Smart Home Savings Calculator UK 2026

Reproducible UK ownership-cost tool

UK Smart-Home Ownership Cost & Payback Planner

Compare the energy and ownership cost of a current setup with a proposed setup using your own figures. The tool calculates low, base and high scenarios, a year-by-year cash position, a local CSV export and copyable scenario data. It does not estimate product savings or recommend a product, tariff, installer or retailer.

Privacy: calculations run in this page. Entries are not stored or sent by this tool. The copy button writes scenario data to your clipboard only when requested; share it only with people you trust and do not include sensitive information.

1. Energy-use comparison

Current setup power (watts)

Proposed setup power (watts)

Number of devices

Hours used per day

Days used per year

Your electricity unit rate (p/kWh)

Use the unit rate on your bill. Do not include the standing charge: changing a device does not normally remove it.

Optional reference only. Ofgem’s average single-rate electricity unit price for Direct Debit customers in England, Scotland and Wales, 1 July–30 September 2026; VAT included. Regional, payment-method, fixed and multi-rate prices differ. Check Ofgem’s source table.

2. Purchase and ongoing costs

Proposed equipment cost (£)

Installation and setup cost (£)

Current annual subscription/maintenance (£)

Proposed annual subscription/maintenance (£)

Proposed replacement cost (£)

Replacement interval (years)

Optional fields may be left blank and are treated as £0. Enter both replacement cost and interval, or leave both blank.

3. Your benefit assumptions and time period

Your base annual non-energy saving (£)

Use £0 if there is none. This is your assumption; Smart Home UK supplies no product-saving percentage.

Sensitivity around that saving (±%)

Planning period (years)

Your calculated comparison

Current annual electricity: —
Proposed annual electricity: —
Annual energy-cost difference: —
Base annual net benefit: —
Base first break-even year-end: —
Upfront proposed cost: —

Position after your planning period

Low: —
Base: —
High: —

Year-by-year cumulative position, including scheduled proposed replacement costs
Year	Low	Base	High	Replacement this year

Open copied scenario data

Paste data copied from this planner. It is parsed only in this page and does not make a network request.

Scenario data

Methodology v2.0 — 30 July 2026

Annual kWh = watts × device count × hours/day × days/year ÷ 1,000.
Annual energy cost = annual kWh × your p/kWh rate ÷ 100.
Annual net benefit = current energy cost − proposed energy cost + your non-energy saving + current ongoing cost − proposed ongoing cost.
Low/high scenarios vary only your non-energy saving by the sensitivity percentage you enter. Energy and recurring-cost entries remain unchanged.
Year 0 starts at equipment plus installation cost. A proposed replacement cost is deducted at each complete interval you enter.
“First break-even year-end” is the first table year whose cumulative base position is zero or higher. It is not an internal-rate-of-return calculation.

The optional Ofgem reference is never inserted automatically. It expires after its stated cap period. Use your own tariff for a household-specific comparison.