What Happens During an Air Source Heat Pump Installation?

The Installation Journey: Overview

Installing an air source heat pump involves more preparation and work than fitting a like-for-like boiler replacement — but most homeowners are pleasantly surprised by how smooth the process is when managed by experienced engineers.

Here's what to expect from start to finish.

Stage 1: Heat Loss Survey

Before any installation, we carry out a full heat loss survey of your property. This involves:

Measuring every room

Assessing insulation levels (walls, roof, floor, windows)

Checking existing radiator sizes

Calculating the total heat demand of the property

This survey determines the correct heat pump size and identifies whether any radiator upgrades are needed.

Stage 2: System Design

Based on the survey, we design the full system including:

Heat pump model and output (kW)

Location of the outdoor unit

Hot water cylinder specification (if required)

Radiator sizing and any upgrades needed

Pipework and electrical layout

We also handle the MCS documentation and Boiler Upgrade Scheme grant application at this stage.

Stage 3: Installation Day(s)

A typical installation takes 2–3 days for a standard property. Here's what happens:

Day 1:

Outdoor unit positioned and mounted (on a pad or brackets)

Refrigerant pipework run between outdoor unit and internal unit

Internal unit positioned (often in utility room or airing cupboard)

Day 2:

Plumbing connections made

Hot water cylinder installed (if applicable)

Electrical connections and commissioning panel installed

Day 3:

System filled and pressure tested

Commissioning and optimisation

Homeowner handover and controls training

Stage 4: Commissioning and Optimisation

Commissioning is critical for heat pump performance. Our engineers set the flow temperature curves (how the system responds to outdoor temperature) and optimise the system controls for your property. This stage significantly affects running costs.

Stage 5: Ongoing Support

After installation, we're always available for questions, and will check in at 3 and 12 months to ensure the system is performing as expected.

To find out if your home is suitable for a heat pump, call Halo Heating on 01483 676108.