Although you can find furnaces with a wide range of efficiency ratings, every furnace you look at will fall into one of two categories: high-efficiency or standard efficiency. High-efficiency furnaces typically have the widest range of AFUE (annual fuel utilization efficiency) ratings, with standard efficiency furnaces often meeting minimum federal standards.
If you're replacing your existing furnace and upgrading to a high-efficiency model, there may be a few extra considerations to maximize the value of your new system. Before selecting your furnace, ask your installer these three essential questions:
1. Do You Need a New 'Manual J' Calculation?
A 'Manual J' is a professional formula used to calculate your home's heating and cooling needs. While you can roughly estimate furnace sizing based on square footage, this more sophisticated calculation accounts for many more factors. A correctly-sized furnace improves efficiency and comfort while ensuring that your system wears out less quickly.
Since high-efficiency furnaces tend to cost more than their standard counterparts, it's important to get the sizing right to both to minimize the upfront costs and reduce the likelihood of failure. If you aren't sure that your previous installer performed this calculation, asking your current installer for a new calculation is the best way to ensure proper sizing.
2. Should You Replace Your Ductwork?
You don't typically need new ductwork when installing a new furnace, but upgrading to a high-efficiency unit means you probably want to maximize your long-term cost savings. If your home has old or leaky ductwork, you may lose a large percentage of your new system's efficiency to air leaks. Leaky ducts can also eliminate some of the comfort advantages of high-efficiency features such as two-stage blowers.
Fortunately, your installer can help you determine if your ductwork requires replacement. An air leakage test will help you gauge how much heated air you lose through your ductwork. While you don't necessarily need to replace ducts with minor leakage, this information can help you make an informed decision.
3. Does Your Need Furnace Require Upgraded Flue Plumbing?
Finally, you should find out whether you'll need upgraded flue plumbing for your new furnace. You may have a metal flue if you currently have an older or standard efficiency furnace. These flues were necessary to contain the hot exhaust gases from less efficient models. However, high-efficiency condensing models produce colder exhaust gas and significantly more condensation.
As a result, your new furnace may require you to install new flue plumbing. Your installer will typically need to replace your old metal flue with PVC pipes. These pipes are less resistant to hot gas (a non-issue with high-efficiency models) but are more immune to the potential corrosion caused by the condensate your new furnace will produce.
For more information, reach out to a furnace installation service near you.