ᐅ Heating costs for KfW55 – electricity costs seem too high to me
Created on: 7 Nov 2018 19:56
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Der-w
Hello everyone,
In the energy performance calculation of the house we are interested in buying, the following is stated:
I think the energy demand is relatively low. The living area is estimated at approximately 145m² (1560 sq ft) in the specifications.
However, the heating costs of about 1200 euros per year seem quite high to me for such a good demand value, since I often read on this forum that many only need around 600 euros.
The heating system is a Rotex HPSU Compact.
Am I missing something?
Thank you.
In the energy performance calculation of the house we are interested in buying, the following is stated:
I think the energy demand is relatively low. The living area is estimated at approximately 145m² (1560 sq ft) in the specifications.
However, the heating costs of about 1200 euros per year seem quite high to me for such a good demand value, since I often read on this forum that many only need around 600 euros.
The heating system is a Rotex HPSU Compact.
Am I missing something?
Thank you.
B
boxandroof8 Nov 2018 08:11Der-w schrieb:
I think the energy demand is quite reasonable. The living area is estimated at around 145sqm (1600 sq ft) in the design.Unfortunately, this is a misconception. The insulation is at the lowest standard for a new build. For KfW 55, a heat transfer coefficient (H‘t) of at least 0.28 is required, or so I thought?!
The seemingly good values are achieved on paper thanks to the heat pump. But if a poorly planned heating system is added—which I would assume here—you will end up with correspondingly high consumption.
The table showing electricity consumption seems to be seriously intended by the provider and apparently refers only to heating. However, as mentioned at the beginning, I would not rely on it for estimating future consumption.
boxandroof schrieb:
If a poorly designed heating system is added, which I would assume in this case, you will have correspondingly high energy consumption.How can this be further determined?M
Mottenhausen8 Nov 2018 10:06Exactly, the background is, in my opinion, the absurd calculation of demand. Depending on the heat source (air-to-water heat pump, pellets, gas, etc.), the house is allowed to have a different level of energy demand while still meeting KfW55 standards. For example, a KfW55 house with an air-to-water heat pump is permitted to lose significantly more heat due to poor insulation than a house heated with gas...
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boxandroof8 Nov 2018 12:40Der-w schrieb:
How can this be determined further? Not really from a distance. You would need to dive into the design of the underfloor heating system and specifically check which supply temperature was planned. Are there buffer tanks in the system, or any hydraulic switches?
Ask for the room-by-room heating load calculation and the installation plans for the underfloor heating.
Maybe there are standardized comparison houses available; otherwise, check databases with consumption data for this heat pump model.
Some aspects you can control yourself later, such as turning off all thermostats or adjusting the heat pump settings.
We are currently paying 300€ for heating costs plus 110€ for hot water, so I expect the total to be around 600€ for this year. Additionally, there will be about 50€ for the controlled ventilation system plus 10€ for filter replacement. Annual maintenance involves just a few simple steps that can be done yourself.
KfW 55, 160 m² (1,722 sq ft).
Of course, I also need to consider how to calculate this. The pump runs on the household electricity supply, so I don’t include the basic electricity fee here since I have to pay that anyway.
KfW 55, 160 m² (1,722 sq ft).
Of course, I also need to consider how to calculate this. The pump runs on the household electricity supply, so I don’t include the basic electricity fee here since I have to pay that anyway.
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