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When you are looking to upgrade the heating system in your Wendell, North Carolina, home, your technician should perform a heat-loss calculation to ensure the right size furnace will be installed. In this article, we are going to explain what a heat-loss calculation is and why the sizing of the furnace is important.

What Is a Heat-Loss Calculation?

A heat-loss calculation, also known as a heat-load calculation, determines how much heat escapes from a home in a certain time. Professionals use the measurements and information obtained during these calculations to help determine what size furnace is best suited for heating your home efficiently. Load refers to how much energy is needed to heat a home sufficiently. There are three basic load calculations which will help HVAC contractors find the best furnace for your home:

  1. Design Load Calculation
  2. Extreme Load Calculation
  3. Part Load Calculation

What Is Design Load?

Design load calculations use constant specifications of a house such as a house’s orientation and layout, as well as its insulation’s R-value to find the required heating energy. Variable specifications such as temperature differences between the outside and inside of your home are known as design conditions.

According to the Manual J guidelines developed by the Air Conditioning Contractors of America, it is necessary to understand what the design conditions are to help size your furnace properly.

It is important to add all of the calculations, including the design conditions, together to find the right size heater for maximum heating efficiency.

What Is Extreme Load?

Extreme load calculation takes into consideration the coldest day of the year — thus the name extreme. Your heating system needs to adequately heat your home during extreme weather, especially if your home is under-insulated. If your home is losing heat faster than the furnace can generate, then you either need a bigger system or better insulation. Factoring in the amount of insulation and its R-value is an important part of the heat-loss calculation.

What Is Part-Load?

Part load is the most important calculation. Normally your home will fall somewhere between the design load and the extreme load. This calculation factors in how your heater will work under normal winter conditions. Part load calculations take in a number of considerations such as:

  • How many occupants are in the home.
  • How high the ceilings are.
  • How many windows and doors are in the house.
  • How much furniture and carpeting there is.
  • How many appliances there are.
  • How much landscaping you have.

These are variables that can change over time, due to home remodeling, additional occupants, or people moving out.

Why Does Size Matter?

Size matters because if it’s not right, the furnace won’t heat your home efficiently. When you turn your heater on, you expect it to warm up your house to a comfortable temperature. If it doesn’t, it’s not appropriate for your home. Let’s look at the issues you will encounter with an improperly sized heater.

  • If the system is too large: it will short-cycle, which means that it turns on and off constantly. If your heater is short-cycling, it doesn’t stay on long enough to sufficiently heat your house. Short-cycling takes an enormous amount of energy, adds wear and tear to the system, and reduces its life span.
  • If the system is too small: it will run constantly without reaching the desired temperature. Not only will your family be chilly, but your energy bills will rise because the system is running all the time. An overworked furnace can lead to a malfunction or premature breakdown of the system. Having the correct sized furnace keeps your home at a comfortable temperature and saves you money.

All three load calculations are necessary to help the HVAC professional find the right size furnace for your home. If your current furnace isn’t performing well, consider upgrading it so your home is comfortable, you save money on energy bills, and with regular preventive maintenance, your furnace will last for years.

Give our knowledgeable team at Alford Mechanical a call today to schedule an appointment for a furnace upgrade. You can reach us at 919-246-5265.

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