@JohnW152 wrote:
If one spouse has already maxed out the credit while filing single, it can't be taken again when filing jointly. The same goes for initially claiming the credit while filing jointly, and later wanting to claim the credit filing single.
See the Lifetime Limitation Worksheet—Line 18 in the Instructions for Form 5695. It makes no distinction as to a taxpayer's current or previous filing status, and uses the limitation amount from the worksheet on the form, itself.
The law was written in such a way that if either spouse used their limit before they were married, then it counts against both spouses on a joint return. It might be possible for spouse #2 to claim the credit if they filed as married filing separately, if spouse #1 had previously claimed the max credit. But filing MFS has many drawbacks and you may lose more than you gain.
The law was also written in such a way that if the home is owned by two unmarried people who use it as their main home, each owner can claim the same maximum on the same improvements. In other words, if two people who are "shacking up" and buy a home together, also buy new windows, they each get $200.
Blame Congress. Whether this was intentional or on purpose, that's how the law was written, and they've never taken steps to change it to make it what we might consider as more "sensible".
