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
T_im_Norden schrieb:
No, you're right, I had forgotten that there is also funding for gas hybrids in existing buildings.
Therefore, I would tend to choose gas here as well.
The savings referred to the 45% or 40% subsidy, meaning that the money from the subsidy I would invest in insulation and possibly a new underfloor heating system.
But I would have the calculations checked to see how much benefit that actually brings.So, you mean that the GAS hybrid option (condensing boiler) combined with solar thermal panels covering 8.5 sqm (91 sq ft) on the roof for heating support is the better choice?
I also plan to replace the first-floor windows with a 20% grant under program 430 (individual measures). Through this program, it would also be possible to insulate the top floor ceiling. But the question is whether anyone has experience with the costs? Specifically, the ratio of material to labor costs. It might be more worthwhile to forgo the subsidy and do some of the work yourself if the labor costs significantly exceed the material costs. Roughly estimated, for 100 sqm (1,076 sq ft) area, I arrived at costs of about 4,000 EUR (3,200 EUR after deducting the 800 EUR subsidy) for walkable insulation. Does that sound about right?
I've also considered installing underfloor heating (which is also subsidized at 40–45%), but I'm hesitant about the additional costs because, for example, the floor coverings would also have to be replaced. I looked it up online, and for dry systems covering 91 sqm (980 sq ft), the cost is about 6,000 EUR. Then, another 6,000 EUR for floor coverings, so that totals around 12,000 EUR, of which only 45% would be covered for heat pump heating. That would be just 6,600 EUR.
If, besides what has been described, all the windows were new, the top floor ceiling insulated, and underfloor heating installed throughout the entire 186 sqm (2,000 sq ft) living area, would it then make sense to switch to a pure air-to-water heat pump?
Best regards
N
nordanney6 May 2020 23:28tiborb schrieb:
If, besides what was already described, all the windows were replaced, the top floor ceiling insulated, and underfloor heating installed throughout the entire living area of 186sqm (2000 sq ft), would a pure air-to-water heat pump then be worthwhile?From my gut feeling: yes. You would save on the gas connection. Have you considered installing low-temperature radiators suitable for heat pumps as an alternative to underfloor heating? This would also save you the cost of underfloor heating and floor coverings. You’d need to calculate whether the radiators provide enough heat. But you should definitely do this—unless you want to renew everything completely and have enough budget to do so.T
T_im_Norden7 May 2020 06:44What exactly do you want to achieve?
Are you aiming to save on heating costs, or is the old heating system broken?
Are you aiming to save on heating costs, or is the old heating system broken?
nordanney schrieb:
Off the top of my head: Yes. You save the gas connection. Have you considered installing low-temperature radiators for the heat pump instead of underfloor heating? You’d then also save on the underfloor heating system and floor coverings. You’d need to calculate if the radiators are sufficient. You should do that—unless you want to replace everything completely and have enough money to spare.Well, a company would install the gas-hybrid solar thermal system with a gas connection for about 34,000 EUR, remove the old oil heating and tank, and retrofit seven radiators (designed for 55°C (131°F) flow temperature).
Regarding the heat pump, we are undecided because of the noise from the outdoor unit with an air-to-water heat pump. One would be from Viessmann or WOLF. Also, the uncertain electricity consumption during the heating season is a concern.
T_im_Norden schrieb:
What exactly do you want to achieve?
Savings on heating costs, or is the old heating system defective?The plan is to save on heating costs and reclaim the basement space where the oil tank is located. The old oil heating still works but is nearly 30 years old.
N
nordanney7 May 2020 09:37Viessmann Low-Temperature Radiator Type 21 500x600x218 mm (H x W x D)
Look up low-temperature radiators or low-temperature heating panels online. A supply temperature of around 30°C (86°F) is sufficient. Which exact model you need must be calculated. My example costs about €550. But you don’t need underfloor heating or floor coverings.
Walk through new housing developments and listen to them. From spring to autumn, you hardly hear anything, since they are barely running (at most for hot water).
In winter, you are at least indoors. Nowadays the outdoor units are very quiet outside as well (and neighbors are also indoors in winter and therefore don’t hear anything).
Do you know your gas consumption in advance? That is just as uncertain.
Look up low-temperature radiators or low-temperature heating panels online. A supply temperature of around 30°C (86°F) is sufficient. Which exact model you need must be calculated. My example costs about €550. But you don’t need underfloor heating or floor coverings.
tiborb schrieb:
because of the noise level of the outdoor unit with an air-to-water heat pump.
Walk through new housing developments and listen to them. From spring to autumn, you hardly hear anything, since they are barely running (at most for hot water).
In winter, you are at least indoors. Nowadays the outdoor units are very quiet outside as well (and neighbors are also indoors in winter and therefore don’t hear anything).
tiborb schrieb:
Also, the uncertain electricity demand at least during the heating season is unknown.
Do you know your gas consumption in advance? That is just as uncertain.
T
T_im_Norden7 May 2020 10:02Okay, if you want to save on heating costs, you need to insulate.
The energy consumption in your house mainly depends on the insulation standard, not the heating system.
First, you need to know the current condition of your house, including the materials and insulation thicknesses.
To get a rough overview, you can use a U-value calculator. Just search for the term online.
The energy consumption in your house mainly depends on the insulation standard, not the heating system.
First, you need to know the current condition of your house, including the materials and insulation thicknesses.
To get a rough overview, you can use a U-value calculator. Just search for the term online.
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