Pool, heating & energy calculators
Solar panels, AC BTUs, furnace size, attic insulation and electrical service size, plus pool volume, chlorine and salt doses.
- BTU calculatorFind the right air conditioner size in BTUs for a room from its square footage, sun exposure, number of people and kitchen use, using the ENERGY STAR chart.
- Electrical load calculatorEstimate a house's electrical load and service size in amps with the NEC 220.82 optional method, from living area, appliances, EV charger and heating or AC.
- Furnace size calculatorEstimate what size furnace your home needs in BTUs from its square footage, climate zone and insulation, and the input rating at your furnace's AFUE.
- Insulation calculatorFind how much attic or floor insulation to add for your climate zone — the ENERGY STAR R-value, the depth of blown fiberglass, cellulose or batts, and bags.
- Pool chlorine calculatorFind how much liquid chlorine, bleach, cal-hypo shock, dichlor or trichlor to add to raise your pool's free chlorine to the target ppm, from the pool's volume.
- Pool salt calculatorCalculate how many pounds and 40 lb bags of salt to add to your saltwater pool to reach your chlorinator's target ppm, from the pool's volume and current level.
- Pool volume calculatorFind how many gallons your pool holds — rectangle with shallow and deep ends, round or oval — plus liters, cubic feet and the salt for a fresh fill.
- Solar panel calculatorFind how many solar panels you need and what size system, from your state's sunshine (NREL data), your monthly electricity use and the panel wattage.