What 20 Energy Advisors Tell First-Time Heat Pump Buyers

Buying a heat pump is one of the biggest home improvement decisions a UK homeowner will make — and it is one where getting the right advice upfront can save thousands of pounds and years of frustration. We asked 20 experienced energy advisors what they tell every first-time buyer. Their collective wisdom covers everything from the questions you should ask installers to the mistakes that cost people the most money.

Energy advisors occupy a unique position in the heat pump journey. Unlike installers, they do not sell equipment. Unlike manufacturers, they have no brand loyalty. Their job is to give impartial advice — and the advice they give most frequently reveals the areas where first-time buyers most need guidance.

We spoke to advisors from the Energy Saving Trust, local authority energy teams, independent energy consultancies, and home energy assessment services across England, Scotland, and Wales. Here is what they said. For the technical deep-dive, see our complete guide to air source heat pumps.

"Insulate First — It Pays for Itself Twice"

"The first thing I say to every homeowner considering a heat pump is: sort your insulation first. Not because a heat pump won't work in a poorly insulated home — it will — but because the economics change dramatically. Better insulation means a smaller heat pump, lower running costs, and a more comfortable home." — Energy advisor, South East England

This was the most consistent piece of advice across all 20 advisors. The logic is compelling: spending £2,000 on cavity wall insulation might reduce your heat pump size requirement from 12 kW to 9 kW, saving £1,500-£2,500 on equipment costs. It also reduces annual running costs by £150-£250. So the insulation pays for itself through equipment savings alone, then continues saving every year thereafter.

Key insulation priorities before a heat pump installation:

• Loft insulation — top up to at least 270mm (£300-£600, often available free through ECO4)
• Cavity wall insulation — fill empty cavities (£800-£2,000, often subsidised)
• Draught-proofing — windows, doors, letterboxes, and loft hatches (£200-£500)

More expensive measures like external wall insulation (£6,000-£12,000) or new glazing (£5,000-£12,000) may not be cost-effective purely as heat pump preparation, but they improve comfort significantly. Some may be available through grant schemes like ECO4 or HUG2.

"Get Your EPC Early — Don't Let It Hold Things Up"

"The number of people who get excited about a heat pump, find an installer, agree a quote — then realise they need an EPC and it delays everything by weeks. Get it done first." — Energy advisor, West Midlands

An Energy Performance Certificate is required for the BUS grant application. It costs £60-£120 and takes about an hour. The assessor evaluates your home's insulation, glazing, heating system, and lighting to produce an energy efficiency rating from A to G.

Critically, the BUS grant requires that any loft or cavity wall insulation recommendations on the EPC have been addressed. If your EPC recommends cavity wall insulation and you have not had it done, the grant application may be rejected. Getting the EPC early gives you time to address any issues before starting the installer process.

"Always Get Three Quotes — and Compare the Design, Not Just the Price"

"The cheapest quote is not always the best. And the most expensive is not always the worst. What matters is the quality of the system design. Look at the heat loss calculation, the proposed flow temperature, and the radiator strategy — not just the bottom line." — Energy advisor, Yorkshire

Advisors reported that heat pump quotes can vary by 30-50% for the same property. Sometimes the most expensive quote includes radiator upgrades that cheaper quotes omit — leading to problems later. Other times, a higher-priced installer is simply charging more for the same work.

What to compare across quotes:

• Heat pump brand and model — are they quoting the same size?
• Heat loss calculation — has every installer done one?
• Radiator plan — which radiators (if any) does each propose upgrading?
• Cylinder specification — is it heat pump optimised?
• Proposed flow temperature — lower is better for efficiency
• Warranty and aftercare — what is included?

Our free quote comparison service connects you with multiple MCS-certified installers so you can compare approaches side by side.

"Understand COP — It's the Number That Determines Your Bills"

"COP stands for Coefficient of Performance. A COP of 3 means for every £1 of electricity, you get £3 of heat. Most homeowners have never heard of it, but it's the most important number in the entire calculation." — Energy advisor, Scotland

The COP your heat pump achieves in practice depends on the flow temperature (lower is better), the outdoor temperature (warmer is better), and the quality of the installation. A well-designed system running at 35-40°C flow temperature can achieve a seasonal COP of 3.5-4.0, while a poorly designed one running at 55°C might only manage 2.5. That difference translates to 30-40% higher running costs for the poorly designed system.

"Ask Every Installer: What Flow Temperature Will My System Run At?"

"This one question tells you more about the quality of the system design than anything else. If the answer is 45°C or below, good. If it's 50°C or above, ask why — there should be a good reason." — Energy advisor, London

Flow temperature is the temperature of the water the heat pump sends to your radiators. Lower flow temperatures mean higher efficiency and lower bills. The best-designed systems run at 35-40°C for most of the year, only increasing to 45-50°C on the coldest days through weather compensation. See our running costs analysis for how flow temperature affects bills.

"Demand Honesty About Radiators"

"Some installers downplay the radiator question because they want the quote to look cheaper. But if your radiators are too small for a 40°C flow temperature, you'll end up either running the system too hot — costing you more — or living with a cold house." — Energy advisor, Wales

The radiator question is one of the most important in the entire process. A good installer will honestly assess each radiator and tell you which ones (if any) need upgrading. Most homes need 0-3 radiator changes, not a complete replacement. Budget £200-£500 per radiator including fitting.

"Plan Your Grant Strategy Before You Get Quotes"

"Know what grants you're eligible for before you start talking to installers. The BUS grant is the obvious one at £7,500, but low-income households might qualify for ECO4 or HUG2, which can cover the entire cost." — Energy advisor, North East England

Our grant eligibility checker helps you identify all available grants in minutes. The comprehensive grants guide covers every scheme and application process. If you live in Scotland, the combined grant and interest-free loan through Home Energy Scotland can cover the entire installation cost.

"Switch to a Heat Pump Electricity Tariff"

"I'm amazed how many heat pump owners are still on standard electricity tariffs. Switching to a heat pump tariff or time-of-use tariff can save £200-£350 per year. It should be one of the first things you do after installation." — Energy advisor, East Midlands

Heat pump-specific tariffs offer cheaper electricity during heating hours. Time-of-use tariffs reward you for running the heat pump during off-peak periods. If you also have solar panels, smart tariffs that pay you for exported electricity while giving you cheap overnight rates can dramatically reduce your total energy costs.

"Set Realistic Expectations"

"A heat pump is not going to cut your bills in half overnight if you're switching from gas. On current electricity prices, many gas-to-heat-pump switchers see similar or slightly lower bills. The savings come from tariff optimisation, solar pairing, and the medium-term trajectory of energy prices." — Energy advisor, South West England

For gas users, the primary motivation is often environmental rather than immediately financial. The carbon savings are immediate and significant — approximately 1.5-2.0 tonnes of CO2 per year. The financial savings depend on tariff choice, system efficiency, and future energy price movements — all of which favour heat pumps over time. Our 10-year bill forecaster shows the medium-term picture.

For oil and LPG users, the financial case is much stronger — savings of £300-£800 per year are typical even at current prices.

"Think 15-20 Years, Not 1-2"

"A heat pump lasts 20-25 years. Over that timeframe, gas prices will almost certainly rise significantly, electricity will get greener and likely cheaper for heating, and the value of your home will be enhanced by having a modern, low-carbon heating system." — Energy advisor, Northern Ireland

The long-term perspective is essential. A heat pump installed in 2026 will still be running in 2046. Over that period, cumulative energy savings are projected at £5,000-£15,000 compared to gas (depending on price trajectory), carbon savings will total 35-55 tonnes, and property value enhancement could add £5,000-£15,000 to your home's worth.

Frequently Asked Questions

What is the first thing an energy advisor checks before recommending a heat pump?

Most start with the property's insulation level via the EPC. If insulation is poor, they recommend addressing it first to reduce the required heat pump size and running costs.

Should I get an EPC before talking to a heat pump installer?

Yes. An EPC costs £60-£120 and is required for the BUS grant. Getting it early prevents delays.

How many heat pump quotes should I get?

At least 3 from different MCS-certified installers. Compare system design approaches, not just prices.

Is it worth waiting for heat pump prices to drop?

Most advisors say no. The £7,500 BUS grant may not last indefinitely, and the sooner you install, the sooner you start saving on bills and carbon.

What questions should I ask a heat pump installer?

Key questions: How many installations have you completed? Can I see the heat loss calculation? What flow temperature will the system run at? How many radiators need upgrading? What COP should I expect? Can you provide customer references?