Getting a Second Opinion on Your Heat Pump Quote

You have had an installer round, they have surveyed your property, and now you are holding a quote for £10,000-14,000. Is it fair? Is the system correctly sized? Are you being charged for work you do not need — or missing something you do? Getting a second (and third) opinion is not just about price comparison — it is about validating the entire design approach. This guide shows you exactly what to compare, what questions to ask, and when a quote should set alarm bells ringing.

Why You Need Multiple Quotes

Heat pump installations are not commodities — they are engineered solutions tailored to your specific property. Two installers surveying the same house can legitimately arrive at different recommendations for brand, system size, and radiator upgrades. Getting 3+ quotes exposes these differences and helps you make an informed decision.

Our analysis of quote data suggests that heat pump quotes for the same property typically vary by 25-40%. Some of that variation reflects genuine differences in approach. Some reflects different profit margins. And some reflects quality issues — undersizing to look cheap, or oversizing to maximise revenue.

Three quotes is the minimum. Five is better if you have the patience. Each quote teaches you something about what your property needs and what the market charges.

What to Compare (Beyond Price)

Price is the most obvious comparison point, but it is the least reliable. A cheap quote that installs the wrong system costs more in the long run than an expensive quote that gets it right. Here is what to compare systematically.

Comparing Heat Loss Calculations

Every MCS installer should provide a room-by-room heat loss calculation. This is the most important technical document in the entire process — it determines everything else. When comparing quotes, compare the heat loss calculations first.

All installers should reach broadly similar total heat loss figures for the same property — typically within 10-15% of each other. If one installer calculates 8kW and another calculates 14kW for the same house, at least one of them is wrong.

Common reasons for different heat loss figures:

• Different U-value assumptions — how well-insulated they assume your walls, roof, and floor are. An installer who measures insulation thickness gives a more accurate figure than one who guesses.
• Different air change rates — how draughty they assume your house is. This can significantly affect the calculation.
• Different design temperatures — the coldest outdoor temperature the system is designed to handle. This should be consistent for the same location but some installers use more conservative (colder) values.
• Errors — incorrect room dimensions, missed rooms, or calculation mistakes.

If the heat loss figures differ significantly, ask each installer to explain their assumptions. The one who gives the most detailed, evidence-based answer is likely the most accurate.

Checking System Sizing

The heat pump size (in kW) should closely match the total heat loss from the heat loss calculation. A small margin (10-15% oversizing) provides headroom for the coldest days. Anything more than 20% oversizing is a red flag that could cause short-cycling and reduced efficiency.

Use our heat pump calculator to get an independent estimate of the right system size for your home. Compare this with the quotes — if the calculator suggests 8kW and an installer quotes 14kW, ask them to explain the difference.

Comparing Radiator Recommendations

This is where quotes diverge most dramatically. One installer might say all your radiators are fine; another might recommend replacing 8 out of 12. Both could be MCS-certified. Who is right?

The answer depends on the design flow temperature. A heat pump running at 45°C needs larger radiators than a gas boiler at 70°C. But a heat pump running at 55°C (less efficient but still viable) might work with existing radiators. The installer's approach to flow temperature drives the radiator recommendation.

Our radiator guide explains the relationship between flow temperature and radiator sizing in detail. The key question to ask each installer: "What flow temperature have you designed the system for, and why?"

An installer who designs for 35°C will recommend more radiator upgrades but deliver better efficiency. An installer who designs for 50°C will recommend fewer upgrades but deliver lower efficiency. Neither is automatically wrong — but you need to understand the trade-off.

Typical Price Ranges 2026

Use these benchmarks to check whether your quote is in the normal range. Prices shown are after the £7,500 BUS grant.

Source: Analysis of MCS installation data and installer pricing surveys, Q1 2026. Prices include heat pump, cylinder, installation, commissioning, and BUS grant deduction.

Quote Red Flags

Beyond the general installer red flags, watch for these specific quote issues:

• Significantly below market price — more than 30% below other quotes for the same spec. This usually means corners are being cut or scope is missing.
• Significantly above market price — more than 30% above other quotes without clear justification (premium brand, extensive radiator work, complex installation).
• "Estimate" not "Quote" — an estimate is not binding. A quote is. Make sure you have a fixed-price quote.
• Exclusions buried in small print — "excludes electrical work," "excludes scaffolding," "excludes radiator upgrades if needed."
• No heat loss calculation attached — the quote should reference or include the design data.
• Grant handled separately — the best installers handle the BUS grant application for you and deduct it from your price.

Getting an Independent Assessment

If you have received quotes that differ significantly and are unsure which to trust, you can commission an independent assessment. This involves hiring a separate MCS-certified professional who is not trying to sell you an installation.

An independent assessor will:

• Conduct their own heat loss calculation
• Recommend appropriate system size
• Assess your radiators and recommend upgrades if needed
• Provide a written report you can compare against your quotes

Cost: £200-400. This is not cheap, but for a £10,000+ investment, having an independent expert validate (or challenge) your quotes provides valuable peace of mind.

Negotiating Your Quote

Heat pump quotes are not fixed in stone. Reasonable negotiation is expected and accepted in the industry.

• Use competing quotes — "I have two other quotes at £X — can you match?" is legitimate and often effective
• Ask about alternative brands — a different brand at a lower price point might deliver similar performance
• Negotiate extras — if the price is firm, ask for extras: extended warranty, first annual service included, smart thermostat upgrade
• Timing flexibility — installers may offer better prices for quieter periods (spring/summer vs autumn/winter)
• Package deals — combining a heat pump with solar panels from the same installer can sometimes secure a better overall price

Do not negotiate on quality. Never ask an installer to reduce the system size, skip radiator upgrades, or cut commissioning to reduce the price. These savings will cost you much more in poor performance over 20 years.

Frequently Asked Questions

How many quotes should I get?

At least 3 from different MCS-certified installers. Five is even better for a comprehensive comparison.

Why do quotes vary so much?

Different brands, system sizes, radiator recommendations, labour rates, and profit margins. A 25-40% variation is normal; more than 50% warrants investigation.

Is the cheapest quote the best?

Not necessarily. Cheap quotes may use lower-quality brands, skip needed radiator upgrades, or cut corners on commissioning. Compare specifications, not just prices.

What should I compare between quotes?

Brand/model, system size, hot water cylinder, radiator upgrades, flow temperature, COP prediction, commissioning, warranty, BUS grant handling, and total cost.

Can I pay for an independent assessment?

Yes — £200-400 from an independent MCS-certified assessor who is not selling you an installation. Provides a neutral benchmark for evaluating quotes.

Should heat loss calculations match between installers?

Broadly yes — within 10-15%. Differences of more than 25% suggest errors or significantly different assumptions. Ask each installer to explain their figures.