Hello everyone,
my brother and I are planning to build a semi-detached house, with each of us owning one half. The living space should be approximately 110 sqm (1,184 sq ft) per semi-detached unit and comfortably designed for 1 to 2 people. We each intend to live in our own half but also want to be prepared to rent out or sell one half. We plan to finance separately. We already have a plot of land that can be divided. We aim to achieve at least KFW55 standard, preferably KFW40 or KFW40 Plus with a ground source heat pump (deep drilling), underfloor heating, and controlled ventilation.
Now about our considerations and the knowledge we have gathered so far, without claiming completeness or accuracy. Perhaps some members here have had similar thoughts and can share their knowledge with us 🙂
- Because of the high costs of deep drilling and the heat pump, we are considering using a shared heating system. However, there are several uncertainties here.
- If a shared system requires double the number of boreholes, the savings on drilling may not apply. From boreholes in the nearby area, I know they were drilled up to nearly 200 m (656 ft) deep.
- The heating room must be accessible to both parties, which must also be registered in the land registry. The room must be in the “warm zone” of the building and must not compromise fire protection measures between the two units.
- Operating costs must be billed according to consumption by law, so costs for heating and hot water must be recorded separately for each semi-detached unit. The heat pump needs a separate electricity meter to qualify for a discounted electricity tariff.
- If the heating system is operated “mainly,” meaning more than 50% with renewable energy, a flat-rate billing option is also possible.
- Preferably, the heat pump should be connected to a photovoltaic system. The system must be registered to one of the two parties, or can it be jointly owned and operated?
- Dimensioning the heat pump and the water storage tank: heat pumps are less efficient in the lower operating range, such as during transitional seasons (spring/fall). Could this be more problematic for a larger system?
- Since the two semi-detached units are not fully independent from each other, banks might have issues with separate financing because the two units cannot be sold independently.
We fully understand that a single person may not have answers to all these points, but if anyone who has dealt with some of these topics could share a little input, we would really appreciate it. And please feel free to correct me if any statements are incorrect 🙂
Many thanks in advance and best regards!
my brother and I are planning to build a semi-detached house, with each of us owning one half. The living space should be approximately 110 sqm (1,184 sq ft) per semi-detached unit and comfortably designed for 1 to 2 people. We each intend to live in our own half but also want to be prepared to rent out or sell one half. We plan to finance separately. We already have a plot of land that can be divided. We aim to achieve at least KFW55 standard, preferably KFW40 or KFW40 Plus with a ground source heat pump (deep drilling), underfloor heating, and controlled ventilation.
Now about our considerations and the knowledge we have gathered so far, without claiming completeness or accuracy. Perhaps some members here have had similar thoughts and can share their knowledge with us 🙂
- Because of the high costs of deep drilling and the heat pump, we are considering using a shared heating system. However, there are several uncertainties here.
- If a shared system requires double the number of boreholes, the savings on drilling may not apply. From boreholes in the nearby area, I know they were drilled up to nearly 200 m (656 ft) deep.
- The heating room must be accessible to both parties, which must also be registered in the land registry. The room must be in the “warm zone” of the building and must not compromise fire protection measures between the two units.
- Operating costs must be billed according to consumption by law, so costs for heating and hot water must be recorded separately for each semi-detached unit. The heat pump needs a separate electricity meter to qualify for a discounted electricity tariff.
- If the heating system is operated “mainly,” meaning more than 50% with renewable energy, a flat-rate billing option is also possible.
- Preferably, the heat pump should be connected to a photovoltaic system. The system must be registered to one of the two parties, or can it be jointly owned and operated?
- Dimensioning the heat pump and the water storage tank: heat pumps are less efficient in the lower operating range, such as during transitional seasons (spring/fall). Could this be more problematic for a larger system?
- Since the two semi-detached units are not fully independent from each other, banks might have issues with separate financing because the two units cannot be sold independently.
We fully understand that a single person may not have answers to all these points, but if anyone who has dealt with some of these topics could share a little input, we would really appreciate it. And please feel free to correct me if any statements are incorrect 🙂
Many thanks in advance and best regards!
Jogidude schrieb:
I would like to ask a few more questions, @i_b_n_a_n, if that’s okay?
You are building two semi-detached houses, each with two dwelling units. I assume that you plan to live in one unit yourselves and rent out the other. So, if I understand correctly, one heat pump supplies two dwelling units each? I’m curious whether you measure the consumption (heating and hot water) of each individual dwelling unit, and if you will charge tenants a flat rate or base the billing on actual consumption? Also, is there a “main apartment” that covers the shared costs and then allocates them proportionally as additional costs to the “secondary apartment”? Hi,
there are no main apartment(s). I will move into one dwelling unit myself, my brother rents out both units (but his son moved into one “spontaneously” shortly before completion due to Corona and lonely home office, relocating here from Hamburg).
We rent “all-inclusive” including everything (flat rate heating including 2500 kWh (8500 BTU) electricity and ?? m³ (?? cubic feet) water per dwelling unit, excluding internet), but we do record the consumption of each dwelling unit through numerous meters, such as electricity, water, and heat.
Good morning!
Thanks again for your feedback. I’ll try to summarize what I’ve learned so far.
Honestly, the topic of the “legionella regulation” was completely new to me, so I had to quickly look it up.
I found the following at first glance:
Now, with a semi-detached house I’m unsure, since by definition it’s not a “two-family house” but rather two independent single-family houses joined together. So here comes the next question :-)
Our cases are actually quite similar :-) After 20 years of relocating for work, I’m moving back to my hometown to be close to family and friends.
I’ll now summarize what I’ve learned into two conceivable models, which you’re welcome to discuss and evaluate further to work out pros and cons:
Model A: Fully independent semi-detached house
- Actual subdivision of the land plot
- Separate financing
- Independent utility systems
Advantages:
- No complicated contractual arrangements
- Straightforward financing
- Easy sale of one or both semi-detached units
- Possibly better sizing and thus efficiency of the heat pump
Disadvantages:
- Higher resource demands
- Higher upfront costs
- Higher operating and maintenance costs
Model B: Declaration as a two-family house
- Financing by one party
- Construction managed by one party
- Afterwards renting/selling/lease-to-own to the second party (options to be reviewed)
- Easements recorded on the land title for the second party, similar to a condominium
- One utility system (heat pump, photovoltaic) operated by one party (“utility provider”)
- Consumption metering and billing via “warm rent” to the second party (“utility recipient”)
- If one party moves out, the remaining party would take over as the “utility provider” and the other semi-detached unit would be rented out
Advantages:
- Lower resource requirements
- Lower upfront costs
- Lower operating and maintenance costs
- Simplified communication with architect, structural engineer, etc. (only one contact)
Disadvantages:
- More complex contracts
- Tax complications
- Mutual dependency of both parties
- Forced sale would require both units to be sold, as they are not independent
- Financing might be more difficult
- Increased effort for consumption metering
- Utility/technical room must be accessible to both parties
I hope these insights are helpful for other members facing similar considerations and I look forward to further feedback.
Many thanks and best regards!
Thanks again for your feedback. I’ll try to summarize what I’ve learned so far.
Tarnari schrieb:
In that sense, doesn’t the legionella regulation also apply to such a building? Meaning 60 degrees?
Honestly, the topic of the “legionella regulation” was completely new to me, so I had to quickly look it up.
I found the following at first glance:
Relevant systems in single-family and two-family houses are not considered large-scale drinking water heating systems according to the Drinking Water Ordinance and are therefore not subject to routine legionella testing.
Now, with a semi-detached house I’m unsure, since by definition it’s not a “two-family house” but rather two independent single-family houses joined together. So here comes the next question :-)
i_b_n_a_n schrieb:
there are no main dwellings, I myself am moving into one unit, my brother rents out both units (but his son moved in “spontaneously” just before completion due to corona and lonely home office from Hamburg)
Our cases are actually quite similar :-) After 20 years of relocating for work, I’m moving back to my hometown to be close to family and friends.
I’ll now summarize what I’ve learned into two conceivable models, which you’re welcome to discuss and evaluate further to work out pros and cons:
Model A: Fully independent semi-detached house
- Actual subdivision of the land plot
- Separate financing
- Independent utility systems
Advantages:
- No complicated contractual arrangements
- Straightforward financing
- Easy sale of one or both semi-detached units
- Possibly better sizing and thus efficiency of the heat pump
Disadvantages:
- Higher resource demands
- Higher upfront costs
- Higher operating and maintenance costs
Model B: Declaration as a two-family house
- Financing by one party
- Construction managed by one party
- Afterwards renting/selling/lease-to-own to the second party (options to be reviewed)
- Easements recorded on the land title for the second party, similar to a condominium
- One utility system (heat pump, photovoltaic) operated by one party (“utility provider”)
- Consumption metering and billing via “warm rent” to the second party (“utility recipient”)
- If one party moves out, the remaining party would take over as the “utility provider” and the other semi-detached unit would be rented out
Advantages:
- Lower resource requirements
- Lower upfront costs
- Lower operating and maintenance costs
- Simplified communication with architect, structural engineer, etc. (only one contact)
Disadvantages:
- More complex contracts
- Tax complications
- Mutual dependency of both parties
- Forced sale would require both units to be sold, as they are not independent
- Financing might be more difficult
- Increased effort for consumption metering
- Utility/technical room must be accessible to both parties
I hope these insights are helpful for other members facing similar considerations and I look forward to further feedback.
Many thanks and best regards!
Jogidude schrieb:
I am now uncertain about a semi-detached house, since by definition it is not a "two-family house" but two separate single-family houses directly attached to each other. This raises the next question.I assume the question concerns the application of the guidelines regarding facility operation. From this perspective, I would consider each half of the semi-detached house as a two-family house for the facility, and for a shared facility serving the entire semi-detached house, practically a four-family house.https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Jogidude schrieb:
... I assume that each of you intends to live in one housing unit and rent out the other. So, if I understand correctly, you are supplying two housing units with one heat pump? I’m curious whether, in this setup, you will measure the consumption (heating and hot water) of each individual unit and whether you plan to bill based on a flat rate or actual consumption? Also, is there a “main residence” that covers the shared costs, which are then proportionally allocated to the “secondary unit” as additional charges?We have been using this principle for over 20 years without any problems:
- Each semi-detached house has its own circulation pump, heat meter, and thermostat (with weekly programming).
This way, everyone can individually control their own temperature setback, frost protection, or daytime program.
(Of course, this requires that the piping for each semi-detached unit has exactly one loop connection point.)
Only the supply temperature is controlled together, based on the outdoor temperature.
Operating and maintenance costs are contractually billed according to each unit’s consumption.
Anyone concerned about legal issues can, if necessary, have an easement registered.
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