What Does BTU Stand For?

What Does BTU MeanThe short answer is that the British Thermal Unit (BTU) a standard of measurement for work done.  A single BTU is the amount of work required for raising the temperature of a pound of water by one degree Fahrenheit.  This is equal to roughly 1,055 joules.  Science mostly uses the joule as the standard unit for work, but BTUs are still used to rate heaters, air conditioners, power generation, and propane systems.  Any furnace or HVAC unit you have installed will be listed in terms of BTUs.  In fact, the price of propane is measured in relation to BTUs.  Propane gas is sold based on the current cost of a single therm (100,000 BTUs).

How Many BTUs Does My Furnace Need?

Similar to how using an air conditioner that is too large or too small for your home will put a strain on the unit, the same goes for your furnace.  To heat your home properly, a furnace uses thousands of BTUs.  A large system may cycle irregularly, decreasing efficiency, while a small unit cannot adequately heat your home.

The best way to ensure the most efficient BTU rating for your furnace is to get a professional evaluation.  Heating professionals and contractors use multiple load calculations to determine exactly how much work a system will need to do to properly regulate your home’s temperature.  The simplest calculation is:

BTUs per Square Foot x Square Footage of Home = BTU Output Needed

The average BTU output you need is based on the climate.  Cooler climates will naturally need a higher BTU rate for heating in the winter than warmer climates.  For residents of our home city, Newark, Delaware, a BTU rating of 40-45 per square foot is roughly optimal.  Of course, our techs here at Boulden Brothers can help you identify the most efficient system for your home.

Of course, a similar measurement can be done to estimate cooling needed for your home during the summer.  Energystar.gov has an excellent guide on selecting BTU capacity for cooling, and for measuring non-rectangular rooms.

How Does This Help Me?

Knowing how many BTUs your home needs for heating or cooling can guide your future decisions.  If you’ve noticed that your home doesn’t heat properly in the winter, a quick check for the BTU output of your furnace can help identify that as the source of the problem.  Rather than paying for inspections and repairs, you can schedule a replacement to a more efficient or higher output model.

If you’re planning to upgrade your home with a new addition, you can estimate how powerful of a central heating and air unit you’ll need in the future.  You might be fine with your current unit, but adding another 500 square feet of space may put too high a strain on your existing system.  You can incorporate the cost of a new central system into the new space, or search for a better solution.  Either way, if you call Boulden Brothers for help we’ll be glad to offer assistance.


If you have any further questions on how to maintain your HVAC system, talk to the licensed, trained technicians at Boulden Brothers.

Visit us on our websiteFacebookTwitter, and Google+ for more useful information and advice.

You can reach us at (302) 368-3848 24 hours a day, 7 days a week for all your plumbing, electric, propane, and HVAC needs.