{"id":1807,"date":"2026-05-07T07:04:05","date_gmt":"2026-05-07T07:04:05","guid":{"rendered":"https:\/\/mywarmhome.co.uk\/newsite\/?p=1807"},"modified":"2026-05-07T07:04:05","modified_gmt":"2026-05-07T07:04:05","slug":"u-values","status":"publish","type":"post","link":"https:\/\/mywarmhome.co.uk\/newsite\/2026\/05\/07\/u-values\/","title":{"rendered":"Insulation and U values."},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">PIR Insulation.<\/h2>\n\n\n\n<p>PIR (Polyisocyanurate) and phenolic foam are both types of rigid insulation boards used in building construction to improve thermal efficiency. <\/p>\n\n\n\n<p>These boards are supplied by many manufacturers including\u00a0<a href=\"https:\/\/celotex.co.uk\/\" target=\"_blank\" rel=\"noreferrer noopener\">Celotex<\/a>, <a href=\"https:\/\/www.recticel.com\/\" target=\"_blank\" rel=\"noreferrer noopener\">Recticel<\/a>, <a href=\"https:\/\/www.kingspan.com\/gb\/en\/\" target=\"_blank\" rel=\"noreferrer noopener\">Kingspan<\/a>,<a href=\"https:\/\/ikogroup.co.uk\/\" target=\"_blank\" rel=\"noreferrer noopener\">Iko<\/a>.<\/p>\n\n\n\n<figure class=\"wp-block-gallery has-nested-images columns-default is-cropped wp-block-gallery-1 is-layout-flex wp-block-gallery-is-layout-flex\">\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" data-id=\"1427\" src=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/03\/insulatedhatch.jpg\" alt=\"\" class=\"wp-image-1427\" srcset=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/03\/insulatedhatch.jpg 800w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/03\/insulatedhatch-300x300.jpg 300w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/03\/insulatedhatch-150x150.jpg 150w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/03\/insulatedhatch-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Loft Hatch PIR<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" data-id=\"2380\" src=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/between1.jpg\" alt=\"\" class=\"wp-image-2380\" srcset=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/between1.jpg 800w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/between1-300x300.jpg 300w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/between1-150x150.jpg 150w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/between1-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Between Rafters PIR<\/figcaption><\/figure>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"800\" data-id=\"2382\" src=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/pir4.jpg\" alt=\"\" class=\"wp-image-2382\" srcset=\"https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/pir4.jpg 800w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/pir4-300x300.jpg 300w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/pir4-150x150.jpg 150w, https:\/\/mywarmhome.co.uk\/newsite\/wp-content\/uploads\/2026\/04\/pir4-768x768.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><figcaption class=\"wp-element-caption\">Between Rafters<\/figcaption><\/figure>\n<\/figure>\n\n\n\n<p>PIR insulation is a type of rigid foam insulation made from polyisocyanurate, a thermoset plastic. It is produced as foam and typically sandwiched between two facings, such as aluminium foil.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Properties.<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>High<a href=\"http:\/\/value\">\u00a0R-Value<\/a>.\u00a0<\/strong>PIR has a high thermal resistance (R-value), which makes it very effective as an insulator.<\/li>\n\n\n\n<li><strong>Moisture Resistance. <\/strong>It has good moisture resistance, which helps prevent mould and mildew.<\/li>\n\n\n\n<li><strong>Cell structure. <\/strong>Usually sold as closed.(can be manufactured closed cell)<\/li>\n\n\n\n<li><strong>Lightweight and Easy to Handle. <\/strong>It is lightweight, making it easy to handle and install..\u00a0<\/li>\n\n\n\n<li><strong>Applications.\u00a0<\/strong>Roof, wall, and floor insulation.<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Phenolic Foam Insulation.<\/h2>\n\n\n\n<p><strong>Description.&nbsp;<\/strong><br>Phenolic foam insulation is made from phenol-formaldehyde resin, a thermosetting plastic. It is produced as a rigid foam and often faced with materials such as foil or glass tissue.<\/p>\n\n\n\n<p><strong>Properties.<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Very High\u00a0<a href=\"https:\/\/mywarmhome.co.uk\/newsite\/newsite\/2026\/03\/20\/thermal-values-explained\/\" data-type=\"post\" data-id=\"1471\">R-Value.<\/a>\u00a0<\/strong>Phenolic foam has an excellent thermal performance, with an R-value typically higher than PIR.<\/li>\n\n\n\n<li><strong>Cell Structure.<\/strong> Mainly sold as a closed cell but can be <a href=\"https:\/\/www.kingspan.com\/vn\/en\/knowledge-articles\/open-versus-closed-cell-phenolic-foams\/\" target=\"_blank\" rel=\"noreferrer noopener\">manufactured as open.<\/a><\/li>\n\n\n\n<li><strong>Durability<\/strong>. It is durable and retains its insulating properties over time.<\/li>\n\n\n\n<li><strong>Applications.\u00a0<\/strong>Used in a variety of applications, including roof, wall, and floor insulation. (and submarines!)<\/li>\n<\/ul>\n\n\n\n<p><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Comparison and use cases.<\/h2>\n\n\n\n<p><strong>Thermal Performance.<\/strong> Both PIR and phenolic foam have high thermal resistance, but phenolic foam generally has a slightly higher <a href=\"https:\/\/mywarmhome.co.uk\/newsite\/newsite\/2026\/03\/20\/thermal-values-explained\/\" data-type=\"post\" data-id=\"1471\">R-value<\/a><br><strong>Moisture Resistance.<\/strong> Both types offer good moisture resistance, though phenolic foam\u2019s closed-cell structure gives it an edge in preventing water absorption.<br><strong>Cost.<\/strong> PIR is typically less expensive than phenolic foam, which can be a consideration for large projects.<br><strong>Applications.<\/strong> Ideal for high-performance insulation requirements, including in walls, between rafters, and floors.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">In Summary.<\/h2>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p class=\"has-accent-5-color has-custom-color-1-background-color has-text-color has-background has-link-color wp-elements-c30003ed8239a1e1d5b09b40e4c90120\">Both PIR and phenolic foam are excellent choices for rigid insulation, each with its own strengths. The choice between them will depend on specific project requirements such as thermal performance, fire resistance, moisture resistance, and budget.<\/p>\n<\/blockquote>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>PIR Insulation. PIR (Polyisocyanurate) and phenolic foam are both types of rigid insulation boards used in building construction to improve thermal efficiency. These boards are supplied by many manufacturers including\u00a0Celotex, Recticel, Kingspan,Iko. PIR insulation is a type of rigid foam insulation made from polyisocyanurate, a thermoset plastic. It is produced as foam and typically sandwiched [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2182,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pagelayer_contact_templates":[],"_pagelayer_content":"","footnotes":""},"categories":[10,11],"tags":[],"class_list":["post-1807","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-efficiency","category-insulation"],"_links":{"self":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1807","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=1807"}],"version-history":[{"count":4,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1807\/revisions"}],"predecessor-version":[{"id":2384,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/posts\/1807\/revisions\/2384"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/media\/2182"}],"wp:attachment":[{"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/media?parent=1807"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/categories?post=1807"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mywarmhome.co.uk\/newsite\/wp-json\/wp\/v2\/tags?post=1807"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}