ᐅ Omitting individual room control? Mechanical ventilation with heat recovery + gas heating, new build
Created on: 15 Mar 2019 08:16
K
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 children’s room and bedroom.
Now the question about the usefulness of 10 room thermostats, which would cost me €1500 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 “new build costs €500,000 but no €1500 for room thermostats,” 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 children’s room and bedroom.
Now the question about the usefulness of 10 room thermostats, which would cost me €1500 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 “new build costs €500,000 but no €1500 for room thermostats,” this is about the principle of not buying something unnecessary and unattractive.
B
boxandroof15 Mar 2019 09:58Kabelmodem87 schrieb:
The next economic nonsense is the requirement to install a solar system on the roof for hot water at a cost of €6000 (about $6500), as a penalty for using a natural gas boiler. It won’t pay off in 30 years, but there will be no exemption for it. Instead of solar, your controlled mechanical ventilation system might be sufficient. For that, you need an energy saving regulation certificate that covers this.
If you are building "energy-efficient" (KfW) housing, the exemption from the energy saving regulation is even more necessary than for the general energy saving ordinance – as far as I know – since the builder for KfW must certify the correct installation of the heating system.
K
Kabelmodem8715 Mar 2019 10:01boxandroof schrieb:
Instead of solar panels, your mechanical ventilation with heat recovery might be sufficient. For this, you need an energy saving regulation certificate that covers this requirement.
If you are building "energy efficient" (KfW), the exemption for the renewable energy requirement (ERR) is actually even more necessary than for the energy saving regulation – as far as I know – because the energy consultant for KfW must certify the correct installation of the heating system.Our architect is trying to make it work, but it seems very difficult to meet the requirements using only mechanical ventilation with heat recovery.
We are not building with KfW funding, so it’s not an issue for us.
B
boxandroof15 Mar 2019 10:16Kabelmodem87 schrieb:
Our architect is trying to make it work, but it seems very difficult to achieve with only controlled residential ventilation. My architect told me that he doesn’t understand many of his calculations (those from the software) or isn’t willing to put in the effort to try. There are general contractors who offer the combination of gas heating plus controlled residential ventilation as a standard for typical energy efficiency regulation pitched roof houses. It is possible.
Kabelmodem87 schrieb:
For a possible retrofit using radio signals, for individual rooms, would it be enough to have a few 3x1.5mm (3x0.0059 inch) cables in the heating circuit distribution? Then wouldn’t control with battery-powered room thermostats and wireless valves be easily possible afterward? Just in case. Yes, but of course in case of need, wired connections would be better.
We had cables prepared for most rooms (the builder/electrician convinced me otherwise), in hindsight I should have stayed consistent there.
K
Kabelmodem8715 Mar 2019 10:19boxandroof schrieb:
My architect told me that he doesn’t understand many of the calculations made by the software or doesn’t bother trying to. There are general contractors who offer the combination of gas heating plus controlled residential ventilation as standard for energy-efficient pitched roof houses. It is possible.
Yes, but in case of problems, cables would of course be better.
We had cables prepared for most rooms (the house builder/electrician convinced me otherwise), looking back, I should have been more consistent.Thanks, we are building a flat roof house; I’m not sure if that makes a difference.
Kabelmodem87 schrieb:
However, the upfront cost is also 5000€ higher, and electricity prices are uncertain. Gas is still well established in Germany, including in many public institutions, which means they are less likely to raise prices drastically anytime soon, at least in my opinion.Well, it depends on the offer. An air-to-water heat pump without photovoltaic should cost less than gas plus solar. An air-to-water heat pump combined with photovoltaic is clearly much more expensive, but after 20 years you will have recouped the investment; with gas and solar, it doesn’t pay off at all.
For example, I paid about 20,000€ for the entire heating system and photovoltaic installation and now have almost zero heating costs. (Just as an extreme example)
boxandroof schrieb:
If you build "energy-efficient" (KfW), the exemption for the renewable energy obligation (ERR) is even more necessary than for the Energy Saving OrdinanceYes, I would avoid that with a KfW loan as well, since you can quickly get into the area of "fraud."
H
hampshire15 Mar 2019 10:29Kabelmodem87 schrieb:
Thanks, we are building a flat-roof house, not sure if that makes a difference. Flat roofs and photovoltaics work great (as long as there is no shading). Raise the edge of the roof slightly, mount a 10kWp east-west system on supports, and you get electricity without changing the architecture. Priority on self-consumption (battery), feed surplus back into the grid. If the liquidity is available, it’s a no-brainer.
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