To set up a gas furnace battery backup system, several essential considerations must be addressed to ensure it functions effectively during power outages. This detailed guide will cover determining the appropriate size of the battery backup system and using a UPS or inverter with a battery.
How to Determine the Power Requirements of Your Gas Furnace?
- Measure the Load: Use a device like a “Kill-a-Watt” meter to measure the power consumption of your gas furnace. This includes the furnace itself, the blower, and any pumps or other components that need to run.
- Calculate Total Load: Sum up the wattage of all components. For example, if your furnace blower draws 300 watts and the pump draws 25 watts, your total load would be 325 watts.
What Type of Inverter-Charger Should You Choose?
- True Sine Wave Inverter: Opt for a true sine wave inverter to ensure compatibility with your furnace’s electronics. Modified sine wave inverters may not work reliably with all appliances.
- Inverter Capacity: Select an inverter that can handle the total load of your furnace. For instance, if your total load is 325 watts, you might choose an inverter with a capacity of at least 500-1000 watts to account for startup surges and efficiency.
How to Select and Size the Batteries?
- Battery Type: Deep cycle batteries are recommended for backup systems. AGM (Absorbent Glass Mat) batteries are a good choice due to their durability and low maintenance.
- Battery Capacity: Calculate the required battery capacity based on the desired backup time and the total load. For example, if you want 8 hours of backup and your total load is 325 watts, you would need a battery capacity of approximately 217 Ah (assuming a 12V battery system).
What are the Charging and Maintenance Requirements?
- Charger Selection: Use a multi-stage charger that can handle the battery type you choose. Ensure the charger has bulk and float stages to maintain battery health.
- Maintenance: Regularly check and maintain the batteries to ensure they remain in good condition. This includes monitoring charge levels and performing periodic equalization charges.
Do You Need an Automatic Transfer Switch?
- Transfer Switch: If your furnace is hardwired, you will need an automatic transfer switch to switch between grid power and battery backup power. This ensures seamless transition during power outages.
How to Install and Test the System?
- Professional Installation: Consider hiring an electrician if you are not comfortable with the electrical work involved. Ensure all connections are secure and meet safety standards.
- Testing: Perform thorough testing of the system to ensure it works as expected. This includes simulating power outages and verifying that the backup system kicks in correctly.
Product Recommendations
- Inverter-Charger: Xantrex Inverter Charger 2000w or 3000w, depending on your load requirements.
- Batteries: Deep cycle AGM batteries, such as those from Renogy or similar manufacturers.
- Charger: A multi-stage charger compatible with your battery type.
