to see such a system in person.
Thank you very much for your help!
Today was finally the appointment with the energy consultant, who encouraged me to continue pursuing the topic of heat pumps.
So far, I have contacted five heating installers; four categorically reject heat pumps in older buildings. One has been trying to schedule a visit for 8 weeks now :/
If anyone here has a recommendation for a heating installer in the Ammersee / LL area, I would be very grateful.
Maybe there is also someone whose heat pump in an older building I could visit (Bavaria area)?
I would really like to see such a system in person.
Thank you very much for your help!
By now, I have found a heating specialist. When it comes to the heat pump, I am facing a difficult choice.
To recap so that you don’t have to go through the entire thread:
* Heat load calculation by energy consultant: 10 kW
* Of which 4.3 kW is for the extension
* Variable occupancy in the house, usually 1 person, often 2–4 people
* The extension is only heated when 2 or more people are in the house
* Often no one is home (vacation, and the house should be protected from freezing)
* Heating support through wood stoves planned (currently there is a stove that will be replaced by a stove with storage function)
All these factors result in a highly fluctuating actual heat load. Nevertheless, I probably need to size my heat pump so it can heat the house alone (monovalent) to a tolerable level. It is important that the pump can modulate its output well.
What size heat pump should we choose? Our heating specialist suggested, based on the data, a 9 kW unit. However, the on-site consultation has not yet taken place.
We also have to decide between split and monoblock systems. An advantage of split is definitely that I would worry less in case of a power outage and/or absence.
Unfortunately, the Panasonic T-Cap series is only available as a monoblock with R32 (J-series). The split units are still from the H-series with R410A.
Does anyone know if and when a T-Cap split with R32 is planned?
The LT series offers both split and monoblock with R32 (J-series).
The LT series would be better suited for installation on the east side due to the smaller outdoor unit. However, the T-Cap seems to be better suited for higher flow temperatures and colder outdoor temperatures, which I will likely encounter with our radiators. Nevertheless, we have mentally accepted the idea of a large T-Cap monoblock on the east side.
Additionally, I am considering installing two wall heating systems inside the house to increase the heating surface areas. As I understand it, running a second heating circuit at a lower flow temperature should not be a major problem. I am currently deciding between wet and dry construction methods and have found manufacturers who offer both wall heating options in wet and dry versions.
My plan would be to equip one interior wall each (hallway + dining room) with such surface heating. Is there any recommendation?
To recap so that you don’t have to go through the entire thread:
* Heat load calculation by energy consultant: 10 kW
* Of which 4.3 kW is for the extension
* Variable occupancy in the house, usually 1 person, often 2–4 people
* The extension is only heated when 2 or more people are in the house
* Often no one is home (vacation, and the house should be protected from freezing)
* Heating support through wood stoves planned (currently there is a stove that will be replaced by a stove with storage function)
All these factors result in a highly fluctuating actual heat load. Nevertheless, I probably need to size my heat pump so it can heat the house alone (monovalent) to a tolerable level. It is important that the pump can modulate its output well.
What size heat pump should we choose? Our heating specialist suggested, based on the data, a 9 kW unit. However, the on-site consultation has not yet taken place.
We also have to decide between split and monoblock systems. An advantage of split is definitely that I would worry less in case of a power outage and/or absence.
Unfortunately, the Panasonic T-Cap series is only available as a monoblock with R32 (J-series). The split units are still from the H-series with R410A.
Does anyone know if and when a T-Cap split with R32 is planned?
The LT series offers both split and monoblock with R32 (J-series).
The LT series would be better suited for installation on the east side due to the smaller outdoor unit. However, the T-Cap seems to be better suited for higher flow temperatures and colder outdoor temperatures, which I will likely encounter with our radiators. Nevertheless, we have mentally accepted the idea of a large T-Cap monoblock on the east side.
Additionally, I am considering installing two wall heating systems inside the house to increase the heating surface areas. As I understand it, running a second heating circuit at a lower flow temperature should not be a major problem. I am currently deciding between wet and dry construction methods and have found manufacturers who offer both wall heating options in wet and dry versions.
My plan would be to equip one interior wall each (hallway + dining room) with such surface heating. Is there any recommendation?
B
Benutzer20030 Dec 2021 12:45meowmeow schrieb:
What size heat pump should we choose? Our heating technician suggested a 9 kW (12 hp) unit based on the data.Sounds like someone knows what they’re talking about. meowmeow schrieb:
Also, we’re deciding between a split system or a monoblock. One advantage of a split system is that I would worry less during a power outage and/or when away from home, right?Why is that? meowmeow schrieb:
Does anyone know if and when a T-Cap split system with R32 refrigerant will be available?It will come. When? No idea. 2022? 2024? Basically, Panasonic makes good units that also perform well at low temperatures. I have two monoblocks myself. These can also manage multiple heating zones with different temperature settings.
Benutzer200 schrieb:
Why? With a monoblock unit, I have to run water pipes outside the house, which can be a problem during a prolonged power outage because they might freeze.
If I need a new heat pump in 10-15 years, a monoblock is probably easier to replace and maintain. That’s why I am leaning toward a monoblock now. The question is whether to choose the T-CAP or HT series?
As I understand it, a monoblock could also operate two heating circuits?
Benutzer200 schrieb:
Sounds like someone knows their stuff. Is that sarcasm?
B
Benutzer20030 Dec 2021 13:51meowmeow schrieb:
With a monoblock, I have to run water pipes outside of the house, which can be problematic during a longer power outage because they might freeze. 1. I can’t remember a suitable power outage since my youth, and 2. you can add antifreeze to the water pipes for protection against freezing.
meowmeow schrieb:
As far as I understand, a monoblock could also manage two heating circuits? Yep, with an additional module XY. But I only know that theoretically, not from practical experience.
meowmeow schrieb:
Is that sarcasm? No, not at all. Often, the heating engineer will recommend a larger heat pump than necessary "just to be safe" for a 10 kW heating load.
P.S. A small bonus of Panasonics: if you had only underfloor heating, you could also use the heat pump for cooling. It just needs to be enabled in the software; nothing more is required.
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