Ian Trott, Head of Training at Baxi, identifies some areas to help deliver excellent customer satisfaction with the installation and performance of ASHPs.
Heat pumps and boilers have more in common than people assume. The skills built up over years of gas work transfer across well, and most heating engineers already have the foundations they need to make a start. The system, the radiators, the pipework calculations: it’s all familiar ground.
Where things change is in the detail. A handful of common areas that, with small changes in approach, can offer big improvements to customer satisfaction.
Tip 1: Piping size matters
Heat loss calculations are the foundation of any good heating system design, whether connected to a gas boiler or a heat pump. That part of the process is the same. The differences come in what you do with the result.
ASHPs run at lower flow temperatures than traditional boilers, so the heat coming out is less intense. To heat the same space, you need more surface area. That might mean upsizing radiators or bringing underfloor heating into the picture. Either way, the heat loss numbers have to flow through to the emitters you choose.
Pipe sizing matters just as much. Heat pumps push water around faster than a boiler, so larger pipes are often needed. That sounds simple enough, but it has knock-on effects. Routing 28mm or 32mm pipe through joists takes more careful planning than smaller bore pipe and getting this right at the planning stage lays the groundwork for a happy customer.
There’s a related point on retrofits. With a boiler swap, dropping a 30-kilowatt (kW) unit where a 28kW one used to sit will usually be fine. ASHPs aren’t quite so forgiving. If the existing pipework can’t carry the flow rates required, the system won’t perform the way it should, so it’s important to take the time to size things properly. Skipping this step creates problems that many homeowners will notice straight away, and rectifying these problems adds time spent to a job and eats into profits.
Tip 2: A different running strategy for ASHPs
The biggest mindset shift, both for installers and homeowners, is how an ASHP is run.
Today’s gas boilers are low content, meaning they hold smaller quantities of water than older models. These boilers heat the water as quickly as they can bringing it up to temperature quickly. The whole approach is built around high heat and quick transfer of that heat into a home. ASHPs work the opposite way. They keep a larger volume of water moving steadily at a lower temperature, ticking along gently for longer rather than firing up on a short cycle.
That’s where controls come into their own. Weather compensation is standard on virtually all ASHPs, adjusting flow temperature based on conditions outside the home rather than reacting only to the room thermostat. Installers need a clear picture of how the homeowner is going to use the system, helping them to set up the system to match.
This can be one of the more rewarding parts of working with heat pumps. There’s more nuance to the system, so the choices made during commissioning have a bigger impact for homeowners, and the technology rewards a good install rather than a rushed one.
Tip 3: A thorough handover is crucial
With a new boiler, most homeowners can get by with a brief explanation. ASHPs are different, and assuming the homeowner will figure it out is one of the most common reasons a perfectly good install ends up generating complaints.
To combat this, installers can plan the handover as part of the job, not as an afterthought. It is best practice to walk the homeowner through how the system works, why it runs the way it does, and what they should and shouldn’t do once you’ve left the site. Talking them through the controls in detail enables them to understand the differences between their new system and the gas boilers they are used to. It helps to make it clear they don’t need to switch the system on and off like a boiler and explain what they’ll see across different seasons.
Follow-up contact tends to pay for itself. A quick call or visit a few weeks in catches small issues before they become complaints and gives the homeowner a chance to ask the questions they didn’t think of on the day of the handover. That second conversation is often where confidence in the system gets built.
This might be the biggest difference for installers. The handover hasn’t always been needed in the same way, but with ASHPs, it’s a priority. It’s what protects the install, the customer relationship and, in the end, your reputation as the engineer who fitted it.
The takeaway
ASHP installations aren’t a leap into the unknown for an experienced gas engineer. The fundamentals of gas installations carry across. Applying the same care that goes into a good boiler install, with a sharper focus on planning, sizing, commissioning, and handovers, will improve how the system performs day-to-day and help ensure the customer is satisfied.
Done well, ASHP work opens up a growing and rewarding part of the heating sector, and gives engineers the chance to deliver work that makes a difference to the homes they’re in.
Images: Baxi
