What this calculator models
Heating controls are the cheapest retrofit measure most homes never finish — and where the savings hide is in the gap between the manufacturer's marketing claim ("save up to 30%") and the typical home's real saving (8-18%). This calculator surfaces the realistic band based on your occupancy pattern: a working-couple home with empty days saves more from scheduling, a retired-couple home with constant occupancy saves more from zoning, and a family home with mixed patterns saves most from full TRV-based zoning combined with weather compensation. The capital cost is small enough that even modest savings produce sub-3-year paybacks.
Inputs
- Property size (rooms heated)
- Current control level (mechanical TRVs, single thermostat, no zoning vs already-zoned)
- Occupancy pattern (always occupied, empty weekdays, empty days+evenings, intermittent)
- Current heating system (combi, system boiler, heat pump, electric direct)
- Annual heating spend
- Boiler / heat pump compatibility with weather compensation
- Comfort temperature preference (room-by-room or single setpoint)
Outputs
- Annual saving (zoning-only, scheduling-only, combined)
- Payback period
- 10-year cumulative saving
- Capital cost (DIY-installable, professionally-installed)
- Comfort improvement narrative (which rooms get warmer)
- Carbon-saving estimate
Typical payback band: 1-3 years for most homes, 0-1 year on always-occupied homes upgrading from no zoning, 3-5 years on already-zoned homes adding only weather compensation
Best for: Homeowners on a constrained budget who need a quick-win saving before investing in fabric or generation work, plus landlords seeking to improve EPC band cheaply.