If submitting a service request after hours or on the weekend, please note it is best to call.
Rated 4.9 out of 5.0 based on 2722 reviews
Houma, LA(985) 206-8073 Larose, LA(985) 999-7069 Berwick, LA(985) 200-5471 Request Service

What Size Heater Do I Need? [Furnace Purchasing Made Easy!]

You’ve made the decision to replace or install a heater, but what do you do now? How do you know what heater is the right size for your home? You don’t want to invest in a system that can’t perform for you, and it can be stressful to shop for big appliances like HVAC systems.

Luckily, Trahan’s Heating & Air Conditioning has your back. We believe in a comprehensive heater replacement service. That means we offer our help and advice every step of the way. If you aren’t sure how to choose the right heater size, our premier Houma heater services are the solution for you!

Why Is Heater Size Important?

For many homeowners, it makes sense to purchase the biggest heater you can afford. However, this tactic might not be the most effective or accurate for your home. The wrong size heater can have several consequences for your home.

  • Uncomfortable temperatures
  • Low airflow
  • High energy use
  • Humid air

The typical heart cycle is designed to give the system enough time to properly heat and filter your air. A heater that’s too small will run long cycles to try and keep up with the demand of your home. A heater that’s too big will run short, powerful cycles that produce heat quickly. However, these short cycles don’t leave enough time for dehumidification, and several short cycles use more energy to turn the system on and off.

Calculating The Right Sized Heater

The primary way to determine the right heater for your home is first figuring out how much heat you need your system to be able to produce. This is called the heat load calculation. The capability of a heater to produce a certain amount of heat is measured in British Thermal Units (BTUs). For the most precise calculation, you should have a professional assess your home. They take into account many factors that affect how your home retains or loses heat.

If you want to get a rough estimate of the heater size your home requires, there is a DIY heat load calculation you can use. First, you need the square footage of your home. This information can be found on the closing documents or blueprints for your home, but you can also manually measure the square footage. Once you have the square footage, multiply it by the average BTUs needed per square foot in the Southern Louisiana area: 35 BTUs.

(Square footage) X (35 BTUs) = Total BTUs Needed


(1,500 square feet) X (35 BTUs) = 52,500 BTUs

Heaters vs Furnaces

Now that you have the needed BTUs, you need to apply it to what kind of heating system you’re getting. The most common two are heaters as a part of an HVAC system and furnaces.

Heaters inside an HVAC system will be measured using tonnage. No, this is not how much the system weighs! Tons are simply a unit of measurement for heating and cooling systems. One ton of heating is equal to 12,000 BTUs.

(Total BTUs) / (12,000 BTUs) = Tons


(52,000 BTUs) / (12,000 BTUs) = 4+ tons

Furnaces will be measured in BTUs, but there is one more factor to be aware of: furnace input and output are two different things. Furnace input is the amount of energy (BTUs) that the system starts with, but during the heating process, some of it is lost as waste. All furnaces will have an efficiency rating that you can use to determine how much input you need to get the desired output.

(Input BTUs) X (Efficiency Rating) = Output BTUs


(60,000 BTUs) X (.8 [80% efficiency]) = 48,000 BTUs

(70,000 BTUs) X (.8 [80% efficiency]) = 56,000 BTUs

Trahan’s Can Do The Math For You!

We know that finding the right-sized heater can be complicated. That’s why Trahan’s Heating & Air Conditioning is the best option for hassle-free heat load calculations and heater installations! Let our team do what we do best every single day. Give us a call for the best heater installation services in Houma.

Why Choose Us?

We stand by our 100% customer satisfaction guarantee

BBB Accredited Business icon
BBB Accredited Business
We have been fully Accredited by the BBB for over 25 years.
professional staff icon
Professional Staff
Our highly trained and certified technicians are dedicated to offering 5-star service every time.
Award Winning Service Icon
Award Winning Service
We're humbled to be considered one of the top home service companies in the Houma area.
hassle-free service icon
We worry so that you don't have to. We offer stress-free service calls and installations.

What Our Customers Are Saying

Terrific company!

Terrific company! Repair/salesman arrived quickly after our call for help. Current unit repaired that day and new units installed shortly thereafter. Experienced, qualified, considerate, hard working, and friendly team. We highly recommend their services!

Deborah C.

Quick and Prompt Service

We are very pleased with our recent service with Trahan’s! We noticed something wasn’t right with our AC and within 15 minutes of calling Tyler was here and working on fixing the problem. We are thankful for quick and prompt service on a Saturday afternoon!

Courtney C.

Professional and Knowledgeable

The serviceman, Tate, was very quick to respond to my call. He was professional and knowledgeable and identified the problem very quickly. The broken part was replaced & my A/C was running perfectly again in less than 15 minutes after he arrived.

Jo T.