Did you know that the installation process is one of the most important steps in getting your new furnace up and running? According to the Department of Energy, a furnace that is not properly installed can waste up to 30% of energy bills.

That’s why it’s essential to make sure you hire a qualified HVAC technician to install your furnace.

This step-by-step guide will walk you through the entire furnace installation process. So, whether you are doing it yourself or hiring a professional, this guide will ensure your installation goes smoothly.


Before starting the furnace installation process, ensure enough venting to circulate carbon monoxide outside the house properly. Check with your fuel provider if there are any laws regulating vent piping. You may also need additional vents to accommodate humidifiers and other appliances installed later on.

Don’t forget about insulation, since it helps stop the heat inside the room after warming up. Also, don’t place too much weight on the wood-burning unit because it’s not designed for that purpose.

Prepare Your Site

Start by ensuring the area surrounding it is clear of any obstacles or other appliances that can block airflow. Also, it will need to have access to both the electrical outlet and gas line. If your house doesn’t have an outdoor vent, use supplementary ones instead.

Consider using a wall mount instead of a floor-standing model if space is at a premium. The area around the furnace should be clear of obstructions before setting it aside for assembly later.

Remove any combustible materials in the vicinity. Remember, these might ignite if they come into contact with exhaust gases expelled by the unit. A clearance of at least three feet on all sides should do.

Read the Manufacturer’s Instructions

Going through the manual is vital before beginning any installation procedures. It includes information on what happens during the furnace installation.

Here are some details included in a heater installation manual:

  • Preparing for installation
  • Making electrical or gas connections
  • Positioning your new furnace and burner pipe assembly
  •  Checking flue pipe clearances for proper venting
  • Testing the furnace electrical and gas systems

Follow these instructions carefully to ensure your new furnace operates properly and safely.

Position the Furnace Properly

Before you do anything else, ensure the furnace is standing on a solid surface. This way, it won’t move while in operation. You’ll also prevent any accidents from happening later on while trying to attach pipes and wires.

As long as it doesn’t move, consider putting down some plywood underneath just in case. Where you put it will depend on your specific unit’s design. Some furnaces are installed in the basement, while others have their designated area in an attic instead.

Before installing a new furnace, please consult with the manufacturer to confirm its location requirements. As such, you will not mistakenly place it somewhere where it won’t work correctly or damage other appliances because of vibration.

Electrical Connection

Make electrical connections by following the manufacturer’s instructions and local building codes. Before starting the installation process, shut off the power supply to the furnace. Use a voltmeter to make sure there are no current leakages.

Take appropriate steps if something goes wrong during testing! The next step is making electrical connections. You can do this by taking one wire out from the terminal located on the right side of the unit or using color-coded cables.

Don’t overload your circuit breaker with too many appliances. Remember that dedicated circuits will be needed depending on the size of your furnace. After finishing these steps, you can start installing the furnace.

Gas Line Installation

You should make sure that the furnace has enough space to prevent clogging or corrosion in the future. This means you need to cut holes in the right places and use appropriate pipe fittings.

Everything should be connected tightly but not too tight because this may cause obstructions.

Starting from 100 to 200 feet, install a gas supply line that can supply up to 7 million BTU of energy per hour. Even if your unit is only rated for 4-5 million BTUs, it will still deliver enough power when needed. This is more important during colder days.

You must calculate your needs beforehand. This will avoid installing a fuel line that doesn’t fit your furnace performance.

Consider using a flexible gas connection pipe between the meter and gas control valve. It allows you some freedom when running piping. If this type of pipe isn’t in the hardware store, use the stainless steel gas line when making your connections.

Drain Down the Unit Properly

Once everything’s set up correctly, drain down the furnace. Open up its air intake damper all the way and allow cool air from outside to enter until water starts trickling out of its drain line.

This should only take a little while since furnaces usually operate under relatively high pressure. It causes water molecules to move in and out of the cooling coils rather quickly.

Test Run It

After hooking up everything, switch on the power again. Wait for about 10 minutes and check whether it works by listening closely for any unusual noises.

If everything’s okay, wait for the unit to accessorize itself using its inducer fan and start heating up. Once it does, check whether the furnace’s power-on light comes on and stays lit at all times without flickering too much. If so, it means you’ve successfully installed a new furnace.

Maintenance Tips

Make sure you clean furnace filters once per month during cold months. This way, the unit will not run out of power due to clogged vents.

It is recommended that you change these filters every 30 days if necessary. Furnace maintenance is essential when operating a unit 24/7. If left without service, it can cause severe damage to its elements.

If you notice any signs of corrosion on vents or more extended warm-up periods, turn off your system immediately and contact professionals.

Need a New Furnace Installation or Repair?

Have your air conditioner started failing or feel that you need a new furnace installation and don’t know where to find the right experts? Worry no more. At P&M Air Conditioning and Heating, we have all your heating installation and servicing needs.

Our technicians are NATE certified, and we provide 24-hour services across Houston, TX Bellaire, TX Pearland, TX Friendswood, and TX West University. For a free estimate or inquiries about our services, please give us a call now for an immediate response.