With the right components, you can improve your old furnace's energy efficiency without having to make extensive replacements. Smart systems, zoning systems, and motor upgrades for your furnace can all have a big impact on your energy bill.
With older furnaces, having more precise control over your thermostat is an easy way to make things more efficient, and smart systems can add plenty of control. A smart thermostat is one of the most important components. Depending on which model you get, a smart thermostat will let you set schedules, adapt temperature settings based on time of day and outdoor temperature, connect to WiFi, and allow you to control settings from your phone or tablet whether you're home or not. Some models may also let you control your thermostat settings with your voice.
Additionally, some will offer data that shows you your usage over time and start to make suggestions on how to improve efficiency. If you want to get even further into customizing your system, look for thermostats that support routines that can do things like detect when you get home and turn on automatically.
When in doubt, talk to an HVAC professional. With your primary goal of efficiency in mind, they can make suggestions as to what kind of features will help you best. This can also be impacted by things like the size of your home, how many people live there, and during which hours people are home the most.
Zoning systems add further control to your furnace by effectively letting you set different temperatures for different areas of your house. This usually works by installing dampers in your ducts and an additional thermostat for each "zone" in your house. This can be useful for comfort purposes, but if you're in a situation where only a few rooms are being used during the day, you can use a zoning system to help make sure that only a few rooms are kept warm during those hours rather than the entire house.
Dampers can often be installed in existing ducts rather than requiring any extensive replacements, though if your ducts are as old as your furnace and haven't been maintained, they may need some repairs at the very least. Talk to an HVAC professional to ask how a zoning system could impact your home and energy bill.
Older furnaces are more likely to have a single-speed motor, which means that they only turn on or off. A variable-speed motor can run at partial power, however, which is often better for energy efficiency. For example, a furnace with a single-speed motor will run at full blast and then shut off, and continue cycling on and off this way. A variable-speed motor has the ability to run constantly at lower power, keeping your home at a more consistent temperature and using less power at the same time.
Motors aren't the cheapest of components, but they're still far less pricey than replacing your entire furnace, and they're often well worth the investment when upgrading an old furnace. Your technician can replace this motor for you and make sure it's running in time for winter.