Calculators
Planning tools for fireplaces & comfortable homes, with visible assumptions and units.
Estimate a yearly household budget for smoke alarm replacement using the number of alarms, expected replacement interval, unit price, and a user-entered allowance for related supplies. This is a planning estimate based on your assumptions, not a safety inspection or replacement schedule.
Convert a heating appliance's heat output from British thermal units per hour (BTU/h) to watts (W) using the standard energy-unit conversion factor.
Estimate the electricity cost of running an electric fireplace over a chosen number of days. Enter its power use, average daily operating time, and your electricity price. The estimate assumes the fireplace uses its stated wattage throughout those hours and does not include other charges on your bill.
Compare estimated electricity costs under two tariffs using your household's monthly usage and each plan's unit rate and fixed daily charge. This simple estimate assumes the rates and usage remain constant for the month.
Estimate the tile coverage area for a rectangular fireplace surround by subtracting the fireplace opening from the measured surround area, then adding a tile waste allowance. Enter all dimensions in feet. The estimate excludes trim, hearths, irregular cuts, and any separate areas not included in your measurements.
Estimate the stacked volume of a firewood pile from its measured length, height, and depth. Enter dimensions in feet to see cubic feet and the equivalent fraction of a standard 128-cubic-foot cord.
Estimate the delivered price per cord by combining your firewood cost and delivery and stacking charges, then dividing by the delivered volume.
Estimate the footprint and total space needed to stack a stated volume of firewood at a chosen stack height. This planning estimate assumes a simple rectangular stack and uses your entered stack volume as a consistent volume unit.
Convert a floor area between square feet, square meters, square yards, and square inches using standard area conversion factors.
Compare a rug's area with your hearth's area and see how much of the rug extends beyond the hearth footprint. This area-only comparison does not check clearances or fire safety.
Estimate a heater’s electricity use in kilowatt-hours from its rated power, daily runtime, days used, and average on-cycle percentage. The estimate assumes the heater draws its rated wattage while on.
Compare estimated heating costs for two options over the same period using energy use, energy price, and fixed charges. The estimate uses the values you provide and does not account for efficiency changes, weather, or other home-specific factors.
Convert a relative humidity reading between percent, fraction, and decimal forms. Enter the value and choose the unit shown on your hygrometer.
Estimate simple payback in years by dividing an insulation project's upfront cost by the estimated annual energy cost savings. This worksheet-style estimate assumes the annual savings amount stays constant and excludes financing, maintenance, incentives, and changes in energy prices.
Estimate the electrical energy a heater uses from its wattage and operating time. The result assumes the heater runs continuously at its rated wattage for the entered hours.
Calculate the top surface area of a rectangular mantel shelf from its length and depth. Enter both measurements in the same unit to get area in square units.
Estimate a room's seasonal heating budget from its heat demand, heating hours, energy price, and heater efficiency. This simplified estimate assumes the entered heat demand stays constant during each heating hour.
Calculate the approximate air volume of a rectangular room from its interior length, width, and height.
Estimate a space heater's electricity cost from its rated wattage, daily operating time, days used, and your electricity price. The estimate assumes the heater draws its full rated power whenever it runs.
Convert an electrical power value in watts to its equivalent heating rate in British thermal units per hour (BTU/h) using the standard conversion factor.