Thermostat, ventilation, degree day, and energy efficiency calculators. Browse our free efficiency tools below — all calculators are instant, accurate, and require no sign-up.
Air Change Rate (ACH) Calculator — Calculate the air changes per hour (ACH) for a room or building. Determine ventilation rate from airflow volume and room size.
Cool Roof Savings Calculator — Calculate cooling energy savings from a cool roof (reflective roofing). Estimate reduced air conditioning costs and payback from high-reflectance roofing materials.
Cooling Degree Days (CDD) Calculator — Calculate cooling degree days from daily temperatures. Estimate CDD for energy analysis, air conditioning cost planning, and cooling season comparisons.
ERV/HRV Savings Calculator — Calculate energy savings from an ERV or HRV ventilation system. Compare heat recovery ventilation costs to standard exhaust-only ventilation.
Green Roof Savings Calculator — Calculate energy savings and benefits from installing a green (vegetated) roof. Estimate insulation value, cooling savings, and stormwater management benefits.
Heat Loss & Degree Day Calculator — Calculate home heat loss using heating degree days. Estimate seasonal heating energy consumption and costs based on HDD and building thermal performance.
Heating Degree Days (HDD) Calculator — Calculate heating degree days from daily temperatures. Estimate HDD for energy analysis, fuel planning, and heating season comparisons.
Programmable Thermostat Savings Calculator — Calculate energy savings from using a programmable thermostat with temperature setbacks. Estimate cost reduction from scheduled heating and cooling adjustments.
Setback Temperature Savings Calculator — Calculate how much you save by lowering your thermostat a specific number of degrees. Estimate savings per degree of temperature setback.
Smart Thermostat Savings Calculator — Calculate annual savings from installing a smart thermostat. Estimate energy reduction from automatic scheduling, learning, and occupancy detection.
Ventilation CFM Calculator — Calculate the required CFM ventilation rate for a room or building. Determine airflow needs based on room size, occupancy, and ASHRAE standards.