Every RetrofitROI Decision Engine
Every engine on this site answers one question: is this specific home-energy purchase worth it, and which option wins, given your own numbers. Jump directly to any of the 120 engines below, grouped by the eight decision areas they cover.
Solar 15 engines
Payback by system-cost class, cash versus loan versus lease versus PPA, and what your actual incentive stack does to the number.
HVAC 15 engines
Heat pump versus gas furnace, SEER-upgrade payback, and the repair-cost threshold where replacing a working system finally becomes the stronger move.
EV Home Charging 15 engines
What a Level 2 charger install actually pays back against public charging and a gas-cost baseline, under your real driving pattern.
Water Heating 15 engines
Tankless versus tank, heat pump versus electric versus gas, and the replacement-timing math that beats waiting for a failure.
Battery & Backup Power 15 engines
Battery versus generator on total cost, backup sized around the outage cost you are actually avoiding, and whether battery makes sense without solar.
Electrification 15 engines
The cost and payback of moving a gas appliance to electric, what a panel upgrade actually adds to that math, and the order that keeps a full conversion affordable.
Insulation & Envelope 15 engines
Attic, wall, and window paybacks by climate zone, and which envelope upgrade actually pays for itself before a bigger equipment purchase does.
Utility Rate Optimization 15 engines
Time-of-use versus flat rate, demand-charge exposure, and community solar compared honestly against rooftop solar and against doing nothing.