ᐅ Is a heat load calculation necessary when specifying desired indoor temperatures?
Created on: 6 Feb 2018 12:04
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Pädda
Hello.
I have often read in the forum that a heating load calculation is absolutely necessary. Recently, we attended a building trade fair and I spoke with three leading gas heating manufacturers. Each of them said that a heating load calculation with specific desired temperatures for individual rooms is unnecessary for a gas heating system because the capacity of the gas heater is always sufficient. According to the exhibitors, a heating load calculation is always performed anyway, but with standard room temperatures, for example, 18°C (64°F) for bedrooms and 21°C (70°F) for living rooms. This is regulated somewhere as a standard temperature. I then told them that we differ a bit from the standard and want 22°C (72°F) in the bedroom and 23°C (73°F) in the living room. The exhibitors said that this is completely irrelevant. With a gas heating system, these temperatures can always be achieved. The heating curve just needs to be adjusted accordingly.
They also said that the installation spacing of the underfloor heating pipes does not really matter. However, if a heat pump is possibly planned for installation at some point in the future, the pipe spacing should be reduced from, for example, 20cm (8 inches) to 10–15cm (4–6 inches).
What do you think about this?
I have often read in the forum that a heating load calculation is absolutely necessary. Recently, we attended a building trade fair and I spoke with three leading gas heating manufacturers. Each of them said that a heating load calculation with specific desired temperatures for individual rooms is unnecessary for a gas heating system because the capacity of the gas heater is always sufficient. According to the exhibitors, a heating load calculation is always performed anyway, but with standard room temperatures, for example, 18°C (64°F) for bedrooms and 21°C (70°F) for living rooms. This is regulated somewhere as a standard temperature. I then told them that we differ a bit from the standard and want 22°C (72°F) in the bedroom and 23°C (73°F) in the living room. The exhibitors said that this is completely irrelevant. With a gas heating system, these temperatures can always be achieved. The heating curve just needs to be adjusted accordingly.
They also said that the installation spacing of the underfloor heating pipes does not really matter. However, if a heat pump is possibly planned for installation at some point in the future, the pipe spacing should be reduced from, for example, 20cm (8 inches) to 10–15cm (4–6 inches).
What do you think about this?
If a heat pump is planned for later use with full-surface underfloor heating, design the pipe spacing for a 35°C (95°F) supply temperature and 25-28°C (77-82°F) return temperature. Underfloor heating systems can also operate at higher supply temperatures, but it is more comfortable and efficient in the long term to design for the lowest possible supply temperature and use a double-loop spiral layout to ensure even heat distribution across the room.
The gas boiler itself will then provide higher temperatures since it cannot be reduced as far. However, this is compensated by return flow mixing and remains the most efficient heating method.
The gas boiler itself will then provide higher temperatures since it cannot be reduced as far. However, this is compensated by return flow mixing and remains the most efficient heating method.
Please keep in mind that you might want different temperatures in the new house compared to your apartment. We experience lower comfortable temperatures in the new house because the walls are warmer, there is underfloor heating, and there are no drafts.
I believe the heating engineer didn’t carry out a very detailed calculation in our case either (I might be wrong about the flow temperature, and he just didn’t show the calculation?), with 15cm (6 inches) insulation in the living areas and 10cm (4 inches) in the bathrooms. Oh, and the heating system is an air-source heat pump.
I believe the heating engineer didn’t carry out a very detailed calculation in our case either (I might be wrong about the flow temperature, and he just didn’t show the calculation?), with 15cm (6 inches) insulation in the living areas and 10cm (4 inches) in the bathrooms. Oh, and the heating system is an air-source heat pump.
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Sondelgeher128 Mar 2018 12:54Hello everyone,
OK, so apparently I don’t need to specify temperatures above the standard values for a gas heating system, but what about a heat pump? Our installer said we should stick to the standard values (for example, living room 20°C (68°F)) because they would calculate that 20°C (68°F) for an outdoor temperature of -16°C (3°F) ... however, it would be possible at normal subzero temperatures to have 22°C (72°F) in the living room. If we specify higher temperatures, I understand that the heating load calculation will be higher and possibly even too high since it rarely reaches -16°C (3°F).
OK, so apparently I don’t need to specify temperatures above the standard values for a gas heating system, but what about a heat pump? Our installer said we should stick to the standard values (for example, living room 20°C (68°F)) because they would calculate that 20°C (68°F) for an outdoor temperature of -16°C (3°F) ... however, it would be possible at normal subzero temperatures to have 22°C (72°F) in the living room. If we specify higher temperatures, I understand that the heating load calculation will be higher and possibly even too high since it rarely reaches -16°C (3°F).
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