HVAC / Boiler Replacement Cost Calculator

How the hvac / boiler replacement cost calculator works

Estimates supply and install cost for boiler, heat pump, or furnace. The calculator takes your dimensions and supplier rates, applies a standard UK trade formula, and returns a quantity with an indicative cost. Every figure is an estimate — site conditions always move the final number.

Typical UK project cost estimators wastage

Cost estimates carry an inherent range — a ±20% spread is normal at planning stage, tightening to ±5% once drawings are tendered. Our defaults reflect common UK trade allowances, and can be adjusted upwards for non-standard geometry or downwards where experience supports a lower figure.

What this tool does not do

It does not replace a professional quote, factor regional pricing, assess structural adequacy, or confirm Building Regulations compliance. Those remain the responsibility of a suitably qualified designer, surveyor, or your building control officer.

On-site considerations for hvac / boiler replacement cost

Rates in this tool are April 2026 UK medians. Regional variation of ±30% is normal — London and the South East run higher, Scotland and the North typically lower.

Building Regulations and compliance

VAT treatment differs by project type: new-builds are zero-rated for a qualifying end user, listed-building work may qualify for 5%, normal renovation is 20%. When in doubt, a pre-application enquiry to the local authority can give early clarity, which tends to be less costly than retrospective correction.

Before you order

Break your budget into build cost, professional fees (8–15%), and contingency (10–20%) from the outset. Blending them hides overruns until it is too late to respond. Cross-checking the calculator’s output against a supplier quote helps catch differences in pricing assumptions — ask for exact product specifications (grade, finish, batch number) and confirm delivery timescales against your programme.

Adjusting the defaults

Every input in this calculator is editable. Enter your own dimensions, supplier prices, and wastage allowance — the output recalculates instantly. If the defaults feel off for your region or project type, your own numbers always override them.

Using this hvac / boiler replacement cost calculator alongside other BuildMetricLab tools

This calculator works best as part of a planning workflow. Pair the quantity with our project contingency, labour-hours, and material-cost calculators to build a complete estimate before you pick up the phone to a supplier. All BuildMetricLab tools run entirely in your browser — no sign-up, no data sent anywhere, and every formula is shown on-page so you can audit the maths.