Job takeoff
Air-source heat pump replacing a boiler takeoff
Replace a boiler with an air-source heat pump (a heat pump, in North America) on the wet system it heated: dust sheets where radiators and pipes change, lagging on the flow and return outside and in cold spaces, and the waste, with the heat-loss design, the base, the unit, the hot-water cylinder (water heater tank), the larger radiators, the flush, the circuit and its isolator (disconnect), the controls and the commissioning listed and never certified.
A takeoff is the trade word for the shopping list a job produces — every material, and how much of each, worked out by its own cited calculator.
- 4Measurements in
- 3Trades out
Give the job once
Every figure on the right follows these, in the units you choose.
Been given a quote for this job?
Paste it into the air-source heat pump quote check: each line is read against these same calculators — what it leaves out, what it adds, and what to ask.
Check the quoteEvery trade, from those dimensions
then change a dimension, and each line shows what moved.
| Trade | Quantity | |
|---|---|---|
Dust sheets over the floors the work crossesMasking and Protection Materials CalculatorSheets for the floors of the rooms you gave, counted at the calculator's opening sheet size: every radiator drained and lifted off lets out water blackened by years of sludge, and boards lifted for pipe runs throw dust across the room. They cover floors, not furniture, and the cylinder's cupboard is often sheeted twice, once for the old cylinder coming out and again for the new one going in; nothing is taped to the walls.
Why this quantity?
Resting on
Change any other figure on the Masking and Protection Materials Calculator | 6 items | |
Lagging outside and in cold spacesPipe Insulation CalculatorFoam sleeves over both pipes between the unit and the wall, twice the route you gave, and over the pipe you counted in a loft, floor void or garage, in the pipe page's sleeves, a metre long (about 3 ft 3 in) in metric and six feet (1.8 m) in imperial, with its allowance for bends. Outside, a heat pump's pipes take a thicker insulation than pipes indoors, finished with a jacket or coating that stands up to sunlight, and the sleeve's bore and wall are chosen for that; the number of sleeves depends on length only. The defrost water's pipe is not here: it is lagged, or trace-heated, with its own run, which is listed.
Why this quantity?
Resting on
The bend and trim waste: the calculator's working figure, a trade convention. | 9 x 6 ft sections | |
Skip (dumpster) or a waste collectionSkip & Dumpster Size CalculatorWhat the changeover throws out, as a loose depth over the rooms you gave, weighed as mixed construction waste: the boiler and its flue terminal, the radiators replaced, an old cylinder and its loft tanks where they go, cut pipe, and the timber crates and cardboard the unit and the cylinder come in, which are bulky for their weight. Boilers, radiators, copper and a cylinder fetch money as scrap and can be weighed in rather than skipped, and the drained system water is emptied to a foul drain, not the container.
Why this quantity?
Resting on
Change any other figure on the Skip & Dumpster Size Calculator | 1 yd³ | |
Dust sheets over the floors the work crossesMasking and Protection Materials CalculatorSheets for the floors of the rooms you gave, counted at the calculator's opening sheet size: every radiator drained and lifted off lets out water blackened by years of sludge, and boards lifted for pipe runs throw dust across the room. They cover floors, not furniture, and the cylinder's cupboard is often sheeted twice, once for the old cylinder coming out and again for the new one going in; nothing is taped to the walls.
Why this quantity? | 6 items | |
Lagging outside and in cold spacesPipe Insulation CalculatorFoam sleeves over both pipes between the unit and the wall, twice the route you gave, and over the pipe you counted in a loft, floor void or garage, in the pipe page's sleeves, a metre long (about 3 ft 3 in) in metric and six feet (1.8 m) in imperial, with its allowance for bends. Outside, a heat pump's pipes take a thicker insulation than pipes indoors, finished with a jacket or coating that stands up to sunlight, and the sleeve's bore and wall are chosen for that; the number of sleeves depends on length only. The defrost water's pipe is not here: it is lagged, or trace-heated, with its own run, which is listed.
Why this quantity? | 16 x 1 m sections | |
Skip (dumpster) or a waste collectionSkip & Dumpster Size CalculatorWhat the changeover throws out, as a loose depth over the rooms you gave, weighed as mixed construction waste: the boiler and its flue terminal, the radiators replaced, an old cylinder and its loft tanks where they go, cut pipe, and the timber crates and cardboard the unit and the cylinder come in, which are bulky for their weight. Boilers, radiators, copper and a cylinder fetch money as scrap and can be weighed in rather than skipped, and the drained system water is emptied to a foul drain, not the container.
Why this quantity? | 0.72 m³ |
Estimates, not a quote. Each row gives its base, the allowance on top, the adjusted figure and what to order; change an allowance on the row, or open its reasoning to see every figure it rests on. A trade's own page carries what it does not cover — open the one you are about to order against.
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Dust sheets over the floors the work crosses2.4 h (1.2–4.8)
- Lagging outside and in cold spaces1.0 h (0.4–2.1)
- Skip (dumpster) or a waste collection0.8 h (0.4–2.3)
About 4.2 person-hours in all, between 2.0 and 9.2.
Trade by trade
- Labourer1 labourerhalf a day
About half a day, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
Labour and programme
Person-hours for the rows going in, from trade rules of thumb: a range for each piece of work, never a price.
- Dust sheets over the floors the work crosses2.4 h (1.2–4.8)
- Lagging outside and in cold spaces1.0 h (0.4–2.1)
- Skip (dumpster) or a waste collection0.7 h (0.4–2.2)
About 4.1 person-hours in all, between 2.0 and 9.1.
Trade by trade
- Labourer1 labourerhalf a day
About half a day, one trade after another at eight hours a day. Left out: drying and curing, deliveries, inspections, trades overlapping.
Setups you have saved
The build-up, the dimensions and any allowance you changed — kept on this device, and reusable on any job. Your prices are not copied in: they stay in your price book, so a setup never holds a stale one.
How far does a budget go?
At your own prices, with this build-up unchanged.
About this job
An air-source heat pump takes heat out of the outside air, even on a frosty day, and hands it to the same water a boiler heated. What changes the house is the temperature of that water. A boiler can run its radiators hot; a heat pump runs cheapest and longest with them only warm, so a room is heated by more radiator surface for more hours rather than by hotter water in short bursts. Which radiators (panel radiators, in North America) must be replaced with larger ones, whether any pipe must be upsized, how large the unit is and what flow temperature and weather curve it runs on all come from a room-by-room heat-loss survey of the house. That survey is the first item on the list and the designer's, and this page sizes none of what follows from it.
The outdoor unit is the part people see. It stands on a level base of slabs, a plinth or a ground frame, or hangs on brackets from a wall that can carry it, with the clearances round it that its maker's manual gives and on anti-vibration feet so its hum stays out of the house. Where it may stand is also a noise question: in England the permitted-development rules ask for a noise check at the nearest neighbour's window, and elsewhere a local rule or a permit may. It makes water as it defrosts, which runs from its drain tray to a gully or a soakaway and must not freeze on the way. Its flow and return enter the house through the wall, and outside they are lagged with a sleeve that stands up to sunlight; that lagging, and the lagging on pipes crossing a loft or a floor void, is what the lagging row counts.
Hot water changes too. A heat pump heats water slowly, so a house on a combination boiler gains a hot-water cylinder (an indirect water heater tank) with a coil large enough for it, and an old cylinder with a small coil is replaced. Usually unvented, it needs its safety valves piped through a tundish to a safe outlet, and full it weighs several times what the wall-hung boiler did, often in an upstairs cupboard or a loft where it stands on timber joists. Whether that floor carries it is flagged here and never answered, and strengthening it is not in this job.
The heat pump has its own circuit, from a new way in the consumer unit (service panel) to a lockable isolator (a disconnect) beside the unit, and the network operator is told of it in Great Britain, or the utility consulted in North America, once the supply has been checked for the extra load. Between the day the system is drained down and the day it is commissioned the household has no heating or hot water from it, which is worth planning outside the coldest weeks; heaters and hot water in the meantime are not in this job. The rows here are the measured work round the heating: the dust sheets in the rooms where radiators and pipes change, the lagging, and the waste. In the UK a grant towards the unit asks for an installer certified under MCS, whose certificate is one of the handover papers; across North America the work is permitted, with mechanical and electrical inspections, and a split system's refrigerant lines are for a technician certified under EPA Section 608.
How each line reads
- Base
- What the calculator gives for these dimensions, before anything is added.
- Allowance
- Cutting waste, a lap or spare stock — named, with where it comes from, and changeable on the row.
- Adjusted
- The base with its allowance on top.
- Order
- What to buy: the adjusted figure in whole boards, bags, rolls or lengths.
The order this happens in
Quantities do not tell you the sequence, and on this job the sequence is where the money goes wrong.
- Have the house surveyed room by room for its heat loss, and settle where the outdoor unit stands (its clearances, the noise at the nearest neighbour's window and a route for its defrost water) and where the cylinder goes, before anything is ordered; have the old boiler's cupboard, its flue and any old pipe lagging checked for asbestos, and tell the network operator (utility) about the new load once the supply has been checked.
- While the old boiler still heats the house, lay the unit's base or fix its wall brackets, core the holes through the wall for the flow and return and the cable, and run the new circuit from the consumer unit (panel) to where its isolator will go.
- On the changeover day sheet the rooms, cap the gas at the old boiler, isolate its electrical supply and empty the wet system into a foul drain; from here the household has no heating or hot water from it until the heat pump is commissioned.
- Take out the old boiler and its flue terminal, the old cylinder and the loft tanks where they go, and the radiators being replaced with larger ones; where the old boiler was open-flued up a chimney, cap and vent the pot from a scaffold.
- Alter the pipework for the lower flow temperature, upsizing the runs the design names and lifting boards only where the rules allow, and hang the larger radiators with their valves; pressure-test every joint while it is in sight, then lag the pipe that crosses the loft and the floor voids.
- Cleanse and power-flush the old radiators and pipework before the heat pump is connected, then set the unit on its base on anti-vibration feet, connect it and lag its flow and return outside in their weatherproof sleeves; stand the cylinder and connect it with its discharge pipe through a tundish, and run the defrost water to a gully or soakaway.
- Fit the isolator beside the unit, the controls and wiring centre and the immersion heater's switch; fill, dose the inhibitor or the maker's antifreeze, and have the installer commission the system and set its weather curve while the electrician tests the new circuit.
- Fill the hole the old flue left and the ones the old pipes crossed, take the scrap and the crates away, and hand over the heat pump's commissioning sheet with its weather curve, the cylinder's and the electrician's certificates, and the MCS certificate where a grant needs one.
What this takeoff does not cover
- The heat-loss survey and the design drawn from it: the unit's output and running temperature, which rooms need a bigger panel, the pipe bores and the hot store's size. One listed item, the designer's; no sizing page is reached here.
- The grant itself, and the MCS scheme a UK grant rests on, which the installer or the household applies to.
- Planning permission, and the noise condition England's permitted-development rules set, or a local noise rule or permit elsewhere. The noise check on where the unit stands is part of the listed design; the permission itself is not in this job.
- Increasing the house's supply or main fuse (service), where the supply check finds it too small: that is the network operator's or the utility's work. Telling them of the new load is listed.
- Fabric work a design may ask for first, such as loft or wall insulation, draught-proofing or new windows, each a job of its own.
- Taking out an oil tank or bottled LPG, a gas fire or a back boiler, or a whole stack; capping the open flue the old boiler used is listed.
- A new cupboard or enclosure round the hot-water store, and strengthening the floor under it, whose weight is flagged.
- The tariff the unit runs on, a new meter, and any export or time-of-use deal with the energy supplier.
- Temporary or portable heaters for the household meanwhile, and its baths and showers taken elsewhere until the new store is hot.
- Cooling, by an air-to-air or ducted system, is another job; the mini-split takeoff covers one room's.
Quote check
Been given a quote for this job?
Paste it into the air-source heat pump quote check. Every line of it is read against these same calculators and your measurements. Quantities only, never prices.
What it leaves out
Every line this takeoff has that nothing on the quote reads as.
What it adds
Labour, removal, hire, fees — each named for what it is.
What to ask
One list of questions, ready to copy. Never a verdict.
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Frequently asked questions
- What does the air-source heat pump takeoff give for a typical job?
- Opened at Floor of the rooms where radiators or pipes change 60 m² · From the outdoor unit to the house wall, one way 3 m · Pipe through cold spaces indoors, each pipe counted 8 m · Loose waste, as a depth over those rooms 0.01 m, it orders: Dust sheets over the floors the work crosses, 6 items; Lagging outside and in cold spaces, 16 x 1 m sections; Skip (dumpster) or a waste collection, 0.72 m³. Opened at Floor of the rooms where radiators or pipes change 650 sq ft · From the outdoor unit to the house wall, one way 10 ft · Pipe through cold spaces indoors, each pipe counted 26 ft · Loose waste, as a depth over those rooms 0.5 in: Dust sheets over the floors the work crosses, 6 items; Lagging outside and in cold spaces, 9 x 6 ft sections; Skip (dumpster) or a waste collection, 1 yd³. Every figure follows the dimensions you give it.
- Which calculators does the air-source heat pump takeoff run?
- 3 calculators, one to a line: Masking and Protection Materials Calculator, Pipe Insulation Calculator, Skip & Dumpster Size Calculator. Each has a page of its own with its formula and its sources; the takeoff runs them all on one set of dimensions.
- What does the air-source heat pump takeoff leave out?
- 10 things, each named on this page: The heat-loss survey and the design drawn from it; The grant itself, and the MCS scheme a UK grant rests on, which the installer or the household applies to; Planning permission, and the noise condition England's permitted-development rules set, or a local noise rule or permit elsewhere; Increasing the house's supply or main fuse (service), where the supply check finds it too small; Fabric work a design may ask for first, such as loft or wall insulation, draught-proofing or new windows, each a job of its own; Taking out an oil tank or bottled LPG, a gas fire or a back boiler, or a whole stack; capping the open flue the old boiler used is listed; A new cupboard or enclosure round the hot-water store, and strengthening the floor under it, whose weight is flagged; The tariff the unit runs on, a new meter, and any export or time-of-use deal with the energy supplier; Temporary or portable heaters for the household meanwhile, and its baths and showers taken elsewhere until the new store is hot; Cooling, by an air-to-air or ducted system, is another job; the mini-split takeoff covers one room's.
- Can I check a quote for this job against the takeoff?
- Yes. The air-source heat pump quote check reads a quote's lines against these same calculators and your measurements, and reports what it leaves out, what it adds and what to ask. It reads quantities, never prices.