Variable Frequency Drive (VFD) — Transparent pool | Stromfeetitle> <meta name="description" content="A Variable Frequency Drive (VFD) is the central control unit for regulating motor speed in swimming pool technology. It per..."> <link rel="canonical" href="https://stromfee-mauritius.ai/en/glaesern/piscine/wizards/drehzahlregler-vfd/"> <script type="application/ld+json">{"@context": "https://schema.org", "@type": "Article", "headline": "Remote monitoring and maintenance of VFDs in the swimming pool", "mainEntityOfPage": "https://stromfee-mauritius.ai/glaesern/piscine/wizards/drehzahlregler-vfd/", "description": "Variable Frequency Drive (VFD) — Component in swimming pool/bath operation (Filtration & Circulation trade). Regulatory framework: Plant technology / Energy efficiency."}</script> <script type="application/ld+json">{"@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [{"@type": "Question", "name": "What is a Variable Frequency Drive (VFD) in swimming pool operation?", "acceptedAnswer": {"@type": "Answer", "text": "A VFD is a frequency converter unit that adjusts pump speed variably for water filtration and circulation."}}, {"@type": "Question", "name": "Why is speed monitoring important?", "acceptedAnswer": {"@type": "Answer", "text": "It allows the flow rate to be adapted to the current number of users and preserves the mechanics by avoiding operation at full load."}}, {"@type": "Question", "name": "How does the 'drehzahl_prozent' value help with maintenance?", "acceptedAnswer": {"@type": "Answer", "text": "It serves as a direct indicator of the pump's condition; deviations from the target value indicate wear or obstructions."}}, {"@type": "Question", "name": "At what point should a Variable Frequency Drive be maintained?", "acceptedAnswer": {"@type": "Answer", "text": "Regular checking of start cycles and monitoring of the VFD module's thermal load are essential for system reliability."}}, {"@type": "Question", "name": "How does a VFD reduce energy costs in a swimming pool?", "acceptedAnswer": {"@type": "Answer", "text": "By reducing speed during low demand, the electrical consumption of the motors is reduced non-linearly."}}, {"@type": "Question", "name": "What role does the VFD play in water filtration?", "acceptedAnswer": {"@type": "Answer", "text": "It ensures that the filtration system is constantly supplied with the optimal flow rate, without having to turn the pumps on and off constantly."}}]}</script> <style>:root{--bg:#fdfcff;--bg-soft:#faf8ff;--surface:#fff;--text:#1d1d1f;--text-2:#515154;--text-3:#86868b;--border:#fed7aa;--border-soft:#efeaf8;--accent:#f97316;--accent-bright:#fdba74;--accent-dim:rgba(234,88,12,.08);--emerald:#ea580c;--font:'Inter',-apple-system,sans-serif;--mono:'JetBrains Mono',monospace;--radius:16px}*{box-sizing:border-box;margin:0;padding:0} body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.6; -webkit-font-smoothing:antialiased} .wrap{max-width:1080px;margin:0 auto;padding:0 24px} header{padding:14px 0;border-bottom:1px solid var(--border-soft);background:rgba(255,255,255,.72); backdrop-filter:saturate(180%) blur(20px);position:sticky;top:0;z-index:9} header a{color:var(--text-2);text-decoration:none;font-size:13px;margin-right:18px} header a:hover{color:var(--accent)} .hero{padding:56px 0 32px} .eyebrow{font-family:var(--mono);font-size:12px;letter-spacing:.12em;text-transform:uppercase; color:var(--accent);margin-bottom:10px} h1{font-size:40px;letter-spacing:-.022em;line-height:1.12;margin-bottom:12px} .lead{font-size:19px;color:var(--text-2);max-width:62ch} h2{font-size:23px;letter-spacing:-.015em;margin:44px 0 6px} .sub{color:var(--text-3);font-size:14px;margin-bottom:18px} .steps{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:12px;margin:22px 0 8px} .step{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px 18px} .step b{display:block;font-size:15px;margin-bottom:4px} .step span{font-size:13px;color:var(--text-3)} .step i{font-family:var(--mono);font-size:11px;color:var(--accent);font-style:normal} .cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px} .c{display:block;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius); padding:16px 18px;text-decoration:none;color:inherit;transition:.16s} .c:hover{border-color:var(--accent-bright);box-shadow:0 8px 26px rgba(234,88,12,.16);transform:translateY(-2px)} .c b{display:block;font-size:15px;letter-spacing:-.01em} .c span{font-size:12.5px;color:var(--text-3);font-family:var(--mono)} .tag{display:inline-block;font-family:var(--mono);font-size:10.5px;padding:2px 7px;border-radius:6px; background:var(--accent-dim);color:var(--accent);margin-top:8px} .tag.de{background:rgba(180,83,9,.09);color:#b45309} .tag.live{background:rgba(234,88,12,.10);color:#ea580c} .note{background:var(--bg-soft);border:1px solid var(--border-soft);border-radius:var(--radius); padding:16px 18px;font-size:14px;color:var(--text-2);margin:22px 0} .note b{color:var(--text)} .nav{display:flex;flex-wrap:wrap;gap:8px;margin:34px 0} .nav a{font-size:13px;padding:7px 13px;border:1px solid var(--border);border-radius:999px; text-decoration:none;color:var(--text-2);background:var(--surface)} .nav a:hover,.nav a.on{border-color:var(--accent);color:var(--accent)} footer{margin-top:64px;padding:26px 0;border-top:1px solid var(--border-soft); font-size:13px;color:var(--text-3)} @media(max-width:640px){h1{font-size:31px}.hero{padding:36px 0 24px}} .hero-w{background:linear-gradient(135deg,var(--accent),var(--accent-bright));color:#fff;padding:2.4rem 20px 3.4rem;text-align:center} .hero-w h1{font-size:2rem;margin:0;letter-spacing:-.01em}.hero-w p{opacity:.9;margin:.4rem 0 0} .step-img{width:100%;border-radius:14px;object-fit:cover;max-height:340px} .step-kicker{font-family:var(--mono);font-size:.78rem;letter-spacing:.1em;text-transform:uppercase;color:var(--accent);margin:0} .step-h{font-size:1.35rem;margin:.3rem 0 .7rem;letter-spacing:-.01em} .step-p{color:var(--text-2);line-height:1.6} .reg{font-family:var(--mono);font-size:.8rem;color:var(--accent);background:var(--accent-dim);padding:.15rem .5rem;border-radius:6px} .szen{margin-top:1.2rem;background:var(--bg-soft);border:1px solid var(--border-soft);border-radius:16px;padding:1.1rem 1.2rem} .szen .mon{font-family:var(--mono);font-size:.75rem;color:var(--accent);margin:0 0 .3rem} .szen-grid{display:grid;grid-template-columns:180px 1fr;gap:1rem;align-items:center} .szen-img{width:100%;border-radius:12px;object-fit:cover} @media(max-width:560px){.szen-grid{grid-template-columns:1fr}} .calcbox{margin-top:1rem;background:var(--bg-soft);border:1px solid var(--border-soft);border-radius:16px;padding:1.1rem 1.2rem} .calcbox input{width:96px;padding:.35rem .5rem;border:1px solid var(--border);border-radius:8px;font-family:var(--mono);font-size:.95rem} #steps{display:flex;background:#fff;border:1px solid var(--border);border-radius:16px;overflow:hidden;margin-bottom:1.4rem;flex-wrap:wrap} .st .no{display:inline-flex;width:1.4rem;height:1.4rem;border-radius:50%;background:var(--border);color:var(--text-2);align-items:center;justify-content:center;font-size:.75rem;margin-right:.35rem} .st.on .no{background:var(--accent);color:#fff} .livebar{display:inline-flex;margin:1.2rem auto 0;padding:.5rem 1.1rem;background:rgba(255,255,255,.92);border:1px solid rgba(255,255,255,.5);border-radius:999px;font-size:.82rem;color:var(--text-2);align-items:center;gap:.5rem;box-shadow:0 6px 20px rgba(0,0,0,.08)} .livedot{width:.6rem;height:.6rem;border-radius:50%;background:#ea580c;box-shadow:0 0 0 0 rgba(234,88,12,.5);animation:lp 2s infinite} @keyframes lp{0%{box-shadow:0 0 0 0 rgba(234,88,12,.4)}70%{box-shadow:0 0 0 .5rem rgba(234,88,12,0)}100%{box-shadow:0 0 0 0 rgba(234,88,12,0)}} .livekpi{background:linear-gradient(135deg,var(--accent-dim),transparent);border:1px solid var(--accent-bright);border-radius:16px;padding:1.1rem 1.3rem;margin:.4rem 0 1rem} .livekpi .lv{font-size:2.2rem;font-weight:700;color:var(--accent);line-height:1;font-family:var(--mono)} .livekpi .ll{font-size:.9rem;color:var(--text-2);margin-top:.3rem} .livekpi .lts{font-size:.72rem;color:var(--text-3);font-family:var(--mono);margin-top:.4rem} .sec{max-width:1000px;margin:2.4rem auto;padding:0 20px} .sec h2{font-size:1.5rem;letter-spacing:-.01em;margin-bottom:.4rem} .sec .lead{color:var(--text-3);margin-bottom:1.2rem} .compgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px} .compgrid a{display:block;background:var(--surface);border:1px solid var(--border);border-radius:14px;overflow:hidden;text-decoration:none;color:inherit;transition:.16s} .compgrid a:hover{border-color:var(--accent-bright);box-shadow:0 8px 24px rgba(234,88,12,.14);transform:translateY(-2px)} .compgrid a img{width:100%;height:118px;object-fit:cover;display:block;background:#fff7ed} .compgrid .ct{padding:12px 15px} .compgrid b{display:block;font-size:14.5px}.compgrid span{font-size:12px;color:var(--text-3);font-family:var(--mono)} .ctaband{background:linear-gradient(135deg,var(--accent),var(--accent-bright));color:#fff;text-align:center;padding:2.6rem 20px;margin-top:2.4rem} .ctaband h2{font-size:1.6rem;margin-bottom:.6rem}.ctaband p{opacity:.92;max-width:60ch;margin:0 auto 1.4rem} .ctaband .btn{display:inline-block;background:#fff;color:var(--accent);font-weight:600;padding:.7rem 1.4rem;border-radius:999px;text-decoration:none;margin:.3rem} .faqsec details{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:.4rem 1rem;margin-bottom:.6rem} .faqsec summary{cursor:pointer;font-weight:600;padding:.6rem 0;font-size:.98rem} .faqsec .faq-a{color:var(--text-2);padding:0 0 .8rem;line-height:1.6} .live-head{display:flex;align-items:center;gap:.7rem;flex-wrap:wrap;margin:.2rem 0 1.1rem} .live-status{font-weight:800;font-size:1.05rem}.live-sub{color:var(--text-3);font-size:.82rem} .kpis{display:grid;grid-template-columns:repeat(3,1fr);gap:.7rem} .kpi{background:linear-gradient(180deg,#fff,var(--bg-soft));border:1px solid var(--border);border-radius:15px;padding:.85rem .95rem} .kpi .kl{font-size:.72rem;letter-spacing:.03em;text-transform:uppercase;color:var(--text-3);font-weight:700} .kpi .kval{font-family:var(--mono);font-weight:700;font-size:1.4rem;color:var(--text);line-height:1.1;margin-top:.15rem} .kpi .kval .ku{font-size:.72rem;color:var(--accent);margin-left:.15rem} .kpi .spark{margin-top:.35rem;height:26px} .kpi.hl{border-color:var(--accent-bright);box-shadow:0 6px 18px rgba(234,88,12,.14)} @media(max-width:640px){.kpis{grid-template-columns:repeat(2,1fr)}} header.site{position:sticky;top:0;z-index:9;background:rgba(255,255,255,.85);backdrop-filter:saturate(180%) blur(18px);border-bottom:1px solid var(--border-soft)} .navrow{display:flex;align-items:center;gap:1rem;height:56px} .brand{font-weight:800;letter-spacing:-.02em;color:var(--text);text-decoration:none;font-size:1.02rem} .nlinks{display:flex;gap:1.1rem;margin-left:auto}.nlinks a{color:var(--text-2);text-decoration:none;font-size:.86rem} .nlinks a:hover{color:var(--accent)} .navcta{background:var(--accent);color:#fff;text-decoration:none;font-weight:700;font-size:.82rem;padding:.5rem 1rem;border-radius:999px} @media(max-width:640px){.nlinks{display:none}} footer.site{margin-top:3rem;padding:2.4rem 0;border-top:1px solid var(--border-soft);background:var(--bg-soft);text-align:center} .fbrand{font-weight:800;color:var(--text);margin-bottom:.4rem} .fclaim{color:var(--text-2);font-size:.9rem;max-width:52ch;margin:0 auto 1rem} .flinks{display:flex;gap:1.2rem;justify-content:center;flex-wrap:wrap;margin-bottom:1rem} .flinks a{color:var(--accent);text-decoration:none;font-size:.85rem} .fcopy{color:var(--text-3);font-size:.78rem} .wiz-wrap{position:relative;z-index:2;margin:-2.6rem auto 0;max-width:1000px;padding:0 20px 2rem} .wiz{background:#fff;border:1px solid var(--border,#fed7aa);border-radius:24px;box-shadow:0 2px 6px rgba(0,0,0,.05),0 30px 70px rgba(249,115,22,.10),0 0 0 1px rgba(249,115,22,.03);overflow:hidden} .wiz-steps{display:flex;gap:0;border-bottom:1px solid var(--border,#fed7aa);background:var(--bg-mute,#fff7ed)} .wiz-steps .st{flex:1;display:flex;align-items:center;justify-content:center;gap:.5rem;padding:.85rem .6rem;font-size:.82rem;font-weight:700;color:var(--text-3,#86868b);position:relative;cursor:pointer} .wiz-steps .st .no{width:22px;height:22px;border-radius:999px;background:#e5e0ee;color:#86868b;display:flex;align-items:center;justify-content:center;font-size:.72rem;font-weight:800;flex:0 0 auto} .wiz-steps .st.on{color:var(--accent)} .wiz-steps .st.on .no{background:var(--accent);color:#fff} .wiz-steps .st.done .no{background:#ea580c;color:#fff} .wiz-steps .st.on::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:3px;background:var(--accent)} .wiz-steps .st .lbl{display:none} .wiz-steps .st{padding:.8rem .3rem} .wiz-body{padding:1.6rem 1.7rem 1.9rem} .wiz-body{padding:1.2rem 1.1rem 1.5rem} .step-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:1.5rem;align-items:center} .step-grid{grid-template-columns:1fr;gap:1.1rem} .step-img{width:100%;aspect-ratio:4/3;object-fit:cover;border-radius:16px;display:block;box-shadow:0 14px 34px rgba(249,115,22,.14)} .step-kicker{font-size:.76rem;letter-spacing:.12em;text-transform:uppercase;color:var(--accent);font-weight:800;margin:0 0 .5rem} .step-h{font-size:clamp(1.35rem,2.6vw,1.7rem);font-weight:800;letter-spacing:-.01em;margin:0 0 .7rem;color:var(--text,#1d1d1f);line-height:1.16} .step-p{font-size:1.02rem;line-height:1.62;color:var(--text-2,#515154);margin:0 0 .8rem} .step-p b{color:var(--text,#1d1d1f)} .chk{list-style:none;padding:0;margin:.4rem 0 0} .chk li{display:flex;gap:.6rem;align-items:flex-start;font-size:.98rem;line-height:1.5;color:var(--text-2,#515154);margin:.55rem 0} .chk li .b{flex:0 0 auto;width:22px;height:22px;border-radius:999px;background:var(--accent-dim);color:var(--accent);display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.8rem;margin-top:.05rem} .wiz-nav{display:flex;justify-content:space-between;align-items:center;gap:.8rem;margin-top:1.5rem;flex-wrap:wrap} .wiz-back{background:none;border:0;color:var(--text-3,#86868b);font-weight:700;font-size:.95rem;cursor:pointer;padding:.6rem .2rem} .wiz-back:hover{color:var(--text,#1d1d1f)} .wiz-next{background:linear-gradient(135deg,var(--accent),var(--accent-bright));color:#fff;border:0;border-radius:999px;padding:.85rem 1.6rem;font-weight:800;font-size:1rem;cursor:pointer;box-shadow:0 10px 26px rgba(249,115,22,.28);text-decoration:none;display:inline-flex;align-items:center;gap:.5rem} .wiz-next:hover{transform:translateY(-1px)} .benefit{background:linear-gradient(135deg,#fff7f0,#fff);border:1px solid var(--accent-ultra);border-radius:18px;padding:1.3rem 1.4rem;margin:.2rem 0 1.1rem} .benefit h3{margin:0 0 .5rem;font-size:1.2rem;font-weight:800;color:var(--text,#1d1d1f)} .benefit p{margin:0;color:var(--text-2,#515154);line-height:1.6}</style></head><body> <header class="site"><div class="wrap navrow"> <a class="brand" href="/glaesern/piscine/">◈ Transparent pool transparent</a> <nav class="nlinks"><a href="/glaesern/piscine/">All trades</a> <a href="https://stromfee-mauritius.ai/glaesern/piscine/filtration.html">Filtration & Circulation</a></nav> <a class="navcta" href="#kontakt">System check →</a></div></header> <div class="hero-w"><h1>Variable Frequency Drive (VFD)</h1><p>Component assistant · Filtration & Circulation</p> </div> <div class="wiz-wrap"> <div id="steps"> <div class="st" data-s="1"><span class="no">1</span> Comprendre </div> <div class="st" data-s="2"><span class="no">2</span>View live</div> <div class="st" data-s="3"><span class="no">3</span>What the AI does</div> <div class="st" data-s="4"><span class="no">4</span>Your benefit</div> </div> <div id="body"></div> </div> <div class="sec"><div class="block"><h3>Thus we connect — read-only</h3><p class="step-p">The value comes from<b>Modbus TCP · GLT · Dosing technique</b>of the installation —<b>read, not controlled</b>. Everything is<b>in the house</b>calculated, nothing leaves the house. No obligation to transmit operational data.</p></div><div class="block"><h3>Your own swimming pool LLM — offline</h3><p class="step-p">Natural language questions, answered by AI<b>Your own installation data</b>— local, no Cloud. The AI runs in the house; the installation remains private.</p></div><div class="note"><b>Regulatory framework:</b>Installation technique / Energy efficiency</div><div class="block"><h3>Link with the entire installation</h3><p class="step-p">Filtration, heating, water treatment and ventilation are linked — AI considers the pool as a system.</p><div style="display:flex;gap:.6rem;flex-wrap:wrap;margin-top:.6rem"><a href="/glaesern/bess/" style="font-size:.85rem;padding:.4rem .9rem;border:1px solid var(--border);border-radius:999px;text-decoration:none;color:var(--accent)">BESS in glass →</a><a href="/glaesern/hotel/" style="font-size:.85rem;padding:.4rem .9rem;border:1px solid var(--border);border-radius:999px;text-decoration:none;color:var(--accent)">Glass hotel →</a></div></div></div><div class="sec faqsec"><h2>FAQ</h2><details><summary>What is a variable frequency drive (VFD) in swimming pool operation?</summary><div class="faq-a">A VFD is a frequency converter unit that adjusts the speed of pumps for filtration and water circulation in a variable manner.</div></details><details><summary>Why is speed monitoring important?</summary><div class="faq-a">It allows the flow rate to be adapted to the current number of users and preserves mechanics by avoiding full-load operation.</div></details><details><summary>How does the 'drehzahl_prozent' value help with maintenance?</summary><div class="faq-a">It serves as a direct indicator of the pump's condition; deviations from the target value indicate wear or obstructions.</div></details><details><summary>From when should a variable frequency drive be maintained?</summary><div class="faq-a">Regular checking of switching cycles and monitoring of the thermal load of the VFD module are essential for system reliability.</div></details><details><summary>How does a VFD reduce energy costs in a swimming pool?</summary><div class="faq-a">By reducing speed during low demand, the power consumption of the motors is reduced non-linearly.</div></details><details><summary>What role does the VFD play in water filtration?</summary><div class="faq-a">It ensures that the filtration system is constantly supplied with the optimal flow rate, without having to turn the pumps on and off constantly.</div></details></div> <footer class="site"><div class="wrap"> <div class="fbrand">◈ Transparent pool</div> <p class="fclaim">Connected in read-only mode · local calculation · no Cloud. The installation remains in the house.</p> <nav class="flinks"><a href="/glaesern/piscine/">All trades</a> <a href="https://stromfee-mauritius.ai/glaesern/piscine/filtration.html">Filtration & Circulation</a> <a href="https://bhkw-anlagen.com/impressum.html">Legal notice</a> <a href="https://bhkw-anlagen.com/datenschutz.html">Data protection</a></nav> <div class="fcopy">© 2026 HR Energiemanagement GmbH · 32257 Bünde · +49 5223 4921030</div> </div></footer> <script> var state={step:1}; function li(t){return '<li>'+t+'</li>';} function nav(s){var b=s>1?'<button class="wiz-back" onclick="go('+(s-1)+')">← Back</button>':'<span></span>'; var n=s<4?'<button class="wiz-next" onclick="go('+(s+1)+')">Next →</button>':'<button class="wiz-next" onclick="go(1)">From the beginning</button>'; return '<div class="wiz-nav">'+b+n+'</div>';} function step1(){return '<div class="step-grid"><img class="step-img" src="../img/filtration.jpg" alt="Variable frequency drive (VFD)">'+ '<div><p class="step-kicker">Step 1 · Understand</p><h2 class="step-h">What is a variable frequency drive (VFD)?</h2>>'+ '<p class="step-p">A speed controller (Variable Frequency Drive, VFD) is the central control unit for regulating motor speed in swimming pool technology. It enables demand-dependent adjustment of circulation pumps and filter systems to the current flow requirement. Precise control reduces mechanical stress and optimizes energy efficiency in the areas of filtration and water circulation.</p></div></div>'+nav(1);} function step2(){return '<div class="step-grid"><div><p class="step-kicker">Step 2 · See live</p><h2 class="step-h">Linked to register <span class="reg">drehzahl_prozent</span></h2><p class="step-p">This wizard is linked to a real register. The value is read as <b>read-only</b> and calculated <b> in the house </b> — nothing leaves the system. It becomes visible via the connected components.</p></div><img class="step-img" src="../img/filtration.jpg" alt="Live view"></div>'+nav(2);} function step3(){return '<div class="step_grid"><div><p class="step-kicker">Step 3 · What the AI does</p>'+ '<h2 class="step-h">What the AI reads from this component</h2><ul class="chk">'+li('Current operating point (drehzahl_prozent) for the <b>determination of the load curve</b>')+li('Comparison of target and actual speed for the <b>detection of mechanical obstructions</b>')+li('Monitoring of operating time for the <b>proactive maintenance</b> of pump mechanics')+li('Analysis of speed variance as an <b>indicator of cavitation or leaks</b> in the piping system')+'</ul></div>'+ '<img class="step-img" src="../img/filtration.jpg" alt="AI monitoring">1'+ '<div class="szen szen-grid"><div><p class="mon">Monitoring: Pressure difference & flow rate per hour</p>'+ '<p class="step-p"><b>The scenario:</b> Blocked filter or continuous operation of the pump at full speed. Up to 35 % of the pool\'s electricity is consumed for unregulated circulation<br>'+ '<b>The AI:</b> The AI adjusts the speed according to actual demand and reports the backwash time based on differential pressure. <b>It detects the trend before the limit value is reached.</</b></p></div></div>'+nav(3);} function step4(){return '<p class="step_kicker">Step 4 · Your benefit</p><h2 class="step-h">Why does this matter?</h2>>'+ '<div class="benefit"><h3>Precise monitoring of the speed reduces energy consumption and extends the lifespan of circulation pumps by avoiding continuous load conditions.</h3><p>Reducing unnecessary operating speeds directly lowers electricity costs. At the same time, early detection of deviations minimises unplanned downtime in swimming pool operations.</p></div>'+ '<div class="calcbox"><p class="step-p">Pump power (kW) <input id="c0" type="number" step="any" value="8" oninput="r()"> · Filter runtime (h/day) <input id="c1" type="number" step="any" value="12" oninput="r()"> · Season length (days/yr) <input id="c2" type="number" step="any" value="300" oninput="r()"> · Speed reduction (%) <input id="c3" type="number" step="any" value="35" oninput="r()"> · Electricity price (ct/kWh) <input id="c4" type="number" step="any" value="22" oninput="r()"> → <b><span id="o" style="color:var(--accent)">—</span> €/year</b></p>'+ '<p class="mon" style="margin-top:.5rem">Calculation: Pump power × Speed reduction × Electricity price — speed control reduces consumption disproportionately.</p></div>'+nav(4);} function r(){var v=[];for(var i=0;i<5;i++){var e=document.getElementById('c'+i);v.push(e?parseFloat(e.value)||0:0);}'o');if(o)o.textContent=(Math.round(res*100)/100).toLocaleString('de-DE');}'body').innerHTML=state.step===1?step1():state.step===2?step2():state.step===3?step3():step4();'#steps .st').forEach(function(el){var n=+el.getAttribute('data-s');el.classList.toggle('on',n===state.step);el.classList.toggle('done',n<state.step);});'smooth'});} document.querySelectorAll('#steps .st').forEach(function(el){el.style.cursor='pointer';el.onclick=function(){go(+el.getAttribute('data-s'));};}); render(); </script></body></html>