Principle
Useful estimate first. Commercial option second.
Calculator results are never hidden behind a form. We do not describe a model output as a contractor quotation, a survey or a guarantee. Inputs remain in the browser unless a future lead form separately explains what will be sent, to whom and why.
Model uk-ac-install-2026.09.1
UK air-conditioning installation cost
The one-room wall-mounted model adds published equipment and labour bands. Multi-room and ducted results use published whole-project ranges and expose a planning allocation between equipment and site work. A standard route adds half a published installer day rate; a complex route adds one day. A confirmed electrical upgrade adds the published £400–£700 allowance.
Property age, property type, room size, postcode and removal of existing equipment are surfaced as quote factors but receive no invented location or percentage adjustment. UK is the only priced country in this version. US, Canadian and Australian price outputs remain unavailable until local equipment, labour, tax and regulatory evidence is configured.
Price sources
Model uk-heat-pump-budget-2026.09.1
UK heat-pump project budget
The visitor supplies the main installation figure and any radiator, hot-water-cylinder, electrical or other work that is not already included. The calculator adds those entries and subtracts the support amount selected, capped at the project total.
The default £12,500 is the government's published 2024/25 median for Boiler Upgrade Scheme air-to-water installations. It is a starting point, not a modelled local quote. The page also reports Energy Saving Trust's current typical air-source figure of around £12,000 so the visitor can see that published benchmarks differ.
Grant selection never confirms eligibility. Boiler Upgrade Scheme amounts shown in the calculator apply to England and Wales and the application is installer-led. The model raises visible checks for nation, system type and the temporary off-gas-grid oil/LPG uplift; it does not invent property, regional or installation multipliers.
Cost and support sources
- GOV.UK: Boiler Upgrade Scheme grant amounts (checked September 2026) ↗
- Ofgem: Boiler Upgrade Scheme scope and installer-led application ↗
- GOV.UK: Boiler Upgrade Scheme 2026–2030 business case and median installation cost ↗
- Energy Saving Trust: Air-source heat-pump costs, upgrades and running-cost factors (updated July 2026) ↗
Model uk-heat-pump-vs-boiler-2026.10.1 · reviewed 2 October 2026
Heat pump versus gas boiler
Both systems receive the same visitor-entered useful heat demand. Heat-pump electricity is useful heat divided by seasonal performance factor; boiler gas is useful heat divided by seasonal efficiency. The relevant unit rate is then applied to each fuel.
Boiler energy cost = (useful heat ÷ seasonal efficiency) × gas rate
The energy-only break-even SPF equals the electricity rate multiplied by boiler efficiency, divided by the gas rate. Maintenance figures and an avoidable gas standing charge are added separately. The standing charge is counted only when the visitor says every gas appliance can be disconnected.
The monthly energy average is annual energy cost divided by 12, not an estimate of an individual month's bill. Electricity standing charge is excluded from both choices because the home still needs electricity. The 1 October–31 December 2026 starting tariffs are Great Britain Direct Debit averages with gas VAT included and no electricity VAT in that period; no extra VAT is applied by the calculator. The visitor's final bill rates should replace these dated examples.
The selected-period result holds every entered rate and performance figure constant in today's money. It is not a tariff forecast and excludes finance, inflation, repair risk, future replacement, property value and carbon pricing.
Comparison sources
- Ofgem: Great Britain Direct Debit price-cap averages, 1 October–31 December 2026 ↗
- Energy Saving Trust: air-source heat-pump installation and running-cost factors ↗
- Energy Saving Trust: gas-boiler cost, system choices and installer requirements ↗
- Ofgem: Seasonal Performance Factor definition and system-performance boundary ↗
Model uk-heat-pump-quote-check-2026.09.1
Heat-pump quote completeness
The visitor marks which of 12 design, scope, price and protection elements appear in each written quote. Published MCS design-information requirements carry the greatest weight. Heat loss, equipment, design performance, price presentation and MCS/consumer-protection information are essential: a result cannot receive the strongest status while any of them is missing.
Payable amount = entered pre-support total − entered support discount
A score of at least 85 with no essential gaps is labelled strong paperwork; 60–84 needs clarification; below 60 is not ready to compare. These are Better Home Climate completeness bands, not regulatory grades. The tool identifies the lowest entered payable amount and most complete paperwork separately, and never labels either installer or quotation the best.
Quote labels, prices and selections stay in the current browser tab. Analytics receive only the calculator name, quote count and whether any essential checklist gap remains.
Quote-check sources
Model uk-boiler-replacement-budget-2026.09.1
UK gas-boiler replacement budget
The visitor supplies the main installer figure and any controls, radiators, cylinder, gas/electrical, flue/condensate or making-good work that is priced outside it. The calculator adds those entries and subtracts only the support contribution entered, capped at the project total.
The £3,500 starting figure is Energy Saving Trust's current average for replacing a G-rated gas boiler with an A-rated boiler and thermostatic radiator valves in Great Britain. It is a replaceable starting point, not a local quote. Northern Ireland results flag that the benchmark does not apply there.
Boiler type, relocation and system conversion raise written-scope checks but do not change the price by an invented multiplier. Any ECO or local support remains a user-entered scenario and never becomes an eligibility decision.
Replacement and compliance sources
- Energy Saving Trust: current average gas-boiler replacement cost and installer guidance ↗
- Gas Safe Register: who can legally work on a gas appliance ↗
- GOV.UK: using a competent person scheme and receiving compliance evidence ↗
- GOV.UK: Energy Company Obligation support and eligibility route ↗
- Approved Document L, 2026 edition: replacement-boiler controls in England ↗
Model uk-boiler-quote-check-2026.09.1
Boiler quote completeness
The visitor marks which of 12 installer, equipment, controls, scope, compliance and contract elements appear in each written quote. Gas Safe details, equipment, controls, compliance documents and fixed price/scope are essential: a quote cannot receive the strongest paperwork status while any is missing.
Payable amount = entered VAT-inclusive total − confirmed support or discount entered
A score of at least 85 with no essential gaps is labelled strong paperwork; 60–84 needs clarification; below 60 is not ready to compare. These are Better Home Climate completeness bands, not safety, regulatory or installer ratings. Lowest price and most complete paperwork are reported separately.
Quote labels, prices and checklist selections stay in the current browser tab. Analytics receive only the calculator name, quote count and whether any essential gap remains.
Quote-check sources
- Citizens Advice: get written quotes and compare complete work, materials, VAT and terms ↗
- Gas Safe Register: who can legally work on a gas appliance ↗
- GOV.UK: competent person schemes, compliance evidence and complaints procedures ↗
- Approved Document L, 2026 edition: replacement-boiler controls in England ↗
- Energy Saving Trust: compare boiler installers, costs and replacement requirements ↗
Model room-ac-btu-2026.09.1
Room air-conditioner BTU sizing
The model begins with ENERGY STAR's floor-area capacity table. It then scales the base against an 8 ft ceiling. Good insulation applies −10%; poor insulation +15%. Window area below 10% of floor area applies −5%; 25–40% applies +10%; above 40% applies +20%.
ENERGY STAR adjustments are then applied: heavy shade −10%, very sunny +10%, 600 BTU/h for each regular occupant above two, and +4,000 BTU/h for a kitchen. Better Home Climate's appliance planning allowance is +500 BTU/h for moderate heat and +1,500 BTU/h for high heat. The answer is rounded to the nearest 500 BTU/h and displayed as a ±10% comparison band.
This is a product-comparison estimate, not a room-by-room professional cooling-load calculation. It does not model full construction assemblies, detailed solar geometry, infiltration, ventilation, outdoor design temperature or heat transfer to adjacent spaces.
Sizing sources
Model appliance-cost-2026.09.1
Appliance electricity running cost
Daily, monthly and seasonal results multiply the same audited hourly figure by the use pattern entered. Currency formatting changes; the formula does not. The visitor supplies the tariff because national rates change and individual tariffs differ. Standing charges are excluded because they are paid whether or not the appliance runs.
Review and change control
What gets updated, and when.
- Price configuration is reviewed at least every quarter and when a named source materially changes.
- Formulas and factors use explicit version labels. A material method change creates a new version.
- Incentives and grants are kept out of base installation prices unless separately sourced with a last-checked date.
- Analytics can include calculator name, country and a broad result band, but not exact entries, postcode, room dimensions or contact details.
- No personal data is passed to a quote partner until a named provider, privacy link and lawful consent flow are configured.
An estimate is a modelled planning range. A quotation is a supplier's priced offer for a defined scope after assessing the property. Always compare inclusions, equipment model, capacity, access, electrics, commissioning, warranty, VAT and making-good—not just the headline total.