Good morning everyone,
I wanted to ask what your house’s electricity consumption is at night when everything is quiet and sleeping, so what is running continuously?
We have a newly built house, moved in summer 2019. Our building services include underfloor heating (air-to-water heat pump), controlled mechanical ventilation (runs at full power 3 times a day for 2 hours each, then reduced), a photovoltaic system, and otherwise the usual nighttime appliances (phone charger plugged into USB outlet, e-bikes charging occasionally, 2 TVs on standby, Alexas on standby, etc.).
At night, we have a continuous consumption of about 232W (with ventilation running at reduced power and when the heat pump is not producing). I can see this in the app for the photovoltaic system. From 0:00 to 6:30 a.m. we consume about 2.8 kWh.
How about you?
Best regards
I wanted to ask what your house’s electricity consumption is at night when everything is quiet and sleeping, so what is running continuously?
We have a newly built house, moved in summer 2019. Our building services include underfloor heating (air-to-water heat pump), controlled mechanical ventilation (runs at full power 3 times a day for 2 hours each, then reduced), a photovoltaic system, and otherwise the usual nighttime appliances (phone charger plugged into USB outlet, e-bikes charging occasionally, 2 TVs on standby, Alexas on standby, etc.).
At night, we have a continuous consumption of about 232W (with ventilation running at reduced power and when the heat pump is not producing). I can see this in the app for the photovoltaic system. From 0:00 to 6:30 a.m. we consume about 2.8 kWh.
How about you?
Best regards
Everyone complains about construction costs and how it’s no longer possible to build a house for 200,000€ (about 220,000 USD), yet no one wants to give up on amenities like a fireplace, electric shutters, or controlled residential ventilation. Naturally, these amenities also require space, which means the house needs to be a few square meters (square feet) larger.
Every extra euro spent adds up over the entire loan term, extending it accordingly and worsening the loan-to-value ratio, which may in turn increase the interest rate. Additionally, the risk after the fixed interest period rises, so people prefer 20 or 30 years instead of 15 years, which also raises interest rates. Altogether, an initial 10,000€ (about 11,000 USD) can end up costing significantly more over time.
It may be true that the impact is much smaller with interest rates of just a fraction of a percent compared to the 4 or 5% rates of the past. However, controlled residential ventilation is just one of many factors.
Every extra euro spent adds up over the entire loan term, extending it accordingly and worsening the loan-to-value ratio, which may in turn increase the interest rate. Additionally, the risk after the fixed interest period rises, so people prefer 20 or 30 years instead of 15 years, which also raises interest rates. Altogether, an initial 10,000€ (about 11,000 USD) can end up costing significantly more over time.
It may be true that the impact is much smaller with interest rates of just a fraction of a percent compared to the 4 or 5% rates of the past. However, controlled residential ventilation is just one of many factors.
Uh, who’s coming here with clichés from the pub? It’s those same people who not only consider controlled residential ventilation a luxury but also completely unnecessary.
- What about the maintenance contract?
- It uses more energy than it saves.
- Birds chirping in the morning – mine are so loud that I can hear them through the closed window. The bunch that’s draining me dry right now.
Damn, I forgot to check how much energy we need at night.
@Ybias78 The new energy-saving regulations have been expected for so long. In the end, you’ll have moved in before they come into effect. This has been going on for a few years. For us, it was supposed to start on 1.1.2019.
- What about the maintenance contract?
- It uses more energy than it saves.
- Birds chirping in the morning – mine are so loud that I can hear them through the closed window. The bunch that’s draining me dry right now.
Damn, I forgot to check how much energy we need at night.
@Ybias78 The new energy-saving regulations have been expected for so long. In the end, you’ll have moved in before they come into effect. This has been going on for a few years. For us, it was supposed to start on 1.1.2019.
haydee schrieb:
Who’s coming here with outdated clichés? These are exactly the people who not only consider a mechanical ventilation with heat recovery to be a luxury but also completely unnecessary.
- How was it with the maintenance contract?
- It uses more energy than it saves
- Birds chirping in the morning – mine are so loud that I can hear them through the closed window. The bunch that’s eating my hair off right now.
Damn, I forgot to check how much energy we use at night.
@Ybias78 The new energy saving regulation has been expected for so long. In the end, you might move in before it comes into effect. This game has been going on for years. For us, it was supposed to start on 1/1/2019. And who are those people? I exclude myself since I’ve written many times that it’s nice to have...
I’ll wait and see. I think the construction contract will be signed at the end of 2020 or beginning of 2021. Let’s see what’s known by then.
Ybias78 schrieb:
2x robot vacuum cleaners (one per floor)
- 1x robotic lawn mower
- household help (earns less than 30€/hour)
If you have at least these, then your calculation is approximately correct. No, probably not in our case. You don’t always have to insist with a hammer. These three things are not worthwhile or don’t work for us.
However, you do benefit from the straightforward bungalow advantage.
Ybias78 schrieb:
I’ve been saying all along that controlled mechanical ventilation is a luxury and not a must-have, but here I am constantly challenged and people try to convince me otherwise. No, but there are arguments that do need to be mentioned.
kati1337 schrieb:
If you are currently satisfied with natural ventilation without controlled mechanical ventilation, why should it be different in a new house? There are older houses where the issue of forced ventilation simply doesn’t arise. It’s not about birdsong or the smell of freshly cut hay.
For me, controlled mechanical ventilation is closely linked to the heating system. As I said before: we try to keep the heat inside the house as much as possible. If I open the patio door, I also go outside and close it behind me.
It’s nonsense that ventilating for 5-10 minutes causes the whole house to cool down significantly. The air is exchanged, but it has a very low heat capacity. After all, it’s a gas with a small total mass, so only a little heat is lost to the outside. Most of the heat is stored within the house itself, in the walls and floors. That’s why it’s warm again shortly after airing out.
I looked up some approximate values for a rough calculation:
Air density about 1.2 kg/m³
Specific heat capacity 1 kJ/(kg*K) (at constant pressure)
My house has roughly 300 m³ (10,600 ft³) of enclosed space, so about 360 kg (800 lbs) of air. If I lower the temperature by 10 K (10°C, 18°F) and exchange all the air during ventilation, that amounts to 3600 kJ (1000 Wh). That equals exactly 1 kWh per ventilation session—and I ventilate twice a day.
These are extreme values. Only during a small part of the year is it cold enough outside to reach a 10°C temperature difference. On average, the difference is certainly less than half.
Mechanical ventilation with heat recovery is therefore more of a replacement for constantly having windows tilted open. This is exactly how proponents describe its advantages.
Just a question—I don’t actually have one: Would mechanical ventilation also help to dehumidify the air? In summer, there are days when the outdoor humidity is very high, and indoor humidity matches that. Over time, I’m concerned about moisture buildup. But ventilation alone doesn’t seem to solve that.
I looked up some approximate values for a rough calculation:
Air density about 1.2 kg/m³
Specific heat capacity 1 kJ/(kg*K) (at constant pressure)
My house has roughly 300 m³ (10,600 ft³) of enclosed space, so about 360 kg (800 lbs) of air. If I lower the temperature by 10 K (10°C, 18°F) and exchange all the air during ventilation, that amounts to 3600 kJ (1000 Wh). That equals exactly 1 kWh per ventilation session—and I ventilate twice a day.
These are extreme values. Only during a small part of the year is it cold enough outside to reach a 10°C temperature difference. On average, the difference is certainly less than half.
Mechanical ventilation with heat recovery is therefore more of a replacement for constantly having windows tilted open. This is exactly how proponents describe its advantages.
Just a question—I don’t actually have one: Would mechanical ventilation also help to dehumidify the air? In summer, there are days when the outdoor humidity is very high, and indoor humidity matches that. Over time, I’m concerned about moisture buildup. But ventilation alone doesn’t seem to solve that.
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