{"id":1771,"date":"2026-05-07T07:04:05","date_gmt":"2026-05-07T07:04:05","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/newsite\/?p=1771"},"modified":"2026-05-07T07:04:05","modified_gmt":"2026-05-07T07:04:05","slug":"sizing","status":"publish","type":"post","link":"https:\/\/mywarmhome.co.uk\/newsite\/2026\/05\/07\/sizing\/","title":{"rendered":"Calculator For Radiator Sizing."},"content":{"rendered":"\n<div class=\"radiator-selector\">\n\n  <h2>UK Radiator Selector Tool (we have used stelrad radiators for this)<\/h2>\n\n  <div class=\"section\">\n    <label>Room Heat Requirement (W)<\/label>\n    <input type=\"number\" id=\"heatReq\" placeholder=\"e.g. 2500\">\n    \n    <label>System Flow Temperature (\u00b0C)<\/label>\n    <select id=\"flowTemp\">\n      <option value=\"70\">Boiler (70\u00b0C)<\/option>\n      <option value=\"55\">Heat Pump (45\u201355\u00b0C)<\/option>\n      <option value=\"35\">Low Temp Heat Pump (35\u00b0C)<\/option>\n    <\/select>\n  <\/div>\n\n  <div class=\"section\">\n    <label>Select Radiator Type<\/label>\n    <select id=\"radType\">\n      <option value=\"K1\">K1 \/ Type 11<\/option>\n      <option value=\"P+\">P+ \/ Type 21<\/option>\n      <option value=\"K2\">K2 \/ Type 22<\/option>\n      <option value=\"K3\">K3 \/ Type 33<\/option>\n    <\/select>\n  <\/div>\n\n  <button onclick=\"selectRadiator()\">Suggest Radiators<\/button>\n\n  <div id=\"radResults\" class=\"result\"><\/div>\n\n<\/div>\n\n<style>\n.radiator-selector { max-width:600px; margin:auto; padding:20px; background:#fff; border-radius:10px; }\n.section { margin-bottom:20px; }\ninput, select, button { width:100%; padding:8px; margin-top:5px; }\nbutton { background:#2563eb; color:#fff; border:none; border-radius:6px; cursor:pointer; }\n.result { margin-top:15px; padding:15px; background:#eef4ff; border-left:4px solid #2563eb; border-radius:8px; }\n<\/style>\n\n<script>\nconst stelradData = [\n  \/\/ [Type, HxW, Output @ \u0394T50 (W)]\n  {type:\"K1\", size:\"600x600\", output:550},\n  {type:\"K1\", size:\"600x1000\", output:900},\n  {type:\"K2\", size:\"600x600\", output:1100},\n  {type:\"K2\", size:\"600x1000\", output:1800},\n  {type:\"K2\", size:\"600x1200\", output:2200},\n  {type:\"K3\", size:\"600x1000\", output:2600},\n  {type:\"K3\", size:\"600x1200\", output:3200},\n  {type:\"P+\", size:\"600x1000\", output:1800},\n  {type:\"P+\", size:\"600x1200\", output:2200}\n];\n\n\/\/ Adjust output for \u0394T (approximation)\nfunction adjustForDeltaT(output, flowTemp) {\n  \/\/ \u0394T50 standard: output given\n  \/\/ simple linear approximation:\n  \/\/ 70\u00b0C -> 100%, 55\u00b0C -> ~70%, 35\u00b0C -> ~50%\n  if(flowTemp == 70) return output;\n  if(flowTemp == 55) return output * 0.7;\n  if(flowTemp == 35) return output * 0.5;\n  return output;\n}\n\nfunction selectRadiator() {\n  const heatReq = parseFloat(document.getElementById(\"heatReq\").value);\n  const flowTemp = parseFloat(document.getElementById(\"flowTemp\").value);\n  const type = document.getElementById(\"radType\").value;\n\n  if(!heatReq || heatReq <= 0) { alert(\"Enter heat requirement\"); return; }\n\n  const candidates = stelradData\n    .filter(r => r.type === type)\n    .map(r => ({...r, adjOutput: adjustForDeltaT(r.output, flowTemp)}))\n    .sort((a,b) => a.adjOutput - b.adjOutput);\n\n  let results = \"<strong>Suggested Radiators:<\/strong><br><br>\";\n\n  candidates.forEach(r => {\n    const qty = Math.ceil(heatReq \/ r.adjOutput);\n    results += `${qty} \u00d7 ${r.type} (${r.size}) \u2192 ${Math.round(r.adjOutput)}W each<br>`;\n  });\n\n  document.getElementById(\"radResults\").innerHTML = results;\n}\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>UK Radiator Selector Tool (we have used stelrad radiators for this) Room Heat Requirement (W) System Flow Temperature (\u00b0C) Boiler (70\u00b0C)Heat Pump (45\u201355\u00b0C)Low Temp Heat Pump (35\u00b0C) Select Radiator Type K1 \/ Type 11P+ \/ Type 21K2 \/ Type 22K3 \/ Type 33 Suggest Radiators<\/p>\n","protected":false},"author":1,"featured_media":1296,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pagelayer_contact_templates":[],"_pagelayer_content":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-1771","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1771","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/comments?post=1771"}],"version-history":[{"count":1,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1771\/revisions"}],"predecessor-version":[{"id":1772,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1771\/revisions\/1772"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/media\/1296"}],"wp:attachment":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/media?parent=1771"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/categories?post=1771"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/tags?post=1771"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}