How to Compare Heat Pump Quotes: What a Good UK Quote Includes (and Red Flags)
How to Compare Heat Pump Quotes: What a Good UK Quote Includes (and Red Flags)
How to Compare Heat Pump Quotes: What a Good UK Quote Includes (and Red Flags)
How to Compare Heat Pump Quotes: What a Good UK Quote Includes (and Red Flags)
How to Compare Heat Pump Quotes: What a Good UK Quote Includes (and Red Flags)
UK Heat pump Help Technical Team
Independent Heat Pump Engineer
A good heat pump quote shows the room-by-room heat loss figure it’s based on, the output of the proposed unit at your design conditions, the flow temperature the system will run at, which radiators are changing, the hot water cylinder, the controls, and exactly what’s included and left out. If two quotes differ on sizing or radiators, the cheaper one isn’t automatically the better deal. Compare like for like first, and ask for the heat loss calculation itself.
You’ve got two or three quotes on the table, and they don’t look alike. One has a 6kW unit, another an 8kW. One includes new radiators, and the others barely mention them. The prices are thousands apart, and everyone sounds confident.
It’s a stressful place to be, because this is one of the biggest spends you’ll make on your home. The good news is that you don’t need to be an engineer to spot a weak quote. You need to know what a proper one should contain, and where the gaps usually hide.
Why the quote matters more than the brand
Most homeowners start by comparing brands. In practice, the design behind the quote matters far more. A well-designed system on a decent unit will outperform a poorly designed system on a premium one.
Problems from a bad design rarely show up on day one. They tend to appear months later as high bills, cold rooms, noisy cycling, or a system that never quite settles. By then the money is spent. It’s far easier and cheaper to catch a problem on paper than after the installers have gone. Our article on heat pump problems after installation explains how awkward it gets once the work is done and nobody wants to own the issue.
Start with the survey, not the price
Before you look at a single number, ask how the quote was produced.
A proper quote follows a survey of your home: the rooms, the existing radiators, the pipework, the cylinder, where the outdoor unit could go. A quote based only on a phone call, a few photos or the size of your old boiler is a guess dressed up as a price.
If you want to know what a good survey should cover, our guide to what an installer should actually check is worth a read. Ask each installer what they measured and when they visited.
The heat loss figure is the foundation
Everything else in the quote depends on one number: how much heat your home loses on a cold day. It should be calculated room by room, not estimated from floor area, bedroom count or your old boiler’s rating.
Ask each installer for the heat loss calculation itself, not just a summary figure. You’re looking for:
A room-by-room breakdown
The design outdoor temperature they used for your area
The indoor temperatures they assumed for each room
A total in kilowatts that the proposed unit is then matched against
If one installer can’t or won’t share it, that tells you something. If you want to understand how the figure is worked out, our article on heat loss calculations walks through it, and our guide to what size heat pump you need covers typical ranges.
Check the size against the figure, not the headline
Once you know the heat loss, look at the unit. The kilowatt number on the brochure is usually measured in mild conditions. What matters is what the unit can deliver on a cold day at the flow temperature your system will actually run at.
So ask: what output does this model give at our design conditions, and how does that compare with the heat loss? You want a sensible match. Too small and you’ll lean on the immersion heater on cold days. Too big and you’ll get short-cycling and higher running costs. Our article on what happens if a heat pump is oversized explains why bigger isn’t safer.
If one installer is quoting a much bigger unit than the others, don’t assume they’re being careful. Ask them to show you why.
What a good quote should list
Use this as a checklist. A good quote doesn’t have to be long, but it should answer each of these.
What to look for | Why it matters | Red flag |
|---|---|---|
Heat loss figure (kW) and how it was calculated | Everything else depends on it | “Based on the size of your house” |
Unit model and output at design conditions | Confirms the size actually fits | Only a headline kW figure |
Design flow temperature | Lower is usually more efficient | Not mentioned at all |
Radiator schedule | Boiler-sized radiators are often too small | “Existing radiators will be reused” with no check |
Hot water cylinder size and type | Affects how well it copes with your household | A cylinder chosen without asking how many people live there |
Controls and weather compensation | A big part of efficiency | No mention of how it will be controlled |
Pipework changes | Old pipework may not carry enough flow | Silence on pipe sizes |
Buffer tank or low loss header, if included | Sometimes needed, often added by default | Included with no explanation |
Electrical work | Supply, consumer unit, cabling, isolator, RCD | “Electrics subject to survey” with no detail |
Outdoor unit position | Affects noise, drainage and pipe runs | No location agreed |
Commissioning and handover | Where many problems start | Not mentioned |
Warranty and guarantees | Manufacturer and workmanship cover | Only the manufacturer’s warranty |
Exclusions and allowances | Where “cheap” quotes make up the difference | Vague “provisional sums” |
Radiators: the item most often missed
Heat pumps usually run at lower flow temperatures than gas boilers, often somewhere in the range of 35 to 50°C. Radiators sized for a boiler can struggle to deliver enough heat at those temperatures, particularly in rooms with the highest heat loss.
A strong quote lists which radiators are changing, and to what size, based on the room-by-room figures. A weak one says the existing radiators will be reused, or doesn’t mention them at all.
Leaving radiators out is one of the easiest ways to make a quote cheaper. You may then end up paying for the upgrade later, or living with a house that doesn’t reach temperature. If you want to understand how this works, our article on heat loss calculations explains how the room figures feed into radiator sizing.
Hot water, controls and extras
These are the sections people skim, and where quotes differ most.
Hot water. Check the cylinder size, whether it suits your household, and what backs it up. A cylinder that’s too small runs out. One that’s too big wastes energy.
Controls. Ask how the system will be controlled. Weather compensation, which adjusts the flow temperature to the outdoor temperature, makes a big difference to efficiency, and it should be part of the design, not an afterthought.
Zoning. More zones isn’t always better. Over-zoned systems can cause problems of their own.
Buffer tanks. Sometimes they’re necessary. Sometimes they’re added by habit. Ask why it’s there.
Electrics. The quote should say whether your supply and consumer unit are suitable, and what work is included. If you want to understand one of the less obvious details, the type of RCD used matters for inverter-driven heat pumps, as we explain in our guide to why a heat pump keeps tripping the breaker.
Outdoor unit. Where it goes affects noise, drainage and pipe runs. Our guide to where an outdoor unit should go covers what to consider.
Red flags that should slow you down
None of these automatically means a bad installer, but each one deserves a question:
No survey, or only a phone or photo quote. A price without a visit is a guess.
Sizing based on your old boiler or floor area. Boilers and heat pumps are sized on different principles.
No heat loss calculation on request. You’re entitled to see it.
The same unit offered to every customer. Houses differ.
A big gap between quotes with no explanation. Find out what’s left out.
Pressure to sign today. A good design survives a few days of thinking.
A large deposit before any design work. Be wary of heavy upfront payments.
“Allowances” for things that should be priced. Vague lines hide cost.
Promises about running costs with no numbers behind them. Ask what they’re based on.
Making sure you’re comparing like with like
Once you have two or three quotes, line them up side by side. Make a simple grid with the quotes across the top and the checklist items down the side. Fill in each cell, and mark anything missing.
You’ll often find the cheaper quote leaves out radiators, electrical work, a cylinder or commissioning. The price gap shrinks when you add those back in.
If the sizes differ, ask each installer to explain their figure. If you’re getting different heat loss numbers for the same house, you’re not alone, and it’s worth getting an independent number. Our Heat Loss Survey is designed for that situation.
Questions to ask every installer
Take this list to each conversation, and write down the answers:
Can I see the room-by-room heat loss calculation?
What output does this unit give at our design conditions?
What flow temperature are you designing for?
Which radiators are changing, and why?
Is a buffer tank or low loss header needed, and why?
What electrical work is included, and what’s excluded?
How will weather compensation be set up?
What does commissioning involve, and what do I receive at handover?
What warranties and guarantees come with the installation?
What would make the price go up after work starts?
A good installer will welcome these questions. Defensiveness is information too.
If you’re applying for a grant
If you plan to use the Boiler Upgrade Scheme, the installer needs to be MCS certified and the installation needs to meet MCS standards. That includes a proper heat loss calculation. Check how the grant will be applied, because it’s usually handled by the installer and shown as a reduction in the price. Make sure the quote shows both figures clearly.
Certification is a baseline, not a guarantee that the design suits your home. We look at that question in more detail in our article on whether MCS certification guarantees correct sizing.
When an independent review makes sense
Even careful comparison has limits. You can check that a quote contains the right items, but judging whether the sizing, flow temperature and radiators really add up takes technical knowledge. And when installers disagree, you need someone with no interest in the answer.
Our Pre-Installation Design & Heat Loss Review is built for exactly this. We’re independent, so we don’t sell equipment or install heat pumps. We review the proposed design, including the heat loss calculation, sizing, flow temperature, radiators, cylinder, pipework and controls where the information is available. We then talk you through the findings on a one-to-one video call, with no site visit needed.
We can’t negotiate your price or tell you which installer is cheapest. What we can tell you is whether the design stacks up, and what to ask your installer to change if it doesn’t.
If you haven’t had a heat loss calculation done yet, a Heat Loss Survey gives you a room-by-room figure to check quotes against.
Frequently asked questions
How many heat pump quotes should I get?
Two or three is usually enough to spot differences. More than that tends to add confusion unless the quotes are detailed and comparable.
Why are heat pump quotes so different in price?
Often because of what’s included. Radiators, electrical work, cylinder, controls and commissioning vary a lot. Different unit sizes and brands also change the price.
Should I just choose the cheapest quote?
Not automatically. Make sure it includes the same scope as the others, and that the sizing and design are sound. A cheap quote that leaves out radiators or uses a poor design can cost more in the long run.
Is it normal for installers to give different sizes?
It happens often, and it’s a good reason to ask for the heat loss calculations. Differences can come from the method used, the assumptions made, or sometimes a safety margin that leads to oversizing.
Do I need to see the heat loss calculation?
Yes. You’re entitled to ask for it, and a good installer should be happy to share it.
Can I get a quote reviewed after I’ve signed?
You can, but changes are harder and may cost more once a contract is in place. It’s much easier to review a design before you commit.
Got a heat pump quote you’re unsure about?
Send us the details and we’ll check whether the design behind it stacks up.
A good heat pump quote shows the room-by-room heat loss figure it’s based on, the output of the proposed unit at your design conditions, the flow temperature the system will run at, which radiators are changing, the hot water cylinder, the controls, and exactly what’s included and left out. If two quotes differ on sizing or radiators, the cheaper one isn’t automatically the better deal. Compare like for like first, and ask for the heat loss calculation itself.
You’ve got two or three quotes on the table, and they don’t look alike. One has a 6kW unit, another an 8kW. One includes new radiators, and the others barely mention them. The prices are thousands apart, and everyone sounds confident.
It’s a stressful place to be, because this is one of the biggest spends you’ll make on your home. The good news is that you don’t need to be an engineer to spot a weak quote. You need to know what a proper one should contain, and where the gaps usually hide.
Why the quote matters more than the brand
Most homeowners start by comparing brands. In practice, the design behind the quote matters far more. A well-designed system on a decent unit will outperform a poorly designed system on a premium one.
Problems from a bad design rarely show up on day one. They tend to appear months later as high bills, cold rooms, noisy cycling, or a system that never quite settles. By then the money is spent. It’s far easier and cheaper to catch a problem on paper than after the installers have gone. Our article on heat pump problems after installation explains how awkward it gets once the work is done and nobody wants to own the issue.
Start with the survey, not the price
Before you look at a single number, ask how the quote was produced.
A proper quote follows a survey of your home: the rooms, the existing radiators, the pipework, the cylinder, where the outdoor unit could go. A quote based only on a phone call, a few photos or the size of your old boiler is a guess dressed up as a price.
If you want to know what a good survey should cover, our guide to what an installer should actually check is worth a read. Ask each installer what they measured and when they visited.
The heat loss figure is the foundation
Everything else in the quote depends on one number: how much heat your home loses on a cold day. It should be calculated room by room, not estimated from floor area, bedroom count or your old boiler’s rating.
Ask each installer for the heat loss calculation itself, not just a summary figure. You’re looking for:
A room-by-room breakdown
The design outdoor temperature they used for your area
The indoor temperatures they assumed for each room
A total in kilowatts that the proposed unit is then matched against
If one installer can’t or won’t share it, that tells you something. If you want to understand how the figure is worked out, our article on heat loss calculations walks through it, and our guide to what size heat pump you need covers typical ranges.
Check the size against the figure, not the headline
Once you know the heat loss, look at the unit. The kilowatt number on the brochure is usually measured in mild conditions. What matters is what the unit can deliver on a cold day at the flow temperature your system will actually run at.
So ask: what output does this model give at our design conditions, and how does that compare with the heat loss? You want a sensible match. Too small and you’ll lean on the immersion heater on cold days. Too big and you’ll get short-cycling and higher running costs. Our article on what happens if a heat pump is oversized explains why bigger isn’t safer.
If one installer is quoting a much bigger unit than the others, don’t assume they’re being careful. Ask them to show you why.
What a good quote should list
Use this as a checklist. A good quote doesn’t have to be long, but it should answer each of these.
What to look for | Why it matters | Red flag |
|---|---|---|
Heat loss figure (kW) and how it was calculated | Everything else depends on it | “Based on the size of your house” |
Unit model and output at design conditions | Confirms the size actually fits | Only a headline kW figure |
Design flow temperature | Lower is usually more efficient | Not mentioned at all |
Radiator schedule | Boiler-sized radiators are often too small | “Existing radiators will be reused” with no check |
Hot water cylinder size and type | Affects how well it copes with your household | A cylinder chosen without asking how many people live there |
Controls and weather compensation | A big part of efficiency | No mention of how it will be controlled |
Pipework changes | Old pipework may not carry enough flow | Silence on pipe sizes |
Buffer tank or low loss header, if included | Sometimes needed, often added by default | Included with no explanation |
Electrical work | Supply, consumer unit, cabling, isolator, RCD | “Electrics subject to survey” with no detail |
Outdoor unit position | Affects noise, drainage and pipe runs | No location agreed |
Commissioning and handover | Where many problems start | Not mentioned |
Warranty and guarantees | Manufacturer and workmanship cover | Only the manufacturer’s warranty |
Exclusions and allowances | Where “cheap” quotes make up the difference | Vague “provisional sums” |
Radiators: the item most often missed
Heat pumps usually run at lower flow temperatures than gas boilers, often somewhere in the range of 35 to 50°C. Radiators sized for a boiler can struggle to deliver enough heat at those temperatures, particularly in rooms with the highest heat loss.
A strong quote lists which radiators are changing, and to what size, based on the room-by-room figures. A weak one says the existing radiators will be reused, or doesn’t mention them at all.
Leaving radiators out is one of the easiest ways to make a quote cheaper. You may then end up paying for the upgrade later, or living with a house that doesn’t reach temperature. If you want to understand how this works, our article on heat loss calculations explains how the room figures feed into radiator sizing.
Hot water, controls and extras
These are the sections people skim, and where quotes differ most.
Hot water. Check the cylinder size, whether it suits your household, and what backs it up. A cylinder that’s too small runs out. One that’s too big wastes energy.
Controls. Ask how the system will be controlled. Weather compensation, which adjusts the flow temperature to the outdoor temperature, makes a big difference to efficiency, and it should be part of the design, not an afterthought.
Zoning. More zones isn’t always better. Over-zoned systems can cause problems of their own.
Buffer tanks. Sometimes they’re necessary. Sometimes they’re added by habit. Ask why it’s there.
Electrics. The quote should say whether your supply and consumer unit are suitable, and what work is included. If you want to understand one of the less obvious details, the type of RCD used matters for inverter-driven heat pumps, as we explain in our guide to why a heat pump keeps tripping the breaker.
Outdoor unit. Where it goes affects noise, drainage and pipe runs. Our guide to where an outdoor unit should go covers what to consider.
Red flags that should slow you down
None of these automatically means a bad installer, but each one deserves a question:
No survey, or only a phone or photo quote. A price without a visit is a guess.
Sizing based on your old boiler or floor area. Boilers and heat pumps are sized on different principles.
No heat loss calculation on request. You’re entitled to see it.
The same unit offered to every customer. Houses differ.
A big gap between quotes with no explanation. Find out what’s left out.
Pressure to sign today. A good design survives a few days of thinking.
A large deposit before any design work. Be wary of heavy upfront payments.
“Allowances” for things that should be priced. Vague lines hide cost.
Promises about running costs with no numbers behind them. Ask what they’re based on.
Making sure you’re comparing like with like
Once you have two or three quotes, line them up side by side. Make a simple grid with the quotes across the top and the checklist items down the side. Fill in each cell, and mark anything missing.
You’ll often find the cheaper quote leaves out radiators, electrical work, a cylinder or commissioning. The price gap shrinks when you add those back in.
If the sizes differ, ask each installer to explain their figure. If you’re getting different heat loss numbers for the same house, you’re not alone, and it’s worth getting an independent number. Our Heat Loss Survey is designed for that situation.
Questions to ask every installer
Take this list to each conversation, and write down the answers:
Can I see the room-by-room heat loss calculation?
What output does this unit give at our design conditions?
What flow temperature are you designing for?
Which radiators are changing, and why?
Is a buffer tank or low loss header needed, and why?
What electrical work is included, and what’s excluded?
How will weather compensation be set up?
What does commissioning involve, and what do I receive at handover?
What warranties and guarantees come with the installation?
What would make the price go up after work starts?
A good installer will welcome these questions. Defensiveness is information too.
If you’re applying for a grant
If you plan to use the Boiler Upgrade Scheme, the installer needs to be MCS certified and the installation needs to meet MCS standards. That includes a proper heat loss calculation. Check how the grant will be applied, because it’s usually handled by the installer and shown as a reduction in the price. Make sure the quote shows both figures clearly.
Certification is a baseline, not a guarantee that the design suits your home. We look at that question in more detail in our article on whether MCS certification guarantees correct sizing.
When an independent review makes sense
Even careful comparison has limits. You can check that a quote contains the right items, but judging whether the sizing, flow temperature and radiators really add up takes technical knowledge. And when installers disagree, you need someone with no interest in the answer.
Our Pre-Installation Design & Heat Loss Review is built for exactly this. We’re independent, so we don’t sell equipment or install heat pumps. We review the proposed design, including the heat loss calculation, sizing, flow temperature, radiators, cylinder, pipework and controls where the information is available. We then talk you through the findings on a one-to-one video call, with no site visit needed.
We can’t negotiate your price or tell you which installer is cheapest. What we can tell you is whether the design stacks up, and what to ask your installer to change if it doesn’t.
If you haven’t had a heat loss calculation done yet, a Heat Loss Survey gives you a room-by-room figure to check quotes against.
Frequently asked questions
How many heat pump quotes should I get?
Two or three is usually enough to spot differences. More than that tends to add confusion unless the quotes are detailed and comparable.
Why are heat pump quotes so different in price?
Often because of what’s included. Radiators, electrical work, cylinder, controls and commissioning vary a lot. Different unit sizes and brands also change the price.
Should I just choose the cheapest quote?
Not automatically. Make sure it includes the same scope as the others, and that the sizing and design are sound. A cheap quote that leaves out radiators or uses a poor design can cost more in the long run.
Is it normal for installers to give different sizes?
It happens often, and it’s a good reason to ask for the heat loss calculations. Differences can come from the method used, the assumptions made, or sometimes a safety margin that leads to oversizing.
Do I need to see the heat loss calculation?
Yes. You’re entitled to ask for it, and a good installer should be happy to share it.
Can I get a quote reviewed after I’ve signed?
You can, but changes are harder and may cost more once a contract is in place. It’s much easier to review a design before you commit.
Got a heat pump quote you’re unsure about?
Send us the details and we’ll check whether the design behind it stacks up.
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Not Sure Which Service You Need?
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Not Sure Which Service You Need?
Not Sure Which Service You Need?
Whether you need help with an existing heat pump, a pre-installation review, cooling advice, servicing or a room-by-room heat loss survey, send us a few details and we'll point you in the right direction.
Whether you need help with an existing heat pump, a pre-installation review, cooling advice, servicing or a room-by-room heat loss survey, send us a few details and we'll point you in the right direction.
Whether you need help with an existing heat pump, a pre-installation review, cooling advice, servicing or a room-by-room heat loss survey, send us a few details and we'll point you in the right direction.
