Sitemap
Browse all calculators, reference guides, regional presets, equipment guides, and policy pages on HowManyBTUs.com.
On this page: Calculators · Reference guides · Regional presets · Equipment & resources · About & policies
Calculators (23)
Cooling & heating sizing
- BTU Calculator (quick) — fast estimate by room size
- Advanced BTU Calculator — detailed load with climate zone, insulation, windows, ducts
- AC Size Calculator — BTUs to tons for central AC
- Mini Split Calculator — single and multi-zone ductless sizing
- Window AC Calculator — room-by-room window unit BTUs
- Portable AC Calculator — SACC-adjusted portable AC sizing
- Heat Pump Calculator — year-round heating + cooling sizing
- Furnace Size Calculator — BTU output by square footage and climate
- Space Heater Calculator — wattage and BTUs for supplemental heating
- Pool Heat Pump Size Calculator — BTU/hr capacity needed to heat your pool
- Garage Heater Calculator — electric or gas heater BTU and wattage sizing by zone, insulation, and door count
- Radiant Floor Heating Calculator — boiler size or electric mat wattage for hydronic or electric radiant floor
Comfort, efficiency & costs
- Dehumidifier Calculator — pint capacity by room size and dampness
- SEER Savings Calculator — compare efficiency ratings and payback
- Energy Cost Calculator — monthly HVAC operating cost by fuel type
- Ceiling Fan Calculator — blade span, CFM, and downrod by room
- Air Filter Size Calculator — filter dimensions, MERV, and replacement schedule
- HRV/ERV Size Calculator — using the ASHRAE 62.2 ventilation rate procedure
- Air Leakage Load Calculator — estimate extra heating or cooling lost to drafts
- Duct Size Calculator — size HVAC ductwork from airflow (CFM)
- HVAC Standby Power Cost Calculator — how much your HVAC costs even when it’s off
- Grow Room Calculator — BTU cooling load, AC size, ventilation CFM, and electricity cost
- EER to SEER2 Calculator — convert between EER, SEER, SEER2, COP, and kW/ton; check DOE 2023 compliance
Reference guides (3)
Quick-reference tables and lookup tools for BTU rates, room sizing, firewood heat content, and equipment tonnage.
- How Many BTUs Do I Need? — room-type estimator with instant BTU result by space type
- BTU Per Square Foot — heating and cooling rate tables by climate zone and insulation quality
- BTU Chart — interactive charts for room sizing, window AC, firewood BTU by species, and equipment tonnage
BTU calculator by region (5)
These pages pre-set climate zones, insulation defaults, and units for your area. You can still adjust all inputs inside the calculator.
United States
- Texas — Zone 2, cooling-focused, SEER2 14.3 minimum
- Florida — Zone 1, humidity and dehumidification guidance
- California — Zone 3, coast vs inland vs desert, Title 24
Canada
- Canada (all provinces) — Zone 6, Canadian building codes, kW conversions
- Ontario — Zone 6, SB-12 insulation, Ontario-specific tips
Equipment & resources
- Heating & Cooling Equipment by BTU Range — shop window ACs, mini splits, heat pumps, space heaters, fans, filters, and more