Grün(e) Energy Consulting
Lower energy costs. Secure subsidies. Increase value.
Rising heating costs, complex subsidy applications, unclear regulations — we bring order to the chaos. We analyze your building, create your personal renovation roadmap and secure up to 50% government subsidies for you.
From Analysis to Funding — Everything Under One Roof
From the first question to the final step — we guide you personally with expertise and dedication.
Residential Energy Consulting
Know where your money escapes through walls and windows — and how to fix it. KfW/BAFA subsidized with up to 50% grant.
Personal Renovation Roadmap (iSFP)
Your personal 15-year plan: Which measures pay off when and how much funding you get for them.
Subsidy Consulting & Applications
BAFA, KfW, regional programs — who can keep track? We can. And we handle the complete application process.
Construction Supervision & Documentation
So that good planning becomes good execution. Expert supervision and complete documentation.
Heating Optimization & Heat Pumps
Heat sustainably and save money. Consulting on heat pumps, modern heating systems and hydraulic balancing.
Energy Certificates (GEG)
Required for sale or rental. Demand-based and consumption-based energy certificates — fast and legally compliant.
Dipl.-Ing. Jesco Grün
Energy Consultant / Efficiency ExpertPersonal. Independent. Competent.
Dipl.-Ing. Jesco Grün combines engineering precision with personal consulting. As a certified energy efficiency expert, I guide you from the initial analysis to the successful implementation of your energy renovation.
With a degree from the Technical University of Darmstadt and extensive hands-on experience, I offer well-founded, manufacturer-independent consulting. My goal: the most economical and ecological solution for your building.
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Calculate Your Savings Potential
Find out how much you can save annually with professional energy consulting and renovation.
Calculate Savings →What Our Customers Say
Mr. Grün advised us excellently. Thanks to his expertise, we were able to secure maximum funding for our roof renovation. Absolutely recommended!
Professional, personal and always available. The renovation roadmap was clear and understandable. We now save significantly on heating costs.
From the first consultation to implementation — everything under one roof. The heat pump was the best decision. Thank you!
Answers to Your Questions
News & Insights
View all articles →BEG Reform 2026: The New Funding Conditions at a Glance
New BEG conditions apply since July 21: climate bonus 16%, cap €28,000, new income and family bonus. All changes at a glance.
Read more →GEG Becomes GModG — The New Heating Law at a Glance
Germany's Building Energy Act becomes the Building Modernisation Act. The 65% rule is dropped, the bio-ladder arrives. What homeowners need to know.
Read more →BEG Subsidies 2026 — What's Funded and How Much?
KfW, BAFA, BEG: All current subsidy programs for renovation and heating replacement at a glance.
Read more →iSFP Explained — Why a Renovation Roadmap Pays Off
5% extra funding, clear priorities, fewer mistakes: What an iSFP delivers and how it works.
Read more →Heating Replacement: What Subsidies Are Available in 2026?
Heat pump, pellets, or hybrid — which subsidies you get for which system.
Read more →Energy Certificate: Consumption vs. Demand — Which Do I Need?
Two types, different informative value. When which energy certificate is required and what it costs.
Read more →Heat Pump in Old Buildings — Does It Work?
Myths vs. reality: When a heat pump makes sense in existing buildings and what to watch out for.
Read more →Hydraulic Balancing — The Underrated Measure
Low cost, big impact: Why hydraulic balancing is often the best first measure.
Read more →Insulation: Exterior Wall, Roof, or Basement — Where to Start?
Not all insulation delivers equal returns. How to set priorities and avoid common mistakes.
Read more →Energy Consulting in Siegen — What Does It Really Cost?
Process, costs, and funding for energy consulting in the Siegen-Wittgenstein region.
Read more →Typical Old Buildings in Siegerland — Spotting Renovation Potential
Half-timbered, 1960s build, or 1980s estate house: What weaknesses your building year has.
Read more →Heating Season Over — Time to Plan Your Renovation
Spring is the best time to plan renovations. How to approach timing, contractors, and subsidy applications.
Read more →Triple Glazing in Old Buildings — Myth or Worth It?
Many hesitate to install modern windows in old buildings. Why triple glazing works and when it pays off.
Read more →Heat Load Calculation — What Is It and Why Do I Need It?
Required for heat pumps and subsidy applications: What a heat load calculation costs, how it works, and why it prevents costly mistakes.
Read more →Solar PV + Battery Storage — Is It Worth It for Your Home in 2026?
Costs, returns, and subsidies: Whether a PV system with battery storage is still worth it for your home in 2026.
Read more →Ventilation with Heat Recovery — Required or Just Smart?
When mechanical ventilation is required, what it costs, and why it almost always makes sense after renovation.
Read more →Solar Thermal vs. Heat Pump — Which Fits Better?
Costs, efficiency, and subsidies compared head-to-head — and when which technology is the better choice.
Read more →Smart Home & Energy Saving — Intelligent Heating Control in Old Buildings
Smart thermostats, window contacts, and energy monitoring: What really saves and what pays off.
Read more →KfW Loan vs. BAFA Grant — When Is Which the Better Choice?
Loan or grant? When which funding path is right and how to optimally combine both.
Read more →Tax Deductions for Renovation — §35c Income Tax Act Explained
Deduct 20% of renovation costs directly from your tax bill: How §35c works and when it pays off more than subsidies.
Read more →Financing Renovation — Which Subsidy Combinations Are Allowed?
BEG, KfW, §35c, state programs: Which you can combine and how to maximize your funding.
Read more →Complete Renovation vs. Individual Measures — What's More Effective?
All at once or step by step? Costs, subsidies, and results compared.
Read more →Tenants vs. Owners — Who Benefits from Renovation?
Modernization surcharge, CO₂ cost sharing, and subsidies: Why renovation is a win for both sides.
Read more →Mold & Moisture — Identify Causes and Renovate Properly
Why mold is a symptom and how proper renovation solves the problem permanently.
Read more →Heritage Protection & Energy Efficiency — What's Allowed?
Which renovation measures are possible under heritage protection, what subsidies exist, and how to combine both.
Read more →Avoiding Summer Heat — Cooling Without Air Conditioning
External sun protection, roof insulation, and night ventilation: How to keep your home cool without AC.
Read more →New Build in Siegen — Planning Your KfW Efficiency House
KfW Efficiency House 40 for new builds: requirements, costs, subsidies, and specifics of the Siegen region.
Read more →Renovating a Half-Timbered House in Siegerland — A Case Study
From 285 to 62 kWh/(m²·a): How a typical Siegerland half-timbered house was energy-renovated — measures, costs, results.
Read more →Ready for Renovation?
Schedule your free initial consultation now and find out how much you can save with professional energy consulting.