Energy Savings & Home Upgrades
ROI on heat pumps, solar, insulation, and every upgrade that lowers your utility bill.
10-Year Energy Cost Projection
Plot cumulative energy costs with and without upgrades over a decade.
Air Changes Per Hour (ACH) Calculator
Calculate minutes to full air exchange based on house volume and fan CFM.
Contractor Bid Analyzer
Flag oversized equipment, missing rebates, and evaluate price reasonableness on contractor bids.
Crawlspace Ventilation Calculator
Determine required vent area using the 1:150 ratio for your crawlspace.
Drafty House Dollar Leakage Tool
Translate blower door test results into monthly dollar losses from air leakage.
Embodied Carbon Estimator
Convert construction material quantities into tons of CO2 equivalent.
Energy Upgrade Sequencing Optimizer
Determine the correct order of upgrades to maximize savings within your budget.
EV Home Charging Impact Tool
Calculate utility bill increases and panel upgrade costs for a Level 2 home charger.
Heat Pump Savings Calculator
Calculate annual savings versus gas furnaces and payback based on climate zone.
Heat Pump vs. Gas Break-Even Tool
Calculate the temperature at which a heat pump becomes cheaper than a gas furnace.
Home Energy Score Estimator
Approximate your DOE Home Energy Score and see an improvement roadmap.
Home Energy Upgrade ROI Calculator
Calculate annual savings and payback periods for air sealing, insulation, and HVAC upgrades.
HVAC Sizing Validator
Check if a contractor's proposed HVAC size is correct for your home's square footage.
HVAC System Efficiency Calculator
Calculate true system efficiency factoring in EER, duct leakage, and filter pressure loss.
Indoor Ventilation CFM Calculator
Determine required CFM per person based on occupants, rooms, and square footage.
Insulation R-Value Calculator
Check if the composite R-value of your wall assembly meets climate zone minimums.
Insulation Upgrade Payback Calculator
Calculate savings per year and payback months based on R-value improvements.
IRA Tax Credit Calculator
Calculate exact Form 5695 credit amounts and multi-year spreading logic for energy upgrades.
LED Upgrade Savings Calculator
Estimate annual savings, upgrade cost, and payback period from switching to LED bulbs.
Passive Solar Window Sizing Calculator
Use the 12% rule to calculate maximum south-facing glass area and thermal mass needs.
Rainwater Harvesting Potential Calculator
Estimate collectable gallons and irrigation offset based on roof area and local rainfall.
Rebate Stack Estimator
Combine federal ITC, state, and local utility rebates based on income and upgrade type.
Solar + Battery ROI Calculator
Determine system size, 25-year savings, and break-even year using utility bills and local rates.
Solar Battery Grid Independence Day Calculator
Predict which day of the year your battery runs out during a grid failure.
Solar Offset Calculator for ADU
Evaluate how much of your ADU's energy usage is covered by solar generation.
Solar Panel Sizing Calculator for ADU
Calculate kW needed, cost, and payback for solar panels on your ADU.
Solar Water Heater Payback Calculator
Calculate annual savings based on household size, fuel type, collector size, and climate zone.
Title 24 Energy Compliance Estimator
Estimate California Title 24 energy code compliance requirements for ADUs.
Utility Cost Minimization Calculator
Optimize monthly utility expenses based on usage patterns and rate tiers.
Window Heat Loss Calculator
Estimate annual heat gain/loss in BTUs and cost based on U-factor, SHGC, and climate zone.