The Complete Heat Pump Installation Process — Survey to Handover

In short

A typical heat pump installation in a Reading home takes 4 to 10 weeks from your first enquiry to handover, with the actual on-site work running 1 to 5 working days. The process has six stages — qualifying call, property survey, design, quote and contract, installation, and commissioning with handover — governed by MCS Installation Standards MIS 3005-I (installation, Issue 1.0, February 2025) and MIS 3005-D (design, Issue 3.0, mandatory from 5 December 2025). The work itself is largely standardised across MCS-certified installers; the variance between installers is in survey depth, design rigour, and the quality of the customer handover.

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On this page

• The six stages, at a glance
• Stage 1 — First contact and qualifying questions
• Stage 2 — The property survey
• Stage 3 — Design
• Stage 4 — Quote and contract
• Stage 5 — Installation week
• Stage 6 — Commissioning and handover
• How long does the whole thing take?
• What separates a good install from an adequate one
• What this means for homes in Reading

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The six stages, at a glance

Stage	What happens	How long
1. Qualifying call	10–20 minute call covering property type, current heating, outdoor space, BUS grant intent	1 call
2. Property survey	On-site visit: room-by-room measurements, radiator condition, electrical supply, outdoor unit siting	60–120 minutes on site
3. Design	Desk-based: heat-loss calculation, system sizing, emitter design, schematic	2–5 working days
4. Quote and contract	Itemised quote with BUS grant deducted; contract and 14-day cooling-off period	Quote in 1–3 days; cooling-off period 14 days
5. Installation	On-site install: outdoor unit, indoor pipework, radiator changes, cylinder, electrical work	1–5 working days
6. Commissioning and handover	System balancing, controls setup, customer demonstration, full documentation pack	Half a day to a full day

Plus a contract-to-install scheduling gap of 2–8 weeks depending on installer availability and BUS grant voucher timing.

Stage 1 — First contact and qualifying questions

Before we book a survey, we have a short call to make sure your property is heat-pump-suitable and to give us enough information to plan the visit properly. A typical qualifying call lasts 10–20 minutes and covers:

• Your property — type (terrace, semi, detached, flat, bungalow), approximate age, approximate floor area, number of bedrooms
• Your current heating — what’s heating the property now (gas combi, gas system, gas regular, oil, LPG, electric), and how your hot water is currently arranged (combi, cylinder, or immersion only)
• Your insulation — loft insulation status, cavity wall insulation status, double glazing (we’ll verify on the survey, but knowing the headlines up front helps us judge whether a heat pump will work efficiently in your home)
• Your outdoor space — where the outdoor unit could potentially go (rear garden, side passage, front, flat roof). Heat pumps need a defined space outdoors with clearances from walls, windows, doors, and neighbouring properties
• Your situation — whether you own the property (BUS-grant eligibility), whether it’s listed or in a conservation area, and your rough timing
• BUS grant — whether you’d like us to apply for the £7,500 Boiler Upgrade Scheme grant on your behalf

The output of the qualifying call is either a scheduled survey date or, occasionally, a polite “the heat pump probably isn’t right for your property — here’s why” with a specific reason. We’d rather catch this up front than waste your survey time.

Stage 2 — The property survey

A heat pump survey is more involved than a gas-boiler survey. We’re gathering the inputs for a proper room-by-room heat-loss calculation that drives every subsequent design decision. A survey typically takes between an hour and two hours on site.

What we’re doing room by room:

• Measuring each room — dimensions, window count and type, external-wall area, ceiling height
• Assessing each radiator — dimensions, type (single panel, double panel, column), age and condition, and whether it can deliver the room’s heat-loss demand at a heat pump’s flow temperature
• Checking your insulation — loft depth, wall construction (solid brick, cavity, timber frame), floor construction, draught-proofing condition
• Looking at your existing pipework — what’s there, what material, what size — and how the heating-water circuit would need to be configured for the heat pump
• Checking your hot water arrangement — existing cylinder size, type, condition; or assessing where a new cylinder could go if your current system is combi-only
• Inspecting your electrical supply — main fuse rating, consumer unit, meter type, and where the heat pump’s electrical connection would land
• Identifying outdoor unit siting options — usually two or three viable locations, balancing performance (airflow, distance to internal connection), noise (clearance from your own bedrooms and your neighbours’), and any planning considerations (conservation area, listed building, condensate drainage)
• Walking through the internal pipework route — from the outdoor unit to the indoor heat exchanger to the hot water cylinder and on to your radiator circuit

For a more detailed look at what a heat-loss survey involves and why it matters, see our heat-loss survey guide.

The survey output is a structured site report and a property-level heat-loss workbook that feeds into Stage 3.

Stage 3 — Design

The design phase is desk-based and typically takes 2 to 5 working days after the survey. This is where the technical decisions that determine how well your heat pump performs are made.

What gets designed:

• Your room-by-room heat-loss calculation at Reading’s design winter temperature (around −3.4°C — the conditions the system must cope with on a cold winter day)
• Heat pump sizing — matched to your property’s total heat-loss with a small margin. Standard UK home installs sit in the 4–12 kW range. We don’t oversize (“just to be safe”) because oversized heat pumps short-cycle and run less efficiently; we don’t undersize because undersized heat pumps lean on backup electric heating in cold weather, which costs more to run
• Emitter design — each room’s existing radiator assessed against the room’s heat-loss demand at the planned flow temperature. Radiators that can deliver enough heat at the heat pump’s lower flow temperature stay; radiators that can’t are replaced (typically with larger versions of the same type, or higher-output column radiators)
• Hot water cylinder sizing — if you need a new cylinder (or your current one needs replacing), sized to your household’s hot water demand profile
• System schematic — the diagram showing how the heat pump, cylinder, controls, and radiator circuit fit together. This becomes part of your handover documentation
• SCOP estimate — the predicted seasonal efficiency for your specific system in your specific property in Reading’s specific climate
• Electrical load assessment — if your existing electrical supply isn’t sized for the heat pump, we’ll flag that and arrange the upgrade with your Distribution Network Operator

For why getting the design right matters so much, see our guide on flow temperature design and our guide on what sizing gets wrong.

Stage 4 — Quote and contract

Once the design is complete, we issue a written quote. A proper heat pump quote itemises:

• The heat pump model and output rating
• The hot water cylinder (if changing)
• Each radiator change, by room
• Electrical work
• Pipework, controls, and accessories
• Commissioning and MCS documentation
• BUS grant £7,500 deducted as a separate line
• VAT (currently 0% under the energy-saving-materials relief until 31 March 2027)
• Total payable

You see the net figure you actually pay, with the grant already deducted. We claim the grant back from Ofgem after commissioning; you never handle BUS money directly. For a detailed look at what your quote should include — and what to look out for — see our quote anatomy guide.

Your 14-day cooling-off period. If we sign the contract in your home (which is typical for heat pump installs), you have a statutory 14-day cooling-off period under the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013. You can cancel within those 14 days with no penalty. If you’d like us to start work inside the cooling-off period, that’s allowed — but you’ll need to confirm in writing. For the full picture of your consumer rights, see our contracts and deposits guide.

Deposit protection. Your deposit is protected by either RECC (the Renewable Energy Consumer Code) or HIES (the Home Insulation and Energy Systems Contractors Scheme) — both Chartered Trading Standards Institute-approved consumer codes and TrustMark Scheme Operators. If we ceased trading between deposit and install, you’d be reimbursed by the scheme’s insurance backing.

Stage 5 — Installation week

For a standard air-to-water heat pump retrofit in a typical Reading home, the on-site install runs 1 to 5 working days. Most installs land at 3 to 5 days when the work includes radiator changes and a new cylinder; 1 to 2 days is achievable for a straightforward replacement-only install.

A typical 3–5 day install shape:

Day 1. Take out your existing boiler. Prepare the outdoor unit’s location — bracketry, plinth, condensate drainage. Run rough-in internal pipework changes. Remove your existing flue. The heat pump outdoor unit arrives.

Day 2. Position, level, and secure the outdoor unit. Run the refrigerant lines (for split systems) or insulated heating-water pipework (for monobloc systems) from the outdoor unit through the external wall. Install the indoor heat exchanger and circulation pump.

Day 3. Install your new hot water cylinder if you’re changing. Carry out radiator changes room by room. Complete internal pipework. Electrical supply changes carried out by a qualified electrician.

Day 4. Fit the controls. Fill the system with water, pressurise it, and leak-test. Lag all the pipework. Commission the outdoor unit’s electrical connection.

Day 5. Commissioning (Stage 6) — see below.

What can extend the timeline: discovering your existing cylinder is incompatible with the new system; an electrical supply upgrade that needs your Distribution Network Operator involved; unexpected internal pipework reroutes; or weather delays affecting the outdoor work.

Ground source heat pump installs run longer — 1 to 3 weeks — because they include the trenching or borehole drilling for the ground loop. Air-to-air installs typically run 1 to 2 days because they don’t involve any heating-water circuit work.

Stage 6 — Commissioning and handover

Commissioning is the formal sign-off process and the most important half-day in the whole install. It’s a regulated act under MCS Installation Standard MIS 3005-I, and it determines whether your system runs at the efficiency it was designed for.

What we do at commissioning:

• Fill, pressure-test, and vent the system — bleed air from radiators and the cylinder
• Hydraulically balance the radiator circuit — set flow rates room by room so each room gets the heat output it was designed for
• Verify refrigerant pressures (for split systems) at design conditions
• Configure the heat pump controls — weather compensation curve set to your property’s specific heat-loss; flow temperature set to the design value; heating schedules programmed; hot water schedules configured (including the weekly Legionella cycle at 60°C+)
• Commission the hot water cylinder — cold inlet protection set, temperature-pressure relief valve tested, immersion backup configured
• Run a system performance test — heat pump operates for 30–60 minutes at design conditions; we log flow temperature, return temperature, and electrical input, and calculate the achieved COP at the commissioning conditions
• Walk you through how the system works — your controls and app, what the system normally sounds like, what a defrost cycle looks like (it can sound a bit dramatic the first time — it’s not a fault), what to do if something looks wrong, and how to schedule your annual service

Your handover pack. Required by MIS 3005-I Appendix D, this includes:

• Your MCS certificate (issued within 14 days of commissioning per MCS scheme rules — the document you’ll need for the BUS grant claim and for future property sale)
• The heat-loss calculation workbook
• Your system schematic
• All product documentation (heat pump, cylinder, controls)
• The commissioning record (flow temperatures, balancing settings, achieved COP at commissioning)
• Warranty documentation — heat pump (typically 5–10 years parts, manufacturer-dependent), cylinder (typically 25 years), installation workmanship (RECC minimum 2 years)
• Recommended customer-side checks and how often to do them
• Annual servicing schedule and how to book yours

Your MCS certificate appears on the MCS Installations Database within 14 days. It’s the document you (and any future owner of your property) can reference as proof of MCS-compliant installation.

How long does the whole thing take?

End-to-end realistic range: 4 to 10 weeks from your first enquiry to handover.

Stage	Typical duration
First contact to scheduled survey	1–7 days
Survey to design complete	2–5 working days
Design to quote issued	1–3 working days
Quote to signed contract	0–14 days (your cooling-off period applies)
Contract to install start	2–8 weeks (installer schedule and BUS voucher timing)
Install week	1–5 days
Install to MCS certificate issued	Within 14 days of commissioning

Most of the elapsed time is the contract-to-install scheduling gap, not any single stage being slow. Peak demand in autumn pushes the upper end; quieter spring and summer scheduling sits at the lower end. If your timing matters (e.g. you’d like to have the install completed before next winter), the time to start the qualifying call is now rather than September.

What separates a good install from an adequate one

Everything above is MCS minimum — any MCS-certified installer has to meet it. The variance you’ll actually experience between installers is in the work above and around that minimum:

• Survey depth. A genuinely thorough room-by-room survey takes 90+ minutes. A survey that takes 30 minutes and “we’ll do the maths later” usually means the system is being sized by rule-of-thumb rather than measured demand — and rule-of-thumb usually means oversized, which means lower efficiency in practice.
• Emitter assessment rigour. A good installer assesses every existing radiator against the design demand at the planned flow temperature and replaces only those that genuinely fall short. A weaker installer either assumes all radiators are fine (resulting in a heat pump running at a higher flow temperature than designed, lower COP) or replaces them all by default (inflating the install cost unnecessarily).
• Controls commissioning depth. Heat pump controls — particularly the weather compensation curve — need tuning to your actual property over the first heating season. A good installer schedules a return visit at 4–6 weeks and again at 6 months to refine the controls based on real performance data. A weaker installer leaves the factory defaults and walks away.
• Customer demonstration time. A 10-minute handover leaves you unprepared for the first defrost cycle and the inevitable summer/winter SCOP variation. A 30–60 minute handover plus a follow-up call at week 1 catches the questions that actually arise once your system is running.
• The 12-month review. A scheduled review at 12 months — to look at actual performance data, refine controls, and address anything that hasn’t worked as expected — is a meaningful differentiator. Our first-year aftercare guide covers this in more detail.

The MCS certification gives you a floor of competence. The work above the floor is what makes the difference between a heat pump that runs at its designed efficiency and one that runs underperforming for years without anyone noticing.

What this means for homes in Reading

The process above is the same for every UK property — what varies by property is the depth of survey work and the specific design decisions.

Modern estates in Lower Earley, Woodley, and the western expansion areas typically have the most straightforward installs. Insulation is already at modern standards, existing radiators often need little or no upgrade, and electrical supplies are usually sized for modern demand. Install timelines tend toward the lower end of the 1–5 day range, and the design work is comparatively straightforward.

Inter-war semis in Tilehurst, Earley, Whitley, and parts of Caversham are the typical case. Most properties need a radiator or two upgraded, occasionally a cylinder retrofit if currently combi-only, but rarely major electrical work. Install timelines tend toward the middle of the range.

Victorian and Edwardian terraces in central Reading and lower Caversham are where the design work earns its keep. These properties typically need more radiator changes (existing radiators sized for a gas boiler’s 70°C flow may not deliver enough heat at a heat pump’s 45–55°C), occasionally pipework reroutes for the heat pump’s wider water-volume requirements, and sometimes electrical upgrades. Install timelines tend toward the upper end of the range. The April 2026 changes to BUS eligibility (the EPC requirement was removed) have made these properties materially easier to qualify on the grant side; the design side still benefits from a particularly careful survey.

Listed buildings and conservation-area properties (parts of central Reading and Caversham Park) need outdoor-unit siting that respects planning constraints. The BUS grant is available; the planning consultation around outdoor-unit positioning is typically the additional element. Our planning permission guide covers the consent path in more detail.

Reading’s typical contract-to-install scheduling gap mirrors the national picture — 2 to 8 weeks depending on installer capacity and time of year. If you’d like the install completed before next winter, qualifying calls during summer for autumn installs is the standard timing.

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Related guides

• Heat loss surveys for heat pumps — what they are, what to expect — a deep look at Stage 2 and Stage 3, the survey-and-design work that determines whether your heat pump performs as designed.
• Reading a heat pump quote — what every quote should include — Stage 4 in detail, with the line items to expect and the warning signs to watch for.
• Heat pump contracts and deposits — your consumer rights — your 14-day cooling-off period, RECC/HIES deposit protection, and what protects you if the installer ceases trading.
• Your first year with a heat pump — aftercare and the 12-month review — what happens after commissioning, including controls refinement and the first-winter learning curve.

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Ready to start the qualifying call?

The first stage is a 10–20 minute call covering your property, your current heating, your outdoor space, and your BUS grant intent. If your property is heat-pump-suitable we’ll book a survey; if it isn’t we’ll tell you up front and explain why.

Get a quote | Call us on 0118 [number] | Email [address]

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