Unit Heater Sizing Calculator

Square Footage	Recommended BTUs
Up to 500	10,000 – 20,000
501 – 1000	20,000 – 40,000
1001 – 1500	30,000 – 50,000
1501 – 2000	40,000 – 60,000
2001 – 2500	50,000 – 70,000
2501 – 3000	60,000 – 80,000
3001 – 3500	70,000 – 90,000
3501 – 4000	80,000 – 100,000
4001 – 4500	90,000 – 110,000
4501 – 5000	100,000 – 120,000

FAQs

What is the formula for unit heater sizing? The formula for unit heater sizing involves calculating the heat load of a space using factors like square footage, insulation, climate, and desired temperature. Generally, the formula is: Required BTUs = Square Footage × Insulation Factor × BTUs per square foot.

What is the rule of thumb for sizing unit heaters? A common rule of thumb for sizing unit heaters is to aim for around 25 to 50 BTUs per square foot of the space you want to heat.

How many BTUs do I need to heat 800 square feet? For 800 square feet, you might need around 20,000 to 40,000 BTUs, based on the rule of thumb.

How many BTU unit heater per square foot? A typical range is 25 to 50 BTUs per square foot for unit heater sizing.

How many BTU do I need for a 900 square foot garage? For a 900 square foot garage, you might need around 22,500 to 45,000 BTUs.

What size heater for 10×10 room? For a 10×10 room, you might need around 2,500 to 5,000 BTUs, based on the rule of thumb.

What is the 3 foot rule for space heaters? The 3-foot rule suggests keeping flammable objects at least 3 feet away from space heaters to reduce the risk of fire.

How many BTU heater do I need for a room size? To determine the BTU heater needed for a room, calculate the heat load based on the room’s size, insulation, climate, and desired temperature.

How much CFM do I need for 2000 square feet? A common rule is around 1 CFM per square foot, so for 2000 square feet, you might need around 2000 CFM.

How big of an area will 50000 BTU heat? A 50,000 BTU heater might heat around 1000-2000 square feet, considering insulation and outdoor temperature.

How many square feet will a 60000 BTU furnace heat? A 60,000 BTU furnace might heat around 1200-2400 square feet, based on insulation and outdoor temperature.

How many BTU do I need to heat 1000 square feet? For 1000 square feet, you might need around 25,000 to 50,000 BTUs, based on the rule of thumb.

What size unit heater for 1000 square feet? A unit heater of around 25,000 to 50,000 BTUs might be suitable for 1000 square feet.

How many square feet will a 24000 BTU heater heat? A 24,000 BTU heater might heat around 480-960 square feet, based on insulation and outdoor temperature.

How big of a heater do I need per square foot? Aim for around 25 to 50 BTUs per square foot when sizing a heater.

What is the best heater for a 900 sq ft garage? A heater around 22,500 to 45,000 BTUs might be suitable for a 900 sq ft garage.

How many BTU do I need to heat 950 square feet? For 950 square feet, you might need around 23,750 to 47,500 BTUs.

How many BTU do I need for 950 sq ft? For 950 square feet, you might need around 23,750 to 47,500 BTUs.

Can a heater be too big for a room? Yes, a heater that’s too big for a room can lead to inefficient operation, short cycling, and discomfort.

Is it cheaper to turn on the heat or use space heaters? It’s generally more cost-effective to use central heating if the entire house needs heating. Space heaters are efficient for spot heating in smaller areas.

What size heater do I need for 1200 square feet? For 1200 square feet, you might need around 30,000 to 60,000 BTUs.

How many house fires do space heaters cause? Space heaters contribute to a significant number of house fires each year. Proper usage and safety precautions are crucial.

Can you leave a space heater unattended overnight? It’s generally not recommended to leave a space heater unattended, especially overnight, due to fire risks.

How far should a space heater be from the wall? A space heater should be placed at least 3 feet away from walls, furniture, curtains, and other flammable objects.

How many BTU do I need to heat a 12×12 room? For a 12×12 room, you might need around 3,000 to 6,000 BTUs.

How many BTU do I need for a 12×12 room? For a 12×12 room, you might need around 3,000 to 6,000 BTUs.

Is 8000 BTU too much for a bedroom? An 8000 BTU heater might be too much for a smaller bedroom, potentially causing discomfort due to overheating.

What is the rule of thumb for CFM per square foot? A common rule of thumb is around 1 CFM per square foot for ventilation.

How many CFM do I need for a 12×12 room? For a 12×12 room, you might need around 144 CFM (1 CFM per square foot).

What size room does 80 CFM cover? An 80 CFM ventilation fan might be suitable for a room of around 80 square feet.

How much space will a 30000 BTU heater heat? A 30,000 BTU heater might heat around 600-1200 square feet, considering insulation and outdoor temperature.

Is there a big difference between 40000 BTU and 50000 BTU? The difference between 40,000 and 50,000 BTUs is significant and can affect the heating coverage area and efficiency.

How much space does a 48000 BTU heater heat? A 48,000 BTU heater might heat around 960-1920 square feet, based on insulation and outdoor temperature.

How many square feet will a 70,000 BTU furnace heat? A 70,000 BTU furnace might heat around 1400-2800 square feet, based on insulation and outdoor temperature.

How many square feet will a 65,000 BTU furnace heat? A 65,000 BTU furnace might heat around 1300-2600 square feet, based on insulation and outdoor temperature.

How many square feet will a 100,000 BTU furnace heat? A 100,000 BTU furnace might heat around 2000-4000 square feet, based on insulation and outdoor temperature.

Do you count the basement when sizing a furnace? Yes, the basement is typically counted when sizing a furnace, as it contributes to the total heated area.

How many BTU is needed for 2000 sq ft? For 2000 square feet, you might need around 50,000 to 100,000 BTUs.

How many BTU do I need for 700 sq ft? For 700 square feet, you might need around 17,500 to 35,000 BTUs.

How many square feet will a 5000 watt heater heat? A 5000 watt (approximately 17,000 BTU) heater might heat around 340-680 square feet.

How do you heat a 1000 square foot garage? To heat a 1000 square foot garage, consider using a heater around 25,000 to 50,000 BTUs, based on insulation and outdoor temperature.

How many square feet will a 7500 watt heater heat? A 7500 watt (approximately 25,500 BTU) heater might heat around 510-1020 square feet.

What is the difference between 12000 BTU and 18000 BTU? The difference between 12,000 BTU and 18,000 BTU is the heating capacity, with 18,000 BTU being more powerful and suitable for larger spaces.

What size heater for 2000 square feet? For 2000 square feet, you might need around 50,000 to 100,000 BTUs.

How many square feet will a 18000 BTU mini split heat? An 18,000 BTU mini-split might heat around 360-720 square feet, considering insulation and outdoor temperature.

How many BTUs do I need to heat a 20×20 garage? For a 20×20 garage, you might need around 40,000 to 80,000 BTUs.

How do you calculate heating for a room size? Calculate heating for a room size by determining the required BTUs based on the room’s square footage, insulation, outdoor temperature, and desired indoor temperature.

How do I calculate the square footage of my room for heating? To calculate the square footage of a room for heating, measure the length and width of the room, then multiply them to get the area.

Is it OK to oversize a garage heater? Oversizing a garage heater can lead to inefficient operation, discomfort, and wasted energy.

How many BTU do I need for a 2 car garage? For a two-car garage, you might need around 30,000 to 60,000 BTUs, depending on insulation and outdoor temperature.

Can a garage heater be too big? Yes, a garage heater can be too big, leading to inefficiency and discomfort.

What size heater for 900 sq ft? For 900 square feet, you might need around 22,500 to 45,000 BTUs.

How many BTU do I need for 900 sq ft? For 900 square feet, you might need around 22,500 to 45,000 BTUs.

How many BTUs do I need to heat and cool 800 square feet? The BTUs needed to heat and cool 800 square feet depend on factors like insulation, climate, and desired comfort level.

How big of an area will 50000 BTU heat? A 50,000 BTU heater might heat around 1000-2000 square feet, based on insulation and outdoor temperature.

How many square feet will 10,000 BTU cover? A 10,000 BTU heater might cover around 200-400 square feet, considering insulation and outdoor temperature.

How many feet will a 10,000 BTU cover? It’s not common to measure heater coverage in linear feet; it’s usually measured in square feet.

How big of a room will a 1500 watt heater heat? A 1500 watt (approximately 5100 BTU) heater might heat around 100-200 square feet, based on insulation and outdoor temperature.

Do bigger space heaters work better? Bigger space heaters can provide more heat, but they need to be appropriately sized for the room to avoid inefficiency.

How many watts does it take to heat a 10×10 room? For a 10×10 room, you might need around 1000-1500 watts (3400-5100 BTUs) to heat adequately.

How much does it cost to run a 1500 watt heater for 30 days? To calculate the cost, multiply the heater’s wattage (1500) by the hours it’s on per day, then divide by 1000 to get kilowatt-hours. Multiply by your electricity rate.

Is it better to heat the whole house or use a space heater? Heating the whole house with central heating is usually more efficient and comfortable than using space heaters for the entire house.

How many BTU do I need for 1500 sq ft? For 1500 square feet, you might need around 37,500 to 75,000 BTUs.

How many BTU do I need to heat 1200 square feet? For 1200 square feet, you might need around 30,000 to 60,000 BTUs.

What kind of space heater causes the most fires? Space heaters with exposed heating elements or inadequate safety features can pose higher fire risks.

What space heaters won’t catch fire? Electric space heaters with modern safety features and proper usage guidelines are less likely to catch fire.

What is the best heater to leave on overnight? Electric heaters with tip-over and overheating protection are generally considered safer for leaving on overnight.

What is the safest heater to leave on overnight? Ceramic or oil-filled electric heaters with safety features are often considered the safest options for leaving on overnight.

What is the 3 foot rule for space heaters? The 3-foot rule advises keeping flammable objects at least 3 feet away from space heaters to reduce the risk of fires.

Where is the best place in a room to put a space heater? Place a space heater on a flat, stable surface away from foot traffic, and ensure it’s at least 3 feet away from flammable objects.

How many BTU do I need for a 12×12 room? For a 12×12 room, you might need around 3,000 to 6,000 BTUs.

How many BTU do I need for a 12×12 room? For a 12×12 room, you might need around 3,000 to 6,000 BTUs.

Is 8000 BTU too much for a bedroom? An 8000 BTU heater might be too much for a smaller bedroom, potentially causing discomfort due to overheating.

How many BTU do I need to heat 1000 square feet? For 1000 square feet, you might need around 25,000 to 50,000 BTUs, based on the rule of thumb.

How many square feet will 8000 BTU heat? An 8000 BTU heater might heat around 160-320 square feet, based on insulation and outdoor temperature.

What happens if the BTU is too high? If the BTU is too high for a space, the heater might overheat the room quickly, leading to discomfort and inefficiency.

How many CFM per square foot for heating? A common guideline is around 1 CFM per square foot for heating.

How many CFM do I need for a 120 square foot room? For a 120 square foot room, you might need around 120 CFM.

Can CFM be too high for a room? Yes, excessively high CFM can create drafts, discomfort, and uneven heating.

What size room does 80 CFM cover? An 80 CFM ventilation fan might cover a room of around 80 square feet.

How long will a Mr. Heater 30000 BTU run on a 20 lb tank? The runtime of a 30,000 BTU Mr. Heater on a 20 lb tank depends on factors like temperature and usage settings.

How much space can a 60000 BTU heater heat? A 60,000 BTU heater might heat around 1200-2400 square feet, considering insulation and outdoor temperature.

How many square feet will a 24000 BTU heater heat? A 24,000 BTU heater might heat around 480-960 square feet, based on insulation and outdoor temperature.

Will 50000 BTU keep you warm? A 50,000 BTU heater might provide ample warmth for a sizeable area, but proper insulation and distribution are essential for comfort.

How many square feet can a 40000 BTU furnace heat? A 40,000 BTU furnace might heat around 800-1600 square feet, based on insulation and outdoor temperature.

How many square feet will a 40000 BTU heater heat? A 40,000 BTU heater might heat around 800-1600 square feet, based on insulation and outdoor temperature.

How many square feet will a 400000 BTU heater heat? A 400,000 BTU heater might heat a substantial area, but professional sizing and safety considerations are crucial.

How much space will a 30000 BTU heater heat? A 30,000 BTU heater might heat around 600-1200 square feet, considering insulation and outdoor temperature.

How much space does 46,000 BTU heat? A 46,000 BTU heater might heat around 920-1840 square feet, based on insulation and outdoor temperature.

How many square feet will a 110,000 BTU furnace heat? A 110,000 BTU furnace might heat around 2200-4400 square feet, based on insulation and outdoor temperature.

How many square feet will a 120,000 BTU furnace heat? A 120,000 BTU furnace might heat around 2400-4800 square feet, based on insulation and outdoor temperature.

How many square feet will a 68,000 BTU heater heat? A 68,000 BTU heater might heat around 1360-2720 square feet, based on insulation and outdoor temperature.

How many BTU furnace does it take to heat a 2000 square foot house? A 2000 square foot house might need a furnace around 50,000 to 100,000 BTUs, based on insulation and climate.

How many square feet will 72000 BTU heat? A 72,000 BTU heater might heat around 1440-2880 square feet, based on insulation and outdoor temperature.

How many square feet will a 4-ton furnace heat? A 4-ton (48,000 BTU) furnace might heat around 960-1920 square feet, based on insulation and outdoor temperature.

What size house will need a 90000 BTU furnace? A 90,000 BTU furnace might be suitable for a house of around 1800-3600 square feet, based on insulation and climate.

How many BTUs do I need for a 2000 square foot house? For a 2000 square foot house, you might need around 50,000 to 100,000 BTUs, based on insulation and climate.

What size AC unit do I need for a 2400 sq ft house? For a 2400 square foot house, you might need an AC unit in the range of 3.5 to 5 tons, based on insulation and climate.

Does the basement count as heated square footage? Yes, the basement typically counts as heated square footage when sizing HVAC systems.

Is it better to undersize or oversize a furnace? It’s better to slightly undersize a furnace than to oversize it significantly, as oversizing can lead to inefficiency and discomfort.

What happens if furnace is oversized? An oversized furnace might short cycle, leading to inconsistent heating, wasted energy, and discomfort.

How many square feet will 30,000 BTU cover? A 30,000 BTU heater might cover around 600-1200 square feet, based on insulation and outdoor temperature.

How many square feet will 10,000 BTU cover? A 10,000 BTU heater might cover around 200-400 square feet, considering insulation and outdoor temperature.