What can you keep?
Three questions about the system you have and the unit you were quoted. The answers come from the manufacturers' own documents, and every one of them is cited on the model page.
What the checker is reading
It estimates nothing. Every answer it gives is a statement from a document somebody opened, and the model page behind it names that document, the printed page it is on and the date it was read. Behind the three questions above: 23 R-454B outdoor models, 29 R-410A models they replace, 22 indoor coils, and 26 manufacturer and distributor documents.
The three answers stay separate because the rules are separate. Your indoor coil, your copper and your furnace are each governed by their own manufacturer statement, and a brand that has published one of them has often published nothing at all about the other two. Where that happens the checker says so instead of filling the gap — an unanswered question is still something to put to your installer, and it is the one this site is most useful for.
What it cannot tell you
Whether the system going into your house is correctly sized, safe or compliant with your local code. That is the job of the licensed contractor who signs the installation, and the disclaimer sets out why this site will not stand in for them. Take the citation to them and ask the question it raises.
Or start from your brand
- American Standard Your existing R-410A coil cannot stay. American Standard states it directly: an R-410A evaporator coil cannot be used or converted with R-454B, and the R-454B coil has to be factory equipped with a mitigation control board.
- Carrier Your existing R-410A indoor coil cannot stay. Carrier states that full furnace coils are not interchangeable and that the refrigerant the indoor coil is designed for must match the outdoor unit's.
This is a starting point, not an approval. Everything here is read from published manufacturer documents and dated, but only the licensed contractor who signs your installation can approve a specific system for your home and your local code. Take the citations on this page to them and ask.