[{"data":1,"prerenderedAt":331},["ShallowReactive",2],{"blog:\u002Fen\u002Fblog\u002Fground-source-vs-air-source-heat-pump":3},{"id":4,"title":5,"author":6,"body":7,"cardImage":302,"category":303,"date":304,"description":13,"draft":305,"excerpt":302,"extension":306,"footerCta":307,"hero":312,"locale":321,"meta":322,"navigation":323,"path":324,"seo":325,"slug":328,"stem":329,"__hash__":330},"blog\u002Fen\u002Fblog\u002Fground-source-vs-air-source-heat-pump.md","Ground Source Vs Air Source Heat Pump","Planeto Team",{"type":8,"value":9,"toc":287},"minimark",[10,14,17,22,30,37,40,48,52,55,63,69,72,75,79,82,85,88,91,95,100,103,106,109,116,119,147,150,154,157,160,164,167,171,174,206,210,216,222,228,232,240,245,248,256,263,271,277,282],[11,12,13],"p",{},"Ask an installer which heat pump you should fit and you will usually get the one\nthey fit most. Ask the internet and you will get a list of bullet points that\ncarefully avoids the only question that matters. That question is not which\ntechnology is better, since ground source wins almost every technical\ncomparison, but where the extra money stops being worth it for your building.",[11,15,16],{},"That crossover point is real, it is calculable, and it sits in a different place\ndepending on four things: how long you will own the building, whether you need\ncooling, what your site allows, and what your emitters run at. Here is how to\nfind it.",[18,19,21],"h2",{"id":20},"the-difference-in-one-paragraph-each","The difference in one paragraph each",[11,23,24,25,29],{},"An ",[26,27,28],"strong",{},"air-source heat pump"," extracts heat from outdoor air using an outdoor unit\n(a fan and a heat exchanger, usually mounted against a wall or standing in the\ngarden) and upgrades it with a compressor. It is straightforward to install,\nneeds no excavation, and can typically be commissioned in a couple of days.",[11,31,32,33,36],{},"A ",[26,34,35],{},"ground-source heat pump"," extracts heat from the ground, via vertical\nboreholes typically 50 to 300 metres deep, or horizontal loops if you have the\nland. A water-glycol mixture circulates through sealed pipes, picks up heat from\nthe rock, and carries it to a heat pump indoors. There is no outdoor unit at\nall. The install involves a drilling rig and takes considerably longer.",[11,38,39],{},"Same principle, very different source. Everything below follows from that one\ndifference.",[41,42],"article-image",{":height":43,":width":44,"alt":45,"caption":46,"src":47},"404","763","A single building with an air-source outdoor unit beside it and a ground loop running beneath it","The visible difference: an air-source system puts a fan and a heat exchanger outside the building, a ground-source system puts everything underground.","\u002Fimg\u002Fproduct\u002FSingle-building.png",[18,49,51],{"id":50},"efficiency-the-gap-is-bigger-than-the-headline-numbers-suggest","Efficiency: the gap is bigger than the headline numbers suggest",[11,53,54],{},"Heat pumps are rated by seasonal performance factor (SPF): the heat delivered\nacross a year divided by the electricity consumed.",[56,57],"comparison-table",{":rows":58,"featureColLabel":59,"heading":60,"themName":61,"usName":62},"[{\"label\":\"Typical SPF (space heating)\",\"us\":\"4 to 5\",\"them\":\"2.5 to 3.5\",\"usWin\":true},{\"label\":\"Source temperature in January\",\"us\":\"8 to 14 °C\",\"them\":\"−5 to +5 °C\",\"usWin\":true},{\"label\":\"Source temperature in August\",\"us\":\"8 to 14 °C\",\"them\":\"25 to 35 °C\",\"usWin\":true},{\"label\":\"Performance on the coldest day\",\"us\":\"Unchanged\",\"them\":\"Lowest of the year\",\"usWin\":true},{\"label\":\"Defrost cycles\",\"us\":\"None\",\"them\":\"Yes, in cold damp weather\",\"usWin\":true},{\"label\":\"Installed cost, single house\",\"us\":\"2 to 3 times higher\",\"them\":\"Lowest of the two\"}]","","Ground source and air source, side by side","Air source","Ground source",[64,65,66],"blockquote",{},[11,67,68],{},"Figures are typical ranges for well-designed systems in temperate European\nclimates. Your numbers will depend on emitters, climate and design.",[11,70,71],{},"The averages understate the difference, because of when the gap appears. An\nair-source unit is least efficient precisely on the coldest morning of the year,\nwhen demand peaks. The source it is drawing from has got colder, the temperature\nlift it must achieve has got bigger, and in damp cold it periodically stops\nheating your house altogether to melt ice off its own coil. Ground temperature,\nby contrast, does not care what the weather is doing. The source you sized for\nin October is the source you have in February.",[11,73,74],{},"For the owner this shows up as a heating bill that is roughly 25 to 40% lower,\nand as a house that stays warm during the week everyone else's system is\nstruggling.",[18,76,78],{"id":77},"capital-cost-the-case-for-air-source","Capital cost: the case for air source",[11,80,81],{},"This is where air source wins, and it wins decisively.",[11,83,84],{},"Drilling is the dominant line in a ground-source budget and it scales with\nmetres, geology and site access. A ground-source installation for a single house\ncommonly runs two to three times the cost of an equivalent air-source system,\noccasionally more on a constrained urban plot where a rig has to work in a\ncourtyard. On a tight budget, or where the building will change hands within a\nfew years, that gap is difficult to argue away on running cost alone.",[11,86,87],{},"Payback of the extra investment through lower bills typically lands somewhere in\nthe 8 to 15 year range for a heating-only building. That is a long time, long\nenough that the decision usually hinges on something other than the energy bill.",[11,89,90],{},"Which brings us to the three things that actually move the decision.",[18,92,94],{"id":93},"what-actually-decides-it","What actually decides it",[96,97,99],"h3",{"id":98},"_1-cooling-changes-the-arithmetic-completely","1. Cooling changes the arithmetic completely",[11,101,102],{},"This is the asymmetry almost every comparison misses.",[11,104,105],{},"An air-source heat pump can cool. Run it in reverse and it becomes an air\nconditioner. But it cools the way an air conditioner does: the compressor runs,\nthe outdoor unit runs, it consumes serious electricity on the hottest\nafternoons, and it dumps heat into a street that is already too hot.",[11,107,108],{},"A ground-source system cools without a compressor at all. Warm water from the\nbuilding's floor or ceiling circuits is passed against the cold brine from the\nboreholes through a heat exchanger. Only a circulation pump runs. Delivering a\nunit of cooling this way typically costs a small fraction of what a compressor\nwould use, commonly cited as a twentieth to a fortieth.",[41,110],{":height":111,":width":112,"alt":113,"caption":114,"src":115},"712","1191","A borehole field sized in Planeto, showing the annual supply curve with both heating and cooling energy generation","The same borehole field delivers heating and cooling across the year, which is what makes the second use of the asset nearly free.","\u002Fimg\u002Fsolutions\u002Fthermal-energy-source-dimensioning\u002Fexcess-heatgeothermal-curves.jpg",[11,117,118],{},"Three consequences follow:",[120,121,122,129,135],"ul",{},[123,124,125,128],"li",{},[26,126,127],{},"Running cost."," Summer cooling is close to free. In a building with real\ncooling demand, this alone can halve the payback period of the ground-source\npremium.",[123,130,131,134],{},[26,132,133],{},"Regulation and planning."," Across much of Europe, active comfort cooling\nfaces scrutiny that passive geocooling does not: capacity limits in energy\ncodes, requirements to justify the need, restrictions on visible outdoor\nunits, boundary noise limits, and a tightening refrigerant regime. Owners who\nset out to install air conditioning frequently find the answer is no.\nGeothermal cooling often passes where a conventional system fails, because\nthere is no outdoor unit, no noise, and almost no electricity involved. (Rules\nvary considerably by country and municipality, so check your site.)",[123,136,137,140,141,146],{},[26,138,139],{},"System life."," Pushing summer heat into the ground regenerates it,\ncounteracting the slow temperature drift that heating-only borehole fields\nsuffer over decades. Cooling does not wear a ground-source system out. It\npreserves it. We cover this in depth in our guide to\n",[142,143,145],"a",{"href":144},"\u002Fblog\u002Fshallow-geothermal-heating-cooling-buildings\u002F","shallow geothermal heating and cooling",".",[11,148,149],{},"If your building needs cooling (and if it is well-insulated, modern, glazed, or\nhas top-floor flats, it probably does), the comparison stops being close.",[96,151,153],{"id":152},"_2-noise-neighbours-and-permission","2. Noise, neighbours and permission",[11,155,156],{},"An air-source outdoor unit makes noise. Not a lot, but continuously, outdoors,\nnear a boundary, at night in winter. In detached houses with space this is a\nnon-issue. In terraces, courtyards, dense urban streets and conservation areas\nit is frequently the issue: boundary noise limits and visual amenity rules are\nthe most common reason an air-source installation is refused or has to be\nrelocated somewhere less efficient.",[11,158,159],{},"A ground-source system has nothing outside. Nothing to see, nothing to hear,\nnothing to argue about. Where planning constraints are tight, this sometimes is\nnot an advantage so much as the only route to a heat pump at all.",[96,161,163],{"id":162},"_3-how-long-youll-hold-the-building","3. How long you'll hold the building",[11,165,166],{},"Payback periods of a decade only matter if you are there for the decade. For a\ndeveloper selling on completion, air source is usually the rational choice\nunless cooling or planning forces the issue. For an owner-occupier, a housing\ncooperative, or an institutional landlord holding for thirty years, the\narithmetic reverses, and the borehole itself is credited with a 50 to 100 year\nservice life, against 15 to 20 for an air-source outdoor unit exposed to the\nweather.",[18,168,170],{"id":169},"where-ground-source-simply-isnt-available","Where ground source simply isn't available",[11,172,173],{},"Honesty requires the reverse case. Ground source is off the table, or heavily\ncompromised, when:",[120,175,176,182,188,194,200],{},[123,177,178,181],{},[26,179,180],{},"You can't drill."," Drinking-water protection zones, certain geological\nformations, contaminated ground and some urban subsurface congestion make\nboreholes restricted or prohibited. Many regions publish admissibility maps;\ncheck yours before anything else.",[123,183,184,187],{},[26,185,186],{},"The plot is too small."," Boreholes need meaningful separation from each\nother and from boundaries, or they steal heat from one another.",[123,189,190,193],{},[26,191,192],{},"There's no rig access."," A drilling rig needs to physically reach the spot.",[123,195,196,199],{},[26,197,198],{},"The permit timeline doesn't fit."," Several months is normal. If the boiler\ndied last week, that is not the constraint you want.",[123,201,202,205],{},[26,203,204],{},"The emitters are high-temperature."," This one applies to both technologies,\nbut bites harder on the ground-source business case: if the building runs\nradiators at 65 to 70 °C, no heat pump will deliver its rated efficiency, and\nyou will have spent ground-source money for air-source performance. Fix the\nemitters first, or don't drill.",[18,207,209],{"id":208},"a-rough-decision-framework","A rough decision framework",[11,211,212,215],{},[26,213,214],{},"Choose air source"," if the building is heating-dominated, the budget is tight,\nyou're selling within a few years, the site can't be drilled, or you have\noutdoor space away from neighbours.",[11,217,218,221],{},[26,219,220],{},"Choose ground source"," if you need cooling, noise or planning rules block an\noutdoor unit, you're holding the building long-term, you already have or are\ninstalling low-temperature emitters, or (the case owners most often overlook)\nthere is more than one building.",[11,223,224,227],{},[26,225,226],{},"Consider a hybrid"," where peak heating demand is large but brief: a\nground-source system sized for the bulk of the year with a small backup for the\ncoldest hours is often cheaper than drilling for the 1% case.",[18,229,231],{"id":230},"the-case-owners-overlook-more-than-one-building","The case owners overlook: more than one building",[11,233,234,235,239],{},"If you own or are developing several buildings on one site, the comparison\nchanges again. Individual air-source units mean one outdoor unit per building,\neach sized for its own peak. A ",[142,236,238],{"href":237},"\u002Fsolutions\u002Flow-temperature-networks\u002F","shared ground\nloop"," serving all of them needs far less\ntotal capacity, because the buildings don't peak simultaneously, and because a\nbuilding that needs cooling can regenerate the ground for one that needs heat.\nThe plant room consolidates. The cost per building falls, sometimes sharply.",[41,241],{":height":43,":width":44,"alt":242,"caption":243,"src":244},"Several buildings connected to one shared low-temperature ground loop with a common borehole field","One shared loop instead of one outdoor unit per building: less total capacity, one plant room, and loads that offset each other.","\u002Fimg\u002Fproduct\u002FUrban-network.png",[11,246,247],{},"This is the point where the decision stops being a product comparison and\nbecomes a design problem, and where it is worth modelling properly before\ncommitting to anything.",[11,249,250,251,255],{},"That modelling is what Planeto does. Our platform, ",[142,252,254],{"href":253},"\u002Fproduct\u002F","Tessa",", brings\nbuilding demand, ground conditions, sources and costs into a single model, so\noptions like these can be built and compared in hours rather than weeks.",[41,257],{":height":258,":width":259,"alt":260,"caption":261,"src":262},"874","1598","Two energy supply scenarios compared side by side in Planeto on net present value, LCOE and IRR","Two scenarios, the same building stock: the comparison that decides the question is financial, not technical.","\u002Fimg\u002Ffeatures\u002Fcompare.png",[11,264,265,266,270],{},"And if you don't have a planning office engaged yet, our energy engineers can\n",[142,267,269],{"href":268},"\u002Fservices\u002Ffeasibility-pre-feasibility-studies\u002F","run the comparison with you",",\nor tell you straight away whether your site rules one of the options out.",[11,272,273],{},[142,274,276],{"href":275},"\u002Fproduct-demo\u002F?ref=blog-gshp-vs-ashp","Talk to our energy experts →",[278,279],"faq-section",{":items":280,"heading":281},"[{\"question\":\"Is a ground-source heat pump always more efficient than air source?\",\"answer\":\"In practice, yes. The ground is a warmer and far more stable source in winter. Typical SPFs are 4 to 5 against 2.5 to 3.5 for air source. The real question is whether the efficiency gain repays the drilling cost within your ownership horizon.\"},{\"question\":\"Can both types provide cooling?\",\"answer\":\"Both can, but very differently. Air source cools with a compressor, like air conditioning. Ground source can cool passively with only a circulation pump, at a small fraction of the electricity and with no outdoor unit, which matters both for running cost and for getting permission.\"},{\"question\":\"How much more does ground source cost?\",\"answer\":\"Commonly two to three times an air-source installation for a single house, driven almost entirely by drilling. The gap narrows in buildings with cooling demand and across multiple buildings on one site.\"},{\"question\":\"Does an air-source heat pump work in cold weather?\",\"answer\":\"Yes, modern units operate well below freezing, but efficiency falls as it gets colder and defrost cycles begin, so output is lowest exactly when demand is highest. Sizing has to account for this.\"},{\"question\":\"Which lasts longer?\",\"answer\":\"Boreholes are credited with 50 to 100 years and the ground-source heat pump itself with 20 to 25. An air-source outdoor unit typically lasts 15 to 20 years, being weather-exposed.\"}]","Frequently asked questions",[283,284],"cta-banner",{"heading":285,"secondary-label":286,"secondary-to":275},"Not sure which heat pump your building should have?","Talk to our energy experts",{"title":59,"searchDepth":288,"depth":288,"links":289},2,[290,291,292,293,299,300,301],{"id":20,"depth":288,"text":21},{"id":50,"depth":288,"text":51},{"id":77,"depth":288,"text":78},{"id":93,"depth":288,"text":94,"children":294},[295,297,298],{"id":98,"depth":296,"text":99},3,{"id":152,"depth":296,"text":153},{"id":162,"depth":296,"text":163},{"id":169,"depth":288,"text":170},{"id":208,"depth":288,"text":209},{"id":230,"depth":288,"text":231},null,"Heat Pumps","2026-09-21",false,"md",{"heading":285,"primary":308,"secondary":311},{"label":309,"to":310},"Start for free","https:\u002F\u002Ftessa.planeto-energy.ch",{"label":286,"to":275},{"heading":313,"subhead":314,"image":315,"primary":319,"secondary":320},"Ground Source vs Air Source Heat Pump: An Honest Comparison","Ground source wins almost every technical comparison, so that is not the question worth asking. The question is where the extra money stops being worth it for your building. That crossover point is real, it is calculable, and four things decide where it sits.",{"src":316,"alt":317,"width":318,"height":318},"\u002Fimg\u002Fblog\u002Fground-source-heat-pump-vs-ai-source-heat-pump.png","An air-source outdoor unit and a geothermal borehole field serving buildings on a shared underground loop",1120,{"label":309,"to":310},{"label":286,"to":275},"en",{},true,"\u002Fen\u002Fblog\u002Fground-source-vs-air-source-heat-pump",{"title":326,"description":327,"ogImage":316},"Ground Source vs Air Source Heat Pump: Honest Comparison","Ground source or air source? Compare efficiency, cost, cooling, noise and lifetime, and find the point where the extra investment stops paying for itself.","ground-source-vs-air-source-heat-pump","en\u002Fblog\u002Fground-source-vs-air-source-heat-pump","LnjWMUxm5TeC1M7BpgZAdHBJ5U4qpw96_z5EilQkqts",1790169687467]