Heat Pump or New Boiler? 7 Checks Before You Decide in Edinburgh

If you are thinking about replacing your heating system, the question is usually pretty simple:

Do you stick with another boiler, or is it time to look at a heat pump?

Most people know where they stand with boilers. They have been in homes for years, they are familiar, and when one breaks down, most homeowners just want the heating and hot water back on quickly.

Heat pumps are different. More people are looking at them now, especially with funding available in Scotland, but they are not something you should choose just because they sound like the modern option.

The honest answer is that it depends on the home.

A heat pump can be a great option in the right property. A new boiler can still make more sense in others. It depends on the house, the current heating system, your budget, how quickly you need the work done, and whether the property is ready for low-temperature heating.

Here are the main things worth checking before you make a decision.

Boiler vs heat pump at a glance

The table is useful, but it will never tell the full story.

Homes across Edinburgh and the Lothians can vary a lot. An older semi-detached house in Corstorphine, a stone terrace in Leith, a newer detached home in South Queensferry, and a flat near the city centre could all need different advice.

That is why a proper survey matters.

1. Determine how urgent the replacement is

If your boiler is failing and you need the heating and hot water back quickly, then a modern boiler replacement is likely to be the more practical option.

With boiler replacements, the upfront cost is often lower and the job can usually be done quicker than a heat pump install. This is especially true with a like-for-like swap, where the new boiler can work with much of what is already in the property, including the existing radiators and pipework.

Heat pump installs need a bit more thought.

The property needs to be surveyed first. The installer should be looking at heat loss, radiator sizes, hot water storage, outdoor unit location, controls, pipework, and whether any upgrades are needed before installation.

So if it is an emergency, a boiler is usually more realistic.

If you are planning ahead, it is worth checking whether an air source heat pump could work for your home.

Either way, replacing your heating system is a good chance to look at the full setup. That includes controls, radiators, pipework, sludge in the system, hot water performance, and whether the current heating system still suits the house.

2. How well insulated is the home?

Heat pumps work best when the house holds onto its heat.

It does not need to be perfect, nowhere near. But heat loss matters more than people expect, and it tends to be the bit that gets skipped over.

An older boiler in a draughty house, the usual answer is just to run it hotter. The heat is leaking out through the roof and the walls and the gaps around the windows, so you turn the flow temperature up and more or less stop thinking about it. You do not really notice, because the gas is doing the work and covering for the house. A heat pump will not let you away with that. It needs to run at lower temperatures to stay efficient, so when the heat is going out faster than it can be put back, you feel the difference.

So the insulation is worth a proper look before anyone gets onto the subject of heat pumps. Loft insulation is the obvious starting point. Cavity walls where the property suits it. Then there are draughts around doors and windows, suspended timber floors, single glazing or older windows that are past their best. Old extensions are worth a mention too, they are often where the cold finds its way in. And a room that stays colder than everywhere else, no matter what you do to it, is usually trying to tell you something.

Edinburgh and the Lothians have a real mix of housing. Some homes are straightforward. Others are not. A stone tenement, a converted flat, a house with an extension on the back and radiators in awkward spots, none of that should be treated like a standard new-build off a plan.

A heat pump might still be the right call. But the design has to come from the actual house in front of you, not a guess.

3. Are your radiators suitable?

This is the one nearly everybody asks. Do I have to rip out all my radiators to get a heat pump?

Sometimes. More often, no, but it depends on the house and you cannot answer it properly without going room by room.

It comes down to temperature. A boiler runs hot water round the system, so even a smallish radiator will warm a room because it is running so hot. A heat pump runs much cooler. Same radiator, less heat coming off it, and in some rooms that just is not enough to keep things comfortable on a cold day. The radiators through most of the house are probably grand. It tends to be the bigger rooms, and the extension that has always sat a degree or two behind everywhere else, where the existing rad cannot give off enough heat at the lower temperature.

The only way to actually know is to work out the heat loss for each room and set that against what your current radiators can realistically deliver. That is a calculation, not a glance round the house. And while they are at it a decent installer is looking at the pipework too, because old microbore can choke the flow, and whether the whole system could do with a flush, and whether there is any underfloor heating already in that would do some of the work for you.

This is where the cheap heat pump quote catches people out. If the radiators are undersized and nobody flags it, the system ends up cranked hotter to make up the difference, which is the one thing a heat pump is not supposed to do. Efficiency falls away, the running costs are nothing like what was promised, and the homeowner writes heat pumps off, when the real problem was radiators that were never up to it. A boiler would have hidden all that. Run it hot enough and an undersized rad still warms the room, so nobody ever finds out. A heat pump does not give you that get-out, which is exactly why the radiators matter far more here than they ever did with a boiler.

4. Do you have space for a hot water cylinder?

Most heat pumps need hot water stored in a cylinder, and that cylinder has to physically live somewhere in the house.

That trips people up, because so many homes round here run on a combi and have done for years. No combi, no cylinder, and in plenty of cases the old airing cupboard got swallowed up for storage or taken out altogether the day the combi went in. So part of the job is finding a home for the tank again. A cupboard, the loft, a corner of the garage, wherever there is room to actually fit it and still get at it when it needs serviced. In a roomy house that is rarely an issue, but cram the same requirement into a tight flat and it can be the one thing that kills the whole idea.

Worth sorting early, because there is no sense designing a whole system around the house and then finding there is nowhere for the tank to go. If there is genuinely no sensible spot for one, that is often what nudges a house back towards a boiler.

5. Is there a good place for the outdoor unit?

An air source heat pump has a unit that lives outside, and it needs air moving freely around it. So it cannot be boxed into a sealed corner or jammed hard against a wall, it cannot really sit right under a bedroom window because of the noise, and the pipe run back into the house has to be sensible rather than snaking halfway round the building.

In a lot of houses none of that is difficult. Down the side, out the back, on the garage wall, no bother. Edinburgh is where it gets interesting, because so much of the stock was never built with this in mind. Stone tenements with a shared back green, flats with no outside space to call your own, tight closes, conservation areas, listed buildings where you cannot just bolt something to the wall. None of that makes a heat pump impossible, but it does mean the easy answer is often not available.

This is also where you should be wary of anyone who promises, hand on heart, that you will not need planning permission. A lot of domestic installs in Scotland do fall under permitted development, true enough. But it is not a free-for-all. The Scottish Government guidance carves out exceptions for things like having more than one unit, conservation areas, World Heritage Sites, and listed buildings or the ground around them.

The whole thing really comes down to whether there is a spot for it. One that works on airflow and pipework, that planning will allow, and that is not going to start a feud with next door. Find one and you are good. If you cannot, it needs sorting before anyone prices the work.

6. What are the real costs?

A heat pump is often more expensive to install than a boiler, and there is no spinning that. What catches people is assuming the dear bit is the unit hanging on the wall outside, when really that is one line on the invoice. The rest is the design and the heat loss survey that have to happen before anyone touches a spanner, plus whatever the house itself needs to take a heat pump in the first place, bigger radiators in some rooms, pipework altered, a bit of electrical work, the controls, a cylinder if there is not one already, and the certification side of it, because the installer and the system both have to meet the scheme's requirements, MCS included, before any grant money comes into it. Home Energy Scotland have put the typical air-to-water job at around £13,000, and that is not a finger in the air, it is what real installs have actually cost once they totted up the invoices. Where you land on it depends on how big a system the house needs and how much of that list applies to you. A boiler, if it is a straight combi-for-combi, skips nearly all of it.

Running costs are the awkward bit, and the bit the cheap quotes lean on.

Everyone knows electricity costs more than gas. The Ofgem cap covering April to June 2026, Scotland in there with England and Wales, has electricity at 24.67p a unit and gas at 5.74p, so per unit it is not even close. Which makes a heat pump sound like it would cost a fortune to run. It does not work like that though, because the heat pump is not turning electricity into heat the way a bar fire does, it is using that electricity to shift heat out of the outside air and into the house, and a good one gives you back several units of heat for every unit of power it pulls. That is the whole reason the per-unit price tells you next to nothing on its own.

Whether it actually saves you money is the part that needs the house looked at, and it lands differently for everyone. The figure you actually pay is never just the unit price, it is the tariff you are on, how the system has been set up and controlled, how much heating and hot water the household gets through across a winter, and the standing charges sitting under all of it. Done properly, in a place that holds onto its heat, on a tariff that suits the way a heat pump runs, it can be genuinely cheap, and if you are getting shot of oil or LPG or those old electric storage heaters that cost a fortune to feed, it is usually a clear win. Up against a decent modern gas boiler it gets a lot tighter. It might still come out cheaper across the years you stay in the house, but that is a sum somebody has to actually sit down and do, not a number off the top of their head.

Be wary of anyone who quotes you a running-cost saving before they have set foot in the house, looked at your radiators and asked how your household actually gets through its heating and hot water. They cannot know the number. So they are guessing, and dressing the guess up as a promise.

7. Could Scottish funding change the decision?

This is a big part of why more people up here are even entertaining a heat pump in the first place. There is real money on the table, and it is money you do not get for putting in a boiler.

Scotland does its own thing on this, so forget the Boiler Upgrade Scheme you might have read about, that is England and Wales. Ours is the Home Energy Scotland Grant and Loan scheme, and as it stands in May 2026 eligible homeowners can get up to £7,500 towards an air, ground or water-to-water heat pump, with another £7,500 on top if you want it as an interest-free loan rather than finding the cash yourself. There is a bit available for insulation and the like as well, and if you are out in the sticks or on one of the islands you can claim an extra £1,500 on top of that. So yes, it can shift the maths quite a long way.

The catch is the small print, and there is a fair bit of it.

It has to be a home in Scotland that already exists and that you actually own and live in, your main place, not a holiday let or a flat you rent out. The heat pump itself has to be one they have approved, and fitted by an installer signed up to the scheme. Usually the work needs flagging in the right energy report first, too. It also needs to cover the whole job, all of the heating and all of the hot water, which rules out the hybrid setups that run a heat pump alongside a gas boiler, since those do not qualify. And none of it is actually yours until the application has gone in and a funding offer has come back in writing. So do not order anything or book anyone in on the assumption the money is coming.

Worth knowing there is a separate scheme too, Warmer Homes Scotland, aimed at households who are genuinely struggling with their energy bills and need heating or insulation work done. It runs on eligibility so it is not for everyone, but if that sounds like your situation it is worth a look.

The funding can absolutely tip a boiler-versus-heat-pump decision. Just do not let it be the whole reason you go for one. The house still has to actually suit a heat pump, money or no money.

Are gas boilers being banned in Scotland?

No. Not in existing homes, anyway, and certainly not in the sense of anyone making you tear out a boiler that is working fine.

The direction of travel is clearly towards cleaner heating, nobody is hiding that, and the Scottish Government still says it wants heat in the country's buildings decarbonised by 2045. But the Heat in Buildings Bill, which was the thing that would have put real rules behind that, got paused back in November 2025, and the plan was to come back to it after the Scottish Parliament election in May 2026. So as things stand, if you need a new boiler in an existing house and that is what makes sense for the property, the budget, the timing, the system you have got, whatever, you can still fit one. Nobody is stopping you.

New builds are a different story. Under the New Build Heat Standard, anything that applied for a building warrant from the first of April 2024 onwards has to use clean heating rather than something that burns gas or oil on site. But that is new build. If you are replacing or upgrading the heating in a house that is already standing, which is really what this whole piece is about, the gas boiler is still very much on the table.

So, should you go for a heat pump or a new boiler?

Here is the honest version.

A boiler is usually the sensible call when the house is not ready for anything else. If the old one has packed in and you need heat back this week, if the budget will only stretch so far, if the insulation is poor, if there is nowhere sensible to put a hot water cylinder, if the only place for the outdoor unit is awkward, or if the radiators were never going to cope with low-temperature heating, then a boiler is probably the realistic answer. Same goes if you are not planning to be in the house long enough to see the benefit of anything bigger.

The heat pump case is partly just the reverse of all that. Decent insulation, somewhere sensible for the outdoor unit, room for a cylinder, radiators that are either up to the job or can be brought up to it. But there are a few reasons that are more specific to heat pumps. If you are coming off oil, LPG, old electric heating, or a system that has been limping along for years, a heat pump can make a real difference. It is also worth a serious look if you want off fossil fuels altogether, or you are planning to stay put long enough for the lower running costs and the grant to actually count. In Scotland that grant support is a genuine part of the sum, not a nice to have.

For a lot of homes you cannot really tell down the phone. Someone has to come and look at the actual house.

A heat pump heats a house low and slow, trickling warmth out across the whole day, and that only works when the rest of the place is set up for it. The radiators have to be big enough to give off heat at that lower temperature, the pipework cannot be fighting it, and there has to be somewhere for the hot water, which catches people out because most heat pumps run off a cylinder and half the houses round here pulled theirs out the day they went combi. Get any of that wrong and it underperforms, and the heat pump gets the blame when the real problem was the install.

Whoever comes out should be telling you where you actually stand, not talking you into the dearer option. Maybe the house is close, give or take a couple of bigger radiators and a cylinder, in which case it comes down to whether that cost stacks up for you. Or maybe the honest answer for now is just a boiler, and there is nothing wrong with that.

Need a straight answer for your home?

That is exactly what Macara Heating is for. We fit boilers, heat pumps and central heating upgrades right across Edinburgh, the Lothians and Scotland's central belt, and a fair bit of the job is just telling people straight which one their house actually wants.

If you cannot work out whether yours is a heat pump or a new boiler, let us come and look. The property, the heating that is in it, how the radiators are set up, what you need out of your hot water, whether there is a funding route worth chasing, all of it. You will get an honest read on what makes sense, not a script and not a nudge towards whatever costs the most.

Get in touch to book a home survey, or just to talk it through with a local engineer first.