ᐅ Replacing the Heating System in an Older Home: Which Option Is Best?
Created on: 4 May 2020 14:51
T
tiborb
Hello everyone,
I need your advice on choosing the heating system for the planned replacement of our heating installation.
Facts:
- Semi-detached house with two separate living units, built in 1972, purchased by us in 2014
- Approx. 220 sqm (2370 sq ft) of heated space, 186 sqm (2002 sq ft) of living area, 95 sqm (1023 sq ft) on the ground floor, 91 sqm (979 sq ft) on the upper floor
- Building envelope insulated with 10 cm (4 inches)
- New triple-glazed windows, conservatories with full glazing on both ground and upper floors
- Roof not insulated
- Heating distribution: (We are currently planning to replace the old tube radiators with low-temperature radiators)
- Replacement of old oil heating from 1989 (low temperature), oil tank with 6000 liters (1585 gallons) steel tank, current consumption about 2500 liters (660 gallons) per year
- No gas connection available
- Additional planned project: photovoltaic system with about 8 – 9.9 kWp on the south side of the roof with a 10 kWh battery storage
- Ideally BAFA subsidy of 40% – 45% per system utilized
There have been many considerations regarding the options for the new heating system:
Option 1: Gas hybrid with solar thermal system of 8.5 sqm (91 sq ft) and 600-liter (160-gallon) water buffer tank
(Offers from Buderus or BOSCH systems)
Option 2: Gas hybrid with 400-liter (105-gallon) water tank and small supplementary air-water heat pump (possibly combined with the rooftop photovoltaic system)
(Offers from WOLF systems)
Option 3: Air-water heat pump with integrated domestic hot water preparation in the indoor unit and outdoor unit (possibly combined with the rooftop photovoltaic system)
(Offers from Vaillant systems)
Each option has its pros and cons, but I am also interested in your opinions and experiences. In particular, I am uncertain about the noise level of the outdoor units of the heat pumps. How loud are they really?
Or maybe some of you are currently planning a replacement with a similar setup. I would be glad to hear your experiences with these systems and which you would recommend for my situation.
Thank you very much for your help!!!
Best regards,
Chippy
I need your advice on choosing the heating system for the planned replacement of our heating installation.
Facts:
- Semi-detached house with two separate living units, built in 1972, purchased by us in 2014
- Approx. 220 sqm (2370 sq ft) of heated space, 186 sqm (2002 sq ft) of living area, 95 sqm (1023 sq ft) on the ground floor, 91 sqm (979 sq ft) on the upper floor
- Building envelope insulated with 10 cm (4 inches)
- New triple-glazed windows, conservatories with full glazing on both ground and upper floors
- Roof not insulated
- Heating distribution: (We are currently planning to replace the old tube radiators with low-temperature radiators)
- Basement: One old tube radiator and about 40 sqm (430 sq ft) of underfloor heating (old system – probably pipes will be reused)
- Ground floor: Underfloor heating with 9 loops, installed in 2014, conservatory still with old underfloor heating system like in the basement
- Upper floor: Six old tube radiators
- Replacement of old oil heating from 1989 (low temperature), oil tank with 6000 liters (1585 gallons) steel tank, current consumption about 2500 liters (660 gallons) per year
- No gas connection available
- Additional planned project: photovoltaic system with about 8 – 9.9 kWp on the south side of the roof with a 10 kWh battery storage
- Ideally BAFA subsidy of 40% – 45% per system utilized
There have been many considerations regarding the options for the new heating system:
Option 1: Gas hybrid with solar thermal system of 8.5 sqm (91 sq ft) and 600-liter (160-gallon) water buffer tank
(Offers from Buderus or BOSCH systems)
Option 2: Gas hybrid with 400-liter (105-gallon) water tank and small supplementary air-water heat pump (possibly combined with the rooftop photovoltaic system)
(Offers from WOLF systems)
Option 3: Air-water heat pump with integrated domestic hot water preparation in the indoor unit and outdoor unit (possibly combined with the rooftop photovoltaic system)
(Offers from Vaillant systems)
Each option has its pros and cons, but I am also interested in your opinions and experiences. In particular, I am uncertain about the noise level of the outdoor units of the heat pumps. How loud are they really?
Or maybe some of you are currently planning a replacement with a similar setup. I would be glad to hear your experiences with these systems and which you would recommend for my situation.
Thank you very much for your help!!!
Best regards,
Chippy
Joedreck schrieb:
I didn’t calculate it, but I wouldn’t rely on the heating support system either. The system needs to be almost perfectly configured and adjusted for it to work properly.
My honest opinion: just install the smallest gas condensing boiler and that’s it. Then perform a hydraulic balancing in the first year and be satisfied with the low costs.
And I say this as a heat pump fan.Yes, I also estimated the heating demand to be around 23,000–24,000 kWh. The oil boiler is definitely not optimally set. That’s why I was surprised that the heating company calculated a heating load of 11,000 kWh.
Great, thanks again for the tips. I would only install the heating support system (solar thermal) because I would then get 40% BAFA funding on all eligible costs. Since I plan several measures, I thought it could make sense to basically get the heating support system for free. Because if I commission the planned measures (gas condensing boiler, oil boiler removal, oil tank removal, gas connection, radiator replacement) without funding, I actually end up with the same or slightly higher costs compared to having the solar system installed on the roof. It’s strange, though.
What do you think?
Best regards
Joedreck schrieb:
...
My honest opinion: just install the smallest gas condensing boiler and that's it. Then perform a hydraulic balancing in the first year and be satisfied with the low costs.
...Since you mentioned the smallest gas condensing boiler. One company wants to install a hybrid system with a gas condensing boiler rated at 24 kW for about 200 m² (2,150 sq ft) living area and approximately 240 m³ (8,470 cu ft) heated volume. Is this gas condensing boiler oversized for that space? Price: 4,200 EUR.
Additionally, solar thermal with vacuum tube collectors, heat pipe type, rooftop complete system 8.24 m² (89 sq ft) with 50 power tubes. It is claimed that solar systems with tube collectors are much more efficient than flat plate collectors? Price: approx. 10,000 EUR.
And domestic hot water preparation with a 600 liter (160 gallon) buffer storage tank. Price: approx. 2,000 EUR.
Total costs including all additional services like gas connection, removal of old oil tank, new heating room setup with circuits, etc., about 33,000 EUR gross before subsidies and 21,500 EUR gross (after subsidies).
If I subtract all the solar thermal components and do not receive the 40% subsidy from BAFA, then I would pay around 24,000 EUR gross.
So, are you recommending I install a very small gas condensing boiler with, for example, a 200 to 300 liter (53 to 79 gallon) storage tank?
What total gross costs should I roughly expect?
Thanks.
Best regards
T
T_im_Norden15 Jun 2020 13:15It is important to consider the minimum heating output; the heating system should be capable of modulating down as much as possible.
T_im_Norden schrieb:
The most important factor is the minimum heating output; the heating system should be able to modulate down as low as possible. The gas condensing boiler offer states a power range of 3.4 kW to 24 kW. Is that what is meant?
I have now checked again with the heating company from the heat pump offer. They said that the heating load of 11 kW was calculated based on oil consumption of 2,500 liters and building data (year of construction, insulation standard, etc.).
The annual performance factor of 3.9 is quite realistic at a supply temperature of 55°C (131°F).
Is there anyone here who has installed an air-to-water heat pump in a similar existing building?
Best regards
N
nordanney15 Jun 2020 14:48How about a small heat pump for the ground floor and continuing to use oil for the upper floor? I will implement this approach now because the upper floor apartment in my house is rented out, so underfloor heating cannot be installed there. This allows me to operate at a maximum supply temperature of 30°C (86°F).
If the upper floor is ever vacated, simply add a second small heat pump for the upper floor (or a larger unit for both levels).
How is the apartment being used by whom?
If the upper floor is ever vacated, simply add a second small heat pump for the upper floor (or a larger unit for both levels).
How is the apartment being used by whom?