Boiler installation
Fixed-price combi, system, regular and LPG boiler installs across Edinburgh and the Lothians.
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Boiler types explained — honestly
Combi, system, regular, or electric — which boiler actually suits your home?
Most new boiler jobs across Edinburgh and the Lothians end up as combi installs — but not every home is a combi home. Here's an honest comparison of the four main boiler types, what each one suits, what they cost, and how to work out which one is right for your property.
Gas Safe registered engineersAdvice at survey, not over the phoneMost combi swaps in 1 day
20+
Years' Experience
Yes
Gas Safe
Yes
LPG Certified
Boiler Types
Fitted for
Flats, semis, large homes
Brands installed
Worcester, Vaillant, Ideal, Baxi
Advice given
At a free home survey
Quick Compare
The four boiler types at a glance.
A ten-second overview before the detail. Scroll down for an honest section on each, covering who it suits, what it doesn't, the install considerations, and the typical cost range we see across Edinburgh and the Lothians.
TypeSuitsHot waterSpace neededTypical installed
Combi1–2 bathroom homes with decent mains pressureHot water: On demand, no cylinderSpace: Minimal — no tanks or cylinder£2,200 – £3,500SystemLarger homes, 2+ bathrooms in use at onceHot water: From a cylinder, strong multi-outlet flowSpace: Airing cupboard for the cylinder£2,800 – £4,200Regular (heat-only)Older properties with existing tanks and low pressureHot water: From a cylinder, fed by a loft tankSpace: Loft tank + airing cupboard cylinder£2,800 – £4,200ElectricFlats and off-grid homes with no gas supplyHot water: Small unit — usually with a cylinderSpace: Compact — fits in a cupboard£1,800 – £3,500Costs are typical installed ranges for a straight replacement in Edinburgh and the Lothians. Conversions between types (e.g. regular to combi) cost more because the tank, cylinder, and pipework all change. We confirm everything in writing after a free home survey.
How To Decide
Four practical questions that decide the right boiler.
The boiler type you end up with isn't really a brand or efficiency-rating decision — it's a property decision. These are the four questions we answer at the survey before recommending anything.
How many bathrooms run at once?
One bathroom almost always means a combi. Two or more used at the same time points towards a system boiler with a properly sized cylinder.
What's your mains water pressure?
A combi needs strong, steady pressure to perform. If yours is variable or low, a system or regular boiler feeding a cylinder is usually the better call.
How much loft and cupboard space do you want to free up?
Combi removes the loft tank and cylinder entirely. System removes the loft tank but keeps the cylinder. Regular keeps both.
Is there a gas supply?
No gas means electric or LPG. Across rural Edinburgh and the Lothians, LPG is usually the more practical off-grid option, not electric.
Most popular across Edinburgh & the Lothians
Combi boilers
Hot water on demand, no cylinder, no loft tank — the right answer for most 1–2 bathroom homes.
A combination (combi) boiler gives you heating and hot water from one unit. It heats mains water on demand as you open a tap, so there's no hot water cylinder and no cold water tank in the loft. For most flats, terraces, and 1–2 bathroom semis across Edinburgh and the Lothians, a combi is the simplest, cheapest, and tidiest option — which is why most new boiler jobs we quote end up as combi installs.
How it works
The combi fires the moment you open a hot tap. Cold water from the mains runs through a heat exchanger inside the boiler, comes out hot, and flows straight to the tap or shower. There's no stored hot water, which means no standing heat losses and no waiting around for a cylinder to reheat.
Typical combi swap (installed)
£2,200 – £3,500
Straight like-for-like replacement in the same position. Includes magnetic filter, flush where needed, controls, and warranty registration.
Suits
- 1–2 bathroom homes where showers and taps aren't running at the same time
- Properties with decent mains water pressure — usually 1.5 bar or above
- Homeowners who want to free up cupboard and loft space
- Flats and smaller houses where storing hot water isn't practical
- People replacing an older combi with a higher-efficiency modern unit
Less ideal when
- Homes running two showers at the same time regularly — flow drops between outlets
- Properties with weak or variable mains pressure
- Large houses with high peak hot water demand (4+ bed, multiple bathrooms)
- Homes wanting to pair with solar thermal or a heat pump — a cylinder-based setup usually makes more sense
Install considerations
- Mains pressure and flow rate are the two things that decide whether a combi will perform well — we measure both at the survey, not over the phone
- Sizing matters: a 30kW combi is the common midpoint for a 3-bed semi; smaller flats may only need 24kW, larger homes push to 35kW+
- Moving the boiler location during a swap adds cost — flue runs, condensate routing, and gas pipe sizing all factor in
- If you're converting from a regular or system boiler, budget for removing the cylinder and tank as well — that's a two-day job, not a one-day swap
Larger homes with multiple bathrooms
System boilers
Pair with a hot water cylinder so two or more outlets can run at once without losing flow.
A system boiler works with a hot water cylinder but — unlike a traditional setup — doesn't need a cold water tank in the loft. Most of the key components (pump, expansion vessel) are built into the boiler itself, which makes for a tidier installation than a regular boiler. System boilers are the right answer in larger homes, houses with two or more bathrooms running at the same time, and anywhere you need reliable strong flow to more than one outlet.
How it works
The boiler heats water and circulates it through the radiators for heating, and through a coil inside the hot water cylinder to heat the stored domestic hot water. When you open a tap, hot water comes straight out of the cylinder — so the flow doesn't drop when a second person turns on the shower upstairs.
Typical system boiler install (installed)
£2,800 – £4,200
Replacement system install with cylinder checks, controls, and any pipework changes. New cylinders are priced at survey.
Suits
- Larger homes — 3-bed-plus with 2 or more bathrooms in use at the same time
- Households with high peak hot water demand (family of four, morning shower overlap)
- Properties with cupboard space for an unvented cylinder
- Homes planning to pair with a heat pump later — system layouts adapt more easily
- Homes currently running a regular boiler that want to remove the loft tank
Less ideal when
- Small flats and 1-bathroom homes — a combi is usually simpler and cheaper
- Properties with no airing cupboard or plant-room space for a cylinder
- Homeowners who specifically want to free up storage space
Install considerations
- Cylinder sizing is the key decision: typical sizes range from 120L (1 bathroom) through 180L (2 bathrooms, family of 3–4) up to 250L+ (3+ bathrooms, larger households)
- Unvented cylinders need a G3 qualified engineer to install and service — we hold that qualification in-house
- Cold mains pressure needs to be strong enough to feed an unvented cylinder — we check this at the survey
- If you're converting from a regular boiler, the loft tank goes and the pipework is simplified — usually a two-day job
Traditional setups in older properties
Regular (heat-only) boilers
Still the right answer for older properties with an existing loft tank, cylinder, and low mains pressure.
A regular boiler — also called a heat-only, conventional, or open-vent boiler — is the traditional layout most older Edinburgh tenements, stone-built semis, and rural Lothian properties were originally fitted with. It works with a separate hot water cylinder in the airing cupboard and a cold water tank in the loft. It's rarely our first recommendation for a new-build job, but for the right property it's often cheaper and less disruptive than ripping the existing setup out.
How it works
Cold water feeds into a storage tank in the loft, drops down to the cylinder under gravity, and is heated by the boiler through a separate loop. A feed-and-expansion tank — also in the loft — keeps the heating circuit topped up. Low-tech, simple, and works well on low mains pressure where a combi or unvented system would struggle.
Typical regular boiler replacement (installed)
£2,800 – £4,200
Straight heat-only replacement working with existing tank and cylinder. New cylinders or tank replacements are quoted separately at survey.
Suits
- Older properties with working loft tanks and cylinders that are already in good shape
- Homes with low or variable mains water pressure — where a combi or unvented system wouldn't perform
- Listed or conservation-area properties where changing the system layout isn't practical
- Larger houses that already work well on gravity-fed hot water
- Homes where budget matters more than modernising the pipework
Less ideal when
- Modern properties with decent mains pressure — a combi or system install is usually tidier
- Homeowners who want to free up loft and cupboard space
- Properties where the existing cylinder or loft tank is past its life
- Anyone planning to pair with a heat pump — a system layout is more flexible
Install considerations
- If the existing cylinder and tank are more than 20–25 years old, factor in replacement cost — corroded tanks and cylinders fail, and it's cheaper to do it at install time than go back later
- Regular boilers can be converted to combi or system boilers in a single project if you'd rather modernise — usually a 2-day conversion including tank and cylinder removal
- Frost protection matters in Scottish lofts — tanks and pipework need lagging, and we'll check condition at the survey
- Heat-only units have fewer moving parts inside, which historically meant long service life — reliability is still a strong point
Off-grid option — flats and no-gas properties
Electric boilers
Silent, compact, and useful where there's no gas supply. Higher running costs, but worth considering in the right situation.
An electric boiler uses mains electricity to heat water for central heating and, in most setups, a hot water cylinder. There's no flue, no gas supply, no combustion, and no annual Gas Safe service. That makes them useful in flats, park homes, rural properties with no gas or LPG supply, and small buildings where installing gas infrastructure isn't practical. The catch is running cost — electricity per kWh is typically 3–4× the cost of mains gas, so they only make sense in the right property.
How it works
Water in the heating circuit passes through an electric heating element inside the boiler and is pumped around the radiators. For hot water, a similar element heats the cylinder directly, or the boiler feeds a separate cylinder. Simple, reliable, no flue needed — but the kWh cost is the deciding factor on whether it suits your property.
Typical electric boiler install (installed)
£1,800 – £3,500
Straight electric boiler install. Final cost depends on kW output, controls, and any consumer-unit upgrades required.
Suits
- Flats and apartments where no gas supply is available
- Rural properties off the mains gas grid where LPG isn't practical
- Small properties with modest heating demand
- Homes with significant solar PV generation (offsets some of the running cost)
- Properties where a quiet, compact, flue-free unit is the priority
Less ideal when
- Any property where mains gas or LPG is available — running costs will be meaningfully higher on electricity
- Large homes with high heating demand — running cost becomes a real issue
- Homes with poor insulation — the electricity bill scales directly with heat loss
- Households on standard single-rate electricity tariffs without any renewable offset
Install considerations
- For off-grid properties, LPG is often the better answer — we're LPG certified and regularly install LPG systems across rural Midlothian, East Lothian, West Lothian, and the Pentlands
- Electric boilers are simpler mechanically, but they're not cheaper to run — kWh economics decide the real annual cost
- Off-peak (Economy 7) tariffs can help for cylinder reheats, but central heating on electric rarely matches mains gas running cost
- They pair reasonably with solar PV or a home battery, but they're rarely the right answer for anything larger than a 2-bed flat
Changing Type
Moving from one type to another?
A big share of our install work is conversions — regular to combi, regular to system, or system to combi — where the existing setup doesn't really suit how the household uses hot water any more. A conversion is usually a two-day job rather than a one-day swap, because tanks, cylinders, and pipework all need to change.
- Regular → combi: removes the loft tank and cylinder, frees up space, and simplifies the pipework. Suits 1–2 bathroom homes where mains pressure is strong.
- Regular → system: keeps the cylinder (or fits a new unvented one), removes the loft tank, and gives you proper flow to multiple bathrooms.
- System → combi: removes the cylinder and reworks the pipework. Only really makes sense for 1–2 bathroom homes with strong mains pressure and decent peak demand.
Conversion install (installed)
£3,200 – £4,800
Typical range for a conversion between boiler types across Edinburgh and the Lothians. Includes tank or cylinder removal, pipework changes, new boiler, and all the standard extras (filter, flush, controls, Gas Safe notification, warranty registration).
Also Useful
Decided which type suits? Here's where to go next.
Whether you're after a full install, a repair, an annual service, or an off-grid LPG setup, the same Gas Safe team handles the whole journey.
Boiler repairs
Same-day diagnosis and repair on combi, system, regular, and LPG boilers when something isn't right.
See repair servicesRepair route
LPG boilers
The usual answer for off-grid properties across rural Midlothian, East Lothian, West Lothian and the Pentlands.
See LPG servicesLPG route
Boiler Type FAQs
Common questions before choosing a boiler type.
Short, honest answers on choosing between combi, system, regular, and electric — plus the cost and timing questions that come up next.
What Comes Up Most
Combi, system, regular, and electric — quick differences
Which boiler type suits your property and water demand
Typical installed cost by boiler type
When conversion from one type to another makes sense
Want advice for your exact property?
The right boiler type depends on your bathrooms, mains pressure, and how you use hot water. Call us and we'll talk it through properly, or book a free home survey.
For most Edinburgh homes, a new combi boiler installed costs between £2,200 and £3,500, depending on the brand, model, and how much pipework needs changing. System and regular boiler installs typically run £2,800 to £4,200 once the cylinder and controls are factored in. We give a fixed written quote after a free survey so you know exactly what you're paying before any work starts.
Book your free survey
Still unsure which boiler type suits? We'll tell you straight.
A free home survey from a Gas Safe engineer — we'll check your mains pressure, hot water demand, and layout, then recommend the boiler type that actually fits your property. No hard sell, no upselling the most expensive option.