ᐅ Combination of split air conditioning, gas heating, and solar energy
Created on: 22 May 2022 20:10
N
NutshellHello fellow home builders,
We have been living since 2014 at an altitude of about 300 meters (1000 feet), in a solidly built house. The house has a rather simple shape. A standard gable roof without dormers or skylights (one gable-side window per room on the upper floor).
Styrofoam was not an option for various reasons, so we chose the more expensive monolithic lightweight concrete blocks with a thermal conductivity of 0.08 W/m·K (lambda).
Size: 111 sqm (1200 sq ft) of living space.
Exterior wall: 36.5 cm (14.4 inches) Ytong blocks // thermal conductivity 0.2 W/m²K
Floor slab insulated with XPS // thermal conductivity 0.21 W/m²K
Upper floor sloped ceiling with 24 cm (9.4 inches) depth, ceiling insulated with 34 cm (13.4 inches) of mineral wool // thermal conductivity 0.12 W/m²K
Doors and windows are triple-glazed and gas-filled // overall including frame 1.05 W/m²K
Heating system:
Gas condensing boiler: Viessmann Vitodens 300
System control: Vitotronic 200
Solar collector 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 for heating from May to September and consumes about 100 kWh over the summer.
In winter, the solar system barely manages to heat the domestic hot water (for two people), so it mostly runs on gas.
Ventilation is decentralized with Lunos e² units, featuring 90% heat recovery.
On average, our annual gas consumption is 8000 kWh.
During cold spells in February, daily consumption is about 45–75 kWh, depending on the outside temperature.
The attic often becomes uncomfortably warm, so we plan to air condition the master bedroom, children’s room, and office with split system air conditioners. We also want to install an indoor unit in the open-plan living room/kitchen on the ground floor.
Outdoor unit:
CU-4Z68TBE
Master bedroom (12 sqm (130 sq ft), east-south facing)
CS-Z20XKEW
Children's room (12 sqm (130 sq ft), west-north facing)
CS-Z25XKEW
Office (12 sqm (130 sq ft), south-west facing)
CS-Z35XKEW
Living room (35 sqm (377 sq ft) + 15 sqm (162 sq ft) kitchen)
CS-Z35XKEW
I would also like to use these for heating, not just cooling. Now that gas prices are very high, this should definitely pay off with such a high-quality, modern air conditioning system. Of course, it’s impractical when it’s minus 10°C (14°F) outside. But if, as private individuals, our gas supply were suddenly cut off, I would have a working fallback solution—even if the usual 23°C (73°F) indoor temperature can’t be maintained everywhere with only one unit on the ground floor. At least it should be suitable as an emergency operation.
What do you think of these expansion plans?
We have been living since 2014 at an altitude of about 300 meters (1000 feet), in a solidly built house. The house has a rather simple shape. A standard gable roof without dormers or skylights (one gable-side window per room on the upper floor).
Styrofoam was not an option for various reasons, so we chose the more expensive monolithic lightweight concrete blocks with a thermal conductivity of 0.08 W/m·K (lambda).
Size: 111 sqm (1200 sq ft) of living space.
Exterior wall: 36.5 cm (14.4 inches) Ytong blocks // thermal conductivity 0.2 W/m²K
Floor slab insulated with XPS // thermal conductivity 0.21 W/m²K
Upper floor sloped ceiling with 24 cm (9.4 inches) depth, ceiling insulated with 34 cm (13.4 inches) of mineral wool // thermal conductivity 0.12 W/m²K
Doors and windows are triple-glazed and gas-filled // overall including frame 1.05 W/m²K
Heating system:
Gas condensing boiler: Viessmann Vitodens 300
System control: Vitotronic 200
Solar collector 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 for heating from May to September and consumes about 100 kWh over the summer.
In winter, the solar system barely manages to heat the domestic hot water (for two people), so it mostly runs on gas.
Ventilation is decentralized with Lunos e² units, featuring 90% heat recovery.
On average, our annual gas consumption is 8000 kWh.
During cold spells in February, daily consumption is about 45–75 kWh, depending on the outside temperature.
The attic often becomes uncomfortably warm, so we plan to air condition the master bedroom, children’s room, and office with split system air conditioners. We also want to install an indoor unit in the open-plan living room/kitchen on the ground floor.
Outdoor unit:
CU-4Z68TBE
Master bedroom (12 sqm (130 sq ft), east-south facing)
CS-Z20XKEW
Children's room (12 sqm (130 sq ft), west-north facing)
CS-Z25XKEW
Office (12 sqm (130 sq ft), south-west facing)
CS-Z35XKEW
Living room (35 sqm (377 sq ft) + 15 sqm (162 sq ft) kitchen)
CS-Z35XKEW
I would also like to use these for heating, not just cooling. Now that gas prices are very high, this should definitely pay off with such a high-quality, modern air conditioning system. Of course, it’s impractical when it’s minus 10°C (14°F) outside. But if, as private individuals, our gas supply were suddenly cut off, I would have a working fallback solution—even if the usual 23°C (73°F) indoor temperature can’t be maintained everywhere with only one unit on the ground floor. At least it should be suitable as an emergency operation.
What do you think of these expansion plans?
T
taschenonkel23 May 2022 11:48Is photovoltaic solar power an option for you? In winter, we also heat with our split air conditioning units when the sun is shining. There are many great videos on YouTube about this—just search for "DIY heat pump."
My brief recommendation: Go for it. Even just for the increased living comfort in summer. We self-installed split systems with Quick Connect in all the relevant rooms and are very happy with them.
My brief recommendation: Go for it. Even just for the increased living comfort in summer. We self-installed split systems with Quick Connect in all the relevant rooms and are very happy with them.
taschenonkel schrieb:
Is solar power an option for you? In winter, when the sun is shining, we also heat using our split systems. There are many great videos on YouTube about this—just search for "DIY heat pump."
My brief advice: Go for it. Even just for the added comfort in summer. We installed split units ourselves as quick connect in all the relevant rooms and are really happy with them.A photovoltaic system costing another roughly €8,000 (about $8,800) is too expensive for me right now. I want to first see how much power the split air conditioners use, and I can still install it later once I have no more financial obligations. I’m currently still paying off a loan.
i_b_n_a_n schrieb:
Even with a loan of 20,000 for a larger photovoltaic system at 3-4% interest, I predict a payback period of under 20 years ;-) I agree. As long as humanity does not eventually achieve nuclear fusion, electricity prices will continue to rise.
I have received a quote.
€11,500 for the split air conditioning system
3 indoor units
Panasonic Etherea Z 2.0 kW
1 indoor unit
Panasonic Etherea Z 3.5 kW
1 outdoor unit
Panasonic 6.8 kW
Thanks to the BEG EG subsidy of -35%,
= €7,475
The application will be submitted on Monday.
€11,500 for the split air conditioning system
3 indoor units
Panasonic Etherea Z 2.0 kW
1 indoor unit
Panasonic Etherea Z 3.5 kW
1 outdoor unit
Panasonic 6.8 kW
Thanks to the BEG EG subsidy of -35%,
= €7,475
The application will be submitted on Monday.
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