Run the numbers.
Planning calculators for homeowners, building owners and building operators. For a real quote, call 314-200-5505.
Ameren Illinois program finder
Answer a few questions to see which programs may fit. Ameren Illinois makes the final eligibility decision.
Programs worth asking about
Plain-language guidance only. Program availability, income limits and qualifying ZIP codes are set by Ameren Illinois. Call 314-200-5505 or email hello@greentitansenergy.com to confirm and sign up.
Repair or replace?
Uses the industry “age × repair cost” rule of thumb plus system age and repair history.
Result
Rule of thumb: if age × repair cost exceeds about $5,000, replacement usually makes more sense. Safety issues (cracked heat exchanger, gas leak) override everything — call us.
HVAC upgrade savings & payback
Estimate what a higher-efficiency furnace and A/C could save versus what you spend now.
Estimated savings
Compares efficiency ratings only; assumes equal comfort settings and flat energy prices. Proper sizing, duct sealing and installation quality can change real results.
Weatherization savings estimator
See how air sealing and attic insulation could cut your heating and cooling costs.
Estimated savings
Planning estimate. ENERGY STAR estimates homeowners can save an average of about 15% on heating and cooling by air sealing and adding attic insulation; leakier, older homes often save more. A blower-door test gives real numbers.
Thermostat setback savings
How much could a smart or programmable thermostat save by easing off while you sleep or are away?
Estimated savings
Based on the U.S. Department of Energy guidance that setting back 7–10°F for 8 hours a day can save up to about 10% a year (roughly 1% per degree for an 8-hour setback). Qualifying Ameren Illinois customers may get a free smart thermostat — see Smart Savers.
Rooftop unit replacement ROI
Estimate electricity savings and payback from replacing older packaged units with high-efficiency equipment.
Estimated results
Compares rated cooling efficiency (EER vs. IEER, which reflects part-load operation) and ignores economizer, fan and heating changes. CO₂ uses ~0.82 lb/kWh (approximate U.S. grid average). Incentive amounts depend on Ameren Illinois program rules — ask us.
Building envelope payback
Weatherization for commercial and multifamily buildings: air sealing, roof insulation, doors and docks.
Estimated results
Planning estimate using typical savings ranges per measure, scaled by envelope condition and capped to avoid double-counting. A site assessment and infrared/blower-door testing give real numbers. Ameren Illinois business programs include weatherization incentives — ask us.
Energy use benchmark (EUI)
Compare your building's site energy use intensity with the national median for its type.
Benchmark
Site EUI = (kWh × 3.412 + therms × 100) ÷ floor area. Medians are approximate U.S. national median site EUIs published by ENERGY STAR Portfolio Manager; weather, hours and occupancy affect real comparisons. For a certified score, benchmark in Portfolio Manager.
Preventive maintenance planner
Pick your equipment and get a 12-month maintenance calendar you can print or send to your team.
Your maintenance calendar
Generic best-practice tasks; always follow manufacturer requirements. Want us to run it? Ask about a commercial maintenance agreement.
After-hours setback savings
What does conditioning an empty building cost? Estimate savings from tighter schedules and setbacks.
Estimated results
Rule-of-thumb estimate (≈1% of HVAC energy per °F of setback per 8 hours), capped at 30%. Fan-only ventilation requirements and building mass affect results.
HVAC downtime cost
What does one equipment failure really cost? Compare it with preventive maintenance.
Estimated results
Your own estimates drive this tool. Results exclude energy savings from well-maintained equipment, which add to the benefit.