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You want to build at the economic minimum and optimised for energy. You are looking for energy supply concepts that go beyond the heat pump, the photovoltaic array or the conventional battery storage unit. You are open to any technology, and the highest attainable degree of energy autonomy in the building is your goal?
We advise you on the current state of the art and on today's technical options for energy supply — in residential as well as in non-residential construction.
Our vision for tomorrow is the energy-autonomous building network: units kept as small as possible that act together locally as a virtual power plant.
The starting point is not the product but the building: its demand across the year, its storage capacity and its interplay with the surroundings. Only from that does the sensible technology follow — technology-neutral and without committing to a type of plant in advance.
Consulting and calculation
- Energy concepts, including sorption and latent heat storage
- Building simulation for demand coverage (yield of heat pumps and solar thermal systems)
- Yield forecasts for wind turbines (hourly simulation, horizontal and vertical axis)
Talk to us while your project is still in the concept phase — that is where it is decided what remains economically feasible later on.
Building energy-efficiently is not in itself building in a climate-friendly or ecologically sustainable way. A building interacts with its immediate environment and with the climatic conditions of the present and the future.
The points below are those that should be considered at an early design stage. They do not list every requirement exhaustively; they give a first overview.
Windows and glazed areas
A low U-value minimises heat loss across the envelope. Setting the windows deep into the reveal exposes them to little direct solar gain in summer, which lowers the cooling load. With the low sun of winter the gain is welcome instead. In the 2226 project in Lustenau, the 76 cm wall produces reveal depths of around 70 cm that exploit precisely this effect. Roof lights and roof windows should be avoided in such a concept.
Covering heat and cooling demand
To minimise heating demand, the waste heat that occurs anyway — from processes, people, equipment and lighting — should be used. Helpful measures are:
- Components with high internal thermal storage capacity — effective to a depth of roughly 10 cm depending on the material
- Open, connected spaces to distribute internal heat gains
- Generous room heights: a large air volume lowers the CO₂ concentration and ventilation heat losses
- Controlled removal of lighting and process waste heat, returned through a heat exchanger
- Short cross-ventilation intervals through controlled vents instead of permanent mechanical ventilation
A well-designed building form can reduce the cooling load to zero. Where technical cooling is nevertheless required, the heating technology should be chosen so that it also serves for cooling in summer. Heating and cooling ceilings are more suitable than wall or floor surfaces because they remain exposed. Thermally activated building systems respond slowly and are unsuitable in residential use.
Energy supply
The aim is to draw as little energy as possible from suppliers. It must be examined which local sources can be used — wind, water, sun, geothermal energy, air — and what quantity can be generated, transported and stored on site for flexibility.
- Photovoltaic arrays on roofs and façades
- Small wind turbines (horizontal or vertical axis)
- Small turbines in flowing water
- Storage with as many charge cycles, as large a capacity and as good a recyclability as possible — on an industrial scale, vanadium redox flow batteries for instance
Heat generation by combustion is defensible only where the fuel releases no more CO₂ than is bound during its regeneration.
Microclimate and rainwater
- Green roofs and façades, including the areas beneath the photovoltaic array, counteract solar heating of the components
- Shading must not cost daylight — compensating with artificial light raises energy consumption. In front of large glazed areas on lower floors, trees at sufficient distance are suitable
- A planting scheme for the outdoor areas counteracts the heating of sealed surfaces; the sealed proportion should be minimised
- Traffic areas with low thermal conductivity and storage capacity, built to be permeable
The building in the climate of 2050
- Mean annual precipitation is rising — drainage must be sized for the increase
- Avoid hollows and high degrees of sealing outdoors; green roofs delay run-off
- Build access areas to be permeable
- The number of hot days above 30 °C rises markedly — measures against local heat stress are therefore obligatory at concept stage
Basis: internal criteria paper “Climate-Neutral Construction — Climate and Ecology Criteria”, as at 30 August 2026.
Five factors govern the procurement and use of building materials in climate-neutral construction.
- Low production energy demand, using CO₂-neutral primary energy
- Low transport energy demand — the case for local resources
- Recyclability and compostability
- CO₂ storage capacity, with a view to a negative balance
- Renewable raw materials
Examples are hemp-lime blocks in a timber or concrete frame for the external wall, or a solid concrete structure with hemp or wood fibre insulation. Flat roof areas can be built as glulam or timber joist decks; above-rafter and between-rafter insulation in wood fibre boards or as blown natural fibre. Renewable raw materials bind CO₂ permanently — set against this is the energy needed for manufacture and transport.
Ecological building materials are not universally compostable, but they are recyclable without environmental pollutants provided no harmful additives were used in production. That deserves attention — as does the separability of the component layers: what cannot be dismantled by material type ends up as waste rather than raw material.
Building physics data
| Material | λ W/(m·K) | ρ kg/m³ | μ | c J/(kg·K) | DIN 4102-1 | DIN EN 13501-1 |
|---|---|---|---|---|---|---|
| Flax mats | 0,039 | 30–40 | 1–2 | 1.550–2.300 | B2 | E |
| Hemp (loose wool) | 0,045 | 50–60 | 1–2 | 2.200 | B2–B1 | E, C-s2, d0 |
| Hemp jute | 0,043 | 35–40 | 1–2 | 2.300 | B2 | E |
| Hemp mats | 0,043 | 30–110 | 1–2 | 1.600–2.300 | B2 | E |
| Wood fibre (loose) | 0,040 | 30–45 | 1–2 | 2.100 | B2 | E |
| Wood fibre mats | 0,038 | 40–55 | 1–3 | 2.100 | B2 | E |
| Wood fibre boards | 0,040 | 110–270 | 2–5 | 2.100 | B2 | E |
| Wood shavings | 0,045 | 90–360 | 2 | n/a | B2 | E |
| Wood wool boards | 0,090 | 330–500 | 2–5 | 2.100 | B1 | B, s1, d0 |
| Jute mats | 0,039 | 30–40 | 1–2 | 2.350 | B2 | E |
| Cork board (expanded) | 0,040 | 120 | 5–10 | 1.800 | B2 | E |
| Cork-clay board | 0,080 | 200–300 | 10 | 1.254 | B2–B1 | E |
| Sheep wool | 0,036 | 20–90 | 1–2 | 1.300–1.730 | B2 | E |
| Reed boards | 0,065 | 150 | 3–6,5 | 1.200 | B2 | E |
| Seagrass | 0,045 | 65–75 | 1–2 | 2.502 | B2 | E |
| Straw bales | 0,052 | 85–115 | 2 | 2.000 | B2 | E |
| Blown straw insulation | 0,043 | 105 | 2,8 | 2.100 | B2 | E |
| Cellulose fibre (loose) | 0,039 | 28–65 | 1–2 | 2.100–2.544 | B2 | E to B-s2, d0 |
| Cellulose boards | 0,042 | 70–145 | 2–3 | 2.000 | B2 | E |
| Polystyrene (expanded) — comparison | 0,035 | 11–30 | 20–100 | 1.400 | B2–B1 | E |
| Stone wool boards — comparison | 0,035 | 15–130 | 1–2 | 830–1.000 | A1 | A1 |
λ as design value. Source: market survey “Dämmstoffe aus nachwachsenden Rohstoffen”, Fachagentur Nachwachsende Rohstoffe e. V. (FNR), order no. 317, 10th edition 2019, p. 13.
Dynamic stiffness
| Material | s′ in MN/m³ |
|---|---|
| Cellulose | 20 |
| Hemp fibre felt | 22 |
| Sheep wool | 50 |
| Flax mats | 57 |
| Cork granulate | 120 |
| Wood fibre boards | 30–150 |
| Reed | 208 |
| Wood wool boards | 300 |
| Cork boards | 500 |
Sorted ascending — the lower s′, the better the impact sound reduction. Source: FNR, order no. 317, 10th edition 2019, p. 11.
For sustainability certification it is recommended not to select XPS, PUR or EPS insulation unless it is genuinely required.
- Principal
- Tino Josef Ritter
- Degree
- M.Sc. in Engineering (Energy Systems)
- Practice
- Planning and consulting practice for building physics and energy efficiency
- Established
- 1 January 2016
Network
Thermal performance decides energy demand, comfort and freedom from damage — and it is won or lost in the details.
Verification and detailing
- Thermal performance certificates for residential and non-residential buildings
- Component build-ups and U-value calculation
- Detailed thermal bridge calculation instead of blanket surcharges
- Assessment of junction details in solid and timber construction
Simulation
- Building simulation (VDI 6007)
- Thermal simulation (DIN EN ISO 13791)
The calculated thermal bridge assessment regularly pays for itself where the blanket surcharge costs an efficiency level — we tell you in advance whether that is the case for your building.
All planning and calculation services required to meet sound insulation requirements — in solid and in timber construction.
Verification to DIN 4109-1:2018 and DIN 4109-5:2020
- Residential buildings, non-residential buildings and heritage-listed properties
- Airborne and impact sound insulation between occupancy units
- Component and junction details in timber construction
- Assessment of external noise and façade requirements
In multi-storey timber construction in particular, early coordination pays off: the acoustically viable solution often determines the floor build-up.
Moisture is the most common cause of building damage. Whether a component stays dry is decided by the interplay of build-up, use and air change.
Moisture control
- Verification to DIN EN ISO 13788
- Verification to DIN 4108-3:2024
- Hygrothermal simulation for critical build-ups
Ventilation
- Ventilation concepts for new build and retrofit
- Sizing and assessment of ventilation measures
After a window replacement in an existing building in particular, the concept is the most effective protection against moisture damage.
We provide all services and calculations for planning and funding under the programmes of KfW and BAFA.
Accreditations: KfW, BAFA, WTA
- Residential KfW Efficiency House (BzA and BnD)
- Non-residential KfW Efficiency House (gBzA and gBnD)
- Individual measures, residential and non-residential, KfW and BAFA
- Heritage-listed residential (BzA and BnD)
- Heritage-listed non-residential (gBzA and gBnD)
- Individual measures on heritage-listed residential and non-residential property, KfW and BAFA
BzA — confirmation for the application · BnD — confirmation after completion · gBzA / gBnD — the corresponding confirmations for non-residential buildings. These are the designations used by the German funding programmes and are given here in their original form.
How it runs
- Initial discussion and classification of the project
- Calculation and comparison of the attainable efficiency levels
- Construction supervision during the works
Funding rates, programme numbers and application deadlines change regularly. We establish the position applicable to your project in the initial discussion.
Enquiry
Submitting opens your email programme with the message prepared. No data is stored on this website.
This is a convenience translation. The German version is the authoritative one.
- Provider
- Tino Josef Ritter, M.Sc. in Engineering (Energy Systems) — Planning and consulting practice for building physics and energy efficiency
- Address
- Feuerwehrstrasse 44, 77933 Lahr, Germany
- Mobile
- +49 (0) 176 8232 9156
- Landline
- +49 (0) 7821 274 501 4
- ritter@bauphysik.direct
- Established
- 1 January 2016
Dispute resolution
We are neither willing nor obliged to take part in dispute resolution proceedings before a consumer arbitration board.
Liability for content and links
The content of these pages has been compiled with the greatest care. We cannot, however, warrant its accuracy, completeness or currency. The operator of any linked external site is responsible for its content; at the time of linking, no legal infringements were apparent.
To be completed: VAT identification number, professional title, chamber, professional indemnity insurance, party responsible under § 18 (2) MStV.
This is a convenience translation. The German version is the authoritative one.
Controller
Tino Josef Ritter, Feuerwehrstrasse 44, 77933 Lahr, Germany — phone +49 (0) 176 8232 9156, email ritter@bauphysik.direct
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The full wording of the privacy notice is to be inserted here.
Draft, and a convenience translation. This text has not been reviewed by a lawyer, the entries marked […] are still to be completed, and only the German version is legally binding. In the event of any discrepancy, the German wording prevails.
§ 1 Scope and incorporation
- These terms apply to all contracts for planning, consulting and calculation services between Tino Josef Ritter, Feuerwehrstrasse 44, 77933 Lahr, Germany (the “Contractor”) and the Client.
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§ 2 Scope of services and delimitation
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- site management, construction supervision and project supervision
- the execution of construction work of any kind
- the conduct of tender procedures and the selection, vetting and appointment of contractors
- the vetting of the professional suitability, reliability or creditworthiness of third parties
- the checking of tender documents for completeness and accuracy, in so far as they were not produced by the Contractor
- Where the Contractor supplies technical contributions for a tender, he is responsible solely for their technical accuracy at the time of handover. The award decision, the appointment and the supervision of the works are made and borne by the Client.
- The Contractor is not liable for damage arising because the Client implements planning results differently, passes them on incompletely, or applies them to a purpose other than the one agreed.
§ 3 The Client's duty to cooperate
- The Client shall provide all documents, drawings, reports and information required for the service in good time, in full and free of charge, and warrants their accuracy.
- The Contractor may rely on the information supplied without checking it, unless its inaccuracy is obvious.
- Delays caused by omitted or late cooperation are not to the Contractor's account; agreed dates shift accordingly.
§ 4 Fees, incidental costs and travel expenses
- Fees are governed by the agreement reached. Absent a specific agreement, an hourly rate of […] euros net applies.
- Travel expenses are borne by the Client at all times. They are charged in addition to the fee and settled as follows:
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§ 5 Payment terms and default
- Clients domiciled in Germany: invoices fall due for payment in full within seven calendar days of receipt of the invoice.
- Clients domiciled outside Germany — in particular in the member states of the European Union and in the Republic of Türkiye: invoices fall due for payment in full within twenty calendar days of receipt of the invoice. Mandatory shorter or longer periods under the law applicable at the Client's domicile remain unaffected.
- In relation to entrepreneurs, default occurs without a separate reminder upon expiry of the relevant period. Default interest is nine percentage points above the base rate, plus a flat charge of 40 euros (§ 288 (2) and (5) German Civil Code). For clients within the European Union, Directive 2011/7/EU applies as transposed into the respective national law.
- In relation to consumers, the occurrence of default is governed by statute. Default interest is five percentage points above the base rate (§ 288 (1) German Civil Code). The consequences of default are pointed out separately in the invoice.
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§ 6 Liability
- The Contractor is liable without limitation for intent and gross negligence, for damage arising from injury to life, body or health, where a guarantee has been assumed, where a defect has been fraudulently concealed, and under the German Product Liability Act.
- In cases of ordinary negligence the Contractor is liable only for breach of a material contractual obligation, that is an obligation whose fulfilment makes the proper performance of the contract possible in the first place and on whose observance the Client may regularly rely. In such cases liability is limited to the foreseeable damage typical of this type of contract.
- Liability for ordinary negligence is otherwise excluded.
- Liability is limited in amount to the sum insured under the Contractor's professional indemnity insurance of […] euros per occurrence. Paragraph 1 remains unaffected.
- The above limitations also operate in favour of the Contractor's employees and agents.
- Limitation periods are governed by statute.
§ 7 Rights of use in the documents
- The Contractor grants the Client the non-exclusive right, limited to the building project forming the subject of the contract, to use the documents handed over. The grant is conditional upon payment of the fee in full.
- Passing the documents to third parties, using them for other projects or altering them requires consent in text form.
- Calculations, certificates and concepts otherwise remain the intellectual property of the Contractor.
§ 8 Confidentiality
Both parties shall treat as confidential all non-public information obtained in the course of the collaboration. The obligation survives the end of the contract. Statutory duties of disclosure remain unaffected.
§ 9 Consumers' right of withdrawal
Consumers have a statutory right of withdrawal in the case of contracts concluded away from business premises and in distance contracts. The details are set out in the withdrawal instruction provided separately.
To be completed: the full withdrawal instruction together with the model withdrawal form pursuant to Article 246a EGBGB. Without it, the withdrawal period extends to twelve months and fourteen days.
§ 10 Governing law and jurisdiction
- The law of the Federal Republic of Germany applies, to the exclusion of the UN Convention on Contracts for the International Sale of Goods.
- Where the Client is a consumer habitually resident in another state, the mandatory consumer protection provisions of that state remain unaffected (Article 6 Rome I Regulation).
- Where the Client is a merchant, a legal person under public law or a special fund under public law, the exclusive place of jurisdiction for all disputes arising from the contractual relationship is Lahr, Germany. The Contractor remains entitled to sue at the Client's general place of jurisdiction.
- In relation to consumers the statutory places of jurisdiction apply. For consumers domiciled in the European Union, Articles 17 to 19 of Regulation (EU) No 1215/2012 apply.
- For contracts with clients domiciled in the Republic of Türkiye: disputes shall be finally settled under the arbitration rules of […]. The seat of arbitration is […]; the language of the proceedings is German or English.
§ 11 Final provisions
- Amendments and additions to the contract require text form. This also applies to any waiver of this clause.
- The Contractor is neither willing nor obliged to take part in dispute resolution proceedings before a consumer arbitration board.
- Should any provision be or become invalid, the validity of the remaining provisions is unaffected. The statutory provisions take the place of the invalid provision.
As at 30 August 2026. Convenience translation — the German version prevails.