First of all, I want to clarify that my goal is not to save the world (sorry, my bad), but solely to reduce heating costs! I have been calculating back and forth for some time now but unfortunately can’t come to an optimal conclusion.
So here’s my attempt to use collective intelligence. Perhaps someone has already considered the same issues.
My house (old, 25cm (10 inches) Ytong blocks) could be improved in terms of U-value by adding a brick-style polystyrene cladding, or I could install a heat pump. Currently, I am heating with oil but could switch to gas. Oil heating still has a certain grandfathering protection for a while, but it’s likely that I will face problems with oil in the future.
Switching to gas would cost me about $8,000, the heat pump around $15,000. The polystyrene (or similar) cladding would indeed lower heating costs, but when I asked for information, no one could really tell me by what percentage my costs would drop if I improved the U-value (currently 0.35 for 25cm (10 inches) Ytong) by a factor X through additional insulation.
Are there tables or simple rough calculations that could help me decide without having to take another university-level math course first?
Thanks in advance for any information from someone who, like me, does not want to wait for the climate transition that will supposedly bring us winter temperatures of +15°C (59°F). 😉
So here’s my attempt to use collective intelligence. Perhaps someone has already considered the same issues.
My house (old, 25cm (10 inches) Ytong blocks) could be improved in terms of U-value by adding a brick-style polystyrene cladding, or I could install a heat pump. Currently, I am heating with oil but could switch to gas. Oil heating still has a certain grandfathering protection for a while, but it’s likely that I will face problems with oil in the future.
Switching to gas would cost me about $8,000, the heat pump around $15,000. The polystyrene (or similar) cladding would indeed lower heating costs, but when I asked for information, no one could really tell me by what percentage my costs would drop if I improved the U-value (currently 0.35 for 25cm (10 inches) Ytong) by a factor X through additional insulation.
Are there tables or simple rough calculations that could help me decide without having to take another university-level math course first?
Thanks in advance for any information from someone who, like me, does not want to wait for the climate transition that will supposedly bring us winter temperatures of +15°C (59°F). 😉
S
Stefan0019 Dec 2021 07:50Höhlenmensch schrieb:
Question why? - If I heat 10 liters (about 2.6 gallons) of water from 20°C (68°F) to 40°C (104°F), the heat pump requires, for example, X watts // I can measure all three values—temperature, kW electricity, time.
Whether I then use the water for showering or for heating—I thought that wouldn’t matter?? 40°C (104°F) is 40°C (104°F).
Maybe I’m not seeing something correctly. I’m always on the quick trial side—(the heat pump unit hardly cost me anything).
And as a small note on skepticism: A long time ago I was advised—by Viessmann—to use a new controller, which was supposed to save energy! The efficiency depends on the temperature difference. Heating from 10°C (50°F) to 20°C (68°F) requires more energy than heating twice from 10°C (50°F) to 15°C (59°F).
It is indeed irrelevant whether you use the 40°C (104°F) water for the heating system or for the shower, but it makes a difference if you operate the heating at 35°C (95°F) and the shower at 50°C (122°F).
The maximum achievable efficiency is given by the coefficient of performance (COP) = T_warm / (T_warm - T_cold), where temperatures have to be in Kelvin. In other words, your efficiency decreases with increasing temperature lift. In addition, the devices do not operate at the theoretical limit and become less efficient themselves at higher temperature differences.
B
Benutzer2009 Dec 2021 10:22Höhlenmensch schrieb:
Since the outside temperature is already quite low, the electric heating elements in the heat pumps switch on as well.No, if planned properly, the heating element (in normal areas, maybe not in the Black Forest at 1,000 meters (3,280 feet) elevation) doesn’t switch on at all—only during the defrost cycle.Regarding the efficiency of air-to-water heat pumps, @Stefan001 has already provided some input. To simplify, it’s comparable to driving a car: maintaining a steady speed of 90–110 km/h (55–70 mph) on the highway is significantly more efficient than constantly accelerating from 80 to 200 km/h (50 to 125 mph) and then braking again.
Höhlenmensch10 Dec 2021 12:24 🙂Thanks, understood.
I’ve packed up my materials for now because the weather has slowed down my activity.
I’ve packed up my materials for now because the weather has slowed down my activity.
hampshire schrieb:
From a purely financial perspective, it makes sense to wait for the upcoming subsidy programs. The coalition agreement includes several measures regarding the renovation of existing buildings.Is there an update on this? I am planning to insulate the facade. Would it be better to wait then?
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