Hello everyone,
for our new single-family house (160 m² (1722 sq ft) living area, 4 people), we received a quote from a general contractor. The planned air-to-water heat pump is:
Vaillant VWL 115/2 aro Therm air/water 8.4 kW.
We are choosing a 300 L (79 gallons) storage tank.
According to our general contractor and their heating installers, a buffer tank is not necessary.
A heating engineer friend thinks that a buffer tank is advisable.
Opinions found online are also very mixed regarding the necessity.
How have you handled this?
If any information is missing, please let me know briefly. Thanks.
for our new single-family house (160 m² (1722 sq ft) living area, 4 people), we received a quote from a general contractor. The planned air-to-water heat pump is:
Vaillant VWL 115/2 aro Therm air/water 8.4 kW.
We are choosing a 300 L (79 gallons) storage tank.
According to our general contractor and their heating installers, a buffer tank is not necessary.
A heating engineer friend thinks that a buffer tank is advisable.
Opinions found online are also very mixed regarding the necessity.
How have you handled this?
If any information is missing, please let me know briefly. Thanks.
B
Bauenaberwie23 Mar 2022 17:41I think 300 liters is fine. Less would also be sufficient, but we prefer to have a bit more rather than too little. Especially since photovoltaic systems are also being used. Everything has already been said about the heating 🙂
B
Benutzer20023 Mar 2022 18:121. A buffer tank with a heat pump reduces efficiency and costs money. There are no real advantages.
2. A 300-liter (79-gallon) hot water tank is suitable for four people. With 150 liters (40 gallons), you won’t be able to shower the whole family one after another (let alone one person taking a bath while others shower). When my three girls come back from the stable and finish in the shower, the water temperature drops quickly from 50°C (122°F) to below 30°C (86°F). That’s the girls for you...
3. Using photovoltaic panels to heat a 300-liter (79-gallon) hot water tank hardly makes a difference because the heat pump uses very little electricity.
4. In my opinion, the heat pump was chosen too large.
2. A 300-liter (79-gallon) hot water tank is suitable for four people. With 150 liters (40 gallons), you won’t be able to shower the whole family one after another (let alone one person taking a bath while others shower). When my three girls come back from the stable and finish in the shower, the water temperature drops quickly from 50°C (122°F) to below 30°C (86°F). That’s the girls for you...
3. Using photovoltaic panels to heat a 300-liter (79-gallon) hot water tank hardly makes a difference because the heat pump uses very little electricity.
4. In my opinion, the heat pump was chosen too large.
D
Deliverer23 Mar 2022 20:37You are in the unique position that your general contractor does not want to install a buffer tank. That’s great, you should be grateful. Usually, it takes a long discussion to get it that way. So just leave it out, along with the room thermostats.
The heat pump should only be selected by the general contractor once the room-by-room heating load calculation is available. Then simply choose the correct heat pump based on the heating load without any safety margins. If it’s intended to be environmentally friendly and future-proof, R290 as the refrigerant is recommended.
The heat pump should only be selected by the general contractor once the room-by-room heating load calculation is available. Then simply choose the correct heat pump based on the heating load without any safety margins. If it’s intended to be environmentally friendly and future-proof, R290 as the refrigerant is recommended.
Bauenaberwie schrieb:
Which energy efficiency class are you building to?The question was left unanswered yesterday. Probably "KFW100".Benutzer200 schrieb:
3. Photovoltaics for a 300-liter (79-gallon) hot water storage tank hardly make a noticeable difference. The heat pump simply uses too little electricity.Either I’m missing something or our understanding of "hardly noticeable" and "too little electricity" differs.
What do you mean by "too little electricity" in numerical terms? How much does the 300-liter (79-gallon) tank consume per day?
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