{"id":311449,"date":"2026-11-02T13:10:46","date_gmt":"2026-11-02T13:10:46","guid":{"rendered":"https:\/\/al-hayakel.com\/ar\/?p=311449"},"modified":"2026-11-02T13:10:46","modified_gmt":"2026-11-02T13:10:46","slug":"a-bananzia-terrace-heat-pump-retrofit-four-steps-that-cut-the-gas-bill","status":"publish","type":"post","link":"https:\/\/al-hayakel.com\/ar\/a-bananzia-terrace-heat-pump-retrofit-four-steps-that-cut-the-gas-bill\/","title":{"rendered":"A Bananzia Terrace Heat-Pump Retrofit: Four Steps That Cut the Gas Bill"},"content":{"rendered":"

The problem on Rowan Street<\/h2>\n

In Bananzia, a 1976 mid-terrace on Rowan Street had an 18 kW gas boiler, single-glazed windows at the back, and an EPC rating of D. The owner, Mira, was spending \u00a31,840 a year on gas and still using a blanket in the living room. The house was not unusually leaky; it was typical. That mattered because the street wanted a repeatable retrofit recipe, not a one-off show home.<\/p>\n

The first survey found the real cause: the boiler was cycling because radiators were oversized in some rooms and undersized in the extension, while draughts through the suspended floor pulled cold air across the hallway. The solution was not a bigger boiler. It was measurement, fabric work, and a heat pump sized for the actual heat loss.<\/p>\n

Step 1: Measure before buying equipment<\/h2>\n

A room-by-room heat-loss survey took three hours and produced a design load of 5.8 kW at -3\u00b0C outside. An air-tightness test measured 6.8 m\u00b3\/(h\u00b7m\u00b2) at 50 Pa, which is normal for a 1970s terrace but high enough to justify targeted sealing. The takeaway is simple: the heat-pump quote should follow the survey, not precede it.<\/p>\n

The Rowan Street house joined a local bananzia<\/a> retrofit pilot that shared survey costs across six homes. That pooled approach reduced each household’s assessment bill and gave the installers comparable data across the terrace.<\/p>\n

Step 2: Insulate and draught-proof first<\/h2>\n

The cheapest wins came before any low-carbon heating: 300 mm of loft insulation, draught strips on the front and back doors, and sealed pipe penetrations into the kitchen extension. Those measures cut the design heat load by 1.2 kW. They also removed the cold-draught complaint that had been blamed on the radiators.<\/p>\n

The cause was ordinary air movement, not mysterious heat loss. The solution was a fabric-first sequence: loft, floor, doors, then windows. Replacing every window would have cost more than the heat pump; sealing the worst gaps cost \u00a3420 and delivered measurable comfort.<\/p>\n

Step 3: Size the heat pump for the real load<\/h2>\n

The installer specified a 7 kW air-source heat pump with a 180-litre cylinder, slightly above the 5.8 kW design load to cover hot-water recovery. Existing radiators in the living room were replaced with larger panels; bedroom radiators stayed because the room-by-room calculation showed they could run at 45\u00b0C flow temperature. That detail matters: lower flow temperatures improve efficiency and make the boiler-to-heat-pump swap less disruptive.<\/p>\n

The cause of poor performance in many retrofits is a heat pump matched to the old boiler’s output rather than the building’s load. The solution here was a measured load, a room-by-room emitter check, and a commitment to run at 45\u00b0C rather than 55\u00b0C.<\/p>\n

Step 4: Commission controls and monitor through winter<\/h2>\n

Commissioning included a weather-compensation curve, a hot-water schedule set to 48\u00b0C, and a two-week monitoring period. In the first winter, gas use fell to zero and electricity for heating and hot water averaged 3,100 kWh. At the pilot’s tariff, that was about \u00a3870, before any smart-tariff shifting. The house also held 21\u00b0C in the living room on the coldest week.<\/p>\n

The result was not a miracle product. It was a sequence: measure, reduce demand, size correctly, then tune. For other terraces in Bananzia, the lesson is to copy the process rather than the exact equipment list.<\/p>\n","protected":false},"excerpt":{"rendered":"

The problem on Rowan Street In Bananzia, a 1976 mid-terrace on Rowan Street had an 18 kW gas boiler, single-glazed windows at the back, and an EPC rating of D. The owner, Mira, was spending \u00a31,840 a year on gas and still using a blanket in the living room. The house was not unusually leaky; […]<\/p>\n","protected":false},"author":123458,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"class_list":["post-311449","post","type-post","status-publish","format-standard","hentry","category-uncategorized-en"],"_links":{"self":[{"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/posts\/311449","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/users\/123458"}],"replies":[{"embeddable":true,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/comments?post=311449"}],"version-history":[{"count":1,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/posts\/311449\/revisions"}],"predecessor-version":[{"id":311450,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/posts\/311449\/revisions\/311450"}],"wp:attachment":[{"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/media?parent=311449"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/categories?post=311449"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/al-hayakel.com\/ar\/wp-json\/wp\/v2\/tags?post=311449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}