Home / Other Calculators / BTU Calculator The BTU Calculator can estimate the amount of BTUs you will need to heat or cool your home, based on the size and the temperature you want for your home.Please note that this calculator can only gauge a rough estimate. You should also consider factors like efficiency decrease of the heater or air conditioner with time, the shape/type of your home or room, insulation conditions, and other factors. 1 watt is approximately 3.41214 BTU/h. good (very few leakages or windows) poor (many leakages or windows) Temperature to Increase or Decrease Depending on your local winter/summer temperature,e.g. 75F for Boston winter, 35F for Atlanta winter. Free Estimation of Your Heating or Cooling Project >>Reference The British Thermal Unit, or BTU, is an energy unit. It is approximately the energy needed to heat one pound of water for 1 Fahrenheit. 1 BTU = 1,055 joules. 1BTU/hour = 0.293 watt. One very well-insulated 1,000-square-foot home in Boston needs around 24,000 BTUs to heat in winter.

One 2,000-square-foot-home with normal insulation conditions in Washington, D.C., needs a 48,000 BTU air conditioner for adequate cooling in summer.portable ac units Other CalculatorsLoveIP SubnetGas MileageConversionGPAGradeTime CardTime ZoneHeightGDPConcreteMarriageAgeMore Other CalculatorsFinancial | hvac unit components I know there are a lot of possible factors that go into determining the size of the air-conditioning system a house needs. commercial wall ac unitIs there a standard way of calculating what is needed, or do A/C companies each devise their own method? Is there a guide somewhere to aid a home-owner in figuring it out? You'll want to check out the ENERGY STAR Air Conditioning Sizing Calculator. To roughly calculate the required BTU output of an air conditioner you will need to total up the results of six calculations.

Square footage of area to be cooled. (Length x Width) x 337 Area of south facing windows. (Height x Width) x 871 Area of north facing windows. (Height x Width) x 166 Heat produced by people (# of people x 400) Heat produced by lights (Total wattage of all lights x 4.25) Total heat produced by appliances (Total wattage of all appliances x 3.15) Add all of these numbers up to determine the BTU output required of the air conditioner (Source). You could also use a site like this Air Conditioner Sizing Worksheet to make the calculations. It probably depends on climate as much as it does the square footage of your house but the general rule is one ton for every 400-500 square feet of house. There are a ton of other factors like vaulted ceilings and if you have dual pane windows and if you have 2x6 construction and therefor more insulation in the walls but for the most part none of that is going to factor into the unit.

It goes more like this: Contractor: How big is your house? You: about 1900 square feet Contractor: I see the house is older You: Yeah, it was built in the 50s Contractor: 5 ton it is! Contractor: I see the house is newer You: Yeah, it was built in the 90s I think you need to look at the Discover Ways for Air Conditioner Sizing in order to get an idea of the size of the AC unit. Two out of three suggested methods include Manual J which is exact science - but not many contractors want to do it for free. There's a ton of variables: A good HVAC pro will be able to do the proper calculations for you.Browse other questions tagged hvac air-conditioning or ask your own question.There is no need to suffer through summer heat when inexpensive, energy-efficient air conditioners are widely available. Since October 26, 2015, all ENERGY STAR rated room air conditioners have been required to meet a new standard, ENERGY STAR 4.0, that sets maximum power use at 10% less than older models following the 2014 guidelines.

And, when used to provide cooling only where they're needed, room air conditioners are less expensive to operate than central units. This guide will help you find the model that is right for you. A room air conditioner's efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity (in British thermal units [Btu] per hour) to the power input (in watts). Each increase of 1.0 on the EER scale represents a 10% increase in energy efficiency. When buying a new room air conditioner, information about the EER can be found on the EnergyGuide label for the unit. Look for an EER of at least 12 and the ENERGY STAR label. Earning the ENERGY STAR means a product meets strict energy efficiency guidelines set by the U.S. Environmental Protection Agency and the U.S. Department of Energy. The required cooling capacity for a room air conditioner depends on the size of the room being cooled. Room air conditioners generally have cooling capacities that range from 5,500 Btu per hour to 14,000 Btu per hour.

Many people buy an air conditioner that is too large, thinking it will provide better cooling. However, an over-sized air conditioner is actually less effective — and wastes energy at the same time. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the room quickly, but only remove some of the humidity. This leaves the room with a damp, clammy feeling. A properly sized unit will remove humidity effectively as it cools.To figure out which size unit is best for your cooling needs, see the Air Conditioner Cooling Needs Calculator below. Verify that your home's electrical system can meet the unit's power requirements. If you are mounting your air conditioner near the corner of a room, look for a unit that can direct its airflow in the desired direction for your room layout. If you need to mount the air conditioner at the narrow end of a long room, look for models that have a “turbo” fan mode that can drive air further into the room.

Other features to look for: For those that keep to a regular schedule and don't have smart home devices installed in their home, a timer will help save money (about $100 on the air conditioner itself and your energy bill) and save you from coming home to a hot, stuffy home. For many, though, the ability to control a room air conditioner from anywhere can be a huge help and cost savings, especially if you don't stick to a schedule. And, you can connect them to other smart home devices so they fit seamlessly into your daily routine. The Frigidaire FFRE0533S1 ($167.99 on Amazon), rated at 5,000BTU, gets high marks for its cooling and dehumidification capabilities of up to 1.1 pints per hour. The unit, which has an EER of 12.2, two cooling and two fan speeds, a 24-hour programmable timer, built-in thermostat with digital temperature readout, remote control and a four-way adjustable vent to direct air flow. The Wi-Fi connected Frigidaire FGRC0844S1 Cool Connect ($296.99 on Amazon) delivers 8,000 BTUs, enough to cool a room up to 350 square feet, with an EER of 12.0.

The unit has 3 fan speeds and 2-way slanted louvers that direct airflow in an upward, circular motion for even cooling. You can create a custom 24-hour schedule or control the unit remotely with the Frigidaire app for iOS and Android or dedicated remote control. If the power goes out, the unit will automatically restart when power is restored.  It has an air ionizer to help remove allergens, like pollen, and other impurities from the air and the magnetic front grill, which has an antibacterial filter, easily detaches for cleaning. A little planning before installing your air conditioner will save you money and energy. The unit should be level when installed, so that the inside drainage system and other mechanisms operate efficiently. If possible, install the unit in a shaded spot on your home's north or east side. Direct sunshine on the unit's outdoor heat exchanger decreases efficiency by as much as 10%. You can plant trees and shrubs to shade the air conditioner, but do not block the airflow.

Don't place lamps or televisions near your air-conditioner's thermostat. The thermostat senses heat from these appliances, which can cause the air conditioner to run longer than necessary. Set your air conditioner's thermostat as high as is comfortably possible in the summer. The less difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. Don't set your thermostat at a colder setting than normal when you turn on your air conditioner; it will not cool your home any faster and could result in excessive cooling and unnecessary expense. Set the fan speed on high, except on very humid days. When humidity is high, set the fan speed on low for more comfort. The low speed on humid days will cool your home better and will remove more moisture from the air because of slower air movement through the cooling equipment. Also, consider using an interior fan in conjunction with your window air conditioner to spread the cooled air more effectively through your home without greatly increasing electricity use.