Scotland Regional Winner, Heating Installer Awards 2026Highly Commended, Scottish Energy Efficiency Awards 2025
🎉 Scotland Regional Winner at the Heating Installer Awards 2026
Scotland Regional Winner, Heating Installer Awards 2026Highly Commended, Scottish Energy Efficiency Awards 2025
🎉 Scotland Regional Winner at the Heating Installer Awards 2026
Home / Blog / The heat pump installation process in Scotland
The heat pump installation process in Scotland takes about five working days on site, and each day has its own job. The outdoor unit and the pipe routes come first, then the old boiler comes out, then the radiators and the new cylinder go in, then the electrics and a flush of the whole system, and the last day belongs to commissioning and the handover.
Knowing that order tells you which days the heating is off, which days the floorboards come up, and what paperwork you should hold when the van drives away.
Sean Hogan · Heat Geek engineer · Updated October 2026 · 13 min read
Five working days is our own figure for a whole-house retrofit. The split between the days below shows how a typical job falls, and your engineer moves tasks around to suit the house: a villa with a long list of radiator changes spends more of the week on them than a two-bedroom flat does.
The air source heat pump installation process has four stages:
Only the install week puts a team in your house, and the table shows how those days run on a typical job.
| Day | Main work | Heating and hot water |
|---|---|---|
| Before day one | Survey, design, quote, install date booked, network operator told about the new load | Old system running |
| Day one | Floors and routes protected, outdoor unit base set, wall cored for the pipes, first pipe runs | Old system still running on a typical job |
| Day two | Old boiler, flue and controls out, old cylinder and loft tank out where the design replaces them | Off from the moment the boiler is disconnected |
| Day three | Radiator changes, pipework upgrades, new cylinder in position | Off |
| Day four | Electrics and controls wired, system flushed, filtered and filled | Off |
| Day five | Commissioning, radiator balancing, weather compensation set, handover | Back on |
| First weeks | Remote checks and fine-tuning where the controls allow it | On |
A house with pipework to replace can use all five days with little to spare. Your engineer confirms the order for your house before the week starts, and the table gives you the right questions to ask.
Every date in the install week comes out of the survey. Your engineer measures the heat loss of each room, checks the radiators, pipework and electrics, and picks the spots for the outdoor unit and the cylinder. The written proposal lists the heat pump, the radiator changes, the cylinder and where each part goes, and the install team works from that list on day one.
The gap between survey and install depends on the diary and on funding. If you are applying for Home Energy Scotland funding, no work can start until the written offer arrives, because Home Energy Scotland does not fund work that has already begun.
Your installer also has to tell the local network operator about the heat pump, since it adds a new load to your supply, and where the supply needs upgrading the operator approves the connection before the unit goes live.
The run-up is the same for a Glasgow four-in-a-block and a stone villa in the capital. If your home is in or around the capital, our page on heat pump installation in Edinburgh sets out how we work there.
“We initially had Sean over to provide a quote, and as we didn’t know much about heat pumps, he explained everything clearly and in a way we could easily understand. He emphasized the importance of proper heat loss calculations for our property, which helped us determine which existing radiators we could keep.”
Marie Penrice, ★★★★★ Google Review
Day one starts with dust sheets and floor protection along each route the team will use, from the front door to the cylinder cupboard and into the rooms where radiators are changing.
Outside, the team sets the base for the outdoor unit in the position agreed at the survey. The base has to sit flat and level, and the unit needs a route for condensate to drain away, because it sheds water each time it defrosts through a Scottish winter.
The Vaillant aroTHERM plus, like many domestic air source heat pumps, is a monobloc unit: the refrigerant stays sealed inside the outdoor unit, and two insulated water pipes and the cables are the only things that cross your wall.
Getting those pipes in means coring a hole through the external wall. On a solid stone wall, which can run well over half a metre thick in older Scottish properties, the drilling is the loudest part of the week. Your engineer picks the entry point to keep the outside pipe run short, since each metre of pipe outdoors loses a little heat and needs protecting from frost.
On a typical job the old boiler is still running at the end of day one, so you go to bed with heating.
Day two on a typical job is when the old system comes out and the heating goes off. On a gas or oil system that means the boiler, its flue and the old programmer and room thermostat. If the house has an old vented cylinder, it goes too, and where the new cylinder runs at mains pressure the cold water tank in the loft that fed the old one often goes with it.
Each fuel brings its own loose ends.
A gas boiler’s supply has to be capped by a registered gas engineer, and your quote states who arranges it.
An oil-fired house has more to settle outside: the survey records the fuel supply and storage, and the proposal sets out what happens to them.
With electric storage heaters, the proposal lists which units come off the walls as the new radiators go in.
Combi households gain a cylinder and give up a cupboard. The choices behind the swap for gas, oil and combi homes are covered in our guide to replacing a boiler with a heat pump in Scotland.
“On the day of the installation, the team showed up on time and got straight to work. They were professional and efficient, and the whole installation went smoothly. They took the time to ensure everything was set up correctly and even cleaned up after themselves, leaving no mess behind.”
Martin Mann, ★★★★★ Google Review
Day three belongs to the radiators on a typical job. A heat pump runs the water cooler than a boiler, so a room whose old radiator can’t give out enough heat at the design flow temperature gets a larger one, and a cold room may gain a second.
The survey has already decided which ones change, using the method in our guide to heat pump radiator sizing. Expect carpets rolled back and a floorboard or two up in rooms where pipes are being replaced.
Pipework is the part of the week that varies most between houses. Narrow microbore pipe can limit how much water reaches the radiators, and the design decides whether to replace a section or work with what is there.
On a Cumbernauld retrofit filmed for our YouTube channel, the ground-floor pipework was buried in concrete, so we kept it and fitted a Panasonic T-CAP with a strong enough circulating pump to push water through it, while the blocked 8 mm microbore upstairs came out and was replaced.
The new cylinder goes into its planned spot, often the old airing cupboard, a utility room or a cupboard under the stairs. In Penny and Monique’s 1920s sandstone end-terrace in Mount Florida, the 250 litre cylinder and the main system components went into a 1.2 metre high basement, which kept the rooms upstairs clear. Cylinder sizes and where they can go are set out in our guide to heat pump hot water.
Day four brings the electrics and the water. An electrician runs a dedicated circuit from your consumer unit to the outdoor unit, with an isolator beside it, and wires the controls, the cylinder and the valves.
Before the heat pump sees any water from the old circuit, the team flushes the pipework and radiators to clear the sludge and magnetite that years of boiler use leave behind, then fits a magnetic filter and strainer to catch what remains. A heat pump fitted straight onto a dirty system clogs its heat exchanger, and we have replaced units that failed for that reason.
The outdoor pipework gets its insulation and frost protection on the same day, either antifreeze valves or glycol in the circuit, so a power cut during a hard frost can’t split the pipes.
Yes, for part of the week. Your heating and hot water go off when the old boiler is disconnected, on day two of a typical job, and come back when the heat pump is commissioned at the end of the week. The survey tells you which days to expect for your house.
If your install week falls in January, have a couple of plug-in heaters ready for the rooms you use most, and ask your engineer whether hot water can be kept going for part of the week. The answer depends on how the old and new cylinders are plumbed, so it changes from house to house.
The rest of the disruption comes in stretches.
Coring the wall on day one is the noisiest job.
Radiator day means rooms emptied around the walls, and the water goes off for short spells while pipes are cut in.
If you work from home, those are the two days to plan your calls around. You can stay in the house all week, and the team tidies the working areas at the end of each day.
Pets are worth a thought too. Doors stay open more than usual while pipe and radiators come in and out, so a cat that bolts at the sight of a van may be happier elsewhere for the first morning.
“Outstanding service, difficult decision to make to change to air source heat pump especially give the level of misinformation. Sean/Aventus Eco were outstanding in helping me explore and decide that this was right solution.”
Robert Henderson, ★★★★★ Google Review
On the last day your engineer brings the system up to pressure, purges the air out and runs the heat pump against the design. Heat pump commissioning means checking the flow rates, temperatures and pressures against the figures in your design and recording them, so you receive the commissioning numbers with the records to prove them.
Two settings decide how well the system runs from here.
The first is the weather compensation curve, which raises the water temperature as the outdoor temperature falls and keeps it as low as the house allows on milder days.
Our design work follows Heat Geek Mastery training, which puts heavy weight on this curve, because a curve set too high wastes electricity on every mild day of the year.
The second is radiator balancing, which sets each radiator’s share of the flow so each room reaches its temperature alongside the others, and we check the result with a thermal imaging camera.
After commissioning, your installer registers the system with MCS and issues your MCS certificate within 10 working days. Keep it with the commissioning records. You will need both for a warranty claim and when you sell the house.
At handover your engineer walks you through the controls and the app, shows you the isolator and the filter, and explains which settings to leave alone.
The manufacturer warranties on the heat pumps we fit run up to 7 years once registered, so warranty registration is part of the handover, and your 5-year workmanship guarantee is written into your quote. Our guide to heat pump manufacturer apps covers what the app shows and how to read it.
The install team leaves on day five, but the tuning carries on. If your controls connect to the manufacturer’s app or service portal, we can watch the system’s data over the first few weeks and adjust the weather compensation from the office, without another visit to the house.
A heat pump runs in a different rhythm from the boiler you had.
All of that is normal.
The first proper cold snap is the real test of the curve, and if a room feels cool when the frost comes, tell us, because a small change to the curve is the usual fix.
Manufacturers expect an annual service to keep the warranty valid, so book the first one for around the anniversary of your install.
About five working days on site for a typical whole-house retrofit in Scotland. Houses with a lot of radiator or pipework changes use the full week with little to spare. The survey and design come before the install week, and fine-tuning continues for a few weeks after it.
For part of the week, yes. The heating and hot water go off when the old boiler is disconnected, on day two of a typical job, and come back at commissioning on the last day. Your engineer tells you the days at the survey stage, and a couple of plug-in heaters cover the coldest rooms in winter.
It depends on the installer’s diary and on funding. If you apply for Home Energy Scotland funding, work cannot start until the written offer arrives. Your engineer gives you an install date once the proposal is agreed.
The old boiler, its flue and controls, and the old cylinder and loft tank where the design replaces them. Radiators come out only where the design swaps them for larger ones. The survey decides what happens to the rest of the old system, including any fuel supply outside.
Yes. You receive the commissioning records at handover, showing the flow rates, temperatures and pressures measured against the design. Your installer also registers the system with MCS and issues the MCS certificate within 10 working days of commissioning.
Plan to be there on the first morning and for the handover on the last day. For the days in between, agree access with your engineer before the week starts.
A £0 survey tells you whether your house suits a heat pump and puts the install week in writing, from the day the boiler comes out to the handover.
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