ᐅ Experience with KfW55 solid construction + gas heating + 5 sqm solar panels
Created on: 1 May 2017 20:11
N
Nutshell
Hello everyone,
I wanted to share my experience with my Kfw55 new build from 2013/2014.
We live at just under 300 meters (985 feet) above sea level and built with solid construction.
The house has a rather simple shape.
A standard gable roof without dormers or skylights (upstairs there is one window per room on the gable side).
Styrofoam was not an option for various reasons, so we chose the rather expensive monolithic plan blocks with a lambda value of 0.08.
Size: 111 sqm (1195 sq ft) living space.
Exterior wall: 36.5 cm (14 inches) Ytong blocks // Lambda 0.2 W/m²K
Floor slab insulated with XPS // 0.21 W/m²K
Ceiling on the upper floor has a sloping roof with 24 cm (9.5 inches) // ceiling insulated with 34 cm (13.5 inches) mineral wool // 0.12 W/m²K
Doors and windows are triple-glazed and gas-filled // overall including frames 1.05 W/m²K
Heat generator:
Gas condensing boiler: Viessmann Vitodens 300
System control: Vitotronic 200
Solar thermal system 5 sqm (54 sq ft): Vitosol 200-F
Solar storage tank: Vitocell 100-W 300 liters (79 gallons)
The solar system is used only for domestic hot water (no heating support).
Our gas boiler is switched off from May to September for heating and still consumes about 100 kWh of gas over the summer.
In winter, the solar system barely manages to heat the hot water (2 people), so it usually runs on gas.
Ventilation is handled by decentralized Lunos e² units with 90% heat recovery.
Over 12 months, we had a gas consumption of 8000 kWh.
That currently corresponds to heating costs of about €28 for the house.
We have the temperature set to 23°C (73°F) throughout the house.
(Electricity costs are about €39.)
Overall, we are very satisfied. Of course, the energy certificate shows lower consumption than we actually have.
There is no night setback, and nothing ever switches off or regulates down.
Maybe someone has had similar experiences?
Personally, I’m relaxed about heating costs; even if energy prices rise, paying twice as much would still be less than I used to pay in my smaller 80 sqm (860 sq ft) apartment built in 1990.
I wanted to share my experience with my Kfw55 new build from 2013/2014.
We live at just under 300 meters (985 feet) above sea level and built with solid construction.
The house has a rather simple shape.
A standard gable roof without dormers or skylights (upstairs there is one window per room on the gable side).
Styrofoam was not an option for various reasons, so we chose the rather expensive monolithic plan blocks with a lambda value of 0.08.
Size: 111 sqm (1195 sq ft) living space.
Exterior wall: 36.5 cm (14 inches) Ytong blocks // Lambda 0.2 W/m²K
Floor slab insulated with XPS // 0.21 W/m²K
Ceiling on the upper floor has a sloping roof with 24 cm (9.5 inches) // ceiling insulated with 34 cm (13.5 inches) mineral wool // 0.12 W/m²K
Doors and windows are triple-glazed and gas-filled // overall including frames 1.05 W/m²K
Heat generator:
Gas condensing boiler: Viessmann Vitodens 300
System control: Vitotronic 200
Solar thermal system 5 sqm (54 sq ft): Vitosol 200-F
Solar storage tank: Vitocell 100-W 300 liters (79 gallons)
The solar system is used only for domestic hot water (no heating support).
Our gas boiler is switched off from May to September for heating and still consumes about 100 kWh of gas over the summer.
In winter, the solar system barely manages to heat the hot water (2 people), so it usually runs on gas.
Ventilation is handled by decentralized Lunos e² units with 90% heat recovery.
Over 12 months, we had a gas consumption of 8000 kWh.
That currently corresponds to heating costs of about €28 for the house.
We have the temperature set to 23°C (73°F) throughout the house.
(Electricity costs are about €39.)
Overall, we are very satisfied. Of course, the energy certificate shows lower consumption than we actually have.
There is no night setback, and nothing ever switches off or regulates down.
Maybe someone has had similar experiences?
Personally, I’m relaxed about heating costs; even if energy prices rise, paying twice as much would still be less than I used to pay in my smaller 80 sqm (860 sq ft) apartment built in 1990.
C
Caspar20209 May 2017 08:41Nutshell schrieb:
Over 12 months, we used 8000 kWh of gas.
That currently amounts to about €28 in heating costs for the house.
We have the thermostat set to 23°C (73°F) throughout the entire house.
(By the way, electricity costs are €39)This should always be mentioned. After all, the heat recovery ventilation (HRV) system also helps keep the warmth inside the house since the heat recovery is based on “electricity.”
Nordlys schrieb:
Your message makes me very happy because we are building something similar. That gives hope regarding gas consumption. KarstenI’m curious to see how it will look for you after one year.
I expect slightly higher gas costs due to the absence of a mechanical ventilation system, which means windows will likely be opened more often. However, electricity consumption should be somewhat lower for the same reason. I have 7 sqm (75 sq ft) of solar panels because the cells also support the heating. The living area is almost identical, just all on one level. Wall construction and windows are also identical. Karsten
As a brief addition,
In the first year (October 19, 2014 - October 19, 2015) 9,900 kWh gas
In the second year (October 19, 2015 - October 23, 2016) 7,730 kWh gas
In the third year (October 23, 2016 - today) 7,282 kWh gas
We will turn off the heating soon and only switch it back on again in September.
This winter was noticeably colder than last.
On average, from October 1, 2015 to May 9, 2016, the temperature was 6.4°C (43.5°F), while from October 1, 2016 to today it has been only 5.0°C (41.0°F).
That’s a significant difference.
For comparison, in the first year from October 1, 2014 to May 9, 2015, the average was 6.3°C (43.3°F) – showing that building moisture and ventilating three times a day caused 27.5% higher heating costs.
In the first year (October 19, 2014 - October 19, 2015) 9,900 kWh gas
In the second year (October 19, 2015 - October 23, 2016) 7,730 kWh gas
In the third year (October 23, 2016 - today) 7,282 kWh gas
We will turn off the heating soon and only switch it back on again in September.
This winter was noticeably colder than last.
On average, from October 1, 2015 to May 9, 2016, the temperature was 6.4°C (43.5°F), while from October 1, 2016 to today it has been only 5.0°C (41.0°F).
That’s a significant difference.
For comparison, in the first year from October 1, 2014 to May 9, 2015, the average was 6.3°C (43.3°F) – showing that building moisture and ventilating three times a day caused 27.5% higher heating costs.
The heating season has now fully ended, with a total of 8107 kWh of gas used over the past 12 months. The solar system has completely covered the hot water production.
Unfortunately, gas and electricity prices have increased compared to last year.
As a result, we face a 12.5% higher cost over the next 12 months with the same consumption due to this price increase…
Unfortunately, gas and electricity prices have increased compared to last year.
As a result, we face a 12.5% higher cost over the next 12 months with the same consumption due to this price increase…
Hello,
Why pay higher prices? Gas and electricity providers are switched annually, and each time the deals are taken advantage of. This significantly reduces costs and takes no more than 30 minutes of effort!
Regarding your consumption:
Honestly, I find it quite high! Before moving into the new house, we lived in a rented house built in 2011 with 130 m² (1400 sq ft) of living space plus a heated basement, built to KfW 100 standard, equipped with a gas heating system and 5 m² (54 sq ft) of solar panels. No mechanical ventilation system or similar—ventilation was simply through windows.
Our gas consumption during the five years we lived there was always around 8000 kWh.
With your house's significantly better standard, your consumption should ideally be well below that!
Best regards,
Andreas
Nutshell schrieb:
Unfortunately, gas and electricity prices have increased compared to last year. As a result, we will face 12.5% higher costs over the next 12 months with the same consumption due to this price increase...
Why pay higher prices? Gas and electricity providers are switched annually, and each time the deals are taken advantage of. This significantly reduces costs and takes no more than 30 minutes of effort!
Regarding your consumption:
Honestly, I find it quite high! Before moving into the new house, we lived in a rented house built in 2011 with 130 m² (1400 sq ft) of living space plus a heated basement, built to KfW 100 standard, equipped with a gas heating system and 5 m² (54 sq ft) of solar panels. No mechanical ventilation system or similar—ventilation was simply through windows.
Our gas consumption during the five years we lived there was always around 8000 kWh.
With your house's significantly better standard, your consumption should ideally be well below that!
Best regards,
Andreas
Price increase, definitely. Although I switch to the cheapest provider every year, there has been a noticeable rise in electricity prices and a slight increase in gas prices.
A friend built at the same time, but a prefabricated house with an air-to-air heat pump, KFW 55 standard. He pays 800€ for electricity for heating and hot water per year, which is more than double what we currently pay (340€).
If I had gone for the more expensive KFW 40 insulation, the costs might have been reduced to around 250€ per year (only 90€ less).
So how is additional insulation supposed to pay off?
A friend built at the same time, but a prefabricated house with an air-to-air heat pump, KFW 55 standard. He pays 800€ for electricity for heating and hot water per year, which is more than double what we currently pay (340€).
If I had gone for the more expensive KFW 40 insulation, the costs might have been reduced to around 250€ per year (only 90€ less).
So how is additional insulation supposed to pay off?
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