How to Choose a Heat Pump Installer

How to choose a heat pump installer

Choosing a heat pump installer is one of the most important decisions in the whole process.

Modern heat pumps from reputable manufacturers tend to perform quite similarly. What really determines comfort, efficiency and running costs is the system design and the skill of the installer.

In many cases the installer and the system design matter more than the specific heat pump brand itself.

I’ve been living with my own setup since October 2022: a 5 kW Vaillant aroTHERM paired with a Mixergy smart hot water cylinder in our 1930 semi-detached house in Sheffield. I was heavily involved in the design alongside award winning installer Damon Blakemore, and since then I’ve properly nerded out on how heat pumps and heating systems actually behave in real homes.

I’ve also done training myself, including completing Heat Geek Awakening and Mastery, and I’ve written loads of heat pump and heating system content on Energy Stats UK. So I’m comfortable judging what “good” looks like, and spotting when something doesn’t quite add up.

This page recommends what to look for when choosing a heat pump installer today.

Table of Contents

Use the Table of Contents below to jump straight to the section that matters most or scroll through at your own pace.

What good heat pump installers do differently

They take learning seriously

Training isn’t everything, but it’s a strong indicator that the installer cares about their own development.

• Heat Geek courses (Awakening, Mastery)

• Warmur / Kimbo style hydronics-focused training

• Ongoing CPD (continued professional development), not just “I did a thing once”

These courses focus on hydronic system design, not just installation.

I compare some of these options in my article Best Heat Pump Training.

Many installers initially complete a short 3-day heat pump course, which is often the minimum required for certification. In reality that short course alone is rarely enough to fully understand the design principles behind efficient heat pump systems.

Proof from real installations

Ask how they prove their installs are running well after commissioning.

Good signs:

• They use monitoring tools like Open Energy Monitor (or equivalent)

• They can show flow temps, return temps, run hours, cycling behaviour, COP or SCOP performance

• They talk about diagnosing systems with data

• The projected COP/SCOP/running costs in the quote match their real world outcomes

Data from existing real installations is far more useful than marketing claims.

A full survey, including emitters and room realities

A proper survey should involve more than a quick walk around the house.

The installer should assess:

• insulation levels and building fabric

• radiator sizes and outputs at lower flow temperatures

• pipework constraints such as microbore

• room-by-room heating requirements

• your household hot water usage

• location of the hot water cylinder and pipe runs to and from it

• electrical supply capacity and any upgrades that may be required

• location of the outdoor unit and potential noise impact

Electrical work is another area that can affect the overall installation cost. Heat pumps require a suitable electrical supply, and installers may need to coordinate with an electrician or notify the Distribution Network Operator (DNO) if supply upgrades or permissions are required.

Noise is sometimes a concern for homeowners and neighbours. Installers should consider this during the survey and assess whether the proposed location will comply with planning rules such as the MCS noise assessment.

If these topics are never mentioned during the survey stage, it’s worth asking about them.

In this Episode of the Energy Unwrapped Podcast (Are Heat Pumps Noisy?) I speak with Jez Climas from City Plumbing about all things noise and heat pumps.

Proper heat loss calculations

Heat loss calculations are so important to the whole design, but the quality varies wildly.

Look for someone who:

• Does room-by-room properly and challenges defaults

• Uses design tooling like Spruce, h2x or Carno

• Asks about existing insulation levels, looks at available drawings / build specs.

• Checks awkward rooms, extensions, loft conversions, odd glazing, drafts, suspended floors

• Does not blindly accept the usually over-specced air change defaults (see Air Changes Per Hour Heat Loss in a Retrofit Home).

• Oversized heat loss calculations are one of the common design mistakes I discuss in Heat Pump Myths.

• The room by room heat loss survey is the key to the design, not just a tick box for MCS purposes.

Your home is not cookie-cutter. The heat loss and design should reflect that your installation is a bespoke project.

Understanding hydronic heating design

Hydronic heating is simply the movement of hot water around a system to deliver heat to rooms efficiently.  See the Warmur Academy description.

A good installer should understand how the heating circuit delivers the required flow rate around your system.

If you mention the index circuit, the installer should understand what you mean.

They should be able to explain:

• how the index circuit is identified

• how pipe sizing affects resistance, pressure drop and velocity

• how pumps are selected to deliver the required flow rate

These concepts sit at the heart of hydronic heating design.

If an installer struggles to explain them clearly, it may suggest the system design hasn’t been fully thought through or their knowledge is lacking (see the training section).

Sensible system design choices and options

This is where good installers separate themselves.

Good design tends to include:

• A clear plan for low flow temperatures

• Open loop, steady state operation where possible

• Avoiding unnecessary zoning

• Avoiding third-party controls

• Using manufacturer controls properly and commissioned well

• A clear approach to weather compensation

Good installers can provide a number of approaches

1. Best efficiency (lowest flow temperatures, potentially more radiators swaps etc)
2. Best bang for buck (aiming for the best value installation whilst still adhering to best practice design principles)

There is a balance to be struck between upfront costs in both options versus the long term running costs.  A good installer will be able to help you navigate these choices.

Hot water is treated as a design topic

A good installer will inspect your existing cylinder if you have one and talk through your actual water usage.  If you are coming from a combi boiler, then different questions would be asked.

They should cover:

• Whether your current cylinder is compatible or needs changing

• Coil sizing and recovery expectations (depending on the heat pump size recommended)

• Location of the cylinder in your house and pipe runs to and from it

• Your household hot water habits (showers, baths, times)

• Why the MCS “45 litres per person per day” assumption may not fit you

Be wary if they just accept these MCS defaults without asking questions.  See Cylinder Sizing and Mixing.

As an example in our house.  45 litres per person for day is nowhere near enough for my family of 4.  What with school. work, gym, dance classes, football etc.  ie, potentially a couple of showers a day each.  Real life stuff.

System flushing and water quality (VDI 2035)

Dirty heating system water is one of the biggest causes of boiler breakdowns, blocked heat exchangers and poor heat pump performance. Sludge, corrosion and debris can build up over time inside radiators and pipework without intervention.

That’s why installers should have a clear plan for:

• flushing the existing heating system

• cleaning out sludge and debris

• installing magnetic filters where appropriate

• treating the system water correctly

Many installers now follow the VDI 2035 standard, which focuses on correct water treatment and ongoing system protection.

Heat pumps rely on high flow rates, so clean pipework and good water quality are essential for efficiency and reliability.

It’s worth asking installers:

• how they plan to flush the system

• whether they follow VDI 2035 or similar water quality standards

• how water quality will be monitored and maintained over time

In this episode of the Energy Unwrapped podcast, heating engineer Ricky Prescott from Thoroughflush explains why water quality is one of the most overlooked parts of heating system design.

Clear commissioning and system setup process

A heat pump is not a “fit it and forget it” appliance.

A good installer will spend time commissioning the system properly.

That should include:

• how do they balance the system (radiators and underfloor manifolds)
• choose the weather compensation curve
• hot water settings
• schedules for both heating and hot water
• explain the controls to the user

Poor commissioning can significantly affect performance, comfort and running costs.

Customer references you can trust

Don’t rely on review platforms alone.

Do this instead:

• Ask for customer references you can speak to or potentially go and visit

• Ask for installs similar to your home type and heat loss level

• Ask what follow-up support looks like after commissioning

• Do they have systems listed on heatpumpmonitor.org so you can see real performance data?

• Use Trustpilot and Google as one input, not the deciding factor

• Look at their social media presence

Consumer protection and standards

Installers should normally be members of a consumer protection scheme such as:

• RECC

• HEIS

MCS certification is also required for some grants like the Boiler Upgrade Scheme.

However, accreditation alone does not guarantee competence. It should be viewed as a baseline requirement rather than proof of design expertise.  See the training section for more information.

Questions you can ask when choosing a heat pump installer

• How do you do heat loss, and what do you do to challenge defaults (like air changes)?

• Do you assess radiators room-by-room, and design for low flow temps?

• What’s your approach to zoning and controls, and why?

• How do you identify the index circuit and ensure correct flow to all emitters?

• How do you design hot water for real household usage, not just MCS assumptions?

• Can you show monitoring and performance numbers from recent installs

• Can I speak to recent customers with similar homes?

• What does commissioning the system involve?

• Are you in RECC or HEIS, and what does your warranty and aftercare look like?

You don’t need to understand every detail of the answers. What matters is whether the installer can explain their approach clearly.

A good installer should also discuss running costs

An installer should be able to explain how the system design affects efficiency and running costs.

That includes discussing:

• expected flow temperatures

• seasonal performance (COP or SCOP)

• how tariffs affect operating costs

I explain these concepts in Heat Pump Performance for Normal People, which looks at how heat pumps actually behave in real homes.

And discuss various electricity tariffs in Best Heat Pump Tariff, which can depend on any existing renewable kit you may have.

How many heat pump installer quotes should you get?

It’s usually sensible to speak to two or three installers.

That gives you a chance to compare:

• design approaches

• equipment recommendations

• proposed flow temperatures

• their approach to aftercare and servicing

• overall cost

Getting only one quote makes it difficult to judge whether the design and price are reasonable.

However, requesting quotes from ten different companies rarely helps either. Heat pump system design takes time, and most reputable installers will want to have meaningful discussions before producing a proposal.

Two or three well-chosen installers is usually enough to make a confident decision

You may also find that some installers charge for a detailed heat loss survey.

This isn’t necessarily a bad sign. A proper survey can take several hours, especially in larger or more complex homes. The installer will need to measure radiators, assess insulation levels, review building plans and calculate room-by-room heat losses.

In many cases the survey fee is deducted from the installation price if you go ahead with that installer.

Charging for this work can actually be a sign that the installer takes system design seriously, rather than producing quick estimates without doing the proper analysis.

The heat loss survey is one of the most important parts of the entire project. If the design is right, the heat pump will usually perform well. If the design is wrong, even the best equipment will struggle.

Should you choose a local heat pump installer?

Working with a local installer can have advantages. They may already understand common housing types in your area and can usually return more easily if support is needed later.

However, some of the best heat pump installers travel further afield, particularly for more complex retrofit projects.

Ultimately, the most important thing is choosing an installer you feel comfortable working with. They will likely be working in your home for several days during the installation, so it’s important that you feel these are the right people for the job.

Look for someone who answers your questions clearly, takes the system design seriously, and gives you confidence in their proposal.

That doesn’t mean national companies should be dismissed either. Many of the larger energy suppliers are now entering the heat pump market and can deliver well-designed systems.

Are large suppliers or specialist installers better value for heat pumps?

In the end, it comes down to how confident you feel in the design, the proposal, and the people delivering the installation.

Why the cheapest installer is often the wrong choice

When people get quotes for things like heat pumps and other home energy upgrades, the natural instinct is to compare the prices and go with the lowest one.

But that can be a mistake.

The headline installation price only tells part of the story. What you are actually paying for includes far more than the equipment and a few days of labour.

Quotes can also vary depending on electrical upgrades, noise considerations, access requirements, or additional design work needed for your property.

You are paying for the installer’s:

• training and personal development

• years of experience designing systems

• accreditations such as MCS and other trade body memberships

• insurance and consumer protection schemes

• time spent on surveys, design work and proposals

• commissioning, setup and aftercare support

All of that has a cost.

A good installer will often spend hours doing the work you do not immediately see, such as desktop design, heat loss calculations, radiator assessment, hydronic design, hot water planning, and control setup.

That effort is invisible in the final quote, but it is part of the value you are paying for.

There is also more built into a professional installer’s costs than many homeowners realise. A decent business may need storage space, vehicles, insurance, office support, trained staff, and cash tied up in stock and equipment. That is part of what allows them to do the job properly and still be around in a few years’ time if you need support.

Cheap quotes usually mean something is missing

If you see a quote that is dramatically cheaper than the others, it is worth asking why.

Sometimes low prices are simply used as a hook to generate leads. Once you are talking to the company, the price may increase as extras are added.

Other times the low price reflects corners being cut. That might mean:

• minimal design work

• little or no system optimisation

• lower quality equipment or components

• poor commissioning, aftercare or support

Sometimes a very low quote is not bad intent at all. It can simply mean the installer has underpriced the job or underestimated the true costs of running this kind of business.

Either way, if the quote looks far cheaper than the rest of the market, it is worth doing some extra due diligence.

And the biggest risk is that the installer may not be around in five or ten years when you need help.

Think about value, not just price

A better approach is to narrow your shortlist to two or three installers you trust.

Speak to them. Ask questions. Look at their previous work and customer feedback. Decide who you believe will do the best job.

Once you have done that, the question becomes:

What am I willing to pay to make sure the job is done properly?

The cheapest option is rarely the one that delivers the best long-term outcome for something as important as your heating system.

Explore more heat pump guides and tools

If you want to go deeper into heat pump design, running costs, tariffs and real-world performance, these are some of the best places to go next here on Energy Stats UK.

My own heat pump installation and performance

If you want to see how a real system works in practice, I’ve documented living with our 5 kW Vaillant aroTHERM heat pump in a 1930s semi-detached house, including day-to-day experience, performance and lessons learned.

You can also look through my monthly heat pump performance history from our Vaillant aroTHERM installation, where I share longer-term data and real-world results.

And you can view hour by hour performance of my heat pump via my Open Energy Monitor link.

Vaillant aroTHERM heating, hot water and weather compensation guides

My Vaillant aroTHERM heat pump guide covering heating, hot water, weather compensation and more pulls together many of the practical guides I’ve written over the years.

Even if you do not own a Vaillant system, much of the thinking around controls, hot water and efficient setup still applies more widely.

Heat pump tools and calculators

I’ve also built a number of tools to help homeowners understand sizing, performance and system behaviour, including my free heat loss survey tool to estimate heat pump size from gas usage, the mass flow rate calculator for heat pump system design, the hot water calculator for heat pump reheat times, and the heat pump cycling calculator for understanding system behaviour.

Heat Pumps Explained is another great landing page on the site.

Energy tariffs, solar and the bigger picture

Running a heat pump well is not just about the hardware. Tariffs, solar generation and battery storage can make a huge difference too.

The Energy Tariff landing page covering Octopus Agile, Cosy, Tracker and EDF Freephase is a good place to start if you want to understand smart tariffs and wholesale linked pricing.

I’ve also written about heat pumps explained for normal homeowners, my solar generation history since 2018, and the holy trinity of solar, batteries and heat pump if you want to look at the wider home energy picture.

Final thought

Most modern heat pumps perform very similarly.

The biggest difference usually comes down to how well the system is designed and installed.

Choosing the right installer is therefore one of the most important decisions you will make.