á Omitting individual room control? Mechanical ventilation with heat recovery + gas heating, new build
Created on: 15 Mar 2019 08:16
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Kabelmodem87
Hello,
I am currently planning the electrical and technical installations for our new build.
We are constructing with 42.5 Poroton bricks without insulation and have planned a gas heating system as well as a central controlled ventilation system with heat recovery. Almost the entire house will be tiled, except for the childrenâs room and bedroom.
Now the question about the usefulness of 10 room thermostats, which would cost me âŹ1500 gross without any self-labor, including valves and wiring, and which I find not very attractive on the wall. Additionally, there is continuous power consumption per radiator.
What I have read so far is that a hydraulic balancing is important, a well-adjusted heating curve depending on the outside temperature, and a system with a low flow temperature; then the individual rooms can be perfectly adjusted through the flow in the radiators. Due to door gaps and the ventilation system, it will anyway be difficult to maintain significant temperature differences.
I do not see what comfort the electronic radiator regulators (ERR) would bring, since the system is slow to respond anyway and would only react hours later when there is solar heat gain.
With modern gas boilers, there should also be the option to control the flow temperature externally via smartphone, for example from vacation, and thus lower or raise the whole house temperature by 1-2 degrees before arriving home.
I know that ERR is initially mandatory and you have to apply for an exemption. Do you see a chance that this will be approved? Is the architect together with the heating installer the right contact for the application? I think our installer always installs the room thermostats without considering whether they make sense.
Has anyone experienced a similar situation or has any tips or advice?
Please refrain from comments like ânew build costs âŹ500,000 but no âŹ1500 for room thermostats,â this is about the principle of not buying something unnecessary and unattractive.
I am currently planning the electrical and technical installations for our new build.
We are constructing with 42.5 Poroton bricks without insulation and have planned a gas heating system as well as a central controlled ventilation system with heat recovery. Almost the entire house will be tiled, except for the childrenâs room and bedroom.
Now the question about the usefulness of 10 room thermostats, which would cost me âŹ1500 gross without any self-labor, including valves and wiring, and which I find not very attractive on the wall. Additionally, there is continuous power consumption per radiator.
What I have read so far is that a hydraulic balancing is important, a well-adjusted heating curve depending on the outside temperature, and a system with a low flow temperature; then the individual rooms can be perfectly adjusted through the flow in the radiators. Due to door gaps and the ventilation system, it will anyway be difficult to maintain significant temperature differences.
I do not see what comfort the electronic radiator regulators (ERR) would bring, since the system is slow to respond anyway and would only react hours later when there is solar heat gain.
With modern gas boilers, there should also be the option to control the flow temperature externally via smartphone, for example from vacation, and thus lower or raise the whole house temperature by 1-2 degrees before arriving home.
I know that ERR is initially mandatory and you have to apply for an exemption. Do you see a chance that this will be approved? Is the architect together with the heating installer the right contact for the application? I think our installer always installs the room thermostats without considering whether they make sense.
Has anyone experienced a similar situation or has any tips or advice?
Please refrain from comments like ânew build costs âŹ500,000 but no âŹ1500 for room thermostats,â this is about the principle of not buying something unnecessary and unattractive.
I also found the ERR pointless, and despite it being mandatory, we omitted it. All those additional valves consume electricity unnecessarily and donât provide any benefit because the system is so slow to respondâno thanks.
Once everything is finished, we simply leave all shut-off valves fully open and regulate the system at the stove (a water-heating pellet boiler, basically for the living room). Since we have to load the pellets manually by the sack anyway, this naturally provides some level of control. Additionally, we have a buffer tank. There is also a wood stove on each floor in case extra heat is really needed.
(A gas heating system was not possible due to the lack of a supply line and the KfW requirements, and a âproper boilerâ was not an option due to the absence of a basement or a dedicated heating room. So the stove in the living area was the only choice.)
Once everything is finished, we simply leave all shut-off valves fully open and regulate the system at the stove (a water-heating pellet boiler, basically for the living room). Since we have to load the pellets manually by the sack anyway, this naturally provides some level of control. Additionally, we have a buffer tank. There is also a wood stove on each floor in case extra heat is really needed.
(A gas heating system was not possible due to the lack of a supply line and the KfW requirements, and a âproper boilerâ was not an option due to the absence of a basement or a dedicated heating room. So the stove in the living area was the only choice.)
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boxandroof15 Mar 2019 16:54Kabelmodem87 schrieb:
Is the hydraulic balancing done by the heating installer based on the flow rate of the individual heating circuits? If I decide that the bathroom should be 1 degree warmer, would I need to manually increase the flow rate at the thermostatic radiator valve (TRV)? If there are two TRVs for the bathroom, should both be adjusted equally? Can this cause confusion and affect other rooms as well?Not much confusion will occur, but yes, the other rooms will become slightly cooler as a result. You will have to do the balancing yourself in the end until everything fits your needs.
If the bathroom doesnât get warm enough despite a high flow rate, the supply temperature must be raised, and at the same time, you need to restrict the other circuits so they donât get too warm. Thatâs why itâs important to plan the underfloor heating according to your desired temperature for each room, especially the bathroom.
This issue becomes particularly challenging with heat pumps, where it is often a recurring problem.
Kabelmodem87 schrieb:
If I want to lower or raise the temperature for the entire house, should I shift the heating curve on the thermostat accordingly?For a permanent adjustment, yes. Otherwise, most heating systems have vacation modes, setpoint adjustments via timers, and similar options.
Kabelmodem87 schrieb:
Does it make sense with controlled ventilation and underfloor heating to lower the temperature, for example from 4 p.m. to midnight, and raise it again from midnight to 4 p.m., in order to account for thermal inertia and reduce temperature by 1â2 degrees at night?No â this is managed automatically through the heating curve. The goal is to maintain a constant temperature inside the house, which also makes balancing easier.
Only with air-source heat pumps or photovoltaic systems do additional manual adjustments make sense.
The hydraulic balancing must be carried out by the system installer or by someone they hire. However, the version that was ordered, which is usually a rough adjustment, is sufficient to be considered free of defects. In other words, the warmest room (bathroom) must reach 24°C (75°F).
A hydraulic balancing that ensures each room reaches the more or less exact desired temperatures is not trivial, which is why ERR exists in the first place. This way, the heating can always be run a bit higher, and in case of potential overheating, it can simply be controlled with the thermostat.
With low-temperature underfloor heating, you have to think in the opposite way compared to conventional radiator heating, and this is where many already fail at the first step (probably including those who introduced the ERR requirement). A nighttime setback makes little sense, and if any, it should be the other way around. In other words, you need to heat during the night and lower the temperature during the day. After all, you need the heat in the morning and evening. Something close to what you described, but even then the savings are only in the fraction of a percent range.
An outdoor temperature-controlled regulation with a (yes, one) thermostat in the southern exposure and a precisely performed hydraulic balancing are sufficient to operate the system efficiently. The mechanical ventilation with heat recovery will then do its job by mixing the temperatures. Differences of 2-3 degrees are achievable. More than that is rather wishful thinking.
A hydraulic balancing that ensures each room reaches the more or less exact desired temperatures is not trivial, which is why ERR exists in the first place. This way, the heating can always be run a bit higher, and in case of potential overheating, it can simply be controlled with the thermostat.
Kabelmodem87 schrieb:
Does it actually make sense with mechanical ventilation with heat recovery and underfloor heating to lower temperatures, for example, between 4 p.m. and midnight, and increase them from midnight to 4 p.m. to reflect thermal inertia, and to reduce by 1-2 degrees at night?
With low-temperature underfloor heating, you have to think in the opposite way compared to conventional radiator heating, and this is where many already fail at the first step (probably including those who introduced the ERR requirement). A nighttime setback makes little sense, and if any, it should be the other way around. In other words, you need to heat during the night and lower the temperature during the day. After all, you need the heat in the morning and evening. Something close to what you described, but even then the savings are only in the fraction of a percent range.
An outdoor temperature-controlled regulation with a (yes, one) thermostat in the southern exposure and a precisely performed hydraulic balancing are sufficient to operate the system efficiently. The mechanical ventilation with heat recovery will then do its job by mixing the temperatures. Differences of 2-3 degrees are achievable. More than that is rather wishful thinking.
Mycraft schrieb:
An outdoor temperature-controlled system with a (yes, a single) thermostat facing southWhy south? That distorts the readings completely when itâs exposed to direct sunlight.
In our case, the sensor is installed facing north.
Musketier schrieb:
Why on the south side? That completely distorts the reading if the sun is shining directly on it.
For us, the sensor is on the north side.Yes, I donât quite understand that either. The outdoor temperature sensor is supposed to reflect the actual outside temperature, ideally protected from wind and direct sunlightâŠ
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wurmwichtel15 Mar 2019 20:31ERR boxes can also be covered with wallpaper, and the electrician can be instructed to combine the control circuits on a single circuit breaker.
In our case, all thermostats remain fully open because otherwise the heating cycles too frequently (currently, at zero degrees Celsius (32°F) outside temperature, it runs twice for four hours each day instead of every two to three hours for less than 60 minutes, due to an ERR being opened and thus lowering the return temperature too much).
BTW:
The payback period for a controlled residential ventilation system is approximately 60 to 100 years.
In our case, all thermostats remain fully open because otherwise the heating cycles too frequently (currently, at zero degrees Celsius (32°F) outside temperature, it runs twice for four hours each day instead of every two to three hours for less than 60 minutes, due to an ERR being opened and thus lowering the return temperature too much).
BTW:
The payback period for a controlled residential ventilation system is approximately 60 to 100 years.
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